Thursday, June 14, 2012

RHQ REST api: Support for JSONP (updated)



I have just committed support for JSONP to the RHQ REST-api.

Update: In the first version a special media type was required. This is now removed, as jQuery seems to have issues sending this type. Also the default name for the callback parameter has been renamed to jsonp.



To use it you need to pass a parameter for the callback. Lets look at an example:


$ curl -i -u rhqadmin:rhqadmin \
http://localhost:7080/rest/1/alert?jsonp=foo \
-Haccept:application/json
HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Pragma: No-cache
Cache-Control: no-cache
Expires: Thu, 01 Jan 1970 01:00:00 CET
X-Powered-By: Servlet 2.4; JBoss-4.2.0.CR2
Content-Type: application/javascript
Transfer-Encoding: chunked
Date: Thu, 14 Jun 2012 09:25:09 GMT

foo([{"name":"test","resource":{"typeName":null, ……..])


The name of the callback parameter is jsonp and the name of the callback function to return is
foo. In the output of the server you see how the json-data is then wrapped inside foo().
The wrapping will only happen when both the right content-type is requested and the callback parameter is present.

The content type returned is then application/javascript.



Setting the name of the callback parameter

Then name of the callback parameter (jsonp in above example) can be set in web.xml :


<filter>
<filter-name>JsonPFilter</filter-name>
<filter-class>org.rhq.enterprise.rest.JsonPFilter</filter-class>
<init-param>
<param-name>filter.jsonp.callback</param-name>
<param-value>jsonp</param-value>
<description>Name of the callback to use for JsonP /description>
</init-param>
</filter>

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