Within views/layouts/application.html I have the line <%= yield %>. This line is ultimately replaced by views directly corresponding to controller actions without any problems.
In one of my controllers, I am trying to render a partial instead of the default behaviour:
def show
#service_groups = ServiceGroup.where(deleted_at: nil)
render partial: 'table', locals: {rows: #service_groups, headers: service_group_headers}
end
I'm using a partial in this way so that I can use the same basic table structure for various different database tables (across different controllers).
This render partial code doesn't seem to work with the <%= yield %> line in the application layout. The partial code is just rendered on its own without the surrounding layout.
Why is this?
How do I rectify the problem?
Please let me know if I should be handling this a different way.
Thanks.
(migrating from comments)
What if you created a show.html.erb for that controller and placed render :partial there? It should work.
Explanation: Partials are to be used from "big" views. So, they are not wrapped in the layout on purpose!
Related
I understand this is a bad idea, but from what I've seen in ApplicationControllers, using:
render :layout => "something" ...
Should render using a layout located at views/layouts/something.html.erb
However, when I am making this call from inside of a view, it errors out with:
Missing partial my_controller_name/something with ...
Searched in:
* "{path here}/app/views"
Which seems to me its looking for a partial, instead of a layout as I specified. Does anyone know what is going on with that?
A sufficient example small enough to reproduce it:
<%= render :layout => 'something' do %>
<div>Hello</div>
<% end %>
This is all under Rails vs 4.0.2
render works differently in controllers than it does in views. In controllers, it's primarily for rendering action templates, while in views, it's primarily for rendering partial templates. When you want to render a specific layout for an action, you have a few options, but all of them are in the controller.
If you want every action in a particular controller to use that layout, you can either specify layout 'something' in that controller (usually near the top) or for a ApplesController, you can create a new layout in app/views/layouts/apples.html.erb and this will automatically be used as the default layout for the ApplesController.
If you want just a single action in a controller to use that layout, you can use your render layout: 'something' inside of a controller action, where the action to render is implied to be the current action.
Links from the Rails docs:
Action Rendering
Partial Rendering
Nested Layouts
Somewhat new to rails, longtime programmer. I've got a question about views, controllers and partials really - wondering if I have this setup well.
I've got a pages controller, and on the index page (really the pages index method) I've got a partial in layouts called featured (ie app/views/layouts/_featured.html.erb) -- I've also got a Featured class. I would like basically the index of the featured class to be drawn here. But of course it's not working. SO the question is:
In the page itself I've got the <%= render 'features/index' %> which I'm beginning to think is the wrong way to go..
Do I axe this partial method and just call <%= render 'features/index' %> and let everything progress natively or
What would be the proper way of routing the featured collection to the partial? Since the controller is actually Pages it seems like I'm fighting against the tide.
<%= render 'features/index' %>
Doing this is wrong given your description. This will try to render a partial from app/views/features/_index.html.erb which you haven't mentioned.
To render the partial at app/views/layouts/_featured.html.erb you would do (perhaps a bit more verbose that is necessary)
<%= render partial: "layouts/featured" %>
The best suggestion I can offer is to pass a collection to this partial
<%= render partial: "layouts/featured", locals: { features: #features } %>
Since it seems your intention is for this partial to appear as a piece of a layout I will assume you wish for this partial to appear on multiple pages. This means on multiple actions you will need to have assigned the set of Feature instances this #features instance variable. One way to do this is a before_action.
before_action :setup_features
# ...
private
def setup_features
#features = Feature.all
end
A good place to start learning more about filters is in the Rails Guide
The partial at "app/view/layouts/_featured.html.erb" can only be rendered with
render 'featured'
and not 'featured/index'
render 'featured/index' will render "app/views/layouts/featured/_index.html.erb
Since the pages controller is really rendering the main index page in it's def index, all I had to do was #features = Feature.all and the variable is available for the partial pulled into the index page.
I need to get used to how simple rails is coming from other languages / frameworks.
Can someone explain the difference between "<%= render %>" and "<%= yield %> with <% content_for :partial do %>/<% end %>"? specifically how the routing changes when switching from one to another, the benefits of using one over the other, when is it practical to use one over the other. THIS is the closest explanation I have found, but isn't quite clear enough for me.
I have been trying for several days to wrap my head around this, but it seems that each configuration I try either comes close, or errors out.
If theres are three views, aaa and bbb and ccc, and each has an index.html.erb, but bbb and ccc have a _content.html.erb partial (signified by the underscore) how can you accomplish getting the bbb or ccc partial in aaa using either render or yield?
The following works:
aaa's index.html.erb :
<div">
<%= render 'bbb/content' %>
</div>
and bbbs _content.html/erb :
<p>Content from bbb.</p>
BUT this does NOT:
aaa's index.html.erb :
<div">
<%= yield :container %>
</div>
and bbbs _content.html/erb :
<% content_for :container do %>
<p>Content from bbb.</p> ### viewed in aaa
<% end>
and cccs _content.html.erb would have nothing, or the content_for, but I still dont get aaa's index.html to be populated with content.
