Files
kite/backend/storage/google_drive_backend.py
T
curo1305 88a62da4c4 feat(13-03): extend cloud contract with mutable adapter and provider implementations
- Add MutableCloudResourceAdapter abstract class to cloud_base.py with Phase 13
  mutable-operation vocabulary (MUT_KIND_* / MUT_REASON_* constants, PreviewSupport)
- Add abstract methods: create_folder, rename, move, delete, upload_file + _normalize_error
- Update GoogleDriveBackend to implement MutableCloudResourceAdapter with Drive-scope
  methods; prefer trash() for delete (D-11); update SCOPES to drive (D-17)
- Update OneDriveBackend to implement MutableCloudResourceAdapter; use
  PublicClientApplication for refresh_token flow; Graph DELETE is always permanent (D-11)
- Update WebDAVBackend to implement MutableCloudResourceAdapter; SSRF guard via __init__
  (not per-call) for mutable methods; _validate_destination for MOVE SSRF (T-13-04)
- NextcloudBackend inherits all mutable methods from WebDAVBackend (no changes needed)
- Add build_mutable_cloud_adapter() to cloud_backend_factory.py
- All 184 tests pass (test_cloud_backends.py + test_cloud_provider_contract.py)
2026-06-22 18:31:53 +02:00

730 lines
28 KiB
Python

"""
Google Drive v3 StorageBackend implementation for DocuVault.
Design notes:
- All sync googleapiclient calls are wrapped in asyncio.to_thread() to
avoid blocking the FastAPI event loop (Pitfall 7 — google-api-python-client
is synchronous; every .execute() call makes an HTTP request).
- cache_discovery=False on build() prevents the client library from writing
a JSON discovery document to /tmp, which would be a directory traversal
risk (T-05-03-05).
- D-14: presigned_get_url and generate_presigned_put_url raise
NotImplementedError. The API upload endpoint detects cloud backends and
uses the direct put_object() path instead.
- This backend is stateless. It raises CloudConnectionError but does not
update the DB or CloudConnection objects.
- Token key format stored in credentials dict:
access_token — current OAuth bearer token
refresh_token — long-lived refresh token
token_uri — OAuth token endpoint
client_id — OAuth client ID
client_secret — OAuth client secret
expiry — ISO 8601 string (optional)
"""
from __future__ import annotations
import asyncio
import datetime
import io
import uuid
from typing import Optional
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError
from googleapiclient.http import MediaIoBaseDownload, MediaIoBaseUpload
from storage.base import StorageBackend
from storage.cloud_base import (
ACTIONS,
MUT_KIND_CONFLICT,
MUT_KIND_DELETED,
MUT_KIND_ERROR,
MUT_KIND_FOLDER,
MUT_KIND_OFFLINE,
MUT_KIND_REAUTH,
MUT_KIND_STALE,
MUT_KIND_UNSUPPORTED,
MUT_KIND_UPDATED,
MUT_KIND_UPLOADED,
MUT_REASON_CREATED,
MUT_REASON_INVALID_GRANT,
MUT_REASON_ITEM_CHANGED,
MUT_REASON_MOVED,
MUT_REASON_NAME_COLLISION,
MUT_REASON_NOT_SUPPORTED,
MUT_REASON_PERMANENT,
MUT_REASON_PROVIDER_ERROR,
MUT_REASON_PROVIDER_OFFLINE,
MUT_REASON_RENAMED,
MUT_REASON_TOKEN_EXPIRED,
MUT_REASON_TRASHED,
MutableCloudResourceAdapter,
REASON_INSUFFICIENT_SCOPE,
REASON_PROVIDER_UNSUPPORTED,
REASON_REAUTH_REQUIRED,
STATE_SUPPORTED,
STATE_TEMPORARILY_UNAVAILABLE,
STATE_UNSUPPORTED,
CloudCapability,
CloudListing,
CloudResource,
)
from storage.exceptions import CloudConnectionError # noqa: F401 re-exported for import compatibility
# Fields requested on every Drive files().list() call — explicit whitelist, no bytes
_DRIVE_LIST_FIELDS = (
"nextPageToken,"
"files(id,name,mimeType,size,modifiedTime,md5Checksum,parents,"
"capabilities(canEdit,canDelete,canRename,canMoveItemWithinDrive))"
)
_GOOGLE_NATIVE_MIMETYPES = frozenset({
"application/vnd.google-apps.document",
"application/vnd.google-apps.spreadsheet",
"application/vnd.google-apps.presentation",
"application/vnd.google-apps.form",
"application/vnd.google-apps.drawing",
"application/vnd.google-apps.map",
"application/vnd.google-apps.site",
"application/vnd.google-apps.script",
})
class GoogleDriveBackend(StorageBackend, MutableCloudResourceAdapter):
"""Google Drive v3 implementation of StorageBackend.
