Merge branch 'chunked'

.gitea/workflows/deploy.yaml

@@ -0,0 +1,41 @@
+name: Deploy
+run-name: ${{ gitea.actor }} deployed latest version 🚀
+on:
+  push:
+    branches:
+      - "main"
+
+jobs:
+  Explore-Gitea-Actions:
+    runs-on: x86
+    container:
+      image: gitea.gregorlohaus.com/gregor/graal:latest
+      credentials:
+        username: lohausgregor@gmail.com
+        password: ${{ secrets.REGPASS }}
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+      - run: /usr/local/bin/docker-entrypoint.sh postgres &
+      - name: build
+        working-directory: ${{ gitea.workspace }}/Backend
+        env:
+          JAVA_HOME: /root/.sdkman/candidates/java/current 
+        run: /root/.sdkman/candidates/gradle/9.4.0/bin/gradle build
+      - name: deploy
+        shell: bash
+        run: |
+          eval "$(ssh-agent -s)"
+          ssh-add <(echo "${{ secrets.DEPLOYSSHKEY }}")
+          mkdir -p ~/.ssh
+          ssh-keyscan 162.55.217.172 >> ~/.ssh/known_hosts
+          scp ${{ gitea.workspace }}/Backend/build/native/nativeCompile/gtransfer anon@162.55.217.172:/home/anon/.local/bin/gtransfernew
+          ssh anon@162.55.217.172 "chmod +x /home/anon/.local/bin/gtransfernew"
+          ssh anon@162.55.217.172 "mv /home/anon/.local/bin/gtransfer /home/anon/.local/bin/gtransferback"
+          ssh anon@162.55.217.172 "mv /home/anon/.local/bin/gtransfernew /home/anon/.local/bin/gtransfer"
+          ssh anon@162.55.217.172 "sudo systemctl restart gtransfer"
+      # - name: upload binary
+      #   uses: https://gitea.com/actions/gitea-upload-artifact@v4
+      #   with:
+      #     name: gtransfer
+      #     path: ${{ gitea.workspace }}/Backend/build/native/nativeCompile/gtransfer

.gitignore

@@ -8,3 +8,4 @@ devenv.local.nix
 # pre-commit
 .pre-commit-config.yaml
 .gradle
+layout.kdl

.ignore

@@ -0,0 +1 @@
+.devenv

Backend/.ignore

@@ -2,3 +2,4 @@
 .gradle
 bin
 build
+.devenv

Backend/build.gradle

@@ -20,12 +20,15 @@ repositories {
 }
 
 dependencies {
+	implementation 'com.google.code.gson:gson:2.10.1'
 	implementation 'org.springframework.boot:spring-boot-starter-web'
 	implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
 	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
 	implementation 'org.webjars:webjars-locator-lite'
 	implementation 'org.webjars.npm:htmx.org:2.0.4'
 	implementation 'org.webjars.npm:bootstrap:5.3.3'
+	implementation platform('software.amazon.awssdk:bom:2.45.1')
+	implementation 'software.amazon.awssdk:s3'
 	runtimeOnly 'org.postgresql:postgresql'
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 	testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
@@ -33,6 +36,16 @@ dependencies {
 	implementation 'io.github.wasabithumb:jtoml-serializer-reflect:1.4.2'
 }
 
+graalvmNative {
+	binaries {
+		main {
+			buildArgs.add("--static-nolibc")
+			buildArgs.add("--libc=glibc")
+			buildArgs.add("--verbose")
+		}
+	}
+}
+
 tasks.named('test') {
 	useJUnitPlatform()
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/GtransferApplication.java

@@ -1,5 +1,6 @@
 package com.gregor_lohaus.gtransfer;
 
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.ImportRuntimeHints;
@@ -9,11 +10,17 @@ import com.gregor_lohaus.gtransfer.config.ConfigRuntimeHints;
 import com.gregor_lohaus.gtransfer.model.ModelRuntimeHints;
 import com.gregor_lohaus.gtransfer.native_image.HibernateRuntimeHints;
 import com.gregor_lohaus.gtransfer.native_image.WebRuntimeHints;
+import com.gregor_lohaus.gtransfer.services.filecleanup.FileCleanupService;
+
+import org.springframework.scheduling.annotation.EnableScheduling;
 
 @SpringBootApplication
 @RestController
+@EnableScheduling
 @ImportRuntimeHints({ConfigRuntimeHints.class, HibernateRuntimeHints.class, ModelRuntimeHints.class, WebRuntimeHints.class})
 public class GtransferApplication {
+	@Autowired
+	private FileCleanupService cleanupService;
 	public static void main(String[] args) {
 		SpringApplication.run(GtransferApplication.class, args);
 	}

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/ConfigEnvironmentPostProcessor.java

@@ -5,9 +5,9 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import com.gregor_lohaus.gtransfer.config.types.Config;
-
+// import com.google.gson.Gson;
+// import com.google.gson.GsonBuilder;
 import org.springframework.boot.EnvironmentPostProcessor;
-// import org.springframework.boot.env.EnvironmentPostProcessor;
 import org.springframework.boot.SpringApplication;
 import org.springframework.core.env.ConfigurableEnvironment;
 
@@ -41,6 +41,10 @@ public class ConfigEnvironmentPostProcessor implements EnvironmentPostProcessor
 				System.exit(1);
 			}
 			Config defaultConfig = DefaultConfig.config;
+			// Gson gson = new GsonBuilder().setPrettyPrinting().serializeNulls().create();
+			// String json = gson.toJson(defaultConfig);
+			// System.out.println(json);
+			
 			table = ConfigSerializer.toToml(defaultConfig);
 			toml.write(CONFIG_FILE_PATH, table);
 		}

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/ConfigRuntimeHints.java

@@ -55,6 +55,16 @@ public class ConfigRuntimeHints implements RuntimeHintsRegistrar {
         MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS,
         MemberCategory.ACCESS_DECLARED_FIELDS,
         MemberCategory.ACCESS_PUBLIC_FIELDS);
+    hints.reflection().registerType(ServerConfig.class,
+        MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+        MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS,
+        MemberCategory.ACCESS_DECLARED_FIELDS,
+        MemberCategory.ACCESS_PUBLIC_FIELDS);
+    hints.reflection().registerType(SslConfig.class,
+        MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+        MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS,
+        MemberCategory.ACCESS_DECLARED_FIELDS,
+        MemberCategory.ACCESS_PUBLIC_FIELDS);
     hints.reflection().registerType(TypeAdapter.class,
         MemberCategory.ACCESS_DECLARED_FIELDS,
         MemberCategory.ACCESS_PUBLIC_FIELDS);

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/DefaultConfig.java

@@ -6,8 +6,10 @@ import com.gregor_lohaus.gtransfer.config.types.Config;
 import com.gregor_lohaus.gtransfer.config.types.DataSourceConfig;
 import com.gregor_lohaus.gtransfer.config.types.JpaConfig;
 import com.gregor_lohaus.gtransfer.config.types.MultipartConfig;
+import com.gregor_lohaus.gtransfer.config.types.ServerConfig;
 import com.gregor_lohaus.gtransfer.config.types.ServletConfig;
 import com.gregor_lohaus.gtransfer.config.types.SpringConfig;
+import com.gregor_lohaus.gtransfer.config.types.SslConfig;
 import com.gregor_lohaus.gtransfer.config.types.StorageService;
 import com.gregor_lohaus.gtransfer.config.types.StorageServiceType;
 import com.gregor_lohaus.gtransfer.config.types.UploadConfig;
@@ -20,6 +22,12 @@ public class DefaultConfig {
     StorageService ss = new StorageService();
     ss.type = StorageServiceType.LOCAL;
     ss.path = Path.of(System.getProperty("user.home"),".local","share","gtransfer").toString();
+    ss.bucket = "";
+    ss.region = "us-east-1";
+    ss.endpoint = "";
+    ss.accessKeyId = "";
+    ss.secretAccessKey = "";
+    ss.pathStyleAccessEnabled = false;
     c.storageService= ss;
     
     SpringConfig sc = new SpringConfig();
@@ -44,9 +52,19 @@ public class DefaultConfig {
 
     c.springConfig = sc;
 
+    ServerConfig svc2 = new ServerConfig();
+    svc2.port = 8080;
+    SslConfig ssl = new SslConfig();
+    ssl.enabled = false;
+    ssl.certificatePrivateKey = "";
+    ssl.certificate = "";
+    svc2.sslConfig = ssl;
+    c.serverConfig = svc2;
+
     UploadConfig uc = new UploadConfig();
     uc.maxDownloadLimit = 100;
     uc.maxExpiryDays = 30;
+    uc.cleanupEnabled = true;
     c.uploadConfig = uc;
 
     config = c;

