This is a definite newb question:
I have a module defined in my lib/ directory that I call from a sweeper and as a rake task. Inside the module I want to reference my spawn plugin. Just including methods from that plugin doesn't work (undefined method error), nor does any version of require or include that I've tried. What do I need to do to include it?
Thank you!
EDIT:
Here is my latest effort:
require 'vendor/plugins/spawn/init.rb'
module MyModule
include Spawn
def self.my_method
spawn(:method => :thread, :nice => 9) do # also tried Spawn::spawn
...
end
end
end
The error I get is:
undefined method 'spawn' for MyModule:Module #spawn or undefined method 'spawn' for Spawn:Module # Spawn::spawn
The including has to be done from within the plugin. When you "reopen" a module (which is in the lib/ dir), remember to require the original file before making changes to it (the module).
EDIT:
Considering that the plugin is third party, you could try:
Spawn.module_eval do
module_function :spawn
public :spawn
end
module MyModule
def self.my_method
Spawn.spawn(...)
end
end
Related
I have about 20 different Active Jobs which I now realise are each going to need a before_perform method in which to set PaperTrail content outside the context of the controller.
I was planning on putting this before_perform method in a helper and then including the helper in each of the jobs but I am getting an error:
undefined method `before_perform' for MyApp:JobHelpers:Module
I am thinking that this is because the module in question is just that, a module and not an Active Job. How can I avoid repeating the same 4 line before_perform method in each of my Active Jobs?
Job_helper:
module MyApp
module JobHelpers
before_perform do |job|
# stuff to do
end
end
end
The_job:
require 'my_app/job_helpers'
class TheJob < ActiveJob::Base
include MyApp::JobHelpers
# Do more stuff
end
Rewrite your helper like this:
module MyApp
module JobHelpers
extend ActiveSupport::Concern
included do
# inside this you can call ActiveJob helpers
before_perform do
# stuff to do
end
end
end
end
I used an included callback to achieve my desired goal. I found a better description of the included callback than I could ever give in another answer here.
While other answers were similar, please find the solution that worked for me below:
module MyApp
module JobHelpers
def self.included(job_class)
job_class.before_perform do |job|
# work to be completed
end
end
end
end
I'm trying to create a rails plugin and the problem I'm facing is that the app won't include my modules when migrating the plugin.
Here's what I have so far:
1. A file lib/patch/settings_helper_patch.rb with extension code
2. An init.rb file with require_dependency 'patch/settings_helper_patch'
3. Some code in settings_helper_patch.rb which is as follows:
module ValidateIssuePatch
module Patch
module SettingsHelperPatch
def self.included(base)
base.send(:include, InstanceMethods)
end
module InstanceMethods
def issue_options
#some code here
end
end
end
end
end
unless SettingsHelper.included_modules.include?(ValidateIssuePatch::Patch::SettingsHelperPatch)
SettingsHelper.send(:include, ValidateIssuePatch::Patch::SettingsHelperPatch)
end
After I migrate the plugin, I wish to use the issue_options method, but I get undefined local variable or method error.
If I run SettingsHelper.included_modules.include?(ValidateIssuePatch::Patch::SettingsHelperPatch) from the console, I get uninitialized constant Patch::SettingsHelperPatch.
However, if I call ValidateIssuePatch from the console, I get => ValidateIssuePatch in response.
Can anyone tell me what is the magic I'm missing here?
Firstly, if your module is only going to have instance methods, I would recommend using the following easy-to-follow syntax:
module ValidateIssuePatch
module Patch
module SettingsHelperPatch
def issue_options
# code
end
end
end
end
SettingsHelper.include(ValidateIssuePatch::Patch::SettingsHelperPatch)
Secondly, the reason why ValidateIssuePatch might be defined is that some other file has it which is being required properly. This file isn't being executed in any way. I would raise an error somewhere that, when raised, will verify that the code is / isn't being executed. Something like the following:
module ValidateIssuePatch
module Patch
module SettingsHelperPatch
raise "All good" # remove this afterwards
def issue_options
# code
end
end
end
end
SettingsHelper.include(ValidateIssuePatch::Patch::SettingsHelperPatch)
Chances are that the error won't be raised and it'll confirm that your file isn't being required - either not at all or not in the right order.
To further verify this, simply open up your console and do the following with your existing code:
ValidateIssuePatch::Patch::SettingsHelperPatch #=> error
require path_of_file
ValidateIssuePatch::Patch::SettingsHelperPatch #=> no more error
Finally, why do you check for the module already being included in SettingsHelper? (referring to the unless condition) Your code should be including the module only once, not "maybe only once".
In Rails, how do you use a specific method from a module. For eg,
# ./app/controllers/my_controller.rb
class MyController < ApplicationController
include MyModule
def action
MyModule.a_method
end
private
def a_method
...
end
end
# ------------------------------------------------ #
# ./app/helpers/my_module.rb
module MyModule
def a_method
...
end
end
MyController includes MyModule. And in action ,I want to use MyModule.a_method (Please note I also have a private a_method in MyController and I don't want to use this.)
Things I've tried :
1) Defining the method in the module as self.
def self.a_method
end
2) Using the :: notation in controller (MyModule::a_method)
The error that I keep getting is
Undefined method:a_method for MyModule:module
For now, I've resorted to using a different name for the modules method. But I'd like to know how to namespace the function with either the Module:: or Module. notation
[UPDATE - 11/24/2014]
adding file structure in code, since Rails heavily relies on convention.