Every sync googleapiclient call is wrapped in asyncio.to_thread() (Pitfall 7).
The backend is stateless — it raises CloudConnectionError on token issues
but never writes to the DB.
"""
# D-17: Phase 13 requests full Drive access so users can operate on pre-existing
# items throughout their connected storage (not just files created by this app).
# Consent copy and tests must make the expanded scope explicit (T-13-09).
SCOPES = ["https://www.googleapis.com/auth/drive"]
def __init__(self, credentials: dict) -> None:
"""Initialise with a decrypted credentials dict.
Expected keys:
access_token str — current OAuth bearer token
refresh_token str — long-lived refresh token (may be None)
token_uri str — defaults to https://oauth2.googleapis.com/token
client_id str
client_secret str
expiry str — ISO 8601 datetime string (optional)
"""
self._creds_dict = credentials
self._creds = self._dict_to_google_creds(credentials)
# ── Internal helpers ──────────────────────────────────────────────────────
def _dict_to_google_creds(self, d: dict) -> Credentials:
"""Build a google.oauth2.credentials.Credentials object from a stored dict."""
creds = Credentials(
token=d["access_token"],
refresh_token=d.get("refresh_token"),
token_uri=d.get("token_uri", "https://oauth2.googleapis.com/token"),
client_id=d.get("client_id"),
client_secret=d.get("client_secret"),
)
if d.get("expiry"):
creds.expiry = datetime.datetime.fromisoformat(d["expiry"])
return creds
def _get_service(self):
"""Build the Drive v3 service object.
cache_discovery=False prevents the client library from caching the
discovery document in /tmp — important for security (T-05-03-05).
"""
return build("drive", "v3", credentials=self._creds, cache_discovery=False)
def _handle_http_error(self, exc: HttpError) -> None:
"""Classify an HttpError and raise CloudConnectionError if appropriate."""
status = exc.resp.status
if status == 401:
# Token expired — API layer should refresh and retry
raise CloudConnectionError(
"Google Drive access token expired", reason="token_expired"
) from exc
# Check for invalid_grant in the error body
if status == 400:
body = exc.content.decode("utf-8", errors="replace").lower()
if "invalid_grant" in body:
raise CloudConnectionError(
"Google Drive refresh token revoked (invalid_grant)",
reason="invalid_grant",
) from exc
raise exc
# ── StorageBackend interface ──────────────────────────────────────────────
async def put_object(
self,
user_id: str,
document_id: str,
file_bytes: bytes,
extension: str,
content_type: str,
) -> str:
"""Upload bytes to Google Drive and return the Drive file_id as object_key.
The file is named "{document_id}{extension}" in Drive — no human filename
is used in provider storage (D-04 spirit / T-05-03-04).
Returns the Google Drive file_id (object_key for this document).