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/types/Config.java

@@ -9,6 +9,9 @@ public class Config implements TomlSerializable {
   @Nested(name = "spring")
   @NoPrefix
   public SpringConfig springConfig;
+  @Nested(name = "server")
+  @NoPrefix
+  public ServerConfig serverConfig;
   @Nested(name = "storageService")
   public StorageService storageService;
   @Nested(name = "upload")

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/types/ServerConfig.java

@@ -0,0 +1,13 @@
+package com.gregor_lohaus.gtransfer.config.types;
+
+import com.gregor_lohaus.gtransfer.config.annotations.Nested;
+import com.gregor_lohaus.gtransfer.config.annotations.Property;
+
+import io.github.wasabithumb.jtoml.serial.TomlSerializable;
+
+public class ServerConfig implements TomlSerializable {
+  @Property(name = "port")
+  public Integer port;
+  @Nested(name = "ssl")
+  public SslConfig sslConfig;
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/types/SslConfig.java

@@ -0,0 +1,14 @@
+package com.gregor_lohaus.gtransfer.config.types;
+
+import com.gregor_lohaus.gtransfer.config.annotations.Property;
+
+import io.github.wasabithumb.jtoml.serial.TomlSerializable;
+
+public class SslConfig implements TomlSerializable {
+  @Property(name = "enabled")
+  public Boolean enabled;
+  @Property(name = "certificate")
+  public String certificate;
+  @Property(name = "certificate-private-key")
+  public String certificatePrivateKey;
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/types/StorageService.java

@@ -9,4 +9,16 @@ public class StorageService implements TomlSerializable {
   public StorageServiceType type;
   @Property(name = "root")
   public String path;
+  @Property(name = "bucket")
+  public String bucket;
+  @Property(name = "region")
+  public String region;
+  @Property(name = "endpoint")
+  public String endpoint;
+  @Property(name = "accessKeyId")
+  public String accessKeyId;
+  @Property(name = "secretAccessKey")
+  public String secretAccessKey;
+  @Property(name = "pathStyleAccessEnabled")
+  public Boolean pathStyleAccessEnabled;
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/config/types/UploadConfig.java

@@ -9,4 +9,6 @@ public class UploadConfig implements TomlSerializable {
   public Integer maxDownloadLimit;
   @Property(name = "maxExpiryDays")
   public Integer maxExpiryDays;
+  @Property(name = "cleanupEnabled")
+  public Boolean cleanupEnabled;
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/controller/DownloadController.java

@@ -0,0 +1,142 @@
+package com.gregor_lohaus.gtransfer.controller;
+
+import java.time.LocalDateTime;
+import java.util.Map;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+import com.gregor_lohaus.gtransfer.model.File;
+import com.gregor_lohaus.gtransfer.model.FileRepository;
+import com.gregor_lohaus.gtransfer.services.filewriter.AbstractStorageService;
+import com.gregor_lohaus.gtransfer.services.filewriter.StorageKeys;
+
+@Controller
+public class DownloadController {
+
+    @Autowired
+    private FileRepository fileRepository;
+
+    @Autowired
+    private AbstractStorageService storageService;
+
+    @GetMapping("/download")
+    public String page() {
+        return "download/page";
+    }
+
+    @GetMapping("/download/{id}/metadata")
+    @ResponseBody
+    @Transactional
+    public ResponseEntity<Map<String, Object>> metadata(@PathVariable String id) {
+        AvailableFile available = getAvailableFile(id);
+        if (!available.found()) {
+            return ResponseEntity.status(available.status()).build();
+        }
+
+        File file = available.file();
+        return ResponseEntity.ok(Map.of(
+                "name", file.getName(),
+                "chunkCount", file.getChunkCount()));
+    }
+
+    @GetMapping("/download/{id}/chunk/{index}")
+    @ResponseBody
+    @Transactional
+    public ResponseEntity<byte[]> chunk(@PathVariable String id, @PathVariable Integer index) {
+        AvailableFile available = getAvailableFile(id);
+        if (!available.found()) {
+            return ResponseEntity.status(available.status()).build();
+        }
+
+        File file = available.file();
+        if (index == null || index < 0 || index >= file.getChunkCount()) {
+            return ResponseEntity.badRequest().build();
+        }
+
+        Optional<byte[]> data = storageService.get(StorageKeys.chunk(file.getId(), index));
+        if (data.isEmpty()) {
+            return ResponseEntity.notFound().build();
+        }
+
+        return ResponseEntity.ok()
+                .contentType(MediaType.APPLICATION_OCTET_STREAM)
+                .body(data.get());
+    }
+
+    @PostMapping("/download/{id}/complete")
+    @ResponseBody
+    @Transactional
+    public ResponseEntity<Void> complete(@PathVariable String id) {
+        AvailableFile available = getAvailableFile(id);
+        if (!available.found()) {
+            return ResponseEntity.status(available.status()).build();
+        }
+
+        File file = available.file();
+        file.setDownloads(file.getDownloads() + 1);
+        fileRepository.save(file);
+
+        if (file.getDownloadLimit() != null && file.getDownloads() >= file.getDownloadLimit()) {
+            deleteStoredFile(file);
+            fileRepository.delete(file);
+        }
+
+        return ResponseEntity.noContent().build();
+    }
+
+    private AvailableFile getAvailableFile(String id) {
+        Optional<File> fileOpt = fileRepository.findById(id);
+        if (fileOpt.isEmpty()) {
+            return AvailableFile.notFound();
+        }
+
+        File file = fileOpt.get();
+        if (file.getExpireyDateTime() != null && LocalDateTime.now().isAfter(file.getExpireyDateTime())) {
+            deleteStoredFile(file);
+            fileRepository.delete(file);
+            return AvailableFile.gone();
+        }
+
+        if (file.getDownloadLimit() != null && file.getDownloads() >= file.getDownloadLimit()) {
+            deleteStoredFile(file);
+            fileRepository.delete(file);
+            return AvailableFile.gone();
+        }
+
+        return AvailableFile.ok(file);
+    }
+
+    private void deleteStoredFile(File file) {
+        for (int i = 0; i < file.getChunkCount(); i++) {
+            storageService.delete(StorageKeys.chunk(file.getId(), i));
+        }
+    }
+
+    private record AvailableFile(File file, HttpStatus status) {
+        static AvailableFile ok(File file) {
+            return new AvailableFile(file, HttpStatus.OK);
+        }
+
+        static AvailableFile notFound() {
+            return new AvailableFile(null, HttpStatus.NOT_FOUND);
+        }
+
+        static AvailableFile gone() {
+            return new AvailableFile(null, HttpStatus.GONE);
+        }
+
+        boolean found() {
+            return file != null;
+        }
+    }
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/controller/Env.java

@@ -1,28 +0,0 @@
-package com.gregor_lohaus.gtransfer.controller;
-
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.core.env.ConfigurableEnvironment;
-import org.springframework.core.env.MutablePropertySources;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.RestController;
-
-import com.gregor_lohaus.gtransfer.services.filewriter.AbstractStorageService;
-
-@RestController
-public class Env {
-	@Autowired
-	private ConfigurableEnvironment env;
-	@Autowired
-	private AbstractStorageService storageService;
-  @GetMapping("/env")
-  public String env() {
-		StringBuilder b = new StringBuilder();
-		MutablePropertySources sources = this.env.getPropertySources();
-		sources.forEach((var m) -> {
-			b.append(m.toString());
-			b.append("\n");
-		});
-		b.append(storageService.getClass().toString());
-		return b.toString();
-  }
-}

Backend/src/main/java/com/gregor_lohaus/gtransfer/controller/UploadController.java

@@ -2,11 +2,15 @@ package com.gregor_lohaus.gtransfer.controller;
 
 import java.io.IOException;
 import java.time.LocalDateTime;
+import java.util.OptionalLong;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.ResponseEntity;
+import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
+import org.springframework.web.server.ResponseStatusException;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestParam;
@@ -15,6 +19,7 @@ import org.springframework.web.multipart.MultipartFile;
 import com.gregor_lohaus.gtransfer.model.File;
 import com.gregor_lohaus.gtransfer.model.FileRepository;
 import com.gregor_lohaus.gtransfer.services.filewriter.AbstractStorageService;
+import com.gregor_lohaus.gtransfer.services.filewriter.StorageKeys;
 
