Ruby: Receive JSON in Request Body

I’ve been building a little Sinatra app to play around with the Google Drive API and one thing I struggled with was processing JSON posted in the request body.

I came across a few posts which suggested that the request body would be available as params['data'] or request['data'] but after trying several ways of sending a POST request that doesn’t seem to be the case.

I eventually came across this StackOverflow post which shows how to do it:

require 'sinatra'
require 'json'
 
post '/somewhere/' do
  request.body.rewind
  request_payload = JSON.parse request.body.read
 
  p request_payload
 
  "win"
end

I can then POST to that endpoint and see the JSON printed back on the console:

dummy.json

{"i": "am json"}

$ curl -H "Content-Type: application/json" -XPOST http://localhost:9393/somewhere/ -d @dummy.json

{"i"=>"am json"}

Of course if I’d just RTFM I could have found this out much more quickly!