I want to create a model called 'File', but it is a reserved model name is rails. I can't think of anything else sane to call the model, so I was wondering if there is a standard way of dealing with this issue, for example adding a prefix or suffix (_File, FileItem, etc)?
This problem is addressed with modules:
Modules are a way of grouping together methods, classes, and
constants. Modules give you two major benefits:
Modules provide a namespace and prevent name clashes.
Modules implement the mixin facility.
[...]
Modules define a namespace, a sandbox in which your methods and
constants can play without having to worry about being stepped on by
other methods and constants.
In your case:
module MyRailsApp
class File
...
end
end
whereby your File class is used as MyRailsApp::File. This is the typical solution in Ruby, in Ruby on Rails this might be handled differently, please see the following references for an in depth discussion:
Handling namespace models (classes) in namespace
ActiveRecord: Can haz namespaces?
Namespaced models and controllers
Namespaced models
A simple alternative to namespaced models
Related
I am using namespacing in my Rails 5 app to try to keep resources organised.
I've been generating resources using the command line by adding the namespace folder to the generate command.
This makes a folder in the models folder for the main folder which the namespaced files are saved in.
I've since been reading posts from others that suggest namespacing models is not a good idea.
An example of what I currently have is:
class Stance::Assessment < ApplicationRecord
It seems to work alright so far.
What is the problem with namespacing models?
If it is a problem, does that mean I can't organise my models into folder groups, or does it mean that the model class doesnt need to be named wiht the "Stance::"?
There is a certain cost of complexity involved with "namespacing" your models. Ruby does not actually have true namespaces. Rather it has has modules which provide encapsulation.
Rails and ActiveRecord was designed around placing your application code in the Main object (the global object). While this might seem like a bad practice it is very simple and works well with the convention over configuration approach. It also allows a much simpler autoloading scheme and avoids the need to nest every single file in an additional folder.
Namespacing does have great organizational merits though and lets you avoid collisions. But there are a few minor aches in the backside:
table prefixes, having the generated table names like my_app_projects_tasks is really inconvenient when you need to write a custom join.
You need to override ActiveModel::Naming so that it does not look for paths like my_app_projects_tasks_path when using the polymorphic route helpers.
You need to explicitly set the class_name option when creating associations or override how ActiveRecord resolves constant names.
you can prefix your models, so instead of Stance::Assessment you would have StanceAssessment. not as clean as a namespace but it's pretty close to it
After upgrading my Rails app, I have run into a problem where the name of one of my models are conflicting with another class in Rails, namely Configuration.
Is there a way for me to (from a controller) explicit use my model class Configuration instead of ActiveSupport::Configurable::Configuration? What is the default namespace for my models?
You can use ::Configuration to call your class. It means that you're referring to the constant Configuration from the toplevel namespace. But I think it's annoying. You can rename your class to avoid this.
I'm having a naming collision between my Address class used for db and the Address class generated using wsdl2ruby (and several other classes). I'm using soap4r.
Is there anyway to generate the soap4r classes in their own namespace so all the soap4r classes can see each other but not conflict with my application?
I'd rather not go with a dynamic generator (handsoap, savon) as this would greatly increase the volume of user code.
Ruby doesn't have namespaces, it has modules. From the source, it looks like the --module_path [desiredModuleName] option for wsdl2ruby is what you're looking for.
I recently authored a gem called 'setting' (found here). The extends ActiveRecord with a module named 'Setting'. I understand that gems are supposed to use the namespace they are named, however when testing this caused collisions with ActiveRecord models with the same name (a Setting model). Does a standard exist for creating a private module namespace? I don't need users of the gem to ever access the module outside the extension in ActiveRecord. Do I have any options outside of picking a less common name?
Since you're writing an Active Record extension, you could place your module inside the ActiveRecord namespace:
module ActiveRecord
module Setting
end
end
Other than that, no, there's no practical namespace solution for gems with very common names.
I am using Ruby on Rails 3 and I would like to handle models (classes) namespaces within namespaces. That is, if I have a namespace named NS1 and a "sub-namespace" of that namespace named NS2, I would like to handle models (classes) in NS2.
If I run a scaffold
rails generate scaffold ns1/ns2/Article id:integer title:string
it will generate following model files:
models/ns1/ns2/article.rb file
models/ns1/articles.rb
The models/ns1/articles.rb contains:
module Ns1::Articles
def self.table_name_prefix
'ns1_articles_'
end
end
What is the models/ns1/articles.rb file? How and why can I use that? Have you advices about using that?
And, in general, what is "the best" way to handle "composed" classes in namespaces using Ruby on Rails?
The
models/ns1/articles.rb
is basically setting the table name prefix for all the model classes under that namespace. Thats its use. It's more DRY'ish to do in there (in a single file), rather than setting the prefix in every model class under that namespace.
I am not a big fan of using namespaces in my models. However you could refer to the following articles to gain a better understanding about using namespaces in modules.
Namespaced models and controllers
Some alternatives to using namespaces in models
A simple alternative to namespaced models
Hope this helps.