Bump doorkeeper 5.5 and define body method for authorization response to support response_mode=form_post

[linhdangduy]

Description

Resolves #92

Because doorkeeper already supported response_mode parameter on master branch, so I create this pull to support this response_mode=form_post on doorkeeper-openid_connect.

What did I do

• OAuth::IdTokenResponse and OAuth::IdTokenTokenResponse:
  • Define body method to return the result when in response_mode=form_post
  • add response_mode_matches to id_token and id_token token response_type.
• add CHANGELOG.md
• add OAuth 2.0 Form Post Response Mode to README

Caution ⚠️

Doorkeeper will released the response_mode=form_post from v5.5.0, these PR should be merged and released at that time.

Update

Doorkeeper released v5.5.0! So this pull is ready to be merged 🎉

[toupeira]

Overall this LGTM, thanks for the contribution! ❤️

I've left some minor comments, please take another look.

[nbulaj]

Good work 🤝

[linhdangduy]

@nbulaj @toupeira

After fixing the comments of @toupeira, I have checked if there are things we have to replace or fix when moving to Doorkeeper v5.5. Finally I find out some of them, added two more commits, and it seem to be ok for now.
Explaining below:

1. 0b681cb delete unnecessary support for dookeeper < v5.5

• Because the minimize doorkeeper's version is v5.5 now, so we can drop the code support for Doorkeeper version that less than v5.5

2. d07ba31 update: using response_mode which supported by doorkeeper v5.5

• Currently, this gem has a class (doorkeeper/openid_connect/response_mode) responsible for getting response_mode from response_type. It is added in this pull. But it is obsolete because response_mode already be supported from doorkeeper v5.5
• So I deleted the above doorkeeper-openid's response_mode class, and fix response_on_fragment? method in lib/doorkeeper/openid_connect/oauth/pre_authorization.rb file, which getting response_mode by using authorization_response_flows in doorkeeper config. (With a comment show that this implementation need to be used in doorkeeper later, so we don't need overwrite this method)
• Beside that, in the method for handling oidc errors (handle_oidc_error!) in lib/doorkeeper/openid_connect/helpers/controller.rb file, instead of defining how to response in this gem, I just use the method redirect_or_render which is already implemented in doorkeeper. A @authorize_response instance variable for authorizations_controller need to be defined, because when response_mode is form_post, @authorize_response is used in form_post template.

Please leave questions if there are somethings unclear. Thanks!

[toupeira]

@linhdangduy sorry for the delay, this fell off my radar again 🙈

This all LGTM now, thanks a lot for your work on this, and also the cleanups! ❤️

I'll merge this and will prepare a new release shortly, I'll bump the version to 1.8.0 due to the Doorkeeper 5.5 requirement. 👍