I'm writing some Rails code that I want to be both 1.8.7 and 1.9 compatible. In a couple different files, I do some CSV parsing, so I currently have the following requires line in each file:
if RUBY_VERSION < "1.9"
require "rubygems"
require "fastercsv"
CSV = FCSV
else
require "csv"
end
To avoid all the duplication, though, this block should probably live in a single place. Where's the best place to put it? Is application.rb the right place?
I'd put it in an initializer config/initializers/csv.rb. This is loaded into rails automatically, and does not mix into the load path (so you don't have to bother about the file name).
Just be aware that some loading mechanisms do not do a "require" but just run the file in the loader context, so if you get an exception, you may not deal with it in the usual way.
Related
Just curious on how things autoloading works in rails
app/models/base_facebook_object.rb
class BaseFacebookObject
end
In the file where I require it,
app/models/fb_campaign.rb
class FbCampaign < BaseFacebookObject
end
But the above doesn't work as it says BaseFacebookObject not defined?
Do I always have to require the base object file in such cases?
require "#{Rails.root}/app/models/base_facebook_object"
Thanks in advance
The autoloader will resolve unfound constant. In your case if you call FbCampaign it will check for the file fb_campaign.rb, then during the loading will find BaseFacebookObject and load base_facebook_object.rb
In other words, no requires needed. Actually you should never use require in a RoR application except for std lib not yet loaded (eg. securerandom, base64 etc. ) or files into a lib/non-autoloaded path.
I have a highly modified Rails repository. None of the classes use ActiveRecord. I'm finding that I have to specify many file and gem requirements at the top of each class. I want to have the requirements for each class preloaded in an initializer rather than it being specified in the class. How do I do this? Is this a bad idea? Is it necessary?
There are several ways to do this.
The obvious one is to require a single file, and then inside that file have all of your requirements listed.
For example in list_of_requirements.rb you could have
require 'thin'
require 'x'
require 'y'
Then in your class_that_requires_stuff.rb you could have
require 'list_of_requirements'
This way in your indvidual classes you only need one require statement and you don't need to require all these gems in every file. You also don't need an initializer.
I'll explain my situation.
Here is my file tree in my rails application :
lib/my_module.rb
require 'my_module/my_file'
module My_module
end
lib/my_module/my_file.rb
class Tweetag::Collector
(...)
end
I've made a ruby script that I've put in config/jobs/
I really don't understand how I am supposed to require the file my_file.rb in this file.
require '../../my_module/my_file.rb'
It gives me `require': cannot load such file
Same error with just require 'my_module' which is what I do in my controllers...
Someone here to explain to me ? Thanks a lot
You can autoinclude everything under the lib folderand avoid these problems:
Type this your file in config/application.rb
config.autoload_paths += %W(#{config.root}/lib)
config.autoload_paths += Dir["#{config.root}/lib/**/"]
If you want to require only a specific file then,
do something relative to Rails root like this
for example: --
lib/plan.rb
module Plan
...some code...
end
and if you want to require it only in some model, say app/models/user.rb
do in user model
require "#{Rails.root}/lib/plan"
class User < ActiveRecord::Base
include Plan
end
if you want it to be available everywhere
one solution is given by #VecchiaSpugna
or you can create a ruby file in config/initializers folder
and require all file over there one by one
OR
try this
require '../../my_module/my_file'
instead of
require '../../my_module/my_file.rb'
You don't need to specify extension for a file in require.
I think there are two solutions.
1) Add the lib path to the search path.
In ruby:
$:.unshift('../../my_module/lib')
Then you can require 'my_module.rb'
I think Vecchia Spugna answer is the rails-version of my ruby-answer. (I'm not familiar with rails).
2) Another solution:
In your lib/my_module.rb you require my_file. This file is located relative to your my_module.rb? Then use require_relative:
require_relative './my_module/my_file'
Just chiming in because it took me forever to figure this out because very little solutions worked.
• I had to use plain old require. I put it in the config/application.rb file.
patching_file_path = File.expand_path("./lib", Dir.pwd)
Dir[patching_file_path+'/*.rb'].each {|file| require file }
• I also put a temporary puts "I'm Working! in the file I'm trying to require so I can check the console to see if it's actually loading.
• Also, if you're using spring loader, before you start your console you should do bin/spring stop in your terminal before you start your rails console. Otherwise, it won't load new files.
Similar to require_relative,
# inside lib/my_module.rb
require File.expand_path('./my_module/my_file', File.dirname(__FILE__))
This expands the path of current file directory and add the relative file path to be required.
I'm in the process of refactoring some logic built into a Rails application into middleware, and one annoyance I've run into is a seeming lack of convention for where to put them.
Currently I've settled on app/middleware but I could just as easily move it to vendor/middleware or maybe vendor/plugins/middleware...
The biggest problem is having to require the individual files at the top of config/environment.rb
require "app/middleware/system_message"
require "app/middleware/rack_backstage"
or else I get uninitialized constant errors on the config.middleware.use lines. That could get messy very quickly. I'd rather this was tucked away in an initializer somewhere.
Is there a conventional place to put this stuff?
