google-api-ruby-client/README.md

# Google API Client

<dl>
  <dt>Homepage</dt><dd><a href="http://code.google.com/p/google-api-ruby-client">http://code.google.com/p/google-api-ruby-client</a></dd>
  <dt>Author</dt><dd><a href="mailto:bobaman@google.com">Bob Aman</a></dd>
  <dt>Copyright</dt><dd>Copyright © 2011 Google, Inc.</dd>
  <dt>License</dt><dd>Apache 2.0</dd>
</dl>

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## Description

The Google API Ruby Client makes it trivial to discover and access supported
APIs.

## Install

Be sure `http://rubygems.org/` is in your gem sources.

For normal client usage, this is sufficient:

    $ sudo gem install google-api-client

The command line interface, the example applications, and the test suite
require additional dependencies. These may be obtained with:

    $ sudo gem install google-api-client --development --force --no-rdoc --no-ri

## Example Usage

    # Initialize the client & Google+ API
    require 'google/api_client'
    client = Google::APIClient.new
    plus = client.discovered_api('plus')

    # Initialize OAuth 2.0 client    
    client.authorization.client_id = '<CLIENT_ID_FROM_API_CONSOLE>'
    client.authorization.client_secret = '<CLIENT_SECRET>'
    client.authorization.redirect_uri = '<YOUR_REDIRECT_URI>'
    
    client.authorization.scope = 'https://www.googleapis.com/auth/plus.me'

    # Request authorization
    redirect_uri = client.authorization.authorization_uri

    # Wait for authorization code then exchange for token
    client.authorization.code = '....'
    client.authorization.fetch_access_token!

    # Make an API call
    result = client.execute(
      :api_method => plus.activities.list,
      :parameters => {'collection' => 'public', 'userId' => 'me'}
    )

    puts result.data

## API Features

### API Discovery

To take full advantage of the client, load API definitions prior to use. To load an API:

    urlshortener = client.discovered_api('urlshortener')

Specific versions of the API can be loaded as well:

    drive = client.discovered_api('drive', 'v2')

Locally cached discovery documents may be used as well. To load an API from a local file:

    doc = File.read('my-api.json')
    my_api = client.register_discovery_document('myapi', 'v1', doc)

### Authorization

Most interactions with Google APIs require users to authorize applications via OAuth 2.0. The client library uses [Signet](https://github.com/google/signet) to handle most aspects of authorization. For additional details about Google's OAuth support, see [Google Developers](https://developers.google.com/accounts/docs/OAuth2). 

Credentials can be managed at the connection level, as shown, or supplied on a per-request basis when calling `execute`.
    
For server-to-server interactions, like those between a web application and Google Cloud Storage, Prediction, or BigQuery APIs, use service accounts. Assertions for service accounts are made with `Google::APIClient::JWTAsserter`.

    client = Google::APIClient.new
    key = Google::APIClient::PKCS12.load_key('client.p12', 'notasecret')
    service_account = Google::APIClient::JWTAsserter(
        '123456-abcdef@developer.gserviceaccount.com',
        'https://www.googleapis.com/auth/prediction',
        key)
    client.authorization = service_account.authorize

### Batching Requests

Some Google APIs support batching requests into a single HTTP request. Use `Google::APIClient::BatchRequest`
to bundle multiple requests together.

Example:

    client = Google::APIClient.new
    urlshortener = client.discovered_api('urlshortner')
    
    batch = Google::APIClient::BatchRequest.new do |result|
        puts result.data
    end
    
    batch.add(:api_method=>urlshortener.url.insert, 
              :body_object => { 'longUrl' => 'http://example.com/foo' })
    batch.add(:api_method=>urlshortener.url.insert, 
              :body_object => { 'longUrl' => 'http://example.com/bar' })
    client.execute(batch)
    
Blocks for handling responses can be specified either at the batch level or when adding an individual API call. For example:

    batch.add(:api_method=>urlshortener.url.insert, :body_object => { 'longUrl' => 'http://example.com/bar' }) do |result|
       puts result.data
    end

### Media Upload

For APIs that support file uploads, use `Google::APIClient::UploadIO` to load the stream. Both multipart and resumable
uploads can be used. For example, to upload a file to Google Drive using multipart

    drive = client.discovered_api('drive', 'v2')
   
    media = Google::APIClient::UploadIO.new('mymovie.m4v', 'video/mp4')
    metadata = {
        'title' => 'My movie',
        'description' => 'The best home movie ever made'
    }
    client.execute(:api_method => drive.files.insert,
                   :parameters => { 'uploadType' => 'multipart' },
                   :body_object => metadata,
                   :media => media )
   
To use resumable uploads, change the `uploadType` parameter to `resumable`. To check the status of the upload
and continue if necessary, check `result.resumable_upload`.

    client.execute(:api_method => drive.files.insert,
               :parameters => { 'uploadType' => 'resumable' },
               :body_object => metadata,
               :media => media )
    upload = result.resumable_upload

    # Resume if needed
    if upload.resumable?
        client.execute(upload)
    end