 @Controller
 public class UploadController {
@@ -41,23 +46,44 @@ public class UploadController {
 
     @PostMapping("/upload")
     public String upload(
-            @RequestParam("file") MultipartFile file,
             @RequestParam("hash") String hash,
             @RequestParam("name") String name,
+            @RequestParam("chunkCount") Integer chunkCount,
             @RequestParam(required = false) Integer expiryDays,
-            @RequestParam(required = false) Integer downloadLimit,
-            Model model) throws IOException {
-
-        storageService.put(hash, file.getBytes());
+            @RequestParam(required = false) Integer downloadLimit) {
+        if (!isValidId(hash) || chunkCount == null || chunkCount < 1) {
+            throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "Invalid upload metadata");
+        }
 
         int days = expiryDays != null ? Math.min(expiryDays, maxExpiryDays) : maxExpiryDays;
         Integer limit = downloadLimit != null ? Math.min(downloadLimit, maxDownloadLimit) : null;
 
         File f = new File(hash, hash, name, LocalDateTime.now().plusDays(days));
+        f.setChunkCount(chunkCount);
         f.setDownloadLimit(limit);
         fileRepository.save(f);
 
-        model.addAttribute("id", hash);
         return "upload/result :: view";
     }
+
+    @PostMapping("/upload/chunk")
+    public ResponseEntity<Void> uploadChunk(
+            @RequestParam("chunk") MultipartFile chunk,
+            @RequestParam("hash") String hash,
+            @RequestParam("index") Integer index) throws IOException {
+        if (!isValidId(hash) || index == null || index < 0) {
+            return ResponseEntity.badRequest().build();
+        }
+
+        OptionalLong written = storageService.put(StorageKeys.chunk(hash, index), chunk.getBytes());
+        if (written.isEmpty()) {
+            return ResponseEntity.internalServerError().build();
+        }
+
+        return ResponseEntity.noContent().build();
+    }
+
+    private boolean isValidId(String id) {
+        return id != null && id.matches("[a-f0-9]{64}");
+    }
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/model/File.java

@@ -13,8 +13,11 @@ public class File {
   private String id;
   private String path;
   private String name;
+  private Integer chunkCount;
   private LocalDateTime expireyDateTime;
   private Integer downloadLimit;
+  @Column(columnDefinition = "integer default 0")
+  private int downloads = 0;
   public LocalDateTime getExpireyDateTime() {
 	return expireyDateTime;
 }
@@ -39,12 +42,24 @@ public class File {
   public void setName(String name) {
 	this.name = name;
   }
+  public Integer getChunkCount() {
+    return chunkCount == null ? 1 : chunkCount;
+  }
+  public void setChunkCount(Integer chunkCount) {
+    this.chunkCount = chunkCount;
+  }
   public Integer getDownloadLimit() {
     return downloadLimit;
   }
   public void setDownloadLimit(Integer downloadLimit) {
     this.downloadLimit = downloadLimit;
   }
+  public int getDownloads() {
+    return downloads;
+  }
+  public void setDownloads(int downloads) {
+    this.downloads = downloads;
+  }
   public File(String id, String path, String name, LocalDateTime expDateTime) {
     this.path = path;
     this.name = name;

Backend/src/main/java/com/gregor_lohaus/gtransfer/model/FileRepository.java

@@ -1,8 +1,16 @@
 package com.gregor_lohaus.gtransfer.model;
 
+import java.time.LocalDateTime;
+import java.util.List;
+
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
 @Repository
 public interface FileRepository extends JpaRepository<File, String> {
+
+    @Query("SELECT f FROM File f WHERE f.expireyDateTime IS NOT NULL AND f.expireyDateTime < :now")
+    List<File> findExpired(@Param("now") LocalDateTime now);
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filecleanup/FileCleanupService.java

@@ -0,0 +1,58 @@
+package com.gregor_lohaus.gtransfer.services.filecleanup;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.gregor_lohaus.gtransfer.model.File;
+import com.gregor_lohaus.gtransfer.model.FileRepository;
+import com.gregor_lohaus.gtransfer.services.filewriter.AbstractStorageService;
+import com.gregor_lohaus.gtransfer.services.filewriter.StorageKeys;
+
+public class FileCleanupService {
+    private Boolean enabled;
+    public FileCleanupService(Boolean enabled) {
+        this.enabled = enabled;
+    }
+    private static final Logger log = LoggerFactory.getLogger(FileCleanupService.class);
+
+    @Autowired
+    private FileRepository fileRepository;
+
+    @Autowired
+    private AbstractStorageService storageService;
+
+    @Scheduled(fixedDelay = 30000)
+    @Transactional
+    public void cleanupExpiredFiles() {
+        log.info("Cleaneup started");
+        if (!enabled) {
+            log.info("Cleaneup skipped");
+            return;            
+        }
+        List<File> expired = fileRepository.findExpired(LocalDateTime.now());
+        if (expired.isEmpty()) {
+            log.info("Nothing to clean up");
+            return;
+        };
+
+        for (File file : expired) {
+            deleteStoredFile(file);
+            fileRepository.delete(file);
+        }
+        log.info("Cleaned up {} expired file(s)", expired.size());
+    }
+
+    private void deleteStoredFile(File file) {
+        for (int i = 0; i < file.getChunkCount(); i++) {
+            storageService.delete(StorageKeys.chunk(file.getId(), i));
+        }
+    }
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filecleanup/FileCleanupServiceConfiguration.java

@@ -0,0 +1,19 @@
+
+package com.gregor_lohaus.gtransfer.services.filecleanup;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import com.gregor_lohaus.gtransfer.config.types.StorageServiceType;
+
+@Configuration
+public class FileCleanupServiceConfiguration {
+  @Bean
+  public FileCleanupService fileCleanupService(
+    @Value("${gtransfer-config.upload.cleanupEnabled}")
+    Boolean enabled
+  ) {
+    return new FileCleanupService(enabled);
+  }
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filewriter/AbstractStorageService.java

@@ -13,4 +13,5 @@ public abstract class AbstractStorageService {
 
   abstract public OptionalLong put(String id, byte[] data);
   abstract public Optional<byte[]> get(String id);
+  abstract public boolean delete(String id);
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filewriter/DummyStorageService.java

@@ -19,4 +19,9 @@ public class DummyStorageService extends AbstractStorageService {
   public Optional<byte[]> get(String id) {
     return Optional.empty();
   }
+
+  @Override
+  public boolean delete(String id) {
+    return false;
+  }
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filewriter/LocalStorageService.java

@@ -15,8 +15,12 @@ public class LocalStorageService extends AbstractStorageService {
   @Override
   public OptionalLong put(String id, byte[] data) {
     try {
-      Files.createDirectories(root);
-      Files.write(root.resolve(id), data);
+      Path target = root.resolve(id);
+      Path parent = target.getParent();
+      if (parent != null) {
+        Files.createDirectories(parent);
+      }
+      Files.write(target, data);
       return OptionalLong.of(data.length);
     } catch (IOException e) {
       return OptionalLong.empty();
@@ -33,4 +37,13 @@ public class LocalStorageService extends AbstractStorageService {
       return Optional.empty();
     }
   }
+
+  @Override
+  public boolean delete(String id) {
+    try {
+      return Files.deleteIfExists(root.resolve(id));
+    } catch (IOException e) {
+      return false;
+    }
+  }
 }

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filewriter/S3StorageService.java

