WebStack

Annotated docs/methods.html

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2005-11-15 paulb file changeset files shortlog [project @ 2005-11-15 15:46:01 by paulb] Added has_key method.
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml"><head>
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  <title>Request Methods</title><meta name="generator" content="amaya 8.1a, see http://www.w3.org/Amaya/" />
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  <link href="styles.css" rel="stylesheet" type="text/css" /></head>
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<body>
 
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<h1>Request Methods</h1>
 
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<p>In order for an application to behave in the right way when someone sends
 
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a request into it, the application must take into consideration the type of
 
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request being sent. The type of request is typically referred to as the
 
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"request method" and indicates the kind of operation the user is attempting
 
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to perform.</p>
 
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<h2>Common Request Methods</h2>
 
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<p>The following table summarises the most common methods defined for Web
 
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applications in the <a href="http://www.w3.org/Protocols/rfc2616/rfc2616.html">HTTP</a> and <a href="http://www.faqs.org/rfcs/rfc2518.html">WebDAV</a> specifications:</p>
 
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<table border="1" cellpadding="5" cellspacing="0">
 
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  <tbody>
 
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    <tr>
 
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      <th>Method</th>
 
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      <th>Type of Operation</th>
 
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    </tr>
 
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    <tr>
 
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      <td>GET</td>
 
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      <td>Retrieve a Web page or resource</td>
 
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    </tr>
 
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    <tr>
 
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      <td>POST</td>
 
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      <td>Present information to an application - for example, submission of
 
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        fields in a form</td>
 
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    </tr>
 
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    <tr>
 
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      <td>PUT</td>
 
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      <td>Upload a new Web page or resource</td>
 
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    </tr>
 
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    <tr>
 
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      <td>DELETE</td>
 
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      <td>Delete a Web page or resource</td>
 
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    </tr>
 
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    <tr>
 
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      <td>PROPFIND</td>
 
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      <td>List resources on a server or in an application</td>
 
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    </tr>
 
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  </tbody>
 
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</table>
 
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<p>Most applications will at least need to support the GET request method in
 
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order to support some kind of user experience, and those which employ forms
 
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in Web pages will most probably want to support the POST request method,
 
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too.</p>
 
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<div class="WebStack">
 
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<h3>WebStack API - Discovering the Request Method</h3>
 
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<p>Transaction objects provide the following method for discovering the
 
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request method:</p>
 
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<dl>
 
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  <dt><code>get_request_method</code></dt>
 
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    <dd>This returns the request method being used in the request being
 
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      handled.</dd>
 
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</dl>
 
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</div>
 
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<h2>Rejecting Certain Request Methods</h2>
 
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<p>Not all request methods are appropriate to every application. Should a
 
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request be received which uses a method not supported by an application, the
 
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most appropriate way of responding is to signal this condition to the sender
 
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of the request. HTTP provides a response code to communicate just this kind
 
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of condition - "405 Method Not Allowed".</p>
 
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<div class="WebStack">
 
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<h3>WebStack API - Signalling Unsupported Methods</h3>
 
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<p>Transaction objects provide the <code>set_response_code</code> method (as
 
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described in <a href="responses.html">"Responses and Presentation"</a>) to
 
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communicate critical information on the success or failure of a request. In
 
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this case, we would use this method on a transaction object
 
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<code>trans</code> as follows:</p>
 
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<pre>trans.set_response_code(405)</pre>
 
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</div>
 
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</body></html>