I'm new to Rails, and have been learning with Rails 3 on a side project. There are times when I want to write some code that does not belong in my models or in my controllers - concerns that are related to a model and/or controller, but i don't want to clutter up either of them with the implementation details of what i am writing.
For example: a project i'm building uses Janrain's authorization system (RPX) so i can get oauth, openid, google, etc. authorization. there's a nice chunk of API code that they provide so i don't have to write it all myself. this code doesn't belong in the login controller or in the user module. it's authorization code, so it needs to be accessible by the login controller, but it's not part of that controller.
Where do you put this code? it's not model code. it doesn't belong in the controller.
... thanks in advance.
You should be able to use lib folder in your root directory (unless it's changed in Rails 3).
You can refer classes from there without require statement.
A 'common' suggestion is to say 'put this stuff in lib'. But there are other places to consider:
Consider making a subfolder in app. Some examples include: app/workers, app/observers, app/sweepers, or whatever makes sense for you.
Consider using config/initializers for initialization code.
Lastly, and only if the above don't make sense, you can use lib. Don't forget you can use subfolders to keep it from getting too junked up.
And, once you get things working and polished, consider extracting your code into gem. See, for example, the RailsCast on Creating a New Gem with Bundler.
Related
Is there any best practice to where third parties wrapper libraries are settled on rails application?
I've been developing with app/service driven way, so it's easy to encapsulate the action behind the scenes.
Ref: http://brewhouse.io/blog/2014/04/30/gourmet-service-objects.html
Now the problem is
Where should I put third party library wrappers for specific needs?
For example,
Mailchimp: wrapper for email subscription
Prawn: The wrapper for PDF receipt
Slack notifier
....
I could create gems for each ones, or put them into models.
If the code is big enough such as PDF receipt wrapper, I could go for creating gem, but if it's small I don't think it's good to put neither model/gem.
Any suggestions?
It's really up to you.
You can put custom code in new files in config/initializers - these will be required automatically.
It's also common to put code in lib/ and add it to the autoload path (there are other questions for this).
You could make a model for each service as well. You don't necessarily need a database table for models (there are other questions for configuring this).
I think this information (where to put custom code) is really integral to rails and I see a lot of beginners confused by it.
In a Rails app I'm creating, I have some code in my controller that I'm wondering whether it's in the proper place. The code is fairly insignificant, it stores ids in an array to show 'recently viewed' pages. It's about 3 lines of code, but I'm thinking to the future, what if this feature expands? I don't want my controller to be bloated.
I could make a module, but in that case where should I store the file?
Is the controller the right place to be doing the session management?
Any suggestions on my code organization?
Thanks
If it is specific to the controller, keep it in the controller.
If it applies to all controllers, it goes in ApplicationController.
If it is shared by some controllers and not others, then inherit from a controller that inherits from ApplicationController, or use include/extend or make a module that extends ActiveSupport::Concern (which is what Rails uses internally fairly commonly).
And it's best to keep everything in app/controllers or some subdirectory, sub-subdirectory, etc. Rails autoloading depends on the path to match up with the module namespace, so A::B::C belongs in app/controllers/a/b/c.rb. Don't make it deep like Java, etc. Just have the number of directories/modules you need to keep it organized.
Note: though controllers aren't as problematic to have in their own modules, in my experience your models should stay in the root, like app/models, or you'll have problems.
I'd also avoid storing too much in session if you can help it. Store in the DB (or long-life cookies, if it is browser-environment specific) instead. For example- if someone logs out and they were looking at one record, they might want to log back in later and have a list containing the link to that record.
BTW- you weren't asking and probably already have the code for storing recently visited pages in session, but here are similar questions/answers:
https://stackoverflow.com/a/10813602/178651
http://www.rorexperts.com/how-to-store-visited-pages-in-session-object-in-rails-t941.html
I'm just starting out in Rails and there's a lot I still need to learn so I'm likely to be on Stackoverflow more often than normal asking beginner Rails / Ruby questions.
I'm just trying to figure out how Helpers work in Rails. From what I've seen so far, Helpers are intended to be used with Views and not so much with your Controllers.
However I would like to make a simple function that will validate the user input given in params (check if certain params are defined and optionally check if their value is valid).
Can anyone explain to me what would be the best way of implementing this? (Keeping in mind that I will want to use this in many different controllers so it should be globally available.)
I also noticed that by default Rails does not generate a lib folder in the main application folder. Are developers to place their libs outside the app folder in the main folder, or does Rails use libraries differently?
With regards to your validation issue, it depends on what you are validating.
If the data makes up objects from your problem domain, also known as models, then you should use the built in validators from ActiveModel. This is probably what you should do, but its hard to say without knowing the exact problem. See the Rails Guides on Validations. You can tell if this is the case by asking yourself if the data that needs validation will be stored after you get it. If so, its most definitely a model. An example of this kind of data would be the title and text fields of a blog post being sent to Rails from a browser form.
If the data is something tertiary to your models, or specific to presentation, then you should be fine using helpers. You noticed that helpers are used mostly in the views, and although this is true, theres nothing stopping you from using them in the controllers, you just have to declare that you will use them using the ActiveController#helper method. Inside the ApplicationController class, a lot of devs will put helper :all to just include all the helpers in all the controllers. Once the code has been required once, it doesn't really incur that big a performance hit.