@@ -0,0 +1,191 @@
+package com.gregor_lohaus.gtransfer.services.filewriter;
+
+import java.net.URI;
+import java.nio.file.Path;
+import java.util.Optional;
+import java.util.OptionalLong;
+
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
+import software.amazon.awssdk.core.ResponseBytes;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.core.sync.RequestBody;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.S3ClientBuilder;
+import software.amazon.awssdk.services.s3.S3Configuration;
+import software.amazon.awssdk.services.s3.model.BucketAlreadyExistsException;
+import software.amazon.awssdk.services.s3.model.BucketAlreadyOwnedByYouException;
+import software.amazon.awssdk.services.s3.model.BucketLocationConstraint;
+import software.amazon.awssdk.services.s3.model.CreateBucketConfiguration;
+import software.amazon.awssdk.services.s3.model.CreateBucketRequest;
+import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+import software.amazon.awssdk.services.s3.model.HeadBucketRequest;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.S3Exception;
+
+public class S3StorageService extends AbstractStorageService {
+  private final S3Client client;
+  private final String bucket;
+  private final String prefix;
+  private final String region;
+
+  public S3StorageService(
+      String bucket,
+      String region,
+      String prefix,
+      String endpoint,
+      String accessKeyId,
+      String secretAccessKey,
+      boolean pathStyleAccessEnabled) {
+    super(Path.of(""));
+    if (bucket == null || bucket.isBlank()) {
+      throw new IllegalArgumentException("S3 storage requires a bucket");
+    }
+    this.bucket = bucket;
+    this.region = blankToDefault(region, "us-east-1");
+    this.prefix = normalizePrefix(prefix);
+    this.client = createClient(this.region, endpoint, accessKeyId, secretAccessKey, pathStyleAccessEnabled);
+    ensureBucketExists();
+  }
+
+  private S3Client createClient(
+      String region,
+      String endpoint,
+      String accessKeyId,
+      String secretAccessKey,
+      boolean pathStyleAccessEnabled) {
+    S3ClientBuilder builder = S3Client.builder()
+        .region(Region.of(blankToDefault(region, "us-east-1")))
+        .serviceConfiguration(S3Configuration.builder()
+            .pathStyleAccessEnabled(pathStyleAccessEnabled)
+            .build());
+
+    if (endpoint != null && !endpoint.isBlank()) {
+      builder.endpointOverride(URI.create(endpoint));
+    }
+
+    if (accessKeyId != null && !accessKeyId.isBlank()) {
+      if (secretAccessKey == null || secretAccessKey.isBlank()) {
+        throw new IllegalArgumentException("S3 storage requires a secretAccessKey when accessKeyId is set");
+      }
+      builder.credentialsProvider(
+          StaticCredentialsProvider.create(AwsBasicCredentials.create(accessKeyId, secretAccessKey)));
+    } else {
+      builder.credentialsProvider(DefaultCredentialsProvider.create());
+    }
+
+    return builder.build();
+  }
+
+  private void ensureBucketExists() {
+    try {
+      client.headBucket(HeadBucketRequest.builder()
+          .bucket(bucket)
+          .build());
+      return;
+    } catch (S3Exception e) {
+      if (e.statusCode() != 404) {
+        throw e;
+      }
+    }
+
+    try {
+      client.createBucket(createBucketRequest());
+    } catch (BucketAlreadyOwnedByYouException e) {
+      return;
+    } catch (BucketAlreadyExistsException e) {
+      throw e;
+    }
+  }
+
+  private CreateBucketRequest createBucketRequest() {
+    CreateBucketRequest.Builder builder = CreateBucketRequest.builder()
+        .bucket(bucket);
+
+    if (!region.equals("us-east-1")) {
+      builder.createBucketConfiguration(CreateBucketConfiguration.builder()
+          .locationConstraint(BucketLocationConstraint.fromValue(region))
+          .build());
+    }
+
+    return builder.build();
+  }
+
+  private String blankToDefault(String value, String defaultValue) {
+    if (value == null || value.isBlank()) {
+      return defaultValue;
+    }
+    return value;
+  }
+
+  private String normalizePrefix(String value) {
+    if (value == null || value.isBlank()) {
+      return "";
+    }
+    String normalized = value;
+    while (normalized.startsWith("/")) {
+      normalized = normalized.substring(1);
+    }
+    while (normalized.endsWith("/")) {
+      normalized = normalized.substring(0, normalized.length() - 1);
+    }
+    return normalized;
+  }
+
+  private String key(String id) {
+    if (prefix.isEmpty()) {
+      return id;
+    }
+    return prefix + "/" + id;
+  }
+
+  @Override
+  public OptionalLong put(String id, byte[] data) {
+    try {
+      PutObjectRequest request = PutObjectRequest.builder()
+          .bucket(bucket)
+          .key(key(id))
+          .contentLength((long) data.length)
+          .build();
+      client.putObject(request, RequestBody.fromBytes(data));
+      return OptionalLong.of(data.length);
+    } catch (SdkException e) {
+      return OptionalLong.empty();
+    }
+  }
+
+  @Override
+  public Optional<byte[]> get(String id) {
+    try {
+      GetObjectRequest request = GetObjectRequest.builder()
+          .bucket(bucket)
+          .key(key(id))
+          .build();
+      ResponseBytes<GetObjectResponse> response = client.getObjectAsBytes(request);
+      return Optional.of(response.asByteArray());
+    } catch (NoSuchKeyException e) {
+      return Optional.empty();
+    } catch (SdkException e) {
+      return Optional.empty();
+    }
+  }
+
+  @Override
+  public boolean delete(String id) {
+    try {
+      DeleteObjectRequest request = DeleteObjectRequest.builder()
+          .bucket(bucket)
+          .key(key(id))
+          .build();
+      client.deleteObject(request);
+      return true;
+    } catch (SdkException e) {
+      return false;
+    }
+  }
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filewriter/StorageKeys.java

@@ -0,0 +1,9 @@
+package com.gregor_lohaus.gtransfer.services.filewriter;
+
+public final class StorageKeys {
+  private StorageKeys() {}
+
+  public static String chunk(String id, int index) {
+    return id + "/chunks/" + index;
+  }
+}

Backend/src/main/java/com/gregor_lohaus/gtransfer/services/filewriter/StorageServiceConfiguration.java

@@ -11,15 +11,27 @@ import com.gregor_lohaus.gtransfer.config.types.StorageServiceType;
 @Configuration
 public class StorageServiceConfiguration {
 
-    //TODO S3 implementation
     @Bean
     public AbstractStorageService storageService(
             @Value("${gtransfer-config.storageService.type}") StorageServiceType type,
-            @Value("${gtransfer-config.storageService.root}") String root) {
+            @Value("${gtransfer-config.storageService.root}") String root,
+            @Value("${gtransfer-config.storageService.bucket:}") String bucket,
+            @Value("${gtransfer-config.storageService.region:us-east-1}") String region,
+            @Value("${gtransfer-config.storageService.endpoint:}") String endpoint,
+            @Value("${gtransfer-config.storageService.accessKeyId:}") String accessKeyId,
+            @Value("${gtransfer-config.storageService.secretAccessKey:}") String secretAccessKey,
+            @Value("${gtransfer-config.storageService.pathStyleAccessEnabled:false}") boolean pathStyleAccessEnabled) {
         return switch (type) {
             case LOCAL -> new LocalStorageService(Path.of(root));
             case DUMMY -> new DummyStorageService(Path.of(root));
-            case S3 -> new LocalStorageService(Path.of(root));
+            case S3 -> new S3StorageService(
+                    bucket,
+                    region,
+                    root,
+                    endpoint,
+                    accessKeyId,
+                    secretAccessKey,
+                    pathStyleAccessEnabled);
         };
     }
 }

Backend/src/main/resources/static/crypto.js

@@ -1,28 +1,60 @@
-async function encryptFile(arrayBuffer) {
+var DEFAULT_CHUNK_SIZE = 4 * 1024 * 1024;
+
+async function encryptFile(file, chunkSize = DEFAULT_CHUNK_SIZE) {
     const key = await crypto.subtle.generateKey(
         { name: 'AES-GCM', length: 256 },
         true,
         ['encrypt', 'decrypt']
     );
 
