Error when executing POST json request

[nicopaez]

I am trying to generate the spec for a POST request that sends json message in the body and I getting the error below.

 ActionDispatch::Http::Parameters::ParseError:
            no implicit conversion of nil into String
          # /usr/local/bundle/gems/actionpack-6.0.3.3/lib/action_dispatch/http/parameters.rb:114:in `rescue in parse_formatted_parameters'
          # /usr/local/bundle/gems/actionpack-6.0.3.3/lib/action_dispatch/http/parameters.rb:110:in `parse_formatted_parameters'
          # /usr/local/bundle/gems/actionpack-6.0.3.3/lib/action_dispatch/http/request.rb:389:in `block in POST'
          # /usr/local/bundle/gems/rack-2.2.3/lib/rack/request.rb:69:in `fetch'
          # /usr/local/bundle/gems/rack-2.2.3/lib/rack/request.rb:69:in `fetch_header'
          # /usr/local/bundle/gems/actionpack-6.0.3.3/lib/action_dispatch/http/request.rb:388:in `POST'
          # /usr/local/bundle/gems/rspec-openapi-0.3.13/lib/rspec/openapi/record_builder.rb:94:in `raw_request_params'
          # /usr/local/bundle/gems/rspec-openapi-0.3.13/lib/rspec/openapi/record_builder.rb:41:in `build'
          # /usr/local/bundle/gems/rspec-openapi-0.3.13/lib/rspec/openapi/hooks.rb:12:in `block in <top (required)>'
          # ------------------
          # --- Caused by: ---
          # TypeError:
          #   no implicit conversion of nil into String
          #   /usr/local/bundle/gems/activesupport-6.0.3.3/lib/active_support/json/decoding.rb:23:in `decode'

this is my rspec:

      it 'create a user' do
        header 'CONTENT_TYPE', 'application/json'
        json_data = { name: 'juan'}.to_json
        post '/users', json_data, { 'Content-Type' => 'application/json' }
        expect(last_response.status).to eq(201)
      end

I notice that if I remove the fist line (header 'CONTENT_TYPE', 'application/json') then the execution completes successfully but the result yaml spec is wrong, it specifies request.content type as application/x-www-form-urlencoded instead of application/json.

I am running ruby 2.5.7p206 and my application is padrino application (not rails).

If anyone can give some guidance I my try to submit a fix.

[k0kubun]

Thanks for trying that out with Padrino. I tried to reproduce it with a request spec for Rails, but header was not defined.

May I ask you to create a small repository that reproduces your issue?

[nicopaez]

Sure. Here you have a sample webapi project I am working on.

To reproduce the issue you can:

1. Clone this repository: git@gitlab.com:fiuba-memo2/ejemplos/webapi-example.git
2. Switch to branch "openapi-generator"
3. Run the ./start_dev_containers.sh script to have a docker dev environment ready to work
4. Run the ./generate_apispec.sh script to reproduce the issue

Please tell me If there is any other thing I could help.

Nico

[k0kubun]

OK, I kind of understood why it's happening. Usually, when you write a request spec with rack-test, last_request.env['rack.input'] is ready to be read:

From: /home/k0kubun/src/github.com/k0kubun/rspec-openapi/spec/requests/roda_spec.rb:24 :

    19:   describe '/roda' do
    20:     context 'when id is given' do
    21:       it 'returns 200' do
    22:         header 'CONTENT_TYPE', 'application/json'
    23:         post '/roda', { id: 1 }.to_json, { 'Content-Type' => 'application/json' }
 => 24:         require "pry";binding.pry
    25:         expect(last_response.status).to eq(200)
    26:       end
    27:     end
    28:   end
    29: end

[1] 3.0.0-p0 (#<RSpec::ExampleGroups::Roda::Roda::WhenIdIsGiven>)> last_request.env['rack.input'].read(128)
=> "{\"id\":1}"

but in this repository's environment, it's not readable unless you rewind it by yourself:

From: /app/spec/app/api_spec.rb:13 :

     8:   describe 'Users' do
     9:     it 'POST /users' do
    10:       header 'CONTENT_TYPE', 'application/json'
    11:       json_data = { name: 'juan'}.to_json
    12:       post '/users', json_data, { 'Content-Type' => 'application/json' }
 => 13:       require "pry";binding.pry
    14:       expect(last_response.status).to eq(201)
    15:     end
    16:
    17:     it 'GET /users' do
    18:       get '/users'

[1] pry(#<RSpec::ExampleGroups::API::Users>)> last_request.env['rack.input'].read(128)
=> nil
[2] pry(#<RSpec::ExampleGroups::API::Users>)> last_request.env['rack.input'].tap(&:rewind).read(128)
=> "{\"name\":\"juan\"}"

Do you have any idea why this happens? Obviously we can fix this by just calling rewind, so I'm okay with it, but I'm curious about what makes the difference.

[nicopaez]

I think that is because of the way I am reading the json when the padrino application wants to access the posted data.

      def user_params
        @body ||= request.body.read
        JSON.parse(@body).symbolize_keys
      end

Up to what I know this is usual method when using padrino/sinatra.

[k0kubun]

Fixed it in v0.3.14. Please try the version.