Stupid WTF! ActionView::MissingTemplate Exception: Missing template users/_user.erb

If you've spent much time working with Ruby on Rails and more especially if you've done anything with json you might have run across errors like this:

ActionView::MissingTemplate Exception: Missing template users/_user.erb

I was having this problem and doing a lot of cursing which is common when I stay up and write code until 2am which I know I should do and I also know that I shouldn't write really long run on sentences but I do it anyway.

This error is usually the result of some code that looks like this:

 
format.json do
  @user_html = render_to_string( :partial => 'users/user', <img src='http://www.justinball.com/wp-includes/images/smilies/icon_surprised.gif' alt=':o' class='wp-smiley' /> bject => @user )
  render :json => { :success => true,
                              :user_html => @user_html  }
end
 

The cause of this error is that the format of the current request is :json. There isn't an _user.json.erb template so Rails tries to find an _user.erb file. That doesn't exist either and boom you spend the night sounding like a sailor.

Now I don't pretend to be an expert but I have been accused of being a hack. I solve the problem by changing the template format:

 
format.json do
  @template.template_format = :html
  @user_html = render_to_string( :partial => 'users/user', <img src='http://www.justinball.com/wp-includes/images/smilies/icon_surprised.gif' alt=':o' class='wp-smiley' /> bject => @user )
  render :json => { :success => true,
                              :user_html => @user_html  }
end
 

The key is the addition of:

 
  @template.template_format = :html
 

Don't yell at me if it breaks. I'm open to better suggestions but for now this does work and now my I can find other reasons to stay up late.

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