-    const iv = crypto.getRandomValues(new Uint8Array(12));
-
-    const ciphertext = await crypto.subtle.encrypt({ name: 'AES-GCM', iv }, key, arrayBuffer);
-
-    // Payload: 12-byte IV prepended to ciphertext
-    const payload = new Uint8Array(12 + ciphertext.byteLength);
-    payload.set(iv, 0);
-    payload.set(new Uint8Array(ciphertext), 12);
-
-    // SHA-256(rawKey) → file identifier sent to server; server never sees the key itself
     const rawKey = await crypto.subtle.exportKey('raw', key);
-    const hash = Array.from(new Uint8Array(await crypto.subtle.digest('SHA-256', rawKey)))
+    const hash = await hashKey(rawKey);
+    const base64urlKey = encodeKey(rawKey);
+    const chunkCount = Math.max(1, Math.ceil(file.size / chunkSize));
+
+    return {
+        hash,
+        base64urlKey,
+        chunkCount,
+        chunks: encryptedChunks(file, key, chunkCount, chunkSize)
+    };
+}
+
+async function* encryptedChunks(file, key, chunkCount, chunkSize) {
+    for (let index = 0; index < chunkCount; index++) {
+        const start = index * chunkSize;
+        const end = Math.min(start + chunkSize, file.size);
+        const plaintext = await file.slice(start, end).arrayBuffer();
+        const iv = crypto.getRandomValues(new Uint8Array(12));
+        const ciphertext = await crypto.subtle.encrypt({ name: 'AES-GCM', iv }, key, plaintext);
+
+        const payload = new Uint8Array(12 + ciphertext.byteLength);
+        payload.set(iv, 0);
+        payload.set(new Uint8Array(ciphertext), 12);
+
+        yield { index, payload };
+    }
+}
+
+async function hashKey(rawKey) {
+    return Array.from(new Uint8Array(await crypto.subtle.digest('SHA-256', rawKey)))
         .map(b => b.toString(16).padStart(2, '0'))
         .join('');
-
-    // Base64url-encode key for URL fragment
-    const base64urlKey = btoa(String.fromCharCode(...new Uint8Array(rawKey)))
-        .replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
-
-    return { payload, hash, base64urlKey };
+}
+
+async function decryptChunk(payload, key) {
+    const bytes = new Uint8Array(payload);
+    const iv = bytes.slice(0, 12);
+    const ciphertext = bytes.slice(12);
+    return crypto.subtle.decrypt({ name: 'AES-GCM', iv }, key, ciphertext);
+}
+
+function encodeKey(rawKey) {
+    return btoa(String.fromCharCode(...new Uint8Array(rawKey)))
+        .replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
+}
+
+function decodeKey(base64url) {
+    const base64 = base64url.replace(/-/g, '+').replace(/_/g, '/');
+    return Uint8Array.from(atob(base64), c => c.charCodeAt(0));
 }

Backend/src/main/resources/static/download.js

@@ -0,0 +1,176 @@
+const fragment = location.hash.slice(1);
+if (!fragment) {
+    showError('No decryption key found in URL.');
+} else try {
+    setStatus('Deriving key\u2026');
+
+    const rawKeyBytes = decodeKey(fragment);
+    const id = await hashKey(rawKeyBytes);
+
+    const key = await crypto.subtle.importKey(
+        'raw', rawKeyBytes, { name: 'AES-GCM' }, false, ['decrypt']
+    );
+
+    setProgress('Loading metadata\u2026', 0, 1);
+    const metadataResponse = await fetch('/download/' + id + '/metadata');
+
+    if (metadataResponse.status === 410) {
+        showError('This file has expired or reached its download limit.');
+    } else if (!metadataResponse.ok) {
+        showError(`Download failed (${metadataResponse.status}).`);
+    } else {
+        const metadata = await metadataResponse.json();
+        const filename = metadata.name || 'download';
+        const chunkCount = metadata.chunkCount || 1;
+        const chunks = [];
+
+        for (let index = 0; index < chunkCount; index++) {
+            setProgress(`Downloading chunk ${index + 1} of ${chunkCount}\u2026`, index, chunkCount);
+            const chunkResponse = await fetch('/download/' + id + '/chunk/' + index);
+            if (chunkResponse.status === 410) {
+                throw new Error('This file has expired or reached its download limit.');
+            }
+            if (!chunkResponse.ok) {
+                throw new Error(`Chunk download failed (${chunkResponse.status})`);
+            }
+
+            setProgress(`Decrypting chunk ${index + 1} of ${chunkCount}\u2026`, index + 0.5, chunkCount);
+            const plaintextChunk = await decryptChunk(await chunkResponse.arrayBuffer(), key);
+            chunks.push(new Uint8Array(plaintextChunk));
+            setProgress(`Downloaded ${index + 1} of ${chunkCount} chunks`, index + 1, chunkCount);
+        }
+
+        const completeResponse = await fetch('/download/' + id + '/complete', { method: 'POST' });
+        if (!completeResponse.ok && completeResponse.status !== 404 && completeResponse.status !== 410) {
+            throw new Error(`Download completion failed (${completeResponse.status})`);
+        }
+
+        setProgress('Preparing preview\u2026', chunkCount, chunkCount);
+        const plaintext = combineChunks(chunks);
+        showPreview(filename, plaintext);
+    }
+} catch (err) {
+    showError(err.message);
+}
+
+function setStatus(msg) {
+    const el = htmx.find('#download-status');
+    if (el) el.textContent = msg;
+}
+
+function setProgress(msg, completed, total) {
+    setStatus(msg);
+    const percent = Math.round((completed / total) * 100);
+    const bar = htmx.find('#download-progress');
+    if (!bar) return;
+    bar.style.width = `${percent}%`;
+    bar.textContent = `${percent}%`;
+    bar.setAttribute('aria-valuenow', String(percent));
+}
+
+function escapeHtml(str) {
+    return str.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+
+function getMimeType(filename) {
+    const ext = filename.split('.').pop().toLowerCase();
+    const types = {
+        jpg: 'image/jpeg', jpeg: 'image/jpeg', png: 'image/png', gif: 'image/gif',
+        webp: 'image/webp', svg: 'image/svg+xml', bmp: 'image/bmp', ico: 'image/x-icon',
+        mp4: 'video/mp4', webm: 'video/webm', ogv: 'video/ogg', mov: 'video/quicktime',
+        mp3: 'audio/mpeg', wav: 'audio/wav', ogg: 'audio/ogg', flac: 'audio/flac',
+        aac: 'audio/aac', m4a: 'audio/mp4',
+        txt: 'text/plain', md: 'text/plain', csv: 'text/csv', log: 'text/plain',
+        json: 'application/json', xml: 'text/xml',
+        js: 'text/plain', ts: 'text/plain', py: 'text/plain', java: 'text/plain',
+        c: 'text/plain', cpp: 'text/plain', h: 'text/plain', sh: 'text/plain',
+        yaml: 'text/plain', yml: 'text/plain', toml: 'text/plain', ini: 'text/plain',
+        pdf: 'application/pdf',
+    };
+    return types[ext] || 'application/octet-stream';
+}
+
+function combineChunks(chunks) {
+    const size = chunks.reduce((sum, chunk) => sum + chunk.byteLength, 0);
+    const combined = new Uint8Array(size);
+    let offset = 0;
+    for (const chunk of chunks) {
+        combined.set(chunk, offset);
+        offset += chunk.byteLength;
+    }
+    return combined.buffer;
+}
+
+function showPreview(filename, plaintext) {
+    const mimeType = getMimeType(filename);
+    const blob = new Blob([plaintext], { type: mimeType });
+    const url = URL.createObjectURL(blob);
+    window.addEventListener('unload', () => URL.revokeObjectURL(url));
+
+    const name = escapeHtml(filename);
+    const downloadBtn = `<button id="download-btn" class="btn btn-outline-success mt-2">Download</button>`;
+    let previewHtml;
+
+    if (mimeType.startsWith('image/')) {
+        previewHtml = `
+            <img src="${url}" alt="${name}" class="preview-media mb-3">
+            <div class="fw-medium mb-2">${name}</div>
+            ${downloadBtn}`;
+    } else if (mimeType.startsWith('video/')) {
+        previewHtml = `
+            <video src="${url}" controls class="preview-media mb-3"></video>
+            <div class="fw-medium mb-2">${name}</div>
+            ${downloadBtn}`;
+    } else if (mimeType.startsWith('audio/')) {
+        previewHtml = `
+            <div class="drop-zone-icon mb-3">&#x1F3B5;</div>
+            <div class="fw-medium mb-2">${name}</div>
+            <audio src="${url}" controls class="preview-audio mb-3"></audio>
+            ${downloadBtn}`;
+    } else if (mimeType === 'application/pdf') {
+        previewHtml = `
+            <div class="fw-medium mb-2">${name}</div>
+            <iframe src="${url}" class="preview-pdf mb-3"></iframe>
+            ${downloadBtn}`;
+    } else if (mimeType.startsWith('text/') || mimeType === 'application/json') {
+        const text = new TextDecoder().decode(plaintext);
+        const preview = text.length > 10000 ? text.slice(0, 10000) + '\n\u2026' : text;
+        previewHtml = `
+            <div class="fw-medium mb-2">${name}</div>
+            <pre class="preview-text mb-3">${escapeHtml(preview)}</pre>
+            ${downloadBtn}`;
+    } else {
+        previewHtml = `
+            <div class="drop-zone-icon mb-3">&#x1F4C4;</div>
+            <div class="fw-medium mb-2">${name}</div>
+            ${downloadBtn}`;
+    }
+
+    htmx.swap(htmx.find('#download-state'), previewHtml, { swapStyle: 'innerHTML' });
+
+    htmx.on(htmx.find('#download-btn'), 'click', () => {
+        const a = document.createElement('a');
+        a.href = url;
+        a.download = filename;
+        a.click();
+        showSuccess(filename);
+    });
+}
+
+function showSuccess(filename) {
+    const name = escapeHtml(filename);
+    htmx.swap(htmx.find('#download-state'), `
+        <div class="drop-zone-icon mb-3">&#x2705;</div>
+        <div class="fw-medium mb-1">${name}</div>
+        <div class="drop-zone-text mb-3">Your download has started.</div>
+        <a href="/" class="btn btn-link drop-zone-text text-decoration-none">Send a file</a>`,
+        { swapStyle: 'innerHTML' });
+}
+
+function showError(msg) {
+    htmx.swap(htmx.find('#download-state'), `
+        <div class="drop-zone-icon mb-3">&#x26A0;</div>
+        <div class="drop-zone-text mb-3">${escapeHtml(msg)}</div>
+        <a href="/" class="btn btn-link drop-zone-text text-decoration-none">Go home</a>`,
+        { swapStyle: 'innerHTML' });
+}

