Nested resource failing to update - ruby-on-rails

Question

I'm trying to do what I think should be simple: do a simple edit on a single text string field with the default update action. But it just doesn't seem to work, despite many attempts and alterations.
There are no errors and the flash message responds successfully, but information isn't saved to the database at all:
routes.rb
resources :interviews do
resources :invitations do
put :accept
end
end
views/invitations/edit.html.haml
= simple_form_for [#interview, #invitation] do |f|
= f.error_notification
= f.input :testing
= f.submit 'Edit Invitstion', :class => 'button small'
controllers/invitations_controller.rb
def update
#invitation = Invitation.find(params[:id])
#interview = Interview.find(params[:interview_id])
#invitation.update_attributes(invitation_params)
if #invitation.update_attributes(invitation_params)
redirect_to edit_interview_invitation_path(#interview, #invitation), notice: "Your profile has been successfully updated."
else
render action: "edit"
end
end
private
def invitation_params
params.permit(:user_id, :interview_id, :invitation_id, :session_time, :workflow_state, :testing)
end
And here's the log:
Started PATCH "/interviews/3/invitations/7" for ::1 at 2016-05-15 19:01:52 +0800
Processing by InvitationsController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"o0U5t0yPN0aE2er+DWK0uxqRGyp4ywfdSrEfvwiSQ3UUaOnr3Fd0raFs1IUqVzizKoqxRU0DDpmvysntB9fdhQ==", "invitation"=>{"interview_id"=>"3", "workflow_state"=>"invited", "session_time"=>"", "testing"=>"testtesttest"}, "commit"=>"Edit Invitstion", "interview_id"=>"3", "id"=>"7"}
User Load (0.3ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT 1 [["id", 7]]
Invitation Load (0.2ms) SELECT "invitations".* FROM "invitations" WHERE "invitations"."id" = $1 LIMIT 1 [["id", 7]]
Role Load (0.2ms) SELECT "roles".* FROM "roles" WHERE "roles"."id" = $1 LIMIT 1 [["id", 3]]
Interview Load (0.2ms) SELECT "interviews".* FROM "interviews" WHERE "interviews"."id" = $1 ORDER BY created_at DESC LIMIT 1 [["id", 3]]
CACHE (0.0ms) SELECT "invitations".* FROM "invitations" WHERE "invitations"."id" = $1 LIMIT 1 [["id", "7"]]
CACHE (0.0ms) SELECT "interviews".* FROM "interviews" WHERE "interviews"."id" = $1 ORDER BY created_at DESC LIMIT 1 [["id", "3"]]
Unpermitted parameters: utf8, _method, authenticity_token, invitation, commit, id
(0.1ms) BEGIN
Invitation Exists (0.4ms) SELECT 1 AS one FROM "invitations" WHERE ("invitations"."user_id" = 3 AND "invitations"."id" != 7 AND "invitations"."interview_id" = 3) LIMIT 1
(0.1ms) COMMIT
Redirected to http://localhost:3000/interviews/3/invitations/7/edit
Completed 302 Found in 12ms (ActiveRecord: 1.6ms)
Started GET "/interviews/3/invitations/7/edit" for ::1 at 2016-05-15 19:01:52 +0800
Processing by InvitationsController#edit as HTML
Parameters: {"interview_id"=>"3", "id"=>"7"}
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT 1 [["id", 7]]
Invitation Load (0.3ms) SELECT "invitations".* FROM "invitations" WHERE "invitations"."id" = $1 LIMIT 1 [["id", 7]]
Role Load (0.2ms) SELECT "roles".* FROM "roles" WHERE "roles"."id" = $1 LIMIT 1 [["id", 3]]
Interview Load (0.2ms) SELECT "interviews".* FROM "interviews" WHERE "interviews"."id" = $1 ORDER BY created_at DESC LIMIT 1 [["id", 3]]
Rendered invitations/edit.html.haml within layouts/application (6.1ms)
Completed 200 OK in 48ms (Views: 39.1ms | ActiveRecord: 1.6ms)

Answer 1

Check the format of your params object in your logs. Your invitation params are being passed within the params["invitation"] key, yet you're whitelisting and updating your object based on the params in the root params hash.
Also note that your logs are reporting that you're trying to update your invitation with unpermitted params:
Unpermitted parameters: utf8, _method, authenticity_token, invitation, commit, id
You can fix this by simply updating your invitation_params to use params[:invitation] rather than params like so:
def invitation_params
params.require(:invitation).permit(:user_id, :interview_id, :invitation_id, :session_time, :workflow_state, :testing)
end
Also, you might want to consider raising an error if you're trying to update a parameter that's not whitelisted to prevent these sorts of issues in the future.
In your rails config:
config.action_controller.action_on_unpermitted_parameters = :raise