Writing to the blostore using the Files API is deprecated. But we can upload a blob to update the blob
This way we do not need GCS (Google Cloud Storage) To use GCS you have to pay for the application
From the docs: An application can use the default GCS bucket, which provides an already configured bucket with free quota. https://developers.google.com/appengine/docs/python/googlecloudstorageclient/
| #!/usr/bin/python | |
| # -*- coding: utf-8 -*- | |
| from __future__ import unicode_literals, with_statement | |
| import webapp2 | |
| import mimetypes | |
| from google.appengine.ext.ndb import blobstore | |
| from google.appengine.ext.webapp import blobstore_handlers | |
| from google.appengine.api import urlfetch | |
| from google.appengine.runtime import DeadlineExceededError | |
| import logging | |
| CRLF = b'\r\n' | |
| BOUNDERY = b'--Th15-Is-ThE-BoUnDeRy--' | |
| max_buffer_size = 1048576 | |
| def create_upload_url(for_url): | |
| return blobstore.create_upload_url(for_url, max_bytes_per_blob=max_buffer_size) | |
| def _fetch_blob_update(payload): | |
| upload_url = create_upload_url(webapp2.uri_for('blob_update', _full=True)) | |
| try: | |
| response = urlfetch.fetch( | |
| url=upload_url, | |
| payload=payload, | |
| method=urlfetch.POST, | |
| deadline=40, | |
| follow_redirects=False, | |
| headers={b'Content-Type': str('multipart/form-data; boundary=%s' % BOUNDERY)} | |
| ) | |
| if response.status_code != 200: | |
| logging.error('URL : %s fetch ERROR : %d' % (upload_url, response.status_code)) | |
| return None | |
| else: | |
| return response.content | |
| except (urlfetch.DownloadError, DeadlineExceededError), e: | |
| logging.error('fetch %s download or deadline error, exception : %s' | |
| % (upload_url, str(e))) | |
| return None | |
| def _encode_multipart(_fields=None, _files=None): | |
| """ Generator inserts fields and files to create a multipart payload """ | |
| for (field_name, field_value) in _fields or []: | |
| yield b'--' + BOUNDERY + CRLF | |
| yield b'Content-Disposition: form-data; name="%s"' % str(field_name) + CRLF | |
| yield CRLF | |
| yield str(field_value) + CRLF | |
| for (file_name, file_data) in _files or []: | |
| yield b'--' + BOUNDERY + CRLF | |
| yield b'Content-Disposition: form-data; name="file"; filename="%s"' \ | |
| % str(file_name) + CRLF | |
| yield b'Content-Type: %s' % mimetypes.guess_type(file_name)[0] + CRLF | |
| yield CRLF | |
| yield file_data + CRLF | |
| yield b'--%s--' % BOUNDERY + CRLF | |
| def blob_update_by_upload(ndb_key, blob): | |
| """ update blob using blobstore upload """ | |
| result = _fetch_blob_update(b''.join(_encode_multipart(_files=[(ndb_key.id(), blob)]))) | |
| return blobstore.BlobKey(result) | |
| class BlobUpdate(blobstore_handlers.BlobstoreUploadHandler): | |
| """ has named route : blob_update : | |
| webapp2.Route(r'/blob_update', handler='....BlobUpdate', name='blob_update') """ | |
| def post(self): | |
| """ blob upload handler returns the new blobkey""" | |
| blob_info = self.get_uploads('file')[0] | |
| logging.info('BlobUpdate : ' + blob_info.filename) | |
| self.response.headers[b'Content-Type'] = b'text/plain' | |
| self.response.write(str(blob_info.key())) |