Backend/src/main/resources/static/style.css

@@ -65,3 +65,37 @@ footer, footer a {
 footer a:hover {
     color: #8b949e;
 }
+
+.preview-media {
+    max-width: 100%;
+    border-radius: 8px;
+    display: block;
+    margin-left: auto;
+    margin-right: auto;
+}
+
+.preview-audio {
+    width: 100%;
+}
+
+.preview-pdf {
+    width: 100%;
+    height: 420px;
+    border: none;
+    border-radius: 8px;
+    display: block;
+}
+
+.preview-text {
+    text-align: left;
+    max-height: 320px;
+    overflow: auto;
+    background: #0d1117;
+    padding: 1rem;
+    border-radius: 8px;
+    font-size: 0.78rem;
+    color: #e6edf3;
+    border: 1px solid #30363d;
+    white-space: pre-wrap;
+    word-break: break-word;
+}

Backend/src/main/resources/static/upload.js

@@ -1,101 +1,120 @@
-const dropZone = document.getElementById('drop-zone');
-const fileInput = document.getElementById('file-input');
+const dropZone = htmx.find('#drop-zone');
+const fileInput = htmx.find('#file-input');
 const promptHtml = dropZone.innerHTML;
 
 let selectedFile = null;
 
-// ── File selection ────────────────────────────────────────────────────────────
-
-dropZone.addEventListener('click', () => {
+htmx.on(dropZone, 'click', () => {
     if (selectedFile === null) fileInput.click();
 });
 
-fileInput.addEventListener('change', e => {
+htmx.on(fileInput, 'change', e => {
     if (e.target.files[0]) onFileSelected(e.target.files[0]);
 });
 
-dropZone.addEventListener('dragover', e => {
+htmx.on(dropZone, 'dragover', e => {
     e.preventDefault();
-    dropZone.classList.add('dragover');
+    htmx.addClass(dropZone, 'dragover');
 });
 
-dropZone.addEventListener('dragleave', () => dropZone.classList.remove('dragover'));
+htmx.on(dropZone, 'dragleave', () => htmx.removeClass(dropZone, 'dragover'));
 
-dropZone.addEventListener('drop', e => {
+htmx.on(dropZone, 'drop', e => {
     e.preventDefault();
-    dropZone.classList.remove('dragover');
+    htmx.removeClass(dropZone, 'dragover');
     if (e.dataTransfer.files[0] && selectedFile === null) onFileSelected(e.dataTransfer.files[0]);
 });
 
 function onFileSelected(file) {
     selectedFile = file;
-    // Use htmx to fetch the options form — server renders max values from config
     htmx.ajax('GET', '/upload/options?name=' + encodeURIComponent(file.name), {
         target: '#drop-zone',
         swap: 'innerHTML'
     });
 }
 
-// ── Upload (called from onclick in server-rendered options form) ──────────────
-
 async function startUpload() {
-    const expiryDays = document.getElementById('expiry-days')?.value;
-    const downloadLimit = document.getElementById('download-limit')?.value;
+    const expiryDays    = htmx.find('#expiry-days')?.value;
+    const downloadLimit = htmx.find('#download-limit')?.value;
 
-    dropZone.innerHTML = `
+    htmx.swap(dropZone, `
         <div class="mb-3">
             <div class="spinner-border text-success" role="status">
                 <span class="visually-hidden">Loading\u2026</span>
             </div>
         </div>
-        <div class="drop-zone-text" id="upload-status">Encrypting\u2026</div>`;
+        <div class="drop-zone-text mb-3" id="upload-status">Preparing\u2026</div>
+        <div class="progress" role="progressbar" aria-label="Upload progress" aria-valuemin="0" aria-valuemax="100">
+            <div id="upload-progress" class="progress-bar bg-success" style="width: 0%">0%</div>
+        </div>`,
+        { swapStyle: 'innerHTML' });
 
     try {
-        const { payload, hash, base64urlKey } = await encryptFile(await selectedFile.arrayBuffer());
+        const encryptedFile = await encryptFile(selectedFile);
 
-        setStatus('Uploading\u2026');
+        for await (const { index, payload } of encryptedFile.chunks) {
+            const chunkCount = encryptedFile.chunkCount;
+            setProgress(`Encrypting chunk ${index + 1} of ${chunkCount}\u2026`, index, chunkCount);
 
-        const formData = new FormData();
-        formData.append('file', new Blob([payload]), selectedFile.name);
-        formData.append('hash', hash);
-        formData.append('name', selectedFile.name);
-        if (expiryDays)    formData.append('expiryDays', expiryDays);
-        if (downloadLimit) formData.append('downloadLimit', downloadLimit);
+            setProgress(`Uploading chunk ${index + 1} of ${chunkCount}\u2026`, index + 0.5, chunkCount);
+            const chunkData = new FormData();
+            chunkData.append('chunk', new Blob([payload]), String(index));
+            chunkData.append('hash', encryptedFile.hash);
+            chunkData.append('index', index);
 
-        const response = await fetch('/upload', { method: 'POST', body: formData });
+            const chunkResponse = await fetch('/upload/chunk', { method: 'POST', body: chunkData });
+            if (!chunkResponse.ok) throw new Error(`Chunk upload failed (${chunkResponse.status})`);
+            setProgress(`Uploaded chunk ${index + 1} of ${chunkCount}`, index + 1, chunkCount);
+        }
+
+        setProgress('Finalizing\u2026', encryptedFile.chunkCount, encryptedFile.chunkCount);
+        const metadata = new FormData();
+        metadata.append('hash', encryptedFile.hash);
+        metadata.append('name', selectedFile.name);
+        metadata.append('chunkCount', encryptedFile.chunkCount);
+        if (expiryDays)    metadata.append('expiryDays', expiryDays);
+        if (downloadLimit) metadata.append('downloadLimit', downloadLimit);
+
+        const response = await fetch('/upload', { method: 'POST', body: metadata });
         if (!response.ok) throw new Error(`Server error ${response.status}`);
 
-        // Server returns HTML fragment; append key fragment client-side
-        dropZone.innerHTML = await response.text();
+        htmx.swap(dropZone, await response.text(), { swapStyle: 'innerHTML' });
         htmx.process(dropZone);
-        document.getElementById('share-link').value += '#' + base64urlKey;
+        htmx.find('#share-link').value = window.location.origin + '/download#' + encryptedFile.base64urlKey;
 
     } catch (err) {
-        dropZone.innerHTML = `
+        htmx.swap(dropZone, `
             <div class="drop-zone-icon mb-3">&#x26A0;</div>
             <div class="drop-zone-text mb-3">${err.message}</div>
-            <button class="btn btn-link drop-zone-text text-decoration-none" onclick="resetUpload()">Try again</button>`;
+            <button class="btn btn-link drop-zone-text text-decoration-none" onclick="resetUpload()">Try again</button>`,
+            { swapStyle: 'innerHTML' });
     }
 }
 
 function setStatus(msg) {
-    const el = document.getElementById('upload-status');
+    const el = htmx.find('#upload-status');
     if (el) el.textContent = msg;
 }
 