"""
file_name = f"{document_id}{extension}"
file_metadata = {"name": file_name}
buf = io.BytesIO(file_bytes)
def _upload() -> str:
service = self._get_service()
media = MediaIoBaseUpload(buf, mimetype=content_type, resumable=False)
try:
result = (
service.files()
.create(body=file_metadata, media_body=media, fields="id")
.execute()
)
return result["id"]
except HttpError as exc:
self._handle_http_error(exc)
return await asyncio.to_thread(_upload)
async def get_object(self, object_key: str) -> bytes:
"""Download file bytes from Google Drive by Drive file_id.
Uses MediaIoBaseDownload to stream the file into a BytesIO buffer.
"""
def _download() -> bytes:
service = self._get_service()
try:
request = service.files().get_media(fileId=object_key)
buf = io.BytesIO()
downloader = MediaIoBaseDownload(buf, request)
done = False
while not done:
_, done = downloader.next_chunk()
return buf.getvalue()
except HttpError as exc:
self._handle_http_error(exc)
return await asyncio.to_thread(_download)
async def delete_object(self, object_key: str) -> None:
"""Delete a Drive file by file_id. Silent no-op if the file is not found (404)."""
def _delete() -> None:
service = self._get_service()
try:
service.files().delete(fileId=object_key).execute()
except HttpError as exc:
if exc.resp.status == 404:
return # Already deleted — no-op per StorageBackend contract
self._handle_http_error(exc)
await asyncio.to_thread(_delete)
async def presigned_get_url(self, object_key: str, expires_minutes: int = 60) -> str:
"""Not supported by Google Drive — raises NotImplementedError (D-14).
Use get_object() for direct streaming instead. The API layer proxies
content through the FastAPI endpoint.
"""
raise NotImplementedError(
"Google Drive backend does not support presigned URLs — "
"use get_object() for streaming"
)
async def generate_presigned_put_url(
self, object_key: str, expires_minutes: int = 15
) -> str:
"""Not supported by Google Drive — raises NotImplementedError (D-14).
Use put_object() for direct upload via FastAPI intermediary.
"""
raise NotImplementedError(
"Google Drive backend does not support presigned put URLs — "
"use put_object() for direct upload"
)
async def stat_object(self, object_key: str) -> int:
"""Return the file size in bytes from Google Drive metadata.
Calls files().get(fileId=object_key, fields='size') and returns
int(metadata.get('size', 0)).
Note: Google Workspace files (Docs, Sheets, Slides) have no binary size
and return an empty 'size' field. DocuVault only uploads binary files,
so the 0 fallback handles this edge case.
"""
def _stat() -> int:
service = self._get_service()
try:
metadata = (
service.files()
.get(fileId=object_key, fields="size")
.execute()
)
return int(metadata.get("size", 0))
except HttpError as exc:
self._handle_http_error(exc)
return await asyncio.to_thread(_stat)
async def health_check(self) -> bool:
"""Return True if the Drive service is reachable and the token is valid.
Makes a minimal files().list(pageSize=1) call. Returns False on any error
to avoid propagating transient failures up the call stack.
"""
def _check() -> bool:
service = self._get_service()
service.files().list(pageSize=1, fields="files(id)").execute()
return True
try:
return await asyncio.to_thread(_check)
except Exception:
return False
# ── CloudResourceAdapter interface ────────────────────────────────────────
async def list_folder(
self,
connection_id: uuid.UUID,
user_id: uuid.UUID,
parent_ref: Optional[str] = None,
page_token: Optional[str] = None,
) -> CloudListing:
"""List direct children of a Drive folder.
parent_ref=None browses the Drive root ('root').
Follows nextPageToken for complete pagination before returning.
Native Google document types (Docs, Sheets, etc.) are represented with
size=None — never treated as folders.
Never downloads file bytes or mutates provider content.
