Serving Google Cloud Storage files from App Engine without having to read them

views.py

import mimetypes

from django.http import HttpResponse
from google.appengine.api import app_identity
from google.appengine.ext import blobstore


def serve_cloud_storage_file(request, object_name):
    """Serve a file from cloud storage by setting a header on the response.
    The blobstore will serve it for you.
    """
    # The default bucket, or use a custom bucket.
    bucket = app_identity.get_default_gcs_bucket_name()
    # object_name is a path like '/foo/bar/myfile.json' inside the bucket. Must
    # start with a slash.
    key = '/{bucket}{object_name}'.format(bucket=bucket, object_name=object_name)
    blob_key = blobstore.create_gs_key('/gs' + key)
    
    content_type, encoding = mimetypes.guess_type(object_name)
    if not content_type:
        content_type='application/octet-stream'

    # Setting the special header on the response means App Engine will return
    # the data from cloud storage for you, without your app having to read it
    # directly.
    response = HttpResponse(content_type=content_type)
    response[blobstore.BLOB_KEY_HEADER] = str(blob_key)

    return response