Upload image in rails3 without using any gem

For image uploading, rails3 having plugins and gems. But here we are going to discuss on how to upload and remove images through rails3 without using gems or plugins.

Here I am going to discuss on how to upload image using rails3 application. There are many gems and plugins available for this. But here we will do it without using any gem or plugin.

First we have to create a table named as  “images” . Please find the following SQL query to generate that table

CREATE TABLE IF NOT EXISTS `images` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`image_name` varchar(255) NOT NULL,
`image_type` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

    Next for images table we need to create image model(app/models/image.rb). Place the following code in the image.rb file.

class Image < ActiveRecord::Base
      # create a virtual uploaded_image field in the class.
      attr_accessor :uploaded_image
      attr_accessible :image_name, :image_type
end

We have taken a virtual field which we will use it while uploading image, before that we will have to define the routes in ‘config\routes.rb’. please place the following code in routes.rb file.

# it means we have public controller having upload_image action
resources :public, :only => [:upload_image]
 
# define the routes
match '/uploadimage', :to => 'public#upload_image'

Now as per the routes we have to create a controller named as PublicController. So create a public_controller.rb in “app\controllers\”. Then place the following code in it.

class PublicController < ApplicationController
def upload_image
      # get all the images from the db
      @images = Image.all
      # creating an object for the Image class
      @image = Image.new
end
 
end

In the action page ‘app\views\public\upload_image.html.erb’, place the following code

{:controller => "public",:action => "uploading",:method => :post}, :html => {:multipart => true} do %>
      
      
 

 

 

 
 0 %>

      
            
               
                '140px', :width => '185px' %>

               Remove
           
      


      No images found

 

     Here the form action is uploading so we have to create another action in PublