Rails 3.2.0.rc1: json and strange respond_with behavior

I have a controller:

class ItemsController < ApplicationController

respond_to :json

def index

  items = Item.all

  respond_with(items)

end

end

I am curling my_app/items.json and see a response with JSON object — just as expected. At this point I don’t have any views associated with controller, specifically I don’t have index.html.erb (.html).

Now if only I create an index.haml (for instance), with a simple %h1 Hello, world! line, requesting (again via curl) my_app/items.json returns an html string with

Hello, world!

. Note that I didn’t alter the controller code — it just remains untouched.

I’m sure I’m missing something. Can anyone explain of what’s going on here?

Observation:

When you rename the index.haml file to index.html.haml, it will work as expected

(at least it works here and I could reproduce your problem).

For json, the default built-in handler for the json format is used.

For html, the index.html.haml template is used

Speculation:

I presume that Rails first checks if for json, a file with any of the standard

handlers is present (from the error message below, that would be :erb,

:builder, :coffee, :haml).

Missing template orders/index, application/index with {:handlers=>[:erb, :builder, :coffee, :haml], :formats=>[:json], :locale=>[:en, :en]}.

Now if it sees a file ending in .html.haml it is clear that this is a html file

(and not an XML or a JSON file) and not use that file as a template.

But for a file index.haml , I presume Rails accepts this also for rendering json,

even without the .json.haml ending …

So, I created 2 additional files:

peterv@e6500:~/b/app/views/orders$ vim index.json.haml

peterv@e6500:~/b/app/views/orders$ rm index.json.haml

peterv@e6500:~/b/app/views/orders$ vim index.haml

peterv@e6500:~/b/app/views/orders$ rm index.haml

And the picking order is clear:

  • highest priority: index.json.haml

  • lesser priority: index.haml

  • default: built-in json renderer

  • never used: index.html.haml

HTH,

Peter

Awesome! Thank you, Peter. Now it’s clear to me of what’s happening.

Also I think the documentation worth mentioning this behavior.