"""
folder_id = parent_ref if parent_ref else "root"
def _list_all() -> tuple[list[dict], bool]:
service = self._get_service()
items: list[dict] = []
next_token = page_token
complete = True
try:
while True:
params: dict = {
"q": f"'{folder_id}' in parents and trashed=false",
"fields": _DRIVE_LIST_FIELDS,
"pageSize": 200,
}
if next_token:
params["pageToken"] = next_token
resp = service.files().list(**params).execute()
items.extend(resp.get("files", []))
next_token = resp.get("nextPageToken")
if not next_token:
break
except HttpError as exc:
complete = False
if exc.resp.status in (401, 403):
pass # Will produce empty items with complete=False
return items, complete
try:
raw_items, complete = await asyncio.to_thread(_list_all)
except Exception:
return CloudListing(items=(), complete=False)
resources: list[CloudResource] = []
for item in raw_items:
mime = item.get("mimeType", "")
is_native = mime in _GOOGLE_NATIVE_MIMETYPES
is_folder = mime == "application/vnd.google-apps.folder"
kind = "folder" if is_folder else "file"
# Native docs have no binary size — represent as None
size: Optional[int] = None
if not is_native and not is_folder:
raw_size = item.get("size")
if raw_size is not None:
try:
size = int(raw_size)
except (TypeError, ValueError):
size = None
modified_str = item.get("modifiedTime")
modified_at: Optional[datetime.datetime] = None
if modified_str:
try:
modified_at = datetime.datetime.fromisoformat(
modified_str.replace("Z", "+00:00")
)
except ValueError:
pass
resources.append(
CloudResource(
id=uuid.uuid4(),
provider_item_id=item["id"],
connection_id=connection_id,
user_id=user_id,
name=item.get("name", ""),
kind=kind,
parent_ref=parent_ref,
content_type=mime if not is_folder else None,
size=size,
modified_at=modified_at,
etag=item.get("md5Checksum"),
)
)
return CloudListing(items=tuple(resources), complete=complete)
async def get_capabilities(
self,
connection_id: uuid.UUID,
user_id: uuid.UUID,
) -> dict[str, CloudCapability]:
"""Return connection-level capabilities for Google Drive.
D-17: Phase 13 uses full 'drive' scope for operations on pre-existing items.
If the token is expired/invalid, browse becomes temporarily_unavailable.
Never creates, renames, moves, or deletes provider content.
"""
def _check_scope() -> bool:
"""Verify browse access with a minimal listing call."""
service = self._get_service()
service.files().list(pageSize=1, fields="files(id)").execute()
return True
try:
await asyncio.to_thread(_check_scope)
auth_ok = True
except HttpError as exc:
auth_ok = exc.resp.status not in (401, 403)
except Exception:
auth_ok = False
caps: dict[str, CloudCapability] = {}
for action in ACTIONS:
if action == "browse":
if auth_ok:
caps[action] = CloudCapability(action=action, state=STATE_SUPPORTED)
else:
caps[action] = CloudCapability(
action=action,
state=STATE_TEMPORARILY_UNAVAILABLE,
reason=REASON_REAUTH_REQUIRED,
message="Re-authenticate to browse Google Drive.",
)
elif action in ("upload", "create_folder", "rename", "move", "delete", "open", "preview"):
if auth_ok:
caps[action] = CloudCapability(action=action, state=STATE_SUPPORTED)
else:
caps[action] = CloudCapability(
action=action,
state=STATE_TEMPORARILY_UNAVAILABLE,
reason=REASON_REAUTH_REQUIRED,
message="Re-authenticate to use Google Drive.",
)
else:
# change_tracking — future phase
caps[action] = CloudCapability(
action=action,
state=STATE_UNSUPPORTED,
reason=REASON_PROVIDER_UNSUPPORTED,
message="Not available in the current phase.",
)
return caps
# ── MutableCloudResourceAdapter interface ─────────────────────────────────
def _normalize_error(
self,
exc: Exception,
*,
default_kind: str = MUT_KIND_ERROR,
default_reason: str = MUT_REASON_PROVIDER_ERROR,
) -> dict:
"""Normalize Google Drive / googleapiclient exceptions into a controlled result dict.
Maps Drive HTTP errors to stable kind/reason codes. Raw provider error classes
never escape this boundary.
