nginx modifying the jsonp response message

[Maxim Dounin]

Hello!

On Mon, Sep 17, 2012 at 04:34:27PM -0400, venkat wrote:

> Hi, 
> 
> We are creating a web api application. In one of our API's if there are any
> validation errors, we are returning the error message in JSONP format. In
> the API Request URL user adds a query string parameter
> ?jsoncallback=xxxxxxxxxx.
> 
> On validation failure we are throwing a 400 bad request JSONP with response
> message in the below format.
> 
> xxxxxxxxxx({"error","error message"})
> 
> It is working good in all the environments, where there is no nginx. In our
> staging environment we have nginx configured. 
> 
> Here it is modifying the output as below. 
> 
> badrequest{"error","error message"})
> 
> Because of this our front end application is unable to read the response
> message. 
> 
> Could you please let me know, what configuration setting of nginx could
> cause this problem?

I would suggest that this is caused by error_page 400 + 
proxy_intercept_errors configured.

Maxim Dounin