Identify GET and POST parameters in Ruby on Rails

Question

You can use the request.get? and request.post? methods to distinguish between HTTP Gets and Posts.

• See http://api.rubyonrails.org/classes/ActionDispatch/Request.html

I don't know of any convenience methods in Rails for this, but you can access the querystring directly to parse out parameters that are set there. Something like the following:

request.query_string.split(/&/).inject({}) do |hash, setting|
  key, val = setting.split(/=/)
  hash[key.to_sym] = val
  hash
end

You can do it using:

request.POST

and

request.GET

There are three very-lightly-documented hash accessors on the request object for this:

• request.query_parameters - sent as part of the query string, i.e. after a ?
• request.path_parameters - decoded from the URL via routing, i.e. controller, action, id
• request.request_parameters - All params, including above as well as any sent as part of the POST body

You can use Hash#reject to get to the POST-only params as needed.

Source: http://guides.rubyonrails.org/v2.3.8/action_controller_overview.html section 9.1.1

I looked in an old Rails 1.2.6 app and these accessors existed back then as well.