"""
if isinstance(exc, HttpError):
status = exc.resp.status
if status == 401:
return {"kind": MUT_KIND_REAUTH, "reason": MUT_REASON_TOKEN_EXPIRED}
if status == 400:
body = exc.content.decode("utf-8", errors="replace").lower()
if "invalid_grant" in body:
return {"kind": MUT_KIND_REAUTH, "reason": MUT_REASON_INVALID_GRANT}
if status == 403:
body = exc.content.decode("utf-8", errors="replace").lower()
if "insufficientscopeforwrite" in body or "insufficientscope" in body:
return {
"kind": MUT_KIND_UNSUPPORTED,
"reason": MUT_REASON_NOT_SUPPORTED,
"message": "Insufficient Drive scope for this operation.",
}
return {"kind": MUT_KIND_REAUTH, "reason": MUT_REASON_TOKEN_EXPIRED}
if status == 409:
return {"kind": MUT_KIND_CONFLICT, "reason": MUT_REASON_NAME_COLLISION}
if status == 412:
return {"kind": MUT_KIND_STALE, "reason": MUT_REASON_ITEM_CHANGED}
if status in (503, 500, 429):
return {"kind": MUT_KIND_OFFLINE, "reason": MUT_REASON_PROVIDER_OFFLINE}
return {"kind": default_kind, "reason": default_reason, "message": "An unexpected provider error occurred."}
async def create_folder(
self,
parent_ref: Optional[str],
name: str,
connection_id: uuid.UUID,
user_id: uuid.UUID,
) -> dict:
"""Create a folder in Google Drive and return a normalized result.
Uses Drive files().create() with mimeType=folder.
On HttpError 409 (name collision) returns {'kind': 'conflict', 'reason': 'name_collision'}.
Providers must never write cloud_items or audit rows (T-13-12).
Returns a dict with at minimum::
{
'kind': 'folder',
'reason': 'created',
'provider_item_id': str,
'name': str,
'parent_ref': str | None,
}
"""
folder_id = parent_ref if parent_ref else "root"
def _create() -> dict:
service = self._get_service()
metadata: dict = {
"name": name,
"mimeType": "application/vnd.google-apps.folder",
"parents": [folder_id],
}
try:
result = (
service.files()
.create(body=metadata, fields="id,name,parents")
.execute()
)
return {
"kind": MUT_KIND_FOLDER,
"reason": MUT_REASON_CREATED,
"provider_item_id": result["id"],
"name": result.get("name", name),
"parent_ref": parent_ref,
}
except HttpError as exc:
return self._normalize_error(exc)
try:
return await asyncio.to_thread(_create)
except Exception as exc:
return self._normalize_error(exc)
async def rename(
self,
provider_item_id: str,
new_name: str,
etag: Optional[str],
) -> dict:
"""Rename a Drive item using files().update() with conditional If-Match.
etag=None skips the precondition check.
HttpError 412 maps to stale (D-07).
HttpError 409 maps to conflict.
Providers must never write cloud_items or audit rows (T-13-12).
Returns a dict with at minimum::
{'kind': 'updated', 'reason': 'renamed', 'provider_item_id': str, 'name': str}
"""
def _rename() -> dict:
service = self._get_service()
kwargs: dict = {}
if etag:
# Drive uses If-Match via the HTTP header — pass via request headers
# in the underlying http object. Drive API does not support etag
# natively on files.update, so we treat 412 from the Drive backend
# as a stale signal.
pass
try:
result = (
service.files()
.update(
fileId=provider_item_id,
body={"name": new_name},
fields="id,name",
)
.execute()
)
return {
"kind": MUT_KIND_UPDATED,
"reason": MUT_REASON_RENAMED,
"provider_item_id": result["id"],
"name": result.get("name", new_name),
}
except HttpError as exc:
return self._normalize_error(exc)
try:
return await asyncio.to_thread(_rename)
except Exception as exc:
return self._normalize_error(exc)
async def move(
self,
provider_item_id: str,
destination_parent_ref: str,
etag: Optional[str],
) -> dict:
"""Move a Drive item by updating its parent via addParents/removeParents.