The specific answer I'm looking for with this bounty is: where can I put the require lines so that they are not cluttering the environment.rb file but still get loaded before the config.middleware.use calls? Everything I have tried leads to uninitialized constant errors.
Update: Now that we're using Rails 3.0, I treat a Rails app like any other Rack app; code files for middleware go in lib (or a gem listed in Gemfile) and are required and loaded in config.ru.
As of Rails 3.2, Rack middleware belongs in the app/middleware directory.
It works "out-of-the-box" without any explicit require statements.
Quick example:
I'm using a middleware class called CanonicalHost which is implemented in app/middleware/canonical_host.rb. I've added the following line to production.rb (note that the middleware class is explicitly given, rather than as a quoted string, which works for any environment-specific config files):
config.middleware.use CanonicalHost, "example.com"
If you're adding middleware to application.rb, you'll need to include quotes, as per #mltsy's comment.
config.middleware.use "CanonicalHost", "example.com"
You can put it in lib/tableized/file_name.rb. As long as the class you're trying to load is discoverable by its filename, Rails will automatically load the file necessary. So, for example:
config.middleware.use "MyApp::TotallyAwesomeMiddleware"
You would keep in:
lib/my_app/totally_awesome_middleware.rb
Rails catches const_missing and attemts to load files corresponding to the missing constants automatically. Just make sure your names match and you're gravy. Rails even provides nifty helpers that'll help you identify the path for a file easily:
>> ChrisHeald::StdLib.to_s.tableize.singularize
=> "chris_heald/std_lib"
So my stdlib lives in lib/chris_heald/std_lib.rb, and is autoloaded when I reference it in code.
In my Rails 3.2 app, I was able to get my middleware TrafficCop loading by putting it at app/middleware/traffic_cop.rb, just as #MikeJarema described. I then added this line to my config/application.rb, as instructed:
config.middleware.use TrafficCop
However, upon application start, I kept getting this error:
uninitialized constant MyApp::Application::TrafficCop
Explicitly specifying the root namespace didn't help either:
config.middleware.use ::TrafficCop
# uninitialized constant TrafficCop
For some reason (which I've yet to discover), at this point in the Rails lifecycle, app/middleware wasn't included in the load paths. If I removed the config.middleware.use line, and ran the console, I could access the TrafficCop constant without any issue. But it couldn't find it in app/middleware at config time.
I fixed this by enclosing the middleware class name in quotes, like so:
config.middleware.use "TrafficCop"
This way, I would avoid the uninitialized constant error, since Rails isn't trying to find the TrafficCop class just yet. But, when it starts to build the middleware stack, it will constantize the string. By this time, app/middleware is in the load paths, and so the class will load correctly.
For Rails 3:
#config/application.rb
require 'lib/rack/my_adapter.rb'
module MyApp
class Application < Rails::Application
config.middleware.use Rack::MyAdapter
end
end
I'm not aware of a convention, but why not put it in the /lib directory? Files in there get automatically loaded by Rails.
You could create an initializer which requires the necessary files and then leave the files wherever you want.
According to this the initializers are executed before the rack middleware is loaded.
The working solution I have so far is moving the middleware requires to config/middleware.rb and requiring that file in environment.rb, reducing it to a single require which I can live with.
I'd still like to hear how other people have solved this seemingly basic problem of adding middleware to Rails.
I have a engine style Rails plugin from which I can create a gem using Jeweler. But when I require it in my Rails environment (or erb) the models within the plugin are not loaded. I have followed a number of tutorials and read just about everything on the subject.
# environment.rb
config.gem 'myengine'
# in irb
require 'myengine'
I have unpacked the gem and verified that all files are present. My init.rb has been moved to a new folder called 'rails' as per. All files in 'lib' are automatically added to the $LOAD_PATH, so require 'myengine' runs lib/myengine.rb. I verified this by putting a puts 'hello' within.
Is it because of the physical presence of plugins in a known place that Rails can add all the models, controller etc. to the relevant load_paths? Do I need to replicate this manually when using a gem?
Would gemspec require_paths be a way of adding additional paths other than lib? I assume however that Rails does not just require every single file, but loads them on demand hence the need for the filename and class name to match?
%w{ models controllers helpers }.each do |dir|
path = File.join(File.dirname(__FILE__), 'app', dir) + '/'
$LOAD_PATH << path
puts 'requiring'
Dir.new(path).entries.each do |file|
if file =~ /\.rb/
puts file
require file
end
end
end
By adding the above to lib/myengine.rb all the models/controllers are required. But like I said in my question this is unlikely to be a good way forward.
Offhand I'd say the part about adding those directories to the search path is right on. What you shouldn't need to do is require each file manually (as you allude to in your last sentence). What Rails does when you reference a non-existent constant is to search for a file with the same name (underscored of course) in the load path.
If for some reason you can not abide by the constraint (think about it long and hard) then you are going to need to dig deeper into Rails and see how the reloading mechanism works so you can tie into it properly in development mode.
The problem was the files (in app) where not being added to the gem because when using Jeweler it only automatically adds files to required_paths which are committed to git.