Working with the Database - eXist: A NoSQL Database and Application Development Platform - page 98

POST Requests
HTTP POST requests can be used for three distinct purposes:
• If the remainder of the URI (the part after /exist/rest ) references an XQuery pro‐
gram stored in the database, it will be executed.
• If the body of the POST request is a valid XUpdate document, the XUpdate pro‐
cessor will be invoked to update the database. An explanation of how this works
and the XUpdate XML format is described in “XUpdate” on page 105 .
• If the body of the POST request is XML and uses the http://exist.source
forge.net/NS/exist namespace, it is interpreted as a so-called extended query
request . These can be used to post complex XQuery scripts that are too large or
too unwieldy to pass in a _query parameter of a GET request. The result will be
wrapped in an exist:result element. The XML format for extended query
requests is described in “Extended query request XML format” on page 99 .
For example, let's fire an HTTP POST request containing an extended query request at
our own database using the eXist httpclient extension module:
let $ URI := 'http://localhost:8080/exist/rest/doesnotmatter'
let $ query := 'for $i in 1 to 10 return <Result index="{$i}"/>'
let $ request :=
<query xmlns = " http://exist.sourceforge.net/NS/exist " start = " 3 " max = " 3 " >
<text> { $ query } </text>
</query>
return
httpclient:post ( xs:anyURI ( $ URI ), $ request , false (), ())
The result will be something like:
<httpclient:response xmlns:httpclient= "http://exist-db.org/xquery/httpclient"
statusCode= "200" >
<httpclient:headers>
<httpclient:header name= "Date" value= "Mon, 17 Sep 2012 12:45:02 GMT" />
<httpclient:header name= "Set-Cookie"
value= "JSESSIONID=4mpvajj2ez99sa2ik31kzjvq;Path=/exist" />
<httpclient:header name= "Expires" value= "Thu, 01 Jan 1970 00:00:00 GMT" />
<httpclient:header name= "Content-Type" value= "application/xml;
charset=UTF-8" />
<httpclient:header name= "Transfer-Encoding" value= "chunked" />
<httpclient:header name= "Server" value= "Jetty(7.5.4.v20111024)" />
</httpclient:headers>
<httpclient:body mimetype= "application/xml; charset=UTF-8" type= "xml" >
<exist:result xmlns:exist= "http://exist.sourceforge.net/NS/exist"
exist:hits= "10"
exist:start= "3" exist:count= "3" >
<Result index= "3" />
<Result index= "4" />
<Result index= "5" />