Fixes Swagger.js no setting jQuery.ajax contentType parameter

[noirbizarre]

This PR fixes a nasty bug with Swagger.js/jQuery.

Context

Swagger.js only set the Content-Type HTTP header on request but does not give the contentType parameter to jQuery.ajax.

Consequence

jQuery consider the request body as url encoded and reencode content. As a side effect, all %20 characters are replaced by + signs.

Resolution

This PR adds a hackish Swagger.js request interceptor which set the jQuery.ajax contentType parameter to the same value than the Content-Type header.
This fixes many side-effects:

• %20 are not replaced by + signs anymore (When URLs are saved, %20 are converted to plus signs #1126)
• default success and error handlers are taken in account (side effect of operation call signature change)
• any places where double encoding was occurring (I'm sure we missed some of them) are fixed too

[noirbizarre]

For reference this is a combination of:

• the default jQuery.ajax contentType parameter
• a change added 2 years ago: Ajax: Only form-encode requests with a body jquery/jquery#2671

This swagger.js issue was inexistant (invisible and without side-effects) before jQuery 2.2.0

[taniki]

Can it be also related to https://swagger.io/docs/specification/2-0/describing-request-body/ ?

consume parameter does not seem to be set to application/json anywhere. Maybe this is not implicit and swagger doesn't provide proper content-type to the js part.

No dev env here. will get a try and review this on tuesday!

[pblayo]

I took the liberty to change the interceptor's comment from

• "swagge as" to
• "swagger has"

Shouldn't an issue be opened in swagger.js itself ?
(with a quick search I didn't find any, except some related but not the same issues in swagger-ui like swagger-api/swagger-ui#2785)

[noirbizarre]

The consume parameter properly set the Content-Type header, this is only the jQuery.ajax call which is broken.

Yes there might be something to fix in upstream swagger.js. Sadly, we are using Swagger.js 2.X and a fix on the 3.x won't be usable to us right now.