Do note that almost all incoming data can be modeled using a model. A big school of thought in the Rails world subscribes to the Fat Model idea. People say that putting as much code as possible in the model and as little in the controller as possible separates concerns properly and leads to more maintainable code. This suggests that even if you don't think the incoming data is modelable (in the sense that you can create a model to represent it), you should try to make it a model and encapsulate the logic around validating it. However, you may find that making a helper function is faster, and either will work.
Your notion of validating user input is a good one. I get the feeling that as you are new to Rails you are used to doing these things yourself, but that doesn't quite apply here. In the Rails world, a lot of the common stuff like validations is handled by the framework. You don't have to check for presence in the params array, instead you call validates_presence_of on the model and let Rails spit the error out to the user. It makes things easier in the long run if you let the framework do what it is designed to.
With regards to your question about the lib folder, it doesn't really matter. You can put miscellaneous support files and libraries in the lib folder in the root directory and they will be available for use in your application (the files in the app folder). You can also choose to abstract your code into a plugin or a gem and include it that way, which a lot of people opt to do. My suggestion for this would be to read up on the notion of gems and plugins before diving in.
Want you want is probably a custom validator (in Rails3):
http://railscasts.com/episodes/211-validations-in-rails-3
You can either add libs in a lib folder you create, or add them to config/initializers in a file you add. Files in the initializers directory are automatically loaded by Rails.
I've read about HMVC (Hierarchic Model View Controller) and it's flexible structure.
Have a look at this picture:
http://techportal.inviqa.com/wp-content/uploads/2010/02/MVC-HMVC.png
I wonder if the Rails 3 plugins are the answer to HMVC in Rails 3?
Based on the comments to Toby's answer it seems that you would like to be able to have MVC apps used as a component within a new app. Rails Engines (See http://rails-engines.org) provides this functionality. You simply install the engines gem and place apps in vendor/plugins and its modles/views/controller are all accessible.
This does not really conform to HMVC where the controllers in the new app delegate to other controllers. But like Toby I do not see the advantage of that.
What is nice about the Engines approach is that you can over ride any of models in the plugin by just adding a version of the model to the new apps app/model folder (same applies for views and controllers)
I have overidden app/views/layouts to give my Authentication app/plugin the same look and feel as the application it is included in.
For Rails 3 Railtie takes the place of engines and is officially supported (and actually used - Action Mailer is a Railtie plugin. I have not used it myself yet though.
Check it out at http://edgeapi.rubyonrails.org/classes/Rails/Railtie.html
A nice write up on it is also here http://www.igvita.com/2010/08/04/rails-3-internals-railtie-creating-plugins/
Rails has had plugins for a long time.
I doubt there is a technical reason why a controller couldn't dispatch to another controller, passing the request object along a chain. I just don't know what you gain by doing so - the diagram looks like spaghetti.
To me it's a misuse of MVC. I would suggest it is much simpler and more maintainable to push logic into lower-level models and classes and create a single controller that fronts the this logic, rather than creating a chain of controllers.
In the Rails 3 blog post, DHH mentioned the Cells project. I haven't used it but I am going to check it out.
The cart example shows well how that kind of functionality might clean up your application code. Code which retrieves data should be placed somewhere in controller. In every action or in a before filter. The Cell seems to be much better solution.
Please look at this rubyonrails-talk post: https://groups.google.com/forum/#!topic/rubyonrails-talk/0c4TT7UOGCw
I have a Rails application with several models-views-controllers which have some similar characteristics, for example 5 different models can be commented on, voted on or tagged, I am also heavily using external plugins.
At the moment I introduced comments, votes, tags, etc. only to a single model (and its view and controller). However, now that I am happy with the results, I want to cut out this common functionality from the particular MVC of one model and allow access to it from all other models.
Some questions before I start doing this (and maybe some general advice will also be great):
1 - How should I go about it? I was thinking creating a module in "lib" directory (is it the same as mixin class?) and then moving reusable view code to common partials. What about the controller code?
2 - As I was just learning Ruby on Rails during the coding of the first model, I went with a probably incorrect way of adding a bunch of methods to the controller. I have a method that adds a comment (addcomment), adds a vote (addvote), etc. All these methods require non-standard (non-RESTful) routing via :collection. From what I understand, the correct way would be to move comments controller functionality to its own controller and access via standard RESTful routes. Is this what I should be doing?
3 - Many plugins (eg. act_as_commentable) do not explicitly require loading a Module, just a line "act_as_commentable" somewhere in the Model. Can I use something like this for my common functionality? How does it work?
A simple way is to split the code into modules and use mixin.
A better way is to write your own plugins for your common code.. like act_as_commentable
you can learn about it here: http://guides.rubyonrails.org/plugins.html
The correct way is to do a comments controller, and have it nested to your models, giving a restful routes like this: /mymodelname/1/comments.
An easy way to make such controllers is by using inherited_resources plugin.
scroll down to the "Polymorphic belongs to" section- there is a comments controller example
For repeated model code, put it in a module in the lib directory.
For controller code, put your duplicate code in ApplicationController.
For your view code, use partials.