chrome/common/extensions/docs/templates/articles/gcm_server.html

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<h1>API Reference for GCM service</h1>

<p>
The <a href="cloudMessaging">Google Cloud Messaging for Chrome</a> service
sends messages to users of a Chrome App.
The service handles all aspects of queueing and delivering messages.
To use the service,
you must agree to the
<a href="gcm_tos">Google Cloud Messaging for Chrome API Terms of Service</a>.
</p>

<p>Messages must conform to these constraints:</p>

<ul>
	<li><strong>Maximum payload length:</strong> 256 bytes</li>
	<li><strong>Maximum subchannels:</strong> 4</li>
	<li><strong>Maximum API requests per day:</strong> 10,000</li>
</ul>

<h2 id="libraries">Google API client libraries</h2>

<p>
You may use the REST interface defined here
to access Google Cloud Messaging for Chrome from your application.
We also offer Google API client libraries for a number
of popular programming languages that can be used to access the API.
For more information, see
<a href="https://developers.google.com/api-client-library">Google APIs Client Libraries</a>.
</p>

<h2 id="insert">Insert method</h2>

<p>
The <code>gcm_for_chrome.messages.insert</code>
method sends a message to your app or extension user.
</p>

<h2 id="authorization">Authentication</h2>

<p>
Authentication is required to send messages to users.
<a href="https://developers.google.com/accounts/docs/OAuth2WebServer">Using OAuth 2.0 for Web Server Applications</a>
describes this in greater detail.
</p>

<h3 id="url">URL</h3>

<p>
The URL used to obtain access to the GCM for Chrome service:
<code>https://accounts.google.com/o/auth2/auth</code>.
</p>

<h3 id="parameters">Required parameters</h3>
<p>
The required set of query string parameters are:
</p>

<table>
  <tr>
    <th scope="col">Parameter</th>
    <th scope="col">Description</th>
  </tr>
  <tr>
    <td><code>client_id</code></td>
    <td>Indicates the app or extension client that is making the request.
    Obtained from the <a href="https://code.google.com/apis/console/">Google APIs Console</a>;
    the parameter value must exactly match the client ID shown
    in the console.
    </td>
  </tr>
  <tr>
    <td><code>client_secret</code></td>
    <td>The client secret obtained during registration in
    	<a href="https://code.google.com/apis/console/">Google APIs Console</a>.</td>
  </tr>
  <tr>
    <td><code>refresh_token</code></td>
    <td>Token associated with app or extension used to obtain new access token.</td>
  </tr>
  <tr>
    <td><code>grant_type</code></td>
    <td>The <code>authorization_code</code> value of <code>refresh_token</code>.</td>
  </tr>
</table>

<h3 id="response">Response</h3>

<p>
The authorization response includes:
</p>

<table>
  <tr>
    <th scope="col">Field</th>
    <th scope="col">Description</th>
  </tr>
  <tr>
    <td><code>access_token</code></td>
    <td>Valid token required to access the GCM for Chrome service.</td>
  </tr>
  <tr>
    <td><code>expires_in</code></td>
    <td>Time until access token expires in seconds.</td>
  </tr>
  <tr>
    <td><code>token_type</code></td>
    <td>The returned token type, <code>Bearer</code>.</td>
  </tr>
</table>

<h2 id="request">Message request</h2>

<h3 id="http">HTTP request</h3>

<p><code>POST https://www.googleapis.com/gcm_for_chrome/v1/messages</code></p>

<h3 id="body">Request body</h3>

<p>
In the request body, supply:
</p>

<table>
  <tr>
    <th scope="col">Parameter</th>
    <th scope="col">Description</th>
  </tr>
  <tr>
    <td><code>Content-Type</code></td>
    <td>The request body content type, <code>application/json</code>.</td>
  </tr>
  <tr>
    <td><code>Authorization</code></td>
    <td><code>Bearer</code> HTTP header including access token, for example,
    <code>Bearer 1/fFBGRNJru1FQd44AzqT3Zg</code>.</td>
  </tr>
  <tr>
    <td><code>channelId</code></td>
    <td>The app or extension channel ID required to push messages back to the app or extension.</td>
  </tr>
  <tr>
    <td><code>subchannelId</code></td>
    <td>The subchannel to send the message on; only values 0-3 are valid.</td>
  </tr>
  <tr>
    <td><code>payload</code></td>
    <td>The message body (up to 256 bytes). This should not include any
      personally identifiable information.</td>
  </tr>
</table>

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