HTTP Client Module

From BaseX Documentation
Revision as of 00:39, 26 February 2012 by CG (talk | contribs)
Jump to navigation Jump to search

This module contains an XQuery function to send HTTP requests and handle HTTP responses. The function send-request, which is introduced with the http: prefix, is linked to the statically declared http://expath.org/ns/http-client namespace and based on the EXPath HTTP Client Module:

http:send-request

Signatures http:send-request($request as element(http:request)?, $href as xs:string?, $bodies as item()*) as item()+
http:send-request($request as element(http:request)) as item()+
http:send-request($request as element(http:request)?, $href as xs:string?) as item()+
Summary Sends an HTTP request and interprets the corresponding response. $request contains the parameters of the HTTP request such as HTTP method and headers. In addition to this it can also contain the URI to which the request will be sent and the body of the HTTP method. If the URI is not given with the parameter $href, its value in $request is used instead. The structure of http:request element follows the EXPath specification.
Notes The attribute auth-method of $request is not considered in our implementation because we are handling only basic authentication.

Examples

Example 1: Simple GET request. As the attribute status-only is set to true, only the response element is returned.

Query: 

http:send-request(<http:request method='get' status-only='true'/>, 'http://basex.org')

Result: 

<http:response status="200" message="OK">
  <http:header name="Date" value="Mon, 14 Mar 2011 20:55:53 GMT"/>
  <http:header name="Content-Length" value="12671"/>
  <http:header name="Expires" value="Mon, 14 Mar 2011 20:57:23 GMT"/>
  <http:header name="Set-Cookie" value="fe_typo_user=d10c9552f9a784d1a73f8b6ebdf5ce63; path=/"/>
  <http:header name="Connection" value="close"/>
  <http:header name="Content-Type" value="text/html; charset=utf-8"/>
  <http:header name="Server" value="Apache/2.2.16"/>
  <http:header name="X-Powered-By" value="PHP/5.3.5"/>
  <http:header name="Cache-Control" value="max-age=90"/>
  <http:body media-type="text/html; charset=utf-8"/>
</http:response>

Example 2: Retrieve Google search home page. TagSoup must be referenced in the class path in order to parse html.

Query: 

http:send-request(<http:request method='get' href='http://www.google.com'/>)

Result: 

<http:response status="200" message="OK">
  <http:header name="Date" value="Mon, 14 Mar 2011 22:03:25 GMT"/>
  <http:header name="Transfer-Encoding" value="chunked"/>
  <http:header name="Expires" value="-1"/>
  <http:header name="X-XSS-Protection" value="1; mode=block"/>
  <http:header name="Set-Cookie" value="...; expires=Tue, 13-Sep-2011 22:03:25 GMT; path=/; domain=.google.ch; HttpOnly"/>
  <http:header name="Content-Type" value="text/html; charset=ISO-8859-1"/>
  <http:header name="Server" value="gws"/>
  <http:header name="Cache-Control" value="private, max-age=0"/>
  <http:body media-type="text/html; charset=ISO-8859-1"/>
</http:response>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"/>
    <title>Google</title>
    <script>window.google={kEI:"rZB-
    ... 
    </script>
    </center>
  </body>
</html>

Example 3: Content-type ending with +xml, e.g. image/svg+xml.

Query: 

http:send-request(<http:request method='get'/>, 'http://upload.wikimedia.org/wikipedia/commons/6/6b/Bitmap_VS_SVG.svg')

Result: 

<http:response status="200" message="OK">
  <http:header name="ETag" value="W/"11b6d-4ba15ed4""/>
  <http:header name="Age" value="9260"/>
  <http:header name="Date" value="Mon, 14 Mar 2011 19:17:10 GMT"/>
  <http:header name="Content-Length" value="72557"/>
  <http:header name="Last-Modified" value="Wed, 17 Mar 2010 22:59:32 GMT"/>
  <http:header name="Content-Type" value="image/svg+xml"/>
  <http:header name="X-Cache-Lookup" value="MISS from knsq22.knams.wikimedia.org:80"/>
  <http:header name="Connection" value="keep-alive"/>
  <http:header name="Server" value="Sun-Java-System-Web-Server/7.0"/>
  <http:header name="X-Cache" value="MISS from knsq22.knams.wikimedia.org"/>
  <http:body media-type="image/svg+xml"/>
</http:response>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="1063" height="638">
  <defs>
    <linearGradient id="lg0">
      <stop stop-color="#3333ff" offset="0"/>
      <stop stop-color="#3f3fff" stop-opacity="0" offset="1"/>
    </linearGradient>
    ...
</svg>

Example 4: POST request to the BaseX REST Service, specifying a username and password.

Query: 

let $request :=
  <http:request href='http://localhost:8984/rest'
    method='post' username='admin' password='admin' send-authorization='true'>
    <http:body media-type='application/xml'>
    <query xmlns="http://basex.org/rest">
      <text><![CDATA[
        <html>{
          for $i in 1 to 3
          return <div>Section {$i }</div>
        }</html>
      ]]></text>
    </query>
    </http:body>
  </http:request>
return http:send-request($request)

Result: 

<http:response xmlns:http="http://expath.org/ns/http-client" status="200" message="OK">
  <http:header name="Content-Length" value="135"/>
  <http:header name="Content-Type" value="application/xml"/>
  <http:header name="Server" value="Jetty(6.1.26)"/>
  <http:body media-type="application/xml"/>
</http:response>
<html>
  <div>Section 1</div>
  <div>Section 2</div>
  <div>Section 3</div>
</html>
Retrieved from "http://docs.basex.org/index.php?title=HTTP_Client_Module&oldid=5802"