JSONP error handling for Exceptions

[adam-patterson]

The new JSONP handler is not handling our exceptions nicely. Typically when we generate an Exception new Exception($errorMsg, 400) presto ensures the HTTP response is the error code and the body would have $errorMsg. For JSONP responses I see the error code handled properly but the error message is not returned in the body. There is no body.

In the /v4/people API I just added throw new Exception('error message', 400); as the first line after the restrictTo call to generate this error.

Request URL:http://app.rubrix.test/v4/people/3065.js?callback=jQuery110105611689402721822_1373486935119&_=1373486935121
Request Method:GET
Status Code:400 API error
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Connection:keep-alive
Cookie:rx-auth=1r%2BQTP7tvwrZt%2BCTLhN6hCeunrpZmXGVGnxMMHF03Ff4%2BOFSfrD%2BlNMtq2%2By6tNKYlvOb2RBtXg6BVEGIGHCE30X7ysuNhMj9hlK8YZ5Y0JFAD4QkxWOIo2ERl%2FiBqI1s%2BnuxbMAO5D84Q3ZbBJ5wCKdSc2WqOZ%2B7v2P%2FXipHIa9O253tifLxPH1IBeu1y9l96F8%2FjcBgBXYT%2BOCKlyjuwkP5N%2Bl81l5La3zMEuOz%2BaK%2FD5L3vkfCgt1YvdnxBvmgySzZ4lq5eeH0H1BfojqW0mldT43vEWIDCDzZddAb6oXYGCCdWgjPDBRQcxoKuBeM4n7jeWdb2M%2Fs%2BOZCq8ktYmAbbSoCmYaBIZJHRNSL53lI078Lq9XmxBvBqcigIAf
Host:app.rubrix.test
Referer:http://reports.rubrix.test/explorable/performance/reviewer.html?codekitCB=395174602.397223
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.116 Safari/537.36
Query String Parametersview sourceview URL encoded
callback:jQuery110105611689402721822_1373486935119
_:1373486935121

Response Headersview source
Cache-Control:private, no-cache, no-store, proxy-revalidate, no-transform
Connection:close
Content-Length:472
Content-Type:application/json
Date:Wed, 10 Jul 2013 20:09:39 GMT
Pragma:no-cache
Server:Apache/2.2.22 (Unix) DAV/2 PHP/5.3.15 with Suhosin-Patch mod_ssl/2.2.22 OpenSSL/0.9.8x
X-Api-Version:presto-v1.11
X-Powered-By:PHP/5.3.15

I will assume that the body of the errors (where they are allowed) also need to be encoded as JSONP as the responses look valid otherwise (testing by hand). Unfortunately Presto manages certain errors from locations other than the encoding logic. This may take some time to resolve.

Can you work with the HTTP status codes for now?

[robotpony]

Related to #74