Shared resource for partial in Rails - ruby-on-rails

Premise: I'm quite new to Rails. I'm trying to render a partial in the application layout that will have to display some Event objects. The partial will have to be displayed in every page of the application (it's basically a sidebar). I am aware that I should pass a local variable to the partial, like
<%= render partial: "shared/aside", locals: {events: #events} %>
But this will only work if I define #events in every single controller of the application. Is there a way of setting it globally?
It might be worth noting that events might not be the only resource needed to the partial.

You could do a before action in the application controller. The before action would go at the top of the file, the private method at the bottom
class ApplicationController < ActiveController::Base
# Place at top of file
before_action :set_events
...your other code...
# Place at bottom of file
private
def set_events
#events = Event.all
end

Related

Rails Override Render

Is it possible to override Rails' render behavior for :html responses? I'd like to always render the same template (ignoring the magic view finding).
I'm writing a single page app, and this seems like it should be possible...basically if it's requested as :json it should render JSON, but if it's requested as :html it should pass the data on to the same view no matter what (where it will be rendered as JSON in the body).
Try to delete the yield part on your application.html.erb, then you will alway get the application.html.erb without any partials.
What if you define one single view and then after every action on every controller you render that view? Like this:
app/controllers/home_controller.rb
class HomeController < ApplicationController
def home
end
end
app/views/home/home.html.erb
<!-- Whatever html code and script tags here -->
app/controllers/another_controller.rb
class AnotherController < ApplicationController
def action
render "home/home"
end
end
You could even define an after_filter
Edit
I tried this and it works. The after filter doesn't seem to work though.
Why not pass the JSON data as an instance variable?
controller
#json_data = whatever_model.to_json
application.html.erb
<script>
<%= #json_data %>
</script>

Rails - Partial in another view can't access its controller

I'm trying to build a profile page that displays posts sent only to the requested user, and allows the visitor to write a post of their own. Because this simplified example should have two distinct controllers: users and posts, I made partials for each post action to render within the user's show action.
Directory structure for my views directory looks like this:
- posts
- _index.html.erb
- _new.html.erb
- users
- show.html.erb
... (etc.)
Section that displays these partials within the user's show.html.erb:
<section>
<h3>Posts:</h3>
<%= render '/posts/new', :post => Post.new %>
<%= render '/posts/index', :posts => Post.where(target_id: params[:id]) %>
</section>
I eventually found out that you could pass variables into the partial in this render line, and though this works, it's very messy and probably doesn't follow the best practices.
Ideally, I'd want these partials to be connected with the posts controller so I can write more complex database queries in a place that isn't the view:
class PostsController < ApplicationController
def new
#post = Post.new
end
def index
#posts = Post.where(target_id: params[:id])
end
def create
#post = Post.new(post_params)
#post.user_id = current_user.id
#post.target_id = params[:post][:target_id]
if #post.save
redirect_to :back, notice: 'You published a post!'
else
render new
end
end
private
def post_params
params.require(:post).permit(:body)
end
end
Currently, I haven't found a way of doing this. I know this is a newb question, but thanks for any help in advance.
You are attempting to treat your controllers like models: doing the post work in post controller and the user work in user controller. But controllers are task-oriented, not model-oriented.
Since you want posts info in your user form, it's typical to gather it in the user controller. E.g.
class UsersController < ApplicationController
def show
...
#posts = Post.where(user_id: user.id)
end
end
That #posts instance variable is visible in the show template and any partials it calls. But many coders prefer to send it explicitly through render arguments, as more functional:
<%= render '/posts/post_list', posts: #posts %>
For one thing it's easier to refactor when you can see at a glance all of the partial's dependencies.
I agree somewhat with #Mori's advice. As he said, you are trying to put too much logic into the controller. I think this was a result of you trying to get it out of the view, which is the right idea, but you want business logic to be in the model.
Also, those index and new actions for PostsController are never going to be called. When you are calling the render posts/new for example, that is rendering the view, not the controller action. So, those controller actions have no reason to exist.
I would implement the fix in perhaps a different way than Mori described. It's a recommended practice to try and pass as few instance variables from the controller to the view as possible (see 3rd bullet in the linked section).
Since it's really the show action of the UsersController we are talking about here, I as someone trying to understand your code would assume the instance variable you are passing to the show view is something like #user.
You may want to use an includes method when instantiating the #user object. The includes statement will allow you to load the additional models you will need to instantiate using the minimum number of queries possible (preventing an N+1 query situation). You probably don't want to load every single one if there are thousands of matching posts, so I put an arbitrary limit of 10 on that.
UsersController
def show
#user = User.find(params[:id]).includes(:received_posts).limit(10)
end
#....
View
<section>
<h3>Posts:</h3>
<% unless #user.id == current_user.id %>
<%= render 'posts/form', post: Post.new(user_id: #user.id) %>
<% end %>
<%= render #user.received_posts %>
</section>
Putting the partial for a new post instead as a view called posts/form will allow you to reuse that form if you want to render an edit action (form_for knows which action to use on submit by calling the passed model's persisted? method).
Note that this code assumes the User model has the second relationship with posts set up to be called received_posts, but you can change it to whatever reflects the reality. By passing the received_posts collection to the render method, Rails is smart enough to know that if you want to render a collection of Post models to look for a posts/_post partial and render one for each Post. It's a little cleaner looking IMO. Just make sure to move your posts/show code into that. posts/show implies this is its own action and not something used as a partial for something else.

