Say I send a HTTP request with the following headers*:
GET /api/useranswers.json?userid=XXXXX&page=1&pagesize=50&sort=recent HTTP/1.1 Accept-Encoding: gzip,deflate Host: superuser.com
I get a response with the following headers*:
HTTP/1.1 200 OK Cache-Control: private Content-Type: application/json; charset=utf-8 Server: Microsoft-IIS/7.0 Date: Fri, 25 Dec 2009 03:56:13 GMT
Note that there's no Content-Encoding in the response headers. The same is true for non "/api/" URLs, like flair. I've confirmed that this behavior is replicated in browsers, so I don't think my method of retrieval is gumming anything up.
All HTML traffic seems to be compressed. JSON is understandably denser than the equivalent HTML, but I'd still expect to see ~25% compression ratios consistently.
So, why is this?
*Omitting some personally identifying information & headers