Rails Photo Gallery

 
class CreateImages < ActiveRecord::Migration
  def self.up
    create_table :images do |t|
      t.column "name", :string
      t.column "width", :integer
      t.column "height", :integer
    end
  end
 
  def self.down
    drop_table :images
  end
end	
 

<%= error_messages_for 'image' %>

<!--[form:image]-->
<p><label for="image_name">Name</label><br/>
<%= text_field 'image', 'name'  %></p>

<p><label for="image_file">File</label><br/>
<input type="file" name="image[file]" /></p>
<!--[eoform:image]-->

 
<% form_tag({:action => 'create'}, :multipart => true)  do %>
 

 
<% form_tag({:action => 'update', :id => @image}, :multipart=>true ) do %>
 

 
# this function should be put to 'app/models/image.rb'
def file= (f)
  @file = f 
end
 

 
# this function should be put to 'app/models/image.rb'
 
def validate 
  # Empty 'name' field is not allowed
  errors.add_on_empty 'name'
 
  # @file should contain file uploaded by HTTP 
  # it is either StringIO object (if file was smaller than 10Kb)
  # or Tempfile (otherwise)
  if not (@file.kind_of? StringIO or @file.kind_of? Tempfile)
    errors.add_to_base("No file selected")
    return
  end
 
  # We can't use StringIO data to call external programs
  # So, if object is StringIO -- we have to create Tempfile
  # Unfortunatly, in Rails it is impossible to force all uploads to be Tempfiles
  if @file.kind_of? StringIO
    # Yes, if @file is StringIO, create new Tempfile and copy everything to it 
    @real_file = Tempfile.new("AEGALLERY")
    while not @file.eof? 
      @real_file.write @file.read
    end
  else
    # Most uploads will be Tempfiles
    @real_file = @file
  end
 
  # Here is a call to ImageMagick tool identity 
  # it prints to standard output 
  # type, width and height of images 
  # (this is specified by -format %m,%w,%h)
  identify = `#{IMAGE_MAGICK_PATH}/identify -format %m,%w,%h #{@real_file.path} 2>&1`
  # Now identity is a string like "JPEG,640,480"
 
  # We split this string to array 
  @jpeg_info = identify.split(',', 3)
  # convert width and height to integer and assign it to object fields 
  self.width = @jpeg_info[1].to_i
  self.height = @jpeg_info[2].to_i      
 
  # Finally, cheking if everything was fine with this image 
  # if file was not valid JPEG -- something will fail here
  if @jpeg_info == nil or @jpeg_info[0] != 'JPEG' or self.width <= 0 or self.height <= 0
     errors.add_to_base("Wrong image format (use only JPEG) or broken data")
     return
  end
 
end
 

 
# these functions should be put to 'app/models/image.rb'
 
def after_save
  dest_photo = "#{RAILS_ROOT}/public/photo/f/#{self.id}.jpeg"
  dest_photo_t = "#{RAILS_ROOT}/public/photo/t/#{self.id}.jpeg"
 
  # Copying Tempfile to our storage, 
  # which is a subdirectory 'photo/f' in 'public' 
  # directory of Rails project
  FileUtils.cp(@real_file.path, dest_photo);
 
  # Setting right permissions 
  FileUtils.chmod 0644, dest_photo
 
  # call image magick 'convert' utility to 
  # generate 200x200 thumbnail 
  `#{IMAGE_MAGICK_PATH}/convert -size 200x200 #{dest_photo} \
  -resize 200x200 -quality 90 +profile \"*\" #{dest_photo_t} 2>&1`
end
 
def after_destroy 
  # Deleting image files
  FileUtils.safe_unlink("#{RAILS_ROOT}/public/photo/f/#{self.id}.jpeg")
  FileUtils.safe_unlink("#{RAILS_ROOT}/public/photo/t/#{self.id}.jpeg")
end 
 
def img_tag 
  "<img src='/photo/f/#{self.id}.jpeg' width='#{self.width}' height='#{self.height}' alt='#{self.name}'>"
end
 
def img_tag_thumbnail
  kf = 200.0 / ( width > height ? width : height ) 
  tw = (width.to_f * kf).to_i
  th = (height.to_f * kf).to_i
  "<img src='/photo/t/#{self.id}.jpeg' width='#{tw}' height='#{th}' alt='#{self.name}'>"
end
 
 

 
<%= @image.img_tag %>
 

 
<% for image in @images %>
  <tr>
  <% for column in Image.content_columns %>
    <td><%=h image.send(column.name) %></td>
  <% end %>
    <%# following line outputs THUMBNAIL: %>
    <td><%= image.img_tag_thumbnail %></td>
    <td><%= link_to 'Show', :action => 'show', :id => image %></td>
    <td><%= link_to 'Edit', :action => 'edit', :id => image %></td>
    <td><%= link_to 'Destroy', { :action => 'destroy', :id => image }, :confirm => 'Are you sure?', :method => :post %></td>
  </tr>
<% end %>