client_options.redirect_uri should fallback to sensible default when missing

[maxbes]

Context: I am setting up Greenlight for use with OpenIDConnect through your library

The initialization happens this way:

      provider :openid_connect,
        issuer: ENV["OPENID_CONNECT_ISSUER"],
        discovery: true,
        scope: [:email, :profile],
        response_type: :code,
        uid_field: ENV["OPENID_CONNECT_UID_FIELD"] || "preferred_username",
        client_options: {
          identifier: ENV['OPENID_CONNECT_CLIENT_ID'],
          secret: ENV['OPENID_CONNECT_CLIENT_SECRET'],
          redirect_uri: redirect
        },

Unless explicitly configured by the user, redirect will have a nil value, which omniauth_openid_connect will handle by constructing the following authorization uri:

http://my.provider/authorize?client_id=1234&nonce=8225bfbd740e8909a54ff97f536c3c18&response_type=code&scope=email%20profile%20openid&state=8f8c4887392f8bcbdcdc195704e53f44

redirect_uri is missing, which is not valid per the OIDC spec

Other Omniauth providers I have looked at use Omniauth's callback_url method to set the redirect_uri to a sensible default value when the user does not explicitely specify it. This makes configuration of OpenID Connect a little easier, by relieving the users from having to try and guess the correct callback URL when configuring an application that uses Omniauth.

I have tried the following change:

diff --git a/lib/omniauth/strategies/openid_connect.rb b/lib/omniauth/strategies/openid_connect.rb
index c7e86f7..ec37c7f 100644
--- a/lib/omniauth/strategies/openid_connect.rb
+++ b/lib/omniauth/strategies/openid_connect.rb
@@ -156,7 +156,7 @@ module OmniAuth
       end
 
       def authorize_uri
-        client.redirect_uri = redirect_uri
+        client.redirect_uri = redirect_uri || callback_url
         opts = {
           response_type: options.response_type,
           response_mode: options.response_mode,

which works for my use case, but breaks the unit tests in ways I cannot understand as someone not very familiar with Ruby

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.