POST /avatar/upload should validate image payload

[zaach]

If the body of the request doesn't look like image data (e.g. {}) the request should fail.

[jrgm]

Yeah, so, the profile server's worker was correctly detecting the error. However, the server did not see the error and would return 200 OK and a URL to where the image had supposedly been stored. The problem can be duplicated with:

curl -s 'https://jrgm4.dev.lcip.org/profile/v1/avatar/upload' \
  -H 'Accept: application/json' \
  -H 'Content-Type: image/png; charset=UTF-8' \
  -H 'Accept-Encoding: deflate, gzip' \
  -H 'Authorization: Bearer 347e17e015dae....' \
  -H 'Content-Length: 2' \
  -X POST \
  -d"{}" | zcat; echo

You need to obviously provide a valid Bearer token above, but if you do, that will return '201 Created' with a payload that has a url.

The problem is that the response from the worker is gzipped, but the server expect uncompressed. Possibly just need to not asking for gzip is a fix:

diff --git a/lib/routes/avatar/upload.js b/lib/routes/avatar/upload.js
index 1c0ab54..b319be2 100644
--- a/lib/routes/avatar/upload.js
+++ b/lib/routes/avatar/upload.js
@@ -30,6 +30,7 @@ function fxaUrl(id) {
 function pipeToWorker(id, payload, headers) {
   return new P(function(resolve, reject) {
     var url = WORKER_URL + '/a/' + id;
+    headers['accept-encoding'] = 'identity';
     var opts = { headers: headers, json: true };
     logger.verbose('pipeToWorker', url);
     payload.pipe(request.post(url, opts, function(err, res, body) {

With the change above, that would now return HTTP 500 with:

{"code":500,"errno":103,"error":"Internal Server Error","message":"Image processing error","_res":{"id":"deadbeefdeadbeef...","error":"Stream yields empty buffer"}}

Probably a little more detail than needed in that response, and a 400 level error would be better for bad input.

[seanmonstar]

I'm thinking of adding a gm(payload).identify() call before trying to resize, so as to detect if the buffer is indeed an image. Otherwise, it's difficult to tell if the error from gm().resize() is because of a non-image or some other reason.