Rails - May 2005 - Rendering XML to file (rather than browser)

Hi everybody!

I''m trying to get a simple XML thingie my app is generating... it  
looks a little something like this (in my "feed" controller):

     def category
         @pages = Page.find_all_by_category_id(Website.find(@params 
[:website_name]).id)
         render_without_layout
     end

(where, in my database, websites has_many categories and categories  
has_many pages...)

It''s being shown by a view called, appropriately enough, category.rxml:

     xml.category{
       for page in @pages
         xml.page("id" => page.id, "title" =>
page.title, "category"
=> page.category.id)
       end
     }

My question: how can I render that XML to a file rather than showing  
it in my browser. My intent is actually to FTP that XML to another  
server, if that helps... maybe there''s a neat-o way to do that in one  
fell swoop, but I can''t find it... any help would be, as always, very  
appreciated...



*** Secret Bonus Hidden Mystery Question for Extra Credit and +4  
Karma ***

That line in the controller (@pages = ...) seems really... dumb.  
Verbose, I mean. Is there a smarter way to write it?

On May 8, 2005, at 11:24 AM, Raymond Brigleb wrote:
> Hi everybody!
Hi Raymond!
> I''m trying to get a simple XML thingie my app is generating... it
> looks a little something like this (in my "feed" controller):
First, lets pull @website from the subdomain.  We could try putting  
it in the route, but that gets messy fast.  This way, foo.mysite.com  
will set @website to Website.find_by_name(''foo''):

class ApplicationController < ActionController::Base
   before_filter :find_website_from_subdomain

   private
     # example.com         => @website = nil
     # foo.example.com     => @website =
Website.find_by_name(''foo'')
     # foo.bar.example.com => @website =
Website.find_by_name(''foo.bar'')
     def find_website_from_subdomain
       website_name = request.subdomains.join(''.'')
       unless website_name.blank?
         # Simple, but allows users to view other users'' websites.
         # @website = Website.find_by_name(website_name)

         # Assume login_user gives me the currently logged-in user.
         @website = login_user.websites.find_first([''name=?'',
website_name])

         # Augh, user is a baddie trying to access another user''s  
website.
         if @website.nil?
           redirect_to :controller => ''home'', :action =>
''naughty_naughty''
         end
       end
     end
end


Now let''s use @website in our category feed:

class FeedController < ApplicationController
   def category
     @category = @website.categories.find(params[:id])
     render_without_layout
   end
end

And munge the view to expect @category rather than @pages:

xml.category(:id => @category.id) do
   for page in @category.pages
     xml.page :id => page.id, :title => page.title
   end
end

> My question: how can I render that XML to a file rather than  
> showing it in my browser. My intent is actually to FTP that XML to  
> another server, if that helps... maybe there''s a neat-o way to do
> that in one fell swoop, but I can''t find it... any help would be,
> as always, very appreciated...
Try a seperate export action that generates the feed and FTPs it to  
the remote server.  Start with a nice route:

# Example: export category 5 by sending a POST to /export/category/5
map.connect ''/export/:feed/:id, :controller =>
''feed'', :action =>
''export''

require ''tempfile''
require ''net/ftp''

class FeedController < ApplicationController
   def export
     case request.method

     # Show export form.
     when :get
       # No setup necessary.

     when :post
       # Nab the feed contents from the other action.
       feed = render_component(:action => params[:feed], :id => params 
[:id])

       # Write the feed to a tempfile and FTP it.
       # Note: the tempfile is deleted at the end of the block.
       Tempfile.open do |file|
         file.write feed

         # Assume ftp_host, ftp_username, ftp_password, and ftp_basedir.
         Net::FTP.open(@website.ftp_host) do |ftp|
           ftp.login @website.ftp_username, @website.ftp_password

           # Switch to the appropriate export directory for this feed.
           ftp.chdir File.join(@website.ftp_basedir, params[:feed])

           # Send the file named as the feed id with an .xml suffix.
           ftp.put file.path, "#{params[:id]}.xml"
         end
       end

       # Return to the export form and let the user know all''s well.
       flash[:notice] = "Exported #{params[:feed]} #{params[:id]} to # 
{@website.ftp_host}"
       redirect_to :action => ''export''
     end
   end
end

For bonus points, add timeouts, rescue Net::FTPError, or switch gears  
and use Jamis Buck''s Net::SFTP.  Better yet, factor the website  
export machinery into its own class and pare your export action down  
to a sweet 8 lines or so.

Enjoy,
jeremy