Fix server file browse flow

platform_web/utils/serverFileTransfer.ts

@@ -12,19 +12,49 @@ export async function downloadServerFileResult(client: PlatformApiClient, result
   if (!result.artifact) {
     return "文件内容尚未可用。";
   }
-  const chunks: ArrayBuffer[] = [];
+  const writer = await createFileWriter(result.filename || result.artifact.filename);
   let offset = 0;
   const chunkSize = Math.max(1, result.artifact.chunkSizeBytes || 1024 * 1024);
-  while (offset < result.artifact.sizeBytes) {
-    const chunk = await client.readArtifactContent(result.artifact.artifactId, offset, Math.min(chunkSize, result.artifact.sizeBytes - offset));
-    chunks.push(chunk.payload);
-    offset += chunk.contentLength;
-    if (chunk.contentLength <= 0) break;
+  try {
+    while (offset < result.artifact.sizeBytes) {
+      const chunk = await client.readArtifactContent(result.artifact.artifactId, offset, Math.min(chunkSize, result.artifact.sizeBytes - offset));
+      if (chunk.contentLength <= 0) throw new Error("文件下载返回空数据");
+      await writer.write(chunk.payload);
+      offset += chunk.contentLength;
+    }
+    await writer.close();
+  } catch (error) {
+    await writer.abort();
+    throw error;
   }
-  saveBlob(new Blob(chunks, { type: result.artifact.contentType || "application/octet-stream" }), result.filename || result.artifact.filename);
   return `下载已开始：${result.filename || result.artifact.filename}`;
 }
 
+interface FileWriter {
+  write(data: ArrayBuffer): Promise<void>;
+  close(): Promise<void>;
+  abort(): Promise<void>;
+}
+
+async function createFileWriter(filename: string): Promise<FileWriter> {
+  const picker = (window as Window & { showSaveFilePicker?: (options?: { suggestedName?: string }) => Promise<{ createWritable(): Promise<FileSystemWritableFileStream> }> }).showSaveFilePicker;
+  if (picker) {
+    const handle = await picker({ suggestedName: safeFilename(filename) });
+    const writable = await handle.createWritable();
+    return {
+      write: async (data) => { await writable.write(data); },
+      close: async () => { await writable.close(); },
+      abort: async () => { await writable.abort(); }
+    };
+  }
+  const chunks: ArrayBuffer[] = [];
+  return {
+    write: async (data) => { chunks.push(data); },
+    close: async () => { saveBlob(new Blob(chunks, { type: "application/octet-stream" }), safeFilename(filename)); },
+    abort: async () => { chunks.length = 0; }
+  };
+}
+
 function saveBlob(blob: Blob, filename: string) {
   const url = URL.createObjectURL(blob);
   const anchor = document.createElement("a");