debut changement vers google drive

app/google_drive.py

@@ -0,0 +1,105 @@
+"""Google Drive storage for contract PDFs.
+
+The application uses an OAuth refresh token for the owner's personal Google
+account. Tokens and client secrets come only from environment variables; the
+database stores opaque file IDs, never a credential or a shareable Drive URL.
+"""
+
+import io
+import os
+
+GOOGLE_DRIVE_FOLDER_ID_ENV = 'GOOGLE_DRIVE_FOLDER_ID'
+GOOGLE_DRIVE_CLIENT_ID_ENV = 'GOOGLE_DRIVE_CLIENT_ID'
+GOOGLE_DRIVE_CLIENT_SECRET_ENV = 'GOOGLE_DRIVE_CLIENT_SECRET'
+GOOGLE_DRIVE_REFRESH_TOKEN_ENV = 'GOOGLE_DRIVE_REFRESH_TOKEN'
+GOOGLE_DRIVE_SCOPE = 'https://www.googleapis.com/auth/drive.file'
+
+
+class GoogleDriveStorageError(RuntimeError):
+    """A configuration or API failure while storing a contract in Drive."""
+
+
+def _setting(name):
+    value = os.getenv(name)
+    if not value:
+        raise GoogleDriveStorageError(f'{name} must be configured for Google Drive document storage.')
+    return value
+
+
+def _drive_service():
+    """Build an authorized Drive client from the owner's refresh token."""
+    try:
+        from google.oauth2.credentials import Credentials
+        from googleapiclient.discovery import build
+    except ImportError as exc:
+        raise GoogleDriveStorageError(
+            'Google Drive dependencies are not installed. Install requirements.txt again.'
+        ) from exc
+
+    credentials = Credentials(
+        token=None,
+        refresh_token=_setting(GOOGLE_DRIVE_REFRESH_TOKEN_ENV),
+        token_uri='https://oauth2.googleapis.com/token',
+        client_id=_setting(GOOGLE_DRIVE_CLIENT_ID_ENV),
+        client_secret=_setting(GOOGLE_DRIVE_CLIENT_SECRET_ENV),
+        scopes=[GOOGLE_DRIVE_SCOPE],
+    )
+    return build('drive', 'v3', credentials=credentials, cache_discovery=False)
+
+
+def upload_file(*, stream, filename, mimetype):
+    """Upload a PDF to the configured owner folder and return its Drive ID."""
+    try:
+        from googleapiclient.http import MediaIoBaseUpload
+
+        stream.seek(0)
+        media = MediaIoBaseUpload(stream, mimetype=mimetype, resumable=True)
+        response = (
+            _drive_service()
+            .files()
+            .create(
+                body={'name': filename, 'parents': [_setting(GOOGLE_DRIVE_FOLDER_ID_ENV)]},
+                media_body=media,
+                fields='id',
+            )
+            .execute()
+        )
+    except GoogleDriveStorageError:
+        raise
+    except Exception as exc:  # Google client exceptions share no stable base class.
+        raise GoogleDriveStorageError('Google Drive rejected the contract upload.') from exc
+
+    file_id = response.get('id')
+    if not file_id:
+        raise GoogleDriveStorageError('Google Drive did not return an uploaded file identifier.')
+    return file_id
+
+
+def download_file(file_id):
+    """Download a Drive file into memory for Flask's authenticated response."""
+    try:
+        from googleapiclient.http import MediaIoBaseDownload
+
+        destination = io.BytesIO()
+        downloader = MediaIoBaseDownload(
+            destination,
+            _drive_service().files().get_media(fileId=file_id),
+        )
+        complete = False
+        while not complete:
+            _status, complete = downloader.next_chunk()
+        return destination.getvalue()
+    except GoogleDriveStorageError:
+        raise
+    except Exception as exc:  # Google client exceptions share no stable base class.
+        raise GoogleDriveStorageError('Google Drive could not download this contract.') from exc
+
+
+def delete_file(file_id):
+    """Permanently delete a Drive document when its contract record is deleted."""
+    try:
+        _drive_service().files().delete(fileId=file_id).execute()
+    except GoogleDriveStorageError:
+        raise
+    except Exception as exc:  # Google client exceptions share no stable base class.
+        raise GoogleDriveStorageError('Google Drive could not delete this contract.') from exc