-// ── Reset (called from onclick in server-rendered fragments) ──────────────────
+function setProgress(msg, completed, total) {
+    setStatus(msg);
+    const percent = Math.round((completed / total) * 100);
+    const bar = htmx.find('#upload-progress');
+    if (!bar) return;
+    bar.style.width = `${percent}%`;
+    bar.textContent = `${percent}%`;
+    bar.setAttribute('aria-valuenow', String(percent));
+}
 
 function resetUpload() {
     selectedFile = null;
     fileInput.value = '';
-    dropZone.innerHTML = promptHtml;
+    htmx.swap(dropZone, promptHtml, { swapStyle: 'innerHTML' });
 }
 
-// ── Copy link (called from onclick in result fragment) ────────────────────────
-
 async function copyLink() {
-    await navigator.clipboard.writeText(document.getElementById('share-link').value);
-    const btn = document.getElementById('copy-btn');
+    await navigator.clipboard.writeText(htmx.find('#share-link').value);
+    const btn = htmx.find('#copy-btn');
     btn.textContent = 'Copied!';
     setTimeout(() => { btn.textContent = 'Copy'; }, 2000);
 }

Backend/src/main/resources/templates/download/page.html

@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html lang="en" xmlns:th="http://www.thymeleaf.org" data-bs-theme="dark">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>GTransfer</title>
+    <link rel="stylesheet" th:href="@{/webjars/bootstrap/dist/css/bootstrap.min.css}">
+    <link rel="stylesheet" th:href="@{/style.css}">
+    <script th:src="@{/webjars/htmx.org/dist/htmx.min.js}" defer></script>
+    <script th:src="@{/crypto.js}" defer></script>
+    <script th:src="@{/download.js}" type="module"></script>
+</head>
+<body class="d-flex flex-column min-vh-100">
+
+    <nav class="navbar px-4 pt-3">
+        <a class="brand fw-bold text-decoration-none fs-4" href="/">G<span>Transfer</span></a>
+        <span class="badge-e2e rounded-pill fw-medium px-3 py-1">&#x1F512; End-to-end encrypted</span>
+    </nav>
+
+    <main class="flex-grow-1 d-flex align-items-center justify-content-center py-5 px-3">
+        <div id="download-state" class="drop-zone text-center py-5 px-4" style="max-width: 520px; width: 100%;">
+            <div class="drop-zone-icon mb-3">&#x1F512;</div>
+            <div class="drop-zone-text mb-3" id="download-status">Preparing&hellip;</div>
+            <div class="progress" role="progressbar" aria-label="Download progress" aria-valuemin="0" aria-valuemax="100">
+                <div id="download-progress" class="progress-bar bg-success" style="width: 0%">0%</div>
+            </div>
+        </div>
+    </main>
+
+    <footer class="text-center p-4 small">
+        <a href="https://github.com/gregor-lohaus/gtransfer">Open source</a>
+        &middot; No tracking &middot; No ads
+    </footer>
+
+</body>
+</html>

Backend/src/main/resources/templates/index.html

@@ -28,7 +28,7 @@
                 </p>
             </div>
             <div class="col-lg-7 d-flex justify-content-center justify-content-lg-end">
-                <input type="file" id="file-input" hidden>
+                <input type="file" id="file-input" accept="*/*" hidden>
                 <div id="drop-zone" class="drop-zone text-center py-5 px-4 w-100">
                     <div class="drop-zone-icon mb-3">&#x1F4C2;</div>
                     <div class="mb-2">
@@ -42,7 +42,7 @@
     </main>
 
     <footer class="text-center p-4 small">
-        <a href="https://github.com/gregor-lohaus/gtransfer">Open source</a>
+        <a href="https://gitea.gregorlohaus.com/gregor/gtransfer">Open source</a>
         &middot; No tracking &middot; No ads
     </footer>
 

Backend/src/main/resources/templates/upload/result.html

@@ -5,8 +5,7 @@
     <div class="drop-zone-icon mb-3">&#x2705;</div>
     <div class="drop-zone-text mb-3">Your file is ready to share</div>
     <div class="input-group mb-2">
-        <input type="text" id="share-link" class="form-control form-control-sm"
-               th:value="@{/download/{id}(id=${id})}" readonly>
+        <input type="text" id="share-link" class="form-control form-control-sm" readonly>
         <button id="copy-btn" class="btn btn-outline-success btn-sm" onclick="copyLink()">Copy</button>
     </div>
     <button class="btn btn-link drop-zone-text text-decoration-none small" onclick="resetUpload()">

Dockerfile

@@ -0,0 +1,12 @@
+FROM postgres:15.17-trixie
+RUN apt update
+RUN apt install -y curl wget zip unzip build-essential zlib1g-dev nodejs ssh
+RUN curl -s "https://get.sdkman.io?ci=true" | bash
+SHELL ["/bin/bash", "-c"]
+RUN source "/root/.sdkman/bin/sdkman-init.sh" \
+  && sdk install java 25.0.2-graalce \
+  && sdk install gradle
+ENV POSTGRES_PASSWORD=gtransfer
+ENV POSTGRES_USER=gtransfer
+ENV POSTGRES_DB=gtransfer
+ENTRYPOINT ["/bin/bash"]

LICENSE

@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+                            NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.

README.md

@@ -0,0 +1,47 @@
+# GTransfer
+
+A self-hosted, end-to-end encrypted file transfer service. The server stores only ciphertext and never has access to encryption keys or plaintext.
+
+### [Canonical Repo Url](https://gitea.gregorlohaus.com/gregor/gtransfer)
+
+## Encryption flow
+
+### Upload
+
+1. **Key generation** — the browser generates a random 256-bit AES-GCM key using the [Web Crypto API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Crypto_API). The key never leaves the browser.
+
+2. **Encryption** — the file is encrypted with AES-GCM. A random 96-bit (12-byte) IV is generated for each upload. The IV is prepended to the ciphertext to produce the payload:
+   ```
+   payload = IV (12 bytes) || ciphertext
+   ```
+
+3. **File ID** — the server needs a way to identify the file without knowing the key. The client computes `SHA-256(rawKey)` and uses the hex digest as the file ID. This is a one-way operation — the server cannot reverse it to obtain the key.
+
+4. **Upload** — the encrypted payload and file ID are sent to the server. The server stores the ciphertext and records the file ID, name, expiry, and download limit in the database.
+
+5. **Share link** — the raw key is base64url-encoded and placed in the [URL fragment](https://developer.mozilla.org/en-US/docs/Web/API/URL/hash):
+   ```
+   https://example.com/download#<base64url(rawKey)>
+   ```
+   Browsers never include the fragment in HTTP requests, so the key is never transmitted to the server.
+
+### Download
+
+1. **Key extraction** — the browser reads the key from the URL fragment and decodes it from base64url.
+
+2. **File lookup** — the client computes `SHA-256(rawKey)` to derive the file ID and fetches the encrypted payload from `/download/<id>/data`.
+
+3. **Decryption** — the IV is read from the first 12 bytes of the payload, and the remainder is decrypted with AES-GCM. AES-GCM is authenticated encryption, so any tampering with the ciphertext causes decryption to fail with an authentication error.
+
+4. **Download** — the plaintext is written to a `Blob` and the browser is prompted to save it.
+
+### Security properties
+
+| Property | Detail |
+|---|---|
+| Encryption | AES-256-GCM |
+| IV | 96-bit random, unique per upload |
+| Key derivation | None — key is randomly generated |
+| File ID | SHA-256(rawKey) — server cannot reverse to key |
+| Key transport | URL fragment — never sent to server |
+| Server access | Ciphertext, file metadata, SHA-256 of key only |

devenv.lock

@@ -3,11 +3,11 @@
     "devenv": {
       "locked": {
         "dir": "src/modules",
-        "lastModified": 1771852244,
-        "narHash": "sha256-4t3gQ4s7kqtDwSiE74Px6szKJtKtcoHgUiNmIm+Xl9Y=",
+        "lastModified": 1777321427,
+        "narHash": "sha256-EV/mIQur/dvCFwHzBjL7LBAgyhT0l3wQBgFjjY6zucg=",
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "c88c14a32d06173867e26b7d4f5daed38a3f6f1e",
+        "rev": "fb3d8df47420022c47a42151c26e5cdaee6c641d",
         "type": "github"
       },
       "original": {
@@ -22,11 +22,11 @@
         "nixpkgs-src": "nixpkgs-src"
       },
       "locked": {
-        "lastModified": 1770434727,
-        "narHash": "sha256-YzOZRgiqIccnkkZvckQha7wvOfN2z50xEdPvfgu6sf8=",
+        "lastModified": 1776852779,
+        "narHash": "sha256-WwO/ITisCXwyiRgtktZgv3iGhAGO+IB5Av4kKCwezR0=",
         "owner": "cachix",
         "repo": "devenv-nixpkgs",
-        "rev": "8430f16a39c27bdeef236f1eeb56f0b51b33d348",
+        "rev": "ec3063523dcd911aeadb50faa589f237cdab5853",
         "type": "github"
       },
       "original": {
@@ -39,11 +39,11 @@
     "nixpkgs-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1769922788,
-        "narHash": "sha256-H3AfG4ObMDTkTJYkd8cz1/RbY9LatN5Mk4UF48VuSXc=",
+        "lastModified": 1776329215,
+        "narHash": "sha256-a8BYi3mzoJ/AcJP8UldOx8emoPRLeWqALZWu4ZvjPXw=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "207d15f1a6603226e1e223dc79ac29c7846da32e",
+        "rev": "b86751bc4085f48661017fa226dee99fab6c651b",
         "type": "github"
       },
       "original": {

devenv.nix

@@ -1,57 +1,41 @@
 { pkgs, lib, config, inputs, ... }:
 
