Rails 5 - Namespacing models - ruby-on-rails

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

Related

Classes in subfolders in app/models don't get loaded?

I would like to have a folder of related Models in my Rails 4 app. Why don't classes in app/models/debt_models get loaded?
I guess there is a work around by how come Rails just doesn't recursively go through folders under app/models? Is there a reason? Seems like this is something Rails should do without me having to tell Rails to do that.
You just have to follow conventions. If you put models in debt_models, it means you namespace them like:
module DebtModels
class Foo
Path: app/models/debt_models/foo.rb

Where do I place my non-model classes?

Where should I put my simple classes that are not models (they don't represent any data) and provides only some functionality?
Like for example:
class FileUploader
def save_uploaded_file(filename, tempfile)
path = Rails.root.join('public', 'uploads', filename)
File.open(path, 'wb+') do |file|
file.write(tempfile.read)
end
end
end
What this does is just simply copies file to predefined place.
Do I must to place this under models? Or do Rails have some other location more suitable for those kind of classes? I tried to put in lib before, but it was just too much of the pain as Rails cached those files inside lib directory (edited config to not cache files, but it still cached inside lib).
So, I placed those files in models but testing becomes very painful (I'm just starting Rails, maybe I'm doing something wrong with the tests) as rake spits out errors about not having set up a test database (I want to test classes that are not related to database in any form or shape - why do I need to set up a database?).
I've taken to adding app/lib to some of my projects to accommodate this, but there's also the new Rails 4 concerns locations like app/models/concerns or app/controllers/concerns depending on where this sort of thing is used.
You're right that it's best to avoid putting non-model classes in app/models.
For service-type objects I put them in app/services.
For model-type objects I put them in app/models. I do not think it is necessary to inherit from ActiveRecord to be considered a model.
I think your object classifies as a 'service object' since it is designed to wrap the service of uploading a file, it isn't really a domain object like a model would be.

what is the correct way to add classes to a controller in rails?

If i need to add (project specific) classes to my controler in rails, what is the correct way/place to put and "include" them/there .rb files? (quotes for: not the ruby keyword include)
I am new to rails, and did not find the correct way. LIB sounds like for more public libraries and - what I have learned - is not reloaded per default in dev mode.
sure, I could put all in controler.rb, but ...
the anser for me:
First: there are no rules, if you keep in mind (or learn like me) the rails rules:
NameOfCla -> name_of_cla(.rb) <-- not using class as word for clearence
name your class how you like:
class ExtendCon #<--- not using controller here for clearence
....
put it in a file extend_con.rb, wait for the path explaination, please. if you named your class 'MYGreatThing' it will be 'm_y_great_thing' (never testet that), so avoid chineese charachters
if your controller uses
#letssee=ExtendCon.new
rails learns that class and file (extend_con) on its own. i still did not figure out if a server restart is needed. (the first time)
choose the path to put the file: (I preferre Daves way) app/myexten or what you like, making it 'app' specific and still distquishes to standard rails 'things'
if you are not lasy like me (i put it in app/ontrollers)
put the path you have choosen into
config/application.rb like (comments are there to find it)
# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/app/controllers)
config.autoload_paths += %W(#{config.root}/app/myexten)
this one workes for me in all modes including "developer" and i did not need to put "my own" things in app/lib
It depends.
I tend to put library code used explicitly (e.g., instantiated, injected, etc. into app-level artifacts) into app/xxx where xxx signifies the "type" of thing, like decorators, services, etc.
Magic stuff tends to end up in lib, like monkey patches, architectural-level artifacts, and so on.
Code anywhere can be added to the autoload paths, required automatically by an initializer, etc.
Rails 4 comes with an internal directory for controllers called concerns. You could try using that.
app/controlls/concerns
If you have concerns/foo_bar.rb, you include it as follows:
class FooController < ApplicationController
include FooBar
end
Models also have their own concerns directory. I find this approach useful, and it can be applied to Rails 3. You just have to add the directories to your load paths.

Models with reserved keywords

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

Rails project organization with many models

I'm working on a rails app that is starting to have what seems (to me) to be a lot of models. There are 15 right now, but I'm thinking about adding 3-4 more to serve as "tag" like models (I need more functionality than Acts As Taggable offers).
So, the reason this bugs me a bit, is that 7 of the 15 models belong to a common parent. Several are belong_to, and a few are has_and_belongs_to_many. All the new models I'm contemplating would belong_to the same parent as well.
So, what I'm wondering is, what is the best "Railsy" way of organizing this kind of situation?
Instead of app/models being super crowded with 6 "first-class" models and 10+ children of one of these, should/can I start using sub folders in my app folder? ie: app/models/parent/child.rb?
I know this is kind of an open-ended question, but I would really appreciate advice as to the best way to handle a rails project with a proliferation of models.
Thanks!
You can do this, I always do :)
Just beware of something: if you create a folder which has the name of one your models, it will fail. Actually, Rails will think you want to extend it.
So in your model folder, prepend the name of your class with whatever fancy you want.
Example: if you want to put models related to users, put them in models/user_related/
You'll have to add this to your application.rb file:
config.autoload_paths += Dir["#{Rails.root.to_s}/app/models/*"].find_all { |f| File.stat(f).directory? }
This will autoload all folders included in modelsdirectory.
I think apneadiving's answer is good approach
Based on research with activesupport 3.0.11, there are some rules to follow when choosing a directory name however:
The name must never match a constant in your system, or LoadError's could occur
The name must be able to be converted to a valid constant name, or NameError's will occur.
Explanation of problem #1
Apneadiving's example of a directory name app/models/user_related works as long as a
constant UserRelated is never used in your code. Otherwise a LoadError could
potentially happen.
For example, assume there was a model called UserProfile and the first time
rails sees the constant is in the UserRelated module. Rails will first try to
load a UserRelated\:\:UserProfile constant and failing that a UserProfile
constant.
If the user_profile file is at app/models/user_related/user_profile.rb, this
matches the underscored path of UserRelated\:\:UserProfile and the file would
be loaded expecting to define the UserRelated::UserProfile constant. This
would raise the following error because it really defines the UserProfile
constant.
Expected app/models/user_related/user_profile.rb to define UserRelated::UserProfile (LoadError)
This happens in the active support dependency code.
Explanation of problem #2
Another caveat is the directory name must be able turned into a valid ruby
constant name (although to follow #1 the constant should be undefined). For
example, if the directory name were app/models/user.related this would result
in the following error inside the active_support dependency code:
wrong constant name User.related (NameError)

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