Ruby on Rails

Comments and changes to this ticket

• 

  RSL August 13th, 2008 @ 01:54 PM

  +1 especially with the option for handling simple one line HTML strings [as discussed in #rails-contrib].

• 

  Frederick Cheung August 13th, 2008 @ 08:09 PM

  Revised version of the patch. use cases now include

  
  render :partial => 'record', :collection => @records, :empty => 'Nothing found'
  render :partial => 'record', :collection => @records, :empty => {:partial => 'nothing_found'}
  render :partial => 'record', :collection => @records, :empty => {:inline => '<%= @something %>'}
  

  • 0001-Add-the-empty-option-when-rendering-collections.patch 7.1 KB
• 

  Steven Bristol August 14th, 2008 @ 01:09 PM

  I like this concept a lot, but I am wondering if it might not be better to have render take a block that is used if the collection is empty? I'm not sure that makes sense for the other uses of render, but I prefer that syntax over supplying html as a string.

• 

  Ryan Bates August 15th, 2008 @ 03:54 PM

  BTW, a discussion of this can be found at this thread.

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  Ryan Bates August 15th, 2008 @ 04:40 PM

  In this thread some have come to the conclusion that it would be best if "render :collection" returned nil instead of a space for an empty array. This way you can do this with a simple "or" operation.

  
  <%= render :partial => @records || "Nothing found" %>
  

  Attached is a patch which does this. I moved some stuff around, so that whenever you're trying to render nil, a space is used in the response body so Safari doesn't complain. This way it happens later on in the response chain so "render :collection" doesn't have to be concerned with it.

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  Ryan Bates August 15th, 2008 @ 04:49 PM

  Correction: you'll need to wrap the render call in parenthesis.

  
  <%= render(:partial => @records) || "Nothing found" %>
  

• 

  Eloy Duran August 15th, 2008 @ 05:43 PM

  +1 for Ryans patch. Seems the best Ruby-ish solution.

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  RSL August 15th, 2008 @ 06:05 PM

  What about the case where you want something more complex than a simple string rendered when the collection is empty?

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  Damian Janowski August 15th, 2008 @ 06:17 PM

  RSL,

  
  <%= render(:partial => @records) || render_very_complex_logic_found_in_helpers__of_course %>
  

• 

  Damian Janowski August 15th, 2008 @ 06:19 PM

  Ryan, why not checking for collection.blank? so that it doesn't fail with nils? Other than that I'm +1.

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  Ryan Bates August 15th, 2008 @ 06:39 PM

  @RSL, as Damian mentioned you can toss it into a helper. Or you can just render a partial right here.

  
  <%= render(:partial => @records) || render(:partial => 'empty') %>
  

  @Damian, I tried this briefly but it still errors out with nil. I don't think the fix is that simple so it should probably go in its own ticket.

• 

  Ryan Bates August 15th, 2008 @ 07:08 PM

  Nevermind, found the problem. Attached is an updated patch which also returns nil when nil is passed.

  • render_empty_collection_or_nil_returns_nil.diff 4.4 KB
• 

  Damian Janowski August 15th, 2008 @ 07:34 PM

  Great :-)

  Tests pass and there's no need for doc changes.

  +1

• 

  RSL August 15th, 2008 @ 07:40 PM

  @ ryan & damien, doy. where is my mind? i like this.

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  S. Brent Faulkner August 15th, 2008 @ 09:53 PM

  +1 for render_empty_collection_or_nil_returns_nil.diff

  definitely.

• 

  Joshua Peek August 19th, 2008 @ 05:43 AM

  • → Assigned user changed from “” to “Joshua Peek”
  • → State changed from “new” to “open”

  +1 to returning just returning nil

• 

  Repository August 20th, 2008 @ 01:09 AM

  • → State changed from “open” to “resolved”

  (from [a8ece12fe2ac7838407954453e0d31af6186a5db]) Return nil instead of a space when passing an empty collection or nil to 'render :partial' [#791 state:resolved]

  Signed-off-by: Joshua Peek josh@joshpeek.com http://github.com/rails/rails/co...

• 

  Andrew Vit November 6th, 2008 @ 10:31 AM

  Just a note, this change crashes XML builder templates with empty collections which use this convention:

  
  @items = []
  xml << render( :collection => @items )
  

  This is because Builder's << operator won't accept nil, and it throws a "can't convert nil to String" error. The easiest workaround seems to be as above, using the || operator with an empty string, but that sure looks funky:

  
  xml << ( render(:collection => @items) || '' )
  

  Or else pass in a :locals option and don't use the << convention:

  
  render( :collection => @items, :locals => {:x => xml} )