Generate your new merb app

      merb-gen app picture_place

Create the picture resource
We will need a picture model to store our pictures, so lets create that now.

      merb-gen resource picture

Install dm-paperclip
Paperclip is a great gem for handling picture uploads. Open up /config/dependencies.rb and add the following

      dependency "dm-paperclip"

Setup the picture model
Add the following to /app/models/picture.rb

      include Paperclip::Resource
      has_attached_file :image,
        :default_url => "/uploads/pictures/:attachment/missing_:style.png",
        :url => "/uploads/pictures/:id/:style/:basename.:extension",
        :path => ":merb_root/public/uploads/pictures/:id/:style/:basename.:extension",
        :styles => {:small => "55x55#", :medium => "100x100#", :large => "600x600>" }

Setup the router
Were going to want to use an action in the picture controller called 'swf_upload' to handle uploads coming from SWFUpload, so lets set that up in the router.

      with(:controller => "pictures") do
        match('/pictures/swf_upload').to(:action => "swf_upload").fixatable
      end

Setup the controller
Open up your pictures controller and add the following.

      def swf_upload
        only_provides :html
        @picture = Picture.new
        @picture.image = params[:Filedata]
        ## If the picture belongs to a user, uncomment this line
        ## @picture.user_id = session.user.id
        if @picture.save
          return "success"
        else
          return ""
        end
      end

Get the necessary files
We are going to need a few javascript files to SWFUpload, so were gonna grab those now. First create a new directory in public/ called swfupload. Then head over here, download all the files and put them in public/swfupload/

Now onto the view
Now for the fun stuff. Open up /app/views/pictures/new.html.haml and add the following

      %script{:type => "text/javascript", :src => "/swfupload/swfupload.js"}
      %script{:type => "text/javascript", :src => "/swfupload/swfupload.queue.js"}
      %script{:type => "text/javascript", :src => "/swfupload/fileprogress.js"}
      %script{:type => "text/javascript", :src => "/swfupload/handlers.js"}
      
      :javascript
        var swfu;
        $(document).ready(function(){
          var settings = {
            upload_url: "/pictures/swf_upload?_picture_place_session_id=#{cookies[:_picture_place_session_id]}",
            flash_url: "/swfupload/swfupload.swf",
            file_size_limit: "10485760", // 10 MB
            file_types: "*.jpg;*.png;*.gif",
            file_types_description: "JPG, GIF, or PNG Image Files",
            file_upload_limit : 100,
            file_queue_limit : 0,
            debug: false,
            custom_settings : {
              progressTarget : "images"
            },
            // Button settings
            button_width: "200",
            button_height: "32",
            button_placeholder_id: "browse",
            button_text: '<span class="theFont">Select files to upload</span>',
            button_text_style: ".theFont { font-size: 16; font-family: arial; }",
            // Handlers
            file_queued_handler : fileQueued,
            file_dialog_complete_handler: fileDialogComplete,
            upload_start_handler: uploadStart,
            upload_progress_handler: uploadProgress,
            upload_error_handler: uploadError,
            upload_success_handler: uploadSuccess,
            upload_complete_handler: uploadComplete
          };
          swfu = new SWFUpload(settings);
          // Add Event Handlers
          $('#browse').click(function() { swfu.selectFiles(); });
          $('#upload').click(function() { swfu.startUpload(); });
        });
      
      %h1 Upload some new pictures
      #upload-actions
        #browse Select Files
        %a.upload-button#upload{:href => '#', 'onclick' => 'return false'} Upload files
      #images

Give it a test run
We now have working uploads, fire up your browser and head to http://localhost:4000/pictures/new and try uploading some pictures. I have a sample app made up on github you can check also look at.

      #RewriteRule ^(.*)$ merb.fcgi [QSA,L]

There is no need for fcgi behind Passenger since Passenger uses rack. Now you should be able to deploy your app behind Passenger without many problems. There is still one problem you may come across. For some reason you can't have local variables set in a controller or your app will fail with the following error message

      /usr/local/lib/rubyEE/lib/ruby/gems/1.8/gems/ParseTree-2.2.0/lib/parse_tree.rb:151: 
      [BUG] Segmentation fault

So instead of this

      def show
        @post = Post.get(params[:id])
        number = 100
        number = number + 100
      end

You would need to do this

      def show
        @post = Post.get(params[:id])
        @number = 100
        @number = @number + 100
      end

I have not yet figured out why local variables cause the segmentation fault, but this is a quick way to get around it so that you app will still work.