feat(download): add file size calculation for DownloadService

This allows the browser to show file size and a time estimate for downloading files.
Does not work for ZipOutputStreams though since dir size doesn't match the zip file size.
Also added no-cache headers so browser won't start caching downloads.

backend/src/main/java/de/grimsi/gameyfin/rest/GamesController.java

@@ -5,11 +5,16 @@ import de.grimsi.gameyfin.entities.DetectedGame;
 import de.grimsi.gameyfin.service.DownloadService;
 import de.grimsi.gameyfin.service.GameService;
 import lombok.RequiredArgsConstructor;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;
 
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.List;
 import java.util.Map;
 
@@ -50,10 +55,21 @@ public class GamesController {
         DetectedGame game = gameService.getDetectedGame(slug);
 
         String downloadFileName = downloadService.getDownloadFileName(game);
+        long downloadFileSize = downloadService.getDownloadFileSize(game);
+
+        HttpHeaders headers = new HttpHeaders();
+        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"%s\"".formatted(downloadFileName));
+        headers.add(HttpHeaders.CACHE_CONTROL, "no-cache, no-store, must-revalidate");
+        headers.add(HttpHeaders.PRAGMA, "no-cache");
+        headers.add(HttpHeaders.EXPIRES, "0");
+        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
+        if (downloadFileSize > 0) {
+            headers.setContentLength(downloadFileSize);
+        }
 
         return ResponseEntity
                 .ok()
-                .header("Content-Disposition", "attachment; filename=\"%s\"".formatted(downloadFileName))
+                .headers(headers)
                 .body(out -> downloadService.sendGamefilesToClient(game, out));
     }
 

backend/src/main/java/de/grimsi/gameyfin/service/DownloadService.java

@@ -6,6 +6,7 @@ import lombok.RequiredArgsConstructor;
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.catalina.connector.ClientAbortException;
+import org.apache.commons.io.FileUtils;
 import org.springframework.core.io.Resource;
 import org.springframework.stereotype.Service;
 import org.springframework.util.StopWatch;
@@ -34,6 +35,23 @@ public class DownloadService {
         return getFilenameWithExtension(path) + ".zip";
     }
 
+    public long getDownloadFileSize(DetectedGame game) {
+        Path path = Path.of(game.getPath());
+
+        try {
+            if (!path.toFile().isDirectory()) {
+                long fileSize = filesystemService.getSizeOnDisk(path);
+                log.info("Calculated file size for {} ({} MB).", path, Math.divideExact(fileSize, 1000000L));
+                return fileSize;
+            } else {
+                // return zero since we cannot set content length for ZipOutputStreams that are used to archive directories
+                return 0;
+            }
+        } catch (IOException e) {
+            throw new DownloadAbortedException();
+        }
+    }
+
     public Resource sendImageToClient(String imageId) {
         String filename = "%s.png".formatted(imageId);
         return filesystemService.getFileFromCache(filename);
@@ -78,6 +96,7 @@ public class DownloadService {
     }
 
     private void sendGamefilesAsZipToClient(Path path, OutputStream outputStream) {
+        log.info("Archiving game path {} for download...", path);
         ZipOutputStream zos = new ZipOutputStream(outputStream) {{
             def.setLevel(Deflater.NO_COMPRESSION);
         }};
@@ -87,6 +106,7 @@ public class DownloadService {
                 @SneakyThrows
                 public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
                     zos.putNextEntry(new ZipEntry(path.relativize(file).toString()));
+                    log.debug("Adding file {} to archive...", file);
                     Files.copy(file, zos);
                     zos.closeEntry();
 

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "frontend",
-  "version": "1.2.3-SNAPSHOT",
+  "version": "1.2.4-SNAPSHOT",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "frontend",
-      "version": "1.2.3-SNAPSHOT",
+      "version": "1.2.4-SNAPSHOT",
       "dependencies": {
         "@angular/animations": "^14.0.0",
         "@angular/cdk": "^14.1.0",

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "frontend",
-  "version": "1.2.3-SNAPSHOT",
+  "version": "1.2.4-SNAPSHOT",
   "scripts": {
     "ng": "ng",
     "start": "ng serve",