Rails部分图像渲染

Question

I'm getting up to speed on rails and ran into an odd problem. I'm rendering some images from the database (Image models attached to another model, Plants). I'm having some trouble when attempting to do it via a partial. I've got show.html.erb

 <fieldset class="fieldset">
      <legend>Images</legend>
      <%=  unless @plant.images.blank? then
                for image in @plant.images
                     debugger 
                     render :partial => 'show_image', :object => image 
                end
           else
                "This plant has no images to display."
           end
      %>
 </fieldset>

And the partial _show_image.html.erb:

 <div class="image_container">
      <% debugger %>
      <img src="<%= url_for(:action => 'picture', :id => object.id) %>"/> 
      <p class='image_caption'><%= object.comment %></p> 
 </div>

When this is rendered it just renders a "#" for each image, rather than the actual image. It seems to be just rendering the object as a string, as in the source I get:

 <fieldset class="fieldset">
      <legend>Images</legend>
      #<Image:0x242c910>
 </fieldset>

When running through the debugger locally:

 /Users/*****/dev/plantmanager/app/views/plants/show.html.erb:54
 debugger
 (rdb:241) image
 #<Image id: 40, comment: "Test", name: "Ixia.gif", content_type: "image/gif", data: "GIF89a2\0002\000####$\205\233\tI\250\"x\224\b?\206\031d|ju####\v\031###\247\bI\257G\222\232\222\227\263\262...", plant_id: 55, thumbnail: nil> 
 (rdb:221) @plant
 #<Plant id: 55, name: "Test", description: "Test", created_at: "2009-05-07 07:19:44", updated_at: "2009-05-07 07:19:44", planted: "2009-05-07 00:00:00", sprouted: "2009-05-15 00:00:00", plant_type_id: 1, finished: "2009-05-27 00:00:00">
 (rdb:221) @plant.images
 [#<Image id: 40, comment: "Test", name: "Ixia.gif", content_type: "image/gif", data: "GIF89a2\0002\000####$\205\233\tI\250\"x\224\b?\206\031d|ju####\v\031###\247\bI\257G\222\232\222\227\263\262...", plant_id: 55, thumbnail: nil>]
 (rdb:221) continue
 /Users/*****/dev/plantmanager/app/views/plants/_show_image.html.erb:2
 <% debugger %>
 (rdb:221) object
 #<Image id: 40, comment: "Test", name: "Ixia.gif", content_type: "image/gif", data: "GIF89a2\0002\000####$\205\233\tI\250\"x\224\b?\206\031d|ju####\v\031###\247\bI\257G\222\232\222\227\263\262...", plant_id: 55, thumbnail: nil>
 (rdb:221) object.id
 40
 (rdb:221) object.comment
 "Test"
 (rdb:221) continue

Here are my models [snipped a bit]:

class Plant < ActiveRecord::Base
     has_many :images

     validates_presence_of :name
     validates_presence_of :plant_type_id
     validates_associated :images


     after_update :save_images

     def image_attributes=(image_attributes)
          image_attributes.each do |attributes|
               # TODO: Probably handle validation in the image model?
               if attributes[:id].blank?
                   unless attributes[:uploaded_picture].blank?
                        tmpImg = images.build()
                        tmpImg.uploaded_picture=attributes[:uploaded_picture]
                        tmpImg.comment = attributes[:comment] 
                   end
               else
                   img = images.detect { |i| i.id == attributes[:id].to_i }
                   img.attributes = attributes
                end
           end
      end


      def save_images
           images.each do |i|
                if i.should_destroy?
                     i.destroy
                else
                     i.save(false)
                end
           end 
      end
 end

 class Image < ActiveRecord::Base 
      validates_format_of :content_type, 
                          :with => /^image/, 
                          :message => "--- you can only upload pictures" 

      attr_accessor :should_destroy

      def should_destroy?
           should_destroy.to_i == 1
      end

      def uploaded_picture=(picture_field)
           self.name = base_part_of(picture_field.original_filename) 
           self.content_type = picture_field.content_type.chomp 
           self.data = picture_field.read
           #image = MiniMagick::Image.from_blob self.data
           #self.thumbnail = resize_and_crop(image, 100).to_blob
      end 

      def base_part_of(file_name) 
           File.basename(file_name).gsub(/[^\w._-]/, '') 
      end
 end 

Answer 1

Try this instead:

<%  unless @plant.images.blank?
                for image in @plant.images
%>
                     <%= render :partial => 'show_image', :object => image %>
                <% end
           else %>
                This plant has no images to display.
           <% end %>

Sorry about the formatting, but you get the idea.

Answer 2

Build a method for the pic in your Image model

class Image < ActiveRecord::Base
   belongs_to :plant
   validates_presence_of :uploaded_picture
   ...
end

In your plants controller

def plant_pic
  img = Image.find(params[:id])      
  # THE NEXT LINE IS THE ONE I THINK YOU ARE MISSING:
  send_data img.uploaded_picture, :filename =>"plant#{img.plant_id}_#{img.id.to_s}+'.jpg', 
                                  :type => 'image/jpeg', 
                                  :disposition => 'inline'
end
...

And then in your plants view:

<fieldset class="fieldset">
  <legend>Images</legend>
  <% if plant.images.blank? -%>
  <p>This plant has no images to display.</p>
  <% else %>
    <%= @plant.images.each do |image| %>
      <div class="img_container"> 
      <img src="<%= url_for(:action => 'plant_pic', :id => image.id) %>"/>
      </div>
    <% end -%>
  <% end -%>
</fieldset>

You may want to encode/decode the uploaded_picture binary field someway (I use Base64.encode and Base64.decode) in your images controller, but that's another issue.

Hope that helps you