getting Malformed JSON in the request body when request.body is not rewindable

[senid231]

I'm using Falcon as http server for sinatra app that uses sinja for json:api.
I've encountered a problem that my request.body is always malformed json.
After digging in I've found that Falcon uses Protocol::HTTP1::Body::Fixed as body class which is not rewindable. method #content? reads first 2 bytes to check if request has body. after that #deserialize_request_body always retrieves part of content, because in this case env['rack.input'] is an instance of Falcon::Adapters::Input which silently ignores rewind, because it's underlying body Protocol::HTTP1::Body::Fixed does not respond to it. I want to leave this issue here - maybe someone will looking solution for same problem.

I think it worth for PR - we can use #empty? on body if it responds to #empty?.

my bugfix is following

module SinjaPatch
  def content?
    return request.body.size > 0 if request.body.respond_to?(:size)
    return !request.body.empty? if request.body.respond_to?(:empty?)
    request.body.rewind
    request.body.read(1)
  end
end

module FalconAdaptersInputPatch
  def empty?
    @body.respond_to?(:empty?) ? @body.empty? : @body.size
  end
end

Falcon::Adapters::Input.include FalconAdaptersInputPatch
# must be added after `register Sinatra::JSONAPI` performed.
MyApp.prepend SinjaPatch

[senid231]

this thread related to this problem
rack/rack#1148

[mwpastore]

Hi @senid231, thank you for reporting this issue. I'll take a look at it over the weekend.