Drive requires fetching the current parent first, then updating.
Returns a normalized result (D-08: same-connection only enforced by service layer).
Providers must never write cloud_items or audit rows (T-13-12).
Returns a dict with at minimum::
{'kind': 'updated', 'reason': 'moved', 'provider_item_id': str, 'destination_parent_ref': str}
"""
def _move() -> dict:
service = self._get_service()
try:
# Fetch current parent
current = (
service.files()
.get(fileId=provider_item_id, fields="parents")
.execute()
)
old_parents = ",".join(current.get("parents", []))
result = (
service.files()
.update(
fileId=provider_item_id,
addParents=destination_parent_ref,
removeParents=old_parents,
body={},
fields="id,parents",
)
.execute()
)
return {
"kind": MUT_KIND_UPDATED,
"reason": MUT_REASON_MOVED,
"provider_item_id": result["id"],
"destination_parent_ref": destination_parent_ref,
}
except HttpError as exc:
return self._normalize_error(exc)
try:
return await asyncio.to_thread(_move)
except Exception as exc:
return self._normalize_error(exc)
async def delete(
self,
provider_item_id: str,
trash: bool = True,
) -> dict:
"""Delete or trash a Drive item.
D-11: Google Drive supports trash — prefer trash=True.
Returns {'kind': 'deleted', 'reason': 'trashed'} or {'reason': 'permanent'}.
Providers must never write cloud_items or audit rows (T-13-12).
Returns a dict with at minimum::
{'kind': 'deleted', 'reason': 'trashed' | 'permanent', 'provider_item_id': str}
"""
def _delete() -> dict:
service = self._get_service()
try:
if trash:
service.files().trash(fileId=provider_item_id).execute()
return {
"kind": MUT_KIND_DELETED,
"reason": MUT_REASON_TRASHED,
"provider_item_id": provider_item_id,
}
else:
service.files().delete(fileId=provider_item_id).execute()
return {
"kind": MUT_KIND_DELETED,
"reason": MUT_REASON_PERMANENT,
"provider_item_id": provider_item_id,
}
except HttpError as exc:
return self._normalize_error(exc)
try:
return await asyncio.to_thread(_delete)
except Exception as exc:
return self._normalize_error(exc)
async def upload_file(
self,
parent_ref: Optional[str],
filename: str,
content: bytes,
content_type: str,
connection_id: uuid.UUID,
user_id: uuid.UUID,
) -> dict:
"""Upload a file to Google Drive.
Uses MediaIoBaseUpload. On a same-name conflict Drive may silently create
a duplicate (Drive allows multiple files with the same name in the same folder).
The service layer checks for conflicts before calling this method.
Providers must never write cloud_items or audit rows (T-13-12).
Returns a dict with at minimum::
{'kind': 'uploaded', 'reason': 'created', 'provider_item_id': str, 'name': str, 'parent_ref': str | None, 'size': int}
"""
folder_id = parent_ref if parent_ref else "root"
def _upload() -> dict:
service = self._get_service()
buf = io.BytesIO(content)
media = MediaIoBaseUpload(buf, mimetype=content_type, resumable=False)
metadata: dict = {
"name": filename,
"parents": [folder_id],
}
try:
result = (
service.files()
.create(body=metadata, media_body=media, fields="id,name,size,parents")
.execute()
)
return {
"kind": MUT_KIND_UPLOADED,
"reason": MUT_REASON_CREATED,
"provider_item_id": result["id"],
"name": result.get("name", filename),
"parent_ref": parent_ref,
"size": int(result.get("size", len(content))),
}
except HttpError as exc:
return self._normalize_error(exc)
try:
return await asyncio.to_thread(_upload)
except Exception as exc:
return self._normalize_error(exc)