 {
-  # https://devenv.sh/basics/
   env.GRAALVM_HOME = "${pkgs.graalvmPackages.graalvm-ce}";
 
-  # https://devenv.sh/packages/
   packages = [
     pkgs.graalvmPackages.graalvm-ce
     pkgs.watchexec
   ];
 
-  # https://devenv.sh/languages/
   languages.java.enable = true;
   languages.java.lsp.enable = true;
   languages.java.gradle.enable = true;
   languages.java.jdk.package = pkgs.jdk25_headless;
-  # https://devenv.sh/processes/
-  # processes.cargo-watch.exec = "cargo-watch";
-  # process.manager.implementation = "mprocs";
   processes.watchbuild = {
-    exec = "watchexec -r -e java,html,css,js -w ./Backend/src -- build-backend";
+    exec = "build-backend";
+    watch = {
+      paths = [./Backend/src];
+      extensions = ["java"  "html"  "css"  "js"];
+    };
   };
   processes.runbin = {
-    exec = "watchexec -r -w ./Backend/buildcompleted.at ./Backend/build/native/nativeCompile/gtransfer";
+    exec = "./Backend/build/native/nativeCompile/gtransfer";
+    watch = {
+      paths = [ ./Backend/buildcompleted.at ];
+    };
   };
-  # https://devenv.sh/services/
   services.postgres.enable = true;
   services.postgres.listen_addresses = "localhost";
   services.postgres.port = 5432;
   services.postgres.initialDatabases = [
     {name="gtransfer";user="gtransfer";pass="gtransfer";}
   ];
-
-  # https://devenv.sh/scripts/
+  services.minio.enable = true;
   scripts.build-backend.exec = ''
     gradle -p ./Backend build && echo $(date) > ./Backend/buildcompleted.at
   '';
 
-  enterShell = ''
-  '';
-
-  # https://devenv.sh/tasks/
-  # tasks = {
-  #   "myproj:setup".exec = "mytool build";
-  #   "devenv:enterShell".after = [ "myproj:setup" ];
-  # };
-
-  # https://devenv.sh/tests/
   enterTest = ''
   '';
-
-  # https://devenv.sh/git-hooks/
-  # git-hooks.hooks.shellcheck.enable = true;
-
-  # See full reference at https://devenv.sh/reference/options/
 }

layout.kdl

@@ -1,337 +0,0 @@
-layout {
-    cwd "/home/anon"
-    tab name="Tab #1" focus=true {
-        pane size=1 borderless=true {
-            plugin location="zellij:tab-bar"
-        }
-        pane command="devenv" cwd="Dev/GTransfer" {
-            args "shell"
-        }
-        pane size=1 borderless=true {
-            plugin location="zellij:status-bar"
-        }
-        floating_panes {
-            pane command="devenv" cwd="Dev/GTransfer" {
-                height 30
-                width 170
-                x 85
-                y 16
-                args "up"
-            }
-            pane command="hx" cwd=".config/gtransfer" {
-                height 30
-                width 170
-                x 87
-                y 18
-                args "config.toml"
-            }
-            pane command="devenv" cwd="Dev/GTransfer" {
-                height 30
-                width 170
-                x 89
-                y 20
-                args "shell"
-            }
-            pane command="claude" cwd="Dev/GTransfer" {
-                height 30
-                width 170
-                x 91
-                y 22
-                args "."
-            }
-            pane command="yy" cwd="Dev/GTransfer" {
-                height 30
-                width 170
-                x 93
-                y 24
-            }
-        }
-    }
-    new_tab_template {
-        pane size=1 borderless=true {
-            plugin location="zellij:tab-bar"
-        }
-        pane cwd="/home/anon"
-        pane size=1 borderless=true {
-            plugin location="zellij:status-bar"
-        }
-    }
-    swap_tiled_layout name="vertical" {
-        tab max_panes=5 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane split_direction="vertical" {
-                    pane
-                    pane {
-                        children
-                    }
-                }
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-        tab max_panes=8 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane split_direction="vertical" {
-                    pane {
-                        children
-                    }
-                    pane {
-                        pane
-                        pane
-                        pane
-                        pane
-                    }
-                }
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-        tab max_panes=12 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane split_direction="vertical" {
-                    pane {
-                        children
-                    }
-                    pane {
-                        pane
-                        pane
-                        pane
-                        pane
-                    }
-                    pane {
-                        pane
-                        pane
-                        pane
-                        pane
-                    }
-                }
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-    }
-    swap_tiled_layout name="horizontal" {
-        tab max_panes=4 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane
-                pane
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-        tab max_panes=8 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane {
-                    pane split_direction="vertical" {
-                        children
-                    }
-                    pane split_direction="vertical" {
-                        pane
-                        pane
-                        pane
-                        pane
-                    }
-                }
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-        tab max_panes=12 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane {
-                    pane split_direction="vertical" {
-                        children
-                    }
-                    pane split_direction="vertical" {
-                        pane
-                        pane
-                        pane
-                        pane
-                    }
-                    pane split_direction="vertical" {
-                        pane
-                        pane
-                        pane
-                        pane
-                    }
-                }
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-    }
-    swap_tiled_layout name="stacked" {
-        tab min_panes=5 {
-            pane size=1 borderless=true {
-                plugin location="tab-bar"
-            }
-            pane {
-                pane split_direction="vertical" {
-                    pane
-                    pane stacked=true {
-                        children
-                    }
-                }
-            }
-            pane size=1 borderless=true {
-                plugin location="status-bar"
-            }
-        }
-    }
-    swap_floating_layout name="staggered" {
-        floating_panes {
-        }
-    }
-    swap_floating_layout name="enlarged" {
-        floating_panes max_panes=10 {
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 1
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 2
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 3
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 4
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 5
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 6
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 7
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 8
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x "5%"
-                y 9
-            }
-            pane cwd="/home/anon" {
-                height "90%"
-                width "90%"
-                x 10
-                y 10
-            }
-        }
-    }
-    swap_floating_layout name="spread" {
-        floating_panes max_panes=1 {
-            pane cwd="/home/anon" {
-                x "50%"
-                y "50%"
-            }
-        }
-        floating_panes max_panes=2 {
-            pane cwd="/home/anon" {
-                width "45%"
-                x "1%"
-                y "25%"
-            }
-            pane cwd="/home/anon" {
-                width "45%"
-                x "50%"
-                y "25%"
-            }
-        }
-        floating_panes max_panes=3 {
-            pane cwd="/home/anon" {
-                height "45%"
-                width "45%"
-                y "55%"
-            }
-            pane cwd="/home/anon" {
-                width "45%"
-                x "1%"
-                y "1%"
-            }
-            pane cwd="/home/anon" {
-                width "45%"
-                x "50%"
-                y "1%"
-            }
-        }
-        floating_panes max_panes=4 {
-            pane cwd="/home/anon" {
-                height "45%"
-                width "45%"
-                x "1%"
-                y "55%"
-            }
-            pane cwd="/home/anon" {
-                height "45%"
-                width "45%"
-                x "50%"
-                y "55%"
-            }
-            pane cwd="/home/anon" {
-                height "45%"
-                width "45%"
-                x "1%"
-                y "1%"
-            }
-            pane cwd="/home/anon" {
-                height "45%"
-                width "45%"
-                x "50%"
-                y "1%"
-            }
-        }
-    }
-}
-