How to upgrade redmine plugin to rails 5, alias_method_chain is deprecated now - ruby

Question

Story mode
Just started learning RoR, but in short period of time I need to add functionality similar to Loading images from LDAP (incompatible version) into our project. Project is abondoned, and I can't find any related info/docs, so I'm asking for help here. Solution, tutorial, anything could work.
Error log
$ ruby bin/rake redmine:plugins RAILS_ENV="production"
rake aborted!
NoMethodError: undefined method `alias_method_chain' for ApplicationHelper:Module
Did you mean? alias_method
...
Monkey patch that needs update
plugins\redmine_gemavatar\lib\application_helper_gemavatar_patch.rb :
require 'application_helper'
module GemAvatarPlugin
module ApplicationAvatarPatch
def self.included(base)
base.send(:include, InstanceMethods)
base.class_eval do
alias_method_chain :avatar, :gemavatar
end
end
module InstanceMethods
def avatar_with_gemavatar(user, options = { })
if Setting.gravatar_enabled? && user.is_a?(User)
options.merge!({:ssl => (defined?(request) && request.ssl?), :default => Setting.gravatar_default})
options[:size] = "64" unless options[:size]
avatar_url = url_for :controller => :pictures, :action => :delete, :user_id => user
return "<img class=\"gravatar\" width=\"#{options[:size]}\" height=\"#{options[:size]}\" src=\"#{avatar_url}\" />".html_safe
else
''
end
end
end
end
end
My attempts / Articles
I've found good article here How To Replace alias_method_chain, but I'm not quite sure how to apply prepend style to redmine plugin's monkey patch. Just can't get it work :/

Answer 1

Is this related to this plugin?
If so, here is how I would do it:
In the init.rb file, change this:
RedmineApp::Application.config.after_initialize do
ApplicationHelper.send(:include, GemAvatarPlugin::ApplicationAvatarPatch)
end
To this:
RedmineApp::Application.config.after_initialize do
ApplicationHelper.prepend(GemAvatarPlugin::ApplicationAvatarPatch)
end
In lib/application_helper_gemavatar_patch.rb, change this:
require 'application_helper'
module GemAvatarPlugin
module ApplicationAvatarPatch
def self.included(base)
base.send(:include, InstanceMethods)
base.class_eval do
alias_method_chain :avatar, :gemavatar
end
end
module InstanceMethods
def avatar_with_gemavatar(user, options = { })
# method content omitted for clarity
end
end
end
end
to this:
module GemAvatarPlugin
module ApplicationAvatarPatch
def avatar(user, options = { })
# method content omitted for clarity
end
end
end
I would remove the require 'application_helper' because I don't see why it's needed

Answer 2

I also tried to update this plugin. I used https://github.com/alexandermeindl/redmine_local_avatars as an example.
In init.rb changed this:
RedmineApp::Application.config.after_initialize do
ApplicationHelper.send(:include, GemAvatarPlugin::ApplicationAvatarPatch)
end
to this:
RedmineApp::Application.config.after_initialize do
ApplicationHelper.include ApplicationAvatarPatch
end
the patched lib/application_helper_gemavatar_patch.rb, looks like this:
module ApplicationAvatarPatch
def self.included(base)
base.send(:include, InstanceMethods)
base.class_eval do
alias_method :avatar_without_gemavatar, :avatar
alias_method :avatar, :avatar_with_gemavatar
end
end
module InstanceMethods
def avatar_with_gemavatar(user, options = { })
if Setting.gravatar_enabled? && user.is_a?(User)
options.merge!({:ssl => (defined?(request) && request.ssl?), :default => Setting.gravatar_default})
options[:size] = "64" unless options[:size]
avatar_url = url_for :controller => :pictures, :action => :delete, :user_id => user
return "<img class=\"gravatar\" width=\"#{options[:size]}\" height=\"#{options[:size]}\" src=\"#{avatar_url}\" alt=\"Gemavatar text\" />".html_safe
else
avatar_without_gemavatar(user, options)
end
end
end
end
I tried it only with Redmine 4.0.3 but it seems to be working. However there are warnings in the webserver log:
127.0.0.1 - - [06/Mar/2020:20:58:23 CET] "GET /gemavatar/164 HTTP/1.1" 200 3545
http://tredmine1:3000/users/164 -> /gemavatar/164
[2020-03-06 20:58:23] WARN Could not determine content-length of response body. Set content-length of the response or set Response#chunked = true
In the redmine_local_avatars plugin there was a different patch for Redmine 4.1.
Update: I set a up a github repository with the changes: https://github.com/pentekl/redmine_gemavatar

Answer 3

You can use alias_method instead of alias_method_chain, but I'm searching for something like prepend solution
alias_method :avatar_without_gemavatar, :avatar
alias_method :avatar, :avatar_with_gemavatar
UPD:
But it throws warnings:
/app/helpers/application_helper.rb:180: warning: already initialized constant ApplicationHelper
::RECORD_LINK
/app/helpers/application_helper.rb:180: warning: previous definition of RECORD_LINK was here
/app/helpers/application_helper.rb:199: warning: already initialized constant ApplicationHelper
::ATTACHMENT_CONTAINER_LINK
/app/helpers/application_helper.rb:199: warning: previous definition of ATTACHMENT_CONTAINER_LI
NK was here
/app/helpers/application_helper.rb:1053: warning: already initialized constant ApplicationHelpe
r::LINKS_RE
/app/helpers/application_helper.rb:1053: warning: previous definition of LINKS_RE was here
Exiting
UPD:
As ste26054 mentioned in his answer and commented here
require 'application_helper' can be deleted to prevent warnings, since it already included in the core.