Set Content-Type for testing from Firefox

Question

I need to do some REST service testing from Firefox where I set the Content-Type HTTP header to a specific value (to retrieve XML or JSON).

Is there a Firefox add-on that can do this?

Answer 1

There's Modify Headers "... You can modify the user-agent string, add headers to spoof a mobile request (e.g. x-up-calling-line-id) ..."

https://addons.mozilla.org/en-US/firefox/addon/967

Answer 2

A firefox plugin called RESTTest could meet Your needs (I am not sure if it has this particular feature, but if it doesn't, what does?).

Construct custom HTTP requests to directly test requests against a server. RESTTest uses the XmlHttpRequest object and allows you to simulate XHR to quickly prototype requests and test security problems. Designed specifically for working with REST sources, supporting all HTTP methods.