CODEWITHSUNDEEP
google-app-enginedartgoogle-cloud-storage
Martin Flucka
Martin Flucka

Reputation: 3285

Serving large file from Google Cloud Storage in Google App Engine

Running a dart server in App Engine Flexible Environment, there seems to be a limitation of serving files larger than 32MB.

There are a few requirements to files I want to serve:

At the moment I try to read the file from the bucket using the gcloud library and then pipe into the request.response. This fails because of the limitation e.g.: HTTP response was too large: 33554744. The limit is: 33554432.

Is there a way to serve larger files from storage? The documentation on this topic is quite confusing (I don't think there is dart specific documentation at all). I keep reading something about the Blobstore but I am not sure if this solution is applicable for dart.

Upvotes: 1

Views: 1037

Answers (1)

Torstein I. Bø
Torstein I. Bø

Reputation: 1379

As @filiph suggest you can use signed urls from Google Cloud Storage.

Server side I have this code in python:

import time
import base64

from oauth2client.service_account import ServiceAccountCredentials


def create_signed_url(file_location):
    # Get credentials
    creds = ServiceAccountCredentials.from_json_keyfile_name('filename_of_private_key.json')
    client_id = creds.service_account_email

    # Set time limit to two hours from now
    timestamp = time.time() + 2 * 3600

    # Generate signature string
    signature_string = "GET\n\n\n%d\n%s" % (timestamp, file_location)
    signature = creds.sign_blob(signature_string)[1]
    encoded_signature = base64.b64encode(signature)
    encoded_signature = encoded_signature.replace("+", "%2B").replace("/", "%2F")

    # Generate url
    return "https://storage.googleapis.com%s?GoogleAccessId=%s&Expires=%d&&Signature=%s" % (
    file_location, client_id, timestamp, encoded_signature)

Upvotes: 2

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