Wrapped parse call into try/catch block

[yunda]

This commit resolves situation when server response holds something like "Forbidden".

[focusaurus]

Could you add a unit test, please? Otherwise seems reasonable to me.

[yunda]

This pull-request supposed to fix #675

[kornelski]

This is a breaking change, and it has inconsistent behaviour between client and the server.

[kornelski]

Returning of unparsed string is dangerous, e.g. let's say the server used to return {accessDenied: false} or Forbidden!

.end(err, res) {
   if (err || res.body.accessDenied) return;
   allowAccess();
}

with this change res.body would be "Forbidden!" and res.body.accessDenied would be undefined and evaluate to falsy value, causing a security issue.

[yunda]

@pornel The idea is to return a response even if it fails to parse body. Otherwise we cannot read status codes or any other necessary information form the response object.

[kornelski]

@yunda you can from the error object, that's what rawResponse was for. Other properties can be added to the error.

[kornelski]

@yunda now there's err.statusCode. Do you need to read other properties during an error?

[kornelski]

I'm closing in favor of err.rawResponse and err.statusCode, which I think are safer and more backwards-compatible.