I get a warning "render :nothing deprecated, use render :file
instead"... but I cannot find any info on how to use render :file to
render nothing. It's also not mentioned on the deprecated items web
page, it this warning a bug?
render :nothing => true should still work and not be deprecated.
Ferd
To add to what Fred said, you may be wondering why you need
:nothing => true
instead of just
:nothing
The reason is that you used to be able to write:
render "path/to/some_file.rhtml"
which was equivalent to
render_file "path/to/some_file.rhtml"
The Rails guys decided to get rid of all the render_xxx methods and
just have a single render method that takes a hash of options:
render :action => 'blah'
render :file => 'blech'
render :inline => '<%= foo %>'
In order to provide backward compatibility, render looks at its
argument. If it's a Hash, it's treated as the new-style way of doing
things. Otherwise, it's assume to be the old render "some_file"
method, so the argument gets passed along to render_file, and a
deprecation warning is issued (since this will go away completely in
Rails 2.0).
So, with all that background,
render :nothing
actually is transformed into
render :file => :nothing
which isn't what you intended.
By writing
render :nothing => true
render receives a Hash as it's argument (because of the => operator),
so you get nothing rendered.
Ruby has an interesting feature in method calls, where a Hash literal
and the *end* of a parameter list does not need to be enclosed in
braces. So
render :nothing => true
is really the same as
render({:nothing => true})
It's a nice feature, because it cuts down on the "line noise" so
common with Perl e.g., but you need to be aware of it because it can
be misleading. For example:
update_attribute :foo, "Bar" # two arguments passed
update_attributes :foo => "Bar" # *one* argument (a Hash) passed
Ah, thanks for the reply both. I noticed it's my own fault (as usual),
I used a string instead of a symbol but the warning message threw me
off:
DEPRECATION WARNING: You called render('nothing'), which is a
deprecated API call. Instead you use render :file => nothing.
