How to receive a JSON object with Rack

Question

I have a very simple Ruby Rack server, like:

app = Proc.new do |env| 
  req = Rack::Request.new(env).params
  p req.inspect 
  [200, { \'Content-Type\' =>         


        

Answer 1

One more way to do that:

# ...
request  = Rack::Request.new env
object   = JSON.parse request.body.gets
# ...

See the documentation: www.rubydoc.info/gems/rack/Rack/Lint/InputWrapper

Answer 2

env['rack.input'].gets

This worked for me. I found that using curl or wget to test POST requests against a Rack (v1.4.1) server required using this code as a fallback to get the request body. POST requests out in the wild (e.g. GitHub WebHooks) didn't have this same problem.

Answer 3

It seems that I'm supposed to use something like:

msg = JSON.parse env['rack.input'].read 

Then just use params in the msg hash.

At least it worked for me this way.