feat(multimodal): 完成阶段F运行管理与收尾验收

backend/app/media_routes.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 
 import asyncio
 import json
+import hashlib
 from contextlib import closing
 from pathlib import Path
 from uuid import uuid4
@@ -22,14 +23,17 @@ MEDIA_SUFFIXES = {".wav", ".mp3", ".flac", ".ogg", ".m4a", ".mp4", ".webm", ".tx
 
 
 @router.post("/attachments", status_code=201)
-async def upload_attachment(request: Request, filename: str = Query(min_length=1, max_length=255)):
+async def upload_attachment(request: Request, filename: str = Query(min_length=1, max_length=255),
+                            idempotency_key: str | None = Header(None, min_length=16, max_length=100, pattern=r"^[a-zA-Z0-9_-]+$")):
     suffix = Path(filename).suffix.lower()
     if suffix not in MEDIA_SUFFIXES:
         raise ApiError(422, "UNSUPPORTED_MEDIA", "Unsupported attachment extension.")
-    attachment_id = f"media_{uuid4().hex}{suffix}"
+    identity = hashlib.sha256(idempotency_key.encode()).hexdigest() if idempotency_key else uuid4().hex
+    attachment_id = f"media_{identity}{suffix}"
     destination = attachment_path(attachment_id)
     destination.parent.mkdir(parents=True, exist_ok=True)
-    temporary = destination.with_suffix(destination.suffix + ".upload")
+    temporary = destination.with_suffix(destination.suffix + f".{uuid4().hex}.upload")
+    digest = hashlib.sha256()
     size = 0
     try:
         with temporary.open("xb") as stream:
@@ -37,10 +41,40 @@ async def upload_attachment(request: Request, filename: str = Query(min_length=1
                 size += len(chunk)
                 if size > MAX_UPLOAD_BYTES:
                     raise ApiError(413, "ATTACHMENT_TOO_LARGE", "Attachment exceeds 25 MiB.")
+                digest.update(chunk)
                 stream.write(chunk)
         if not size:
             raise ApiError(422, "EMPTY_ATTACHMENT", "Attachment is empty.")
-        temporary.replace(destination)
+        content_hash = digest.hexdigest()
+        if idempotency_key:
+            with closing(connect()) as conn:
+                conn.execute("CREATE TABLE IF NOT EXISTS media_upload_idempotency (idempotency_key TEXT PRIMARY KEY, attachment_id TEXT NOT NULL, filename TEXT NOT NULL, content_hash TEXT NOT NULL)")
+                conn.execute("BEGIN IMMEDIATE")
+                try:
+                    row = conn.execute("SELECT attachment_id,filename,content_hash FROM media_upload_idempotency WHERE idempotency_key=?", (idempotency_key,)).fetchone()
+                    if row:
+                        if row["filename"] != Path(filename).name or row["content_hash"] != content_hash:
+                            raise ApiError(409, "IDEMPOTENCY_CONFLICT", "同一上传标识不能用于不同附件。")
+                        existing = attachment_path(row["attachment_id"])
+                        if not existing.is_file() or hashlib.sha256(existing.read_bytes()).hexdigest() != content_hash:
+                            raise ApiError(409, "IDEMPOTENCY_EXPIRED", "该上传标识对应的附件已不存在，请开始一次新提交。")
+                        attachment_id = row["attachment_id"]
+                    else:
+                        if destination.exists() and hashlib.sha256(destination.read_bytes()).hexdigest() != content_hash:
+                            raise ApiError(409, "IDEMPOTENCY_CONFLICT", "同一上传标识不能用于不同附件。")
+                        if not destination.exists():
+                            temporary.replace(destination)
+                        conn.execute("INSERT INTO media_upload_idempotency VALUES (?,?,?,?)",
+                                     (idempotency_key, attachment_id, Path(filename).name, content_hash))
+                    conn.execute("COMMIT")
+                except BaseException:
+                    conn.execute("ROLLBACK")
+                    raise
+        elif destination.exists():
+            if hashlib.sha256(destination.read_bytes()).digest() != digest.digest():
+                raise ApiError(409, "IDEMPOTENCY_CONFLICT", "同一上传标识不能用于不同附件。")
+        else:
+            temporary.replace(destination)
     finally:
         temporary.unlink(missing_ok=True)
     return {"attachment_id": attachment_id, "filename": Path(filename).name, "size": size}