Rails render partial with block

Question

I'm trying to re-use an html component that i've written that provides panel styling. Something like:

  <div class="v-panel">
    <div class="v-panel-tr"></div>
    <h3>Some Title</h3>
    <div class="v-panel-c">
      .. content goes here
    </div>
    <div class="v-panel-b"><div class="v-panel-br"></div><div class="v-panel-bl"></div></div>
  </div>

So I see that render takes a block. I figured then I could do something like this:

# /shared/_panel.html.erb
<div class="v-panel">
  <div class="v-panel-tr"></div>
  <h3><%= title %></h3>
  <div class="v-panel-c">
    <%= yield %>
  </div>
  <div class="v-panel-b"><div class="v-panel-br"></div><div class="v-panel-bl"></div></div>
</div>

And I want to do something like:

#some html view
<%= render :partial => '/shared/panel', :locals =>{:title => "Some Title"} do %>
  <p>Here is some content to be rendered inside the panel</p>
<% end %>

Unfortunately this doesn't work with this error:

ActionView::TemplateError (/Users/bradrobertson/Repos/VeloUltralite/source/trunk/app/views/sessions/new.html.erb:1: , unexpected tRPAREN

old_output_buffer = output_buffer;;@output_buffer = '';  __in_erb_template=true ; @output_buffer.concat(( render :partial => '/shared/panel', :locals => {:title => "Welcome"} do ).to_s)
on line #1 of app/views/sessions/new.html.erb:
1: <%= render :partial => '/shared/panel', :locals => {:title => "Welcome"} do -%>
...

So it doesn't like the = obviously with a block, but if I remove it, then it just doesn't output anything.

Does anyone know how to do what I'm trying to achieve here? I'd like to re-use this panel html in many places on my site.

Solution 1

While both of those answers above work (well the example that tony links to anyway) I ended up finding the most succinct answer in that above post (comment by Kornelis Sietsma)

I guess render :layout does exactly what I was looking for:

# Some View
<%= render :layout => '/shared/panel', :locals => {:title => 'some title'} do %>
  <p>Here is some content</p>
<% end %>

combined with:

# /shared/_panel.html.erb
<div class="v-panel">
  <div class="v-panel-tr"></div>
  <h3><%= title -%></h3>
  <div class="v-panel-c">
    <%= yield %>
  </div>
</div>

Solution 2

Here's an alternative based on previous answers.

Create your partial on shared/_modal.html.erb:

<div class="ui modal form">
  <i class="close icon"></i>
  <div class="header">
    <%= heading %>
  </div>
  <div class="content">
    <%= capture(&block) %>
  </div>
  <div class="actions">
    <div class="ui negative button">Cancel</div>
    <div class="ui positive button">Ok</div>
  </div>
</div>

Define your method on application_helper.rb:

def modal_for(heading, &block)
  render(
    partial: 'shared/modal',
    locals: { heading: heading, block: block }
  )
end

Call it from any view:

<%= modal_for('My Title') do |t| %>
  <p>Here is some content to be rendered inside the partial</p>
<% end %>

Solution 3

You can use the capture helper, and even inline in the render call :

<%= render 'my_partial',
           :locals => { :title => "Some Title" },
           :captured => capture { %>
    <p>Here is some content to be rendered inside the partial</p>
<% } %>

and in shared/panel:

<h3><%= title %></h3>
<div class="my-outer-wrapper">
  <%= captured %>
</div>

which will produce:

<h3>Some Title</h3>
<div class="my-outer-wrapper">
  <p>Here is some content to be rendered inside the partial</p>
</div>

See http://api.rubyonrails.org/classes/ActionView/Helpers/CaptureHelper.html

Solution 4

Based on the accepted answer this is what worked well for me using Rails 4.

We can render a panel as such:

= render_panel('Non Compliance Reports', type: 'primary') do
  %p your content goes here!

This requires a helper method and a shared view:

helper method (ui_helper.rb)

def render_panel(heading, options = {}, &block)
  options.reverse_merge!(type: 'default')
  options[:panel_classes] = ["panel-#{options[:type]}"]

  render layout: '/ui/panel', locals: { heading: heading, options: options } do
    capture(&block)
  end
end

View (/ui/panel.html.haml)

.panel{ class: options[:panel_classes] }
  .panel-heading= heading
  .panel-body
    = yield

Solution 5

I think it will work (just did quick dirty test) if you assign it to a variable first and then output it.

<% foo = render :partial => '/shared/panel', :locals =>{:title => "Some Title"} do %>
<p>Here is some content to be rendered inside the panel</p>
<% end %>
<%= foo %>

View more solutions

Comments

[fabi]

The accepted answer is correct, but since Rails 5.0.0 this is possible without the layout-workaround, see guides.rubyonrails.org/…

[Siwei]

in Rails 3.2.2, I think you have to use <%= %> instead of <% %>, e.g. <%= render :layout => '/shared/panel',

[brad]

you're right, this post makes no assumptions about the Rails version, I'm sure people can figure that one out.

[equivalent8]

like this one (solves my problem so +1), but is this good practice? won't there be some slowdown for some reason ? Maybe database triggers sooner than it suppose to because of another yield (don't have time to investigate that by-myself now, just wondering)

[sequielo]

If the outside panel is a form (variable name f), you should use yield f instead.

[Vadorequest]

Any way to know if a content has been yielded? In case of it's optional.

[mahemoff]

The inline pattern is nice for a partial needing multiple blocks.

[Jonathan Allard]

This seems to mess up the context for I18n.t >:(

[anka]

Working with Rails 4.2.7 and got an error like LocalJumpError (no block given). Found out that when using layout: you have to name the hash for local parameters explicitly. e.g. = render layout: 'mylaoyut', locals: {param1: 'Test'} do

[Kris]

This works in Rails 5.x too, I just needed to change panel.html.haml to _panel.html.haml

[Jay Mitchell]

In Rails 5.0 there was a change so this is general to all partials, not just layouts. You can change the first line of the calling code to: <%= render '/shared/panel', title: 'some title' do %>