If I use the render, I can explicitly place the content in. But I thought that the benefit of using the yield :whatever would allow me to choose what to populate it with, and I can't get it to populate anything as soon as I change it from render to yield. Do I also have to update the routes file? If so, how do I choose which one to populate it with? Does that mean its in the controller? and needs an action?
I also have though that it depends on which file is initially routed to, but like I said, I think I need to understand the difference between the two before I can begin to use the partials to my advantage.
First of all, yield is ruby, render is rails. Usually one uses a common layout for the application whose inner content changes according to action/context. The problem usually lies in defining where our layout ends and context-specific template begins. Take, for instance, the HTML title tag. Let's say you have an application called Cities. In most cases, you want your page title to be "Cities" all the time. But, if you're for instance, inside Amsterdam page, then you would like the have "Amsterdam" as your page title.
# application.html.erb
<html>
<head>
<%= content_for?(:page_title) ? yield(:page_title) : "Cities" %>
......
# city/index.html.erb
<% content_for :page_title do %>
<%= #city.name %>
<% end %>
<div class="bla"...
Within Rails you usually define your application title in your application layout. One strategy for changing the page title would be to use content_for in the specific cities template and change accordingly.
Render, on the other hand, accomplishes different rendering strategies. Straight. When you call render, it renders. content_for/yield doesn't render automatically, it is stored somewhere and then fills up the missing spots in the due places. So, you can think of it as more as a "store/search/replace" in comparison to render, which just plain renders.
Good rule of thumb to use one over the other is: if the template you are writing needs to present different information per context, strongly consider using content_for.
yield
Ruby code (Proc class) and takes your block and does what it is supposed to do with it. Yield is also fast compared with other Ruby based ways of doing the same thing.
I'd assume (and I only) use it in the layouts because it's quick and I mindlessly do what's normal in Rails. yield is also used to pass content to a specific spot in your layout. I often have <%= yield :head %> in the head, just above the head tag, so that I can pass random weirdness that sometimes comes up.
Common Uses:
Mostly just used in layouts
(if you are fancy/inclined to do so in a Model) as a true Ruby Proc
statement.
render
Rails code that you pass arguments to that, as the docs say, "Renders the content that will be returned to the browser as the response body". partials, actions, text, files...etc.
Common Uses:
Used in both views and the controller.
When your controller method exits, it renders the associated file. So the edit controller renders edit.html.erb. It uses the specified layout or application.html.erb if none is specified.
Within your layout file, when you call yield it will fill in the information from your render. If you call yield with a parameter, it will look for a content_for section in your render file matching that parameter. I'm not completely sure, but I don't think you can call yield from outside of your layout file, and I don't think it will fill in any information except that found in your render file.
Anywhere in your layout file or your rendered file, you can render a partial by calling render with the partial name minus the underscore.
I hope that helps.
Edit to answer question in comment:
yield and render perform similar functions however yield only looks in the render file whereas render specifies which file to render. Also, render outputs the entire file, but yield with a parameter can output just a subsection of the file.
Here's a visual to put them both in perspective:
The render method is called at the end of a controller action and orchestrates what block is passed to the method that is actually rendering the application.html.erb by yielding the passed block.
https://richstone.io/debunk/
What I want to do is have 2 different controllers, client and test_client. The client controller is already built and I want to create a test_client controller that i can use to play around with the UI of the client and adjust it as needed. I am mainly trying to get around the validation i have built into the client and its dependence on an admin controller that loads the data.
so i want the test_client controller to load a sample data set and then render the client controller's index view so i can adjust the clients UI. That is all.
I tried this in the test_clients index method:
class TestClient
def index
render :template => 'client/index'
end
end
but i get an error because it cannot find the client partials as it is looking in the current controllers view for them...
So I have looked into this already and most people say that you should never make such a call but i think that this case is a reasonable usage...I just need to figure out how to get it to work.
You will need to adjust your view so that the path to the partial you need is in the form 'controller/partial'. In this case probably 'client/partial'. Then you can simply use render 'client/index' as before.
So say somewhere in your view you have this:
<%= render :partial => 'info' %>
You will want to change it to this:
<%= render :partial => 'client/info' %>
Convert your client controller views to partials, create empty views for all actions in test_client controller, render client partials for respective test_client views.
Example:
client view
index.html.erb to _index.html.erb
test_client view
index.html.erb
in this view, <%=render :partial => 'clients/index', :locals =>{ }%>
You could do this in a number of ways and everyone is different. One way you could do it, is by putting your finders into a presenter. Then turn some data in the index view into a partial or you can render the template with layout set to false.
Then in the client_test view you can render that index with the presenter associated with it.
How do I render a view within another view... in rails... is it possible?
#hotdog_controller
def show
# by default renders template hotdog/show.html.erb
end
#hotdog/show.html.erb
<%= render :template => 'ketchup' -%>
Use view partials
See section 3.4 http://guides.rubyonrails.org/layouts_and_rendering.html
A complete view inside another a view? Normally the way you would handle something like this in rails would be with partials.
Create a set of shared partials, and then just render them in each of the views.
I do the same thing a few times, but I load the sub views in through AJAX. And that AJAX is instantiated within the partial.