Do not attempt to convert ActionDispatch::Http::Headers to JSON

[y-yagi]

Since Rails 5.0, the headers object contains the request object.
rails/rails@34fa665

These include objects for which to_json conversion is not guaranteed.
Until Rails 5.1, these objects contained an IO object, which caused an error in converting to JSON.

However, IO#to_json was added in Rails 5.2(rails/rails@813f8e3).
As a result, there was no explicit error due to conversion, and SystemStackError got to happen.

To avoid this, fixed to convert only the actual http header to JSON.

Fixes #137

[modosc]

hey @y-yagi , thanks for this pr.

i just pushed a branch with the basic tests we use on the other rails versions - currently everything passes. could you add a test that shows this failure case please?

[y-yagi]

Hi @modosc. Thank you for the push the branch.

You seem to have used Rails 5.1.4 in test for 5.2.0.beta2.
https://github.com/dejan/rails_panel/blob/rails-5-2-support/meta_request/test/functional/rails-5.2.0.beta2/Gemfile#L10

If you change the version, test should fail as shown below.

Run Test

$ cd test/functional/rails-5.2.0.beta2 && bundle install && bundle exec rake test 

# Running:

E

Error:
MetaRequestTest#test_it_shold_have_a_request_id_header:
SystemStackError: stack level too deep
    test/integration/meta_request_test.rb:11:in `block in <class:MetaRequestTest>'


bin/rails test test/integration/meta_request_test.rb:15


E

Error:
MetaRequestTest#test_it_should_have_a_meta_request_version_header:
SystemStackError: stack level too deep
    test/integration/meta_request_test.rb:11:in `block in <class:MetaRequestTest>'


bin/rails test test/integration/meta_request_test.rb:19

E

Error:
MetaRequestTest#test_should_serve_a_meta_request:
SystemStackError: stack level too deep
    test/integration/meta_request_test.rb:11:in `block in <class:MetaRequestTest>'


bin/rails test test/integration/meta_request_test.rb:27

E

Error:
MetaRequestTest#test_should_create_a_request_file:
SystemStackError: stack level too deep
    test/integration/meta_request_test.rb:11:in `block in <class:MetaRequestTest>'


bin/rails test test/integration/meta_request_test.rb:23



Finished in 0.857378s, 4.6654 runs/s, 0.0000 assertions/s.
4 runs, 0 assertions, 0 failures, 4 errors, 0 skips

For the confirmation, added a test of 5.2 to this branch.

[modosc]

You seem to have used Rails 5.1.4 in test for 5.2.0.beta2.

hah, that explains a lot.