So I am not really sure what you are trying to accomplish with your module but a quick solution to get it working is below.
Move my_module.rb out of helpers and into lib/my_module.rb. The helpers directory is for methods that you use in your views. The convention is to utilize helpers that are namespaced after their respective controller or the application_helper.rb for global methods for your views. Not sure if that's what you are trying to accomplish with your module but wanted to throw that out there.
Create an initializer (you can all it whatever) in config/initializers/custom_modules.rb and add require 'my_module'
Update the a_method back to be self.a_method
You can now call MyModule.a_method in your app
Don't forget to restart your server for changes to lib/my_module.rb to take effect.
Also, a lot of people reference this post by Yehuda Katz as guidance on where to store code for your app. Thought it might be a helpful reference.
if you include MyModule into MyController, all the "instance methods" of the first will be mixed-in into the 2nd.
So if you only want to call MyModule.a_method, no need to include your module.
Then you'd want to require (or better autoload) your module before using it. To do so place it in controllers/concerns/my_module.rb, rails (4 at least) should autoload it, otherwise require its file in an intializer
# my_module.rb
module MyModule
def self.a_method
...
end
end
should work, but doing
# my_module.rb
module MyModule
extend self
def a_method
...
end
end
is more clean to me. You'd like to have a look to rails active support concern to understand the "rails way" on this topic.
Using Rails 2.3.11, I'm creating a plugin for Redmine that add methods to ApplicationController.
I've created the following module, in the plugin :
module ApplicationControllerPatch
def self.included(base) # :nodoc:
base.class_eval do
rescue_from AnException, :with => :rescue_method
def rescue_method(exception)
...
end
end
end
end
Now, if I include this module directly into the application_controller.rb file, like this:
class ApplicationController < ActionController::Base
include ApplicationControllerPatch
...
end
Everything works just fine, however I would like to avoid editing the core source by including this module from the plugin itself.
So far, if I do:
ApplicationController.send(:include, ApplicationControllerPatch)
directly from this module file (located in the plugin folder). This will load properly for the request and then it gets overwritten by the controller (I guess).
What's is the way to accomplish this ?
A common pattern is to use Dispatcher.to_prepare inside your plugin's init.rb. This is required because in development mode (or generally if config.cache_classes = false) Rails reloads all classes right before each request to pick up changes without the need to completely restart the application server each time.
This however means the you have to apply your patch again after the class got reloaded as Rails can't know which modules got injected later on. Using Dispatcher.to_prepare you can achieve exactly that. The code defined in the block is executed once in production mode and before each request in development mode which makes it the premier place to monkey patch core classes.
The upside of this approach is that you can have your plugins self-contained and do not need to change anything in the surrounding application.
Put this inside your init.rb, e.g. vendor/plugins/my_plugin/init.rb
require 'redmine'
# Patches to the Redmine core.
require 'dispatcher'
Dispatcher.to_prepare do
ApplicationController.send(:include, MyPlugin::ApplicationControllerPatch) unless ApplicationController.include?(RedmineSpentTimeColumn::Patches::IssuePatch)
end
Redmine::Plugin.register :my_plugin do
name 'My Plugin'
[...]
end
Your patch should always be namespaced inside a module named after your plugin to not run into issues with multiple plugins defining the same module names. Then put the patch into lib/my_plugin/application_controller_patch.rb. That way, it will be picked up automatically by the Rails Autoloader.
Put this into vendor/plugins/my_plugin/lib/my_plugin/application_controller_patch.rb
module MyPlugin
module ApplicationControllerPatch
def self.included(base) # :nodoc:
base.class_eval do
rescue_from AnException, :with => :rescue_method
def rescue_method(exception)
[...]
end
end
end
end
end
This kind of problem occurs only in dev because the classes are reloaded but not gems.
So add your send method in a config.to_prepare block within config/environments/development.rb
Read Rails doc concerning initialization process for further details.
I have written some custom code that make changes to some of the methods in ActionView::Helpers::AssetTagHelper
An example:
module ActionView
module Helpers
module AssetTagHelper
alias old_existing_method existing_method
def existing_method
puts "Does foobar"
return old_existing_method
end
end
end
end
Now normally i would keep this code code in RAILS_ROOT/config/initializers/asset_helper_overrides.rb
This works as expected.
Now i want to turn this into a plugin.
I copied this file to the plugin location and the i would require it in init.rb file.
However, this doesn't seem to work.
I'm not sure why this doesn't work.
I'm guessing maybe its because the file is required before ActionView::Helpers are required. Not sure.
Can someone help me out here. Thank you.
I'd suggest creating a module for this, and including your module into the helper. Here's an example:
module AssetTagExtensions
def self.included(base)
base.alias_method_chain :existing_method, :added_cleverness
end
def existing_method_with_added_cleverness
puts "Does foobar"
existing_method_without_added_cleverness
end
end
Then, in your init.rb file you should do something like:
ActionView::Helpers::AssetTagHelper.module_eval do
include AssetTagExtensions
end
It's important to call module_eval (or send) on the ActionView::Helpers::AssetTagHelper class rather than reopening it, to ensure you don't prevent it from loading correctly.