Question

We have a function in our Rails code that accepts a JSON POST body:

contacts = ActiveSupport::JSON.decode(request.raw_post.gsub("+", ""))

(I’m aware that I can get this from params["_json"] as well, but we have extremely large (MBs) POST bodies that do not get put into params["_json"] for some reason (and + throws errors too).

Since the JSON is usually sent from a mobile client, it’s important to us to optimize the upload size. We want to switch to having the POST body gzipped.

However, no matter what we do, we get the same error with no line number:

MultiJson::DecodeError (743: unexpected token at ''):

We have tried:

  gzipped_contacts = Zlib::GzipReader.new(StringIO.new(request.raw_post)).read
  contacts = ActiveSupport::JSON.decode(gzipped_contacts.gsub("+", ""))

This:

   gzipped_contacts = ActiveSupport::Gzip.decompress(request.raw_post)
   contacts = ActiveSupport::JSON.decode(gzipped_contacts.gsub("+", ""))

And the solution found here: Rails: how to unzip a compressed xml request body?

I’m pretty sure this is not occurring at the controller level because I can’t log anything there, so it needs to be done in the middleware or at the server (but I can’t find anything for Nginx that lets us deflate). Please assist!

Answer 1

Ok, turns out the iPhone client was sending the wrong headers. So the solution for anyone encountering this is to see the advice here:

Rails: how to unzip a compressed xml request body?

And verify that you are sending Content-Type: gzip/json.