Using Cloud Storage

You can use Cloud Storage to store and serve files, such as movies or images or other static content.

This document describes how to use the Google Cloud Client Library to store and retrieve data using Cloud Storage in an App Engine app.


Prerequisites and setup

Follow the instructions in "Hello, World!" for Ruby on App Engine to set up your environment and project, and to understand how Ruby apps are structured in App Engine. Write down and save your project ID, because you will need it to run the sample application described in this document.

Make sure you create a Cloud Storage bucket for your application by invoking the following command:

gsutil mb gs://[your-bucket-name]

And make it publically readable so it can serve files:

gsutil defacl set public-read gs://[your-bucket-name]

Clone the repository

Download the sample:

git clone
cd ruby-docs-samples/appengine/storage

Edit project configuration and install dependencies

In app.yaml, set the GCLOUD_STORAGE_BUCKET to the Cloud Storage you previously created for your project.

runtime: ruby
vm: true
entrypoint: bundle exec ruby app.rb -p 8080

  GCLOUD_STORAGE_BUCKET: <your-bucket-name>

Note that you must include the gcloud library in Gemfile to use Cloud Storage functions.

source ""

gem "sinatra"
gem "google-cloud-storage"

Application code

The sample application presents a web page prompting the user to supply a file to be stored in Cloud Storage. When the user selects a file and clicks submit, the upload handler loads the file content into a blob and writes it to Cloud Storage.

Notice that after the file is uploaded to Cloud Storage, the public URL to this file is returned, which you can use to serve the file directly from Cloud Storage. You should store this value in your app for future use.

require "sinatra"
require "google/cloud"

gcloud  =
storage =
bucket  = storage.bucket ENV["GCLOUD_STORAGE_BUCKET"]

get "/" do
  # Present the user with an upload form
    <form method="POST" action="/upload" enctype="multipart/form-data">
      <input type="file" name="file">
      <input type="submit" value="Upload">

post "/upload" do
  file_path = params[:file][:tempfile].path
  file_name = params[:file][:filename]

  # Upload file to Google Cloud Storage bucket
  file = bucket.create_file file_path, file_name, acl: "public"

  # The public URL can be used to directly access the uploaded file via HTTP

For more information

For complete information on Cloud Storage, see the Cloud Storage documentation.

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