Dynamic size

src/main/java/com/cfdeployer/service/ChunkedUploadService.java

@@ -61,13 +61,21 @@ public class ChunkedUploadService {
                             fileType, fileState.getTotalChunks(), totalChunks));
         }
 
-        // Write chunk to file using streaming to avoid loading entire chunk into memory
+        // Write chunk to file using sequential append mode
+        // This supports variable chunk sizes - chunks MUST be uploaded in order (0, 1, 2, ...)
         Path targetPath = fileState.getTargetPath();
-        long offset = (long) chunkIndex * getChunkSize();
 
-        try (RandomAccessFile raf = new RandomAccessFile(targetPath.toFile(), "rw");
-             var inputStream = chunk.getInputStream()) {
-            raf.seek(offset);
+        // Verify chunks are uploaded in order
+        if (chunkIndex != fileState.getReceivedChunkCount()) {
+            throw new IllegalArgumentException(
+                    String.format("Chunks must be uploaded in order. Expected chunk %d but received %d",
+                            fileState.getReceivedChunkCount(), chunkIndex));
+        }
+
+        try (var inputStream = chunk.getInputStream();
+             var outputStream = Files.newOutputStream(targetPath,
+                     java.nio.file.StandardOpenOption.CREATE,
+                     java.nio.file.StandardOpenOption.APPEND)) {
 
             // Stream chunk data in smaller buffers to reduce memory pressure
             byte[] buffer = new byte[8192]; // 8KB buffer
@@ -75,12 +83,12 @@ public class ChunkedUploadService {
             long totalWritten = 0;
 
             while ((bytesRead = inputStream.read(buffer)) != -1) {
-                raf.write(buffer, 0, bytesRead);
+                outputStream.write(buffer, 0, bytesRead);
                 totalWritten += bytesRead;
             }
 
-            log.debug("Wrote chunk {} ({} bytes) to {} at offset {}",
-                    chunkIndex, totalWritten, targetPath.getFileName(), offset);
+            log.debug("Appended chunk {} ({} bytes) to {}",
+                    chunkIndex, totalWritten, targetPath.getFileName());
         }
 
         fileState.markChunkReceived(chunkIndex);
@@ -160,11 +168,6 @@ public class ChunkedUploadService {
         }
     }
 
-    private int getChunkSize() {
-        // Default chunk size - should match client-side
-        return 5 * 1024 * 1024; // 5MB
-    }
-
     public int getActiveSessionCount() {
         return activeSessions.size();
     }