rails: use jbuilder template in various controller methods

Is it possible to reuse jbuilder-template in another controller method? In other words: how to explicitly say controller method to use concrete jbuilder-template?
From Rails guide.
Rendering an Action's Template from Another Controller.
What if you want to render a template from an entirely different
controller from the one that contains the action code? You can also do
that with render, which accepts the full path (relative to app/views)
of the template to render. For example, if you're running code in an
AdminProductsController that lives in app/controllers/admin, you can
render the results of an action to a template in app/views/products
this way
def my_action
# some code here
render "products/show"
end
def my_action
# some code here
render "products/show.json"
end
or
def my_action
# some code here
render "show.json"
end
without the .json it will try to render an html file.

Sharing views among multiple controllers

I am not able to share views among multiple controllers in Ruby ob Rails application.
Please help.
you can even use partials or explicitly render another template in controller's action.eg: -
def UsersController < ApplicationController
def index
#records = User.all
render '/products/index' # instead of user's index i rendered product's index template
end
end
You can use this in the view you are trying to render the other view
abc - The name of the folder in which the other view exists (views/abc/view_name.html.erb)
xyz - The name of the view
<%= render :template "abc/xyz" %>

Rendering different views in one action

I want to have 2 kinds of views for the same posts in my rails application. For instance - in one where a logged in user can update and edit the post, and in the other any user can just view it and comment on it or select it.
How should I go about this? Do I need a separate class? I know I need a separate view for each, but how about the model and the controller?
1.case: your views are going to have similar content, but only the signed in users will have extra options like editing.
You should use a partial view and in your main view you should write something like this:
<% if signed_in? %>
<%= render 'edit_form' %>
<% end %>
Remember, the name of the partial should always start with a underscore, so your partial in this case would be called _edit_form.html.erb or _edit_form.html.haml, depending on what you are using.
2.case: depending on if the user is signed in or not, you want to render completely different views, then you should handle it in your controller:
def show
if signed_in?
render 'show_with_edit'
else
render 'show_without_edit`
end
end
And your files would be named show_with_edit.html.erb and show_without_edit.html.erb
Also, if your view for a signed in user was called show then you could just do this:
def show
render 'show_without_edit' unless signed_in?
end
3.case: if you want to change basically EVERYTHING depending if the user is signed in or not, you could create some custom methods and call them inside your original action like this:
def show
if singed_in?
show_signed_in
else
show_not_signed_in
end
end
private
def show_signed_in
# declaring some instance variables to use in the view..
render 'some_view'
end
def show_not_signed_in
# declaring some other instance variables to use in the view..
render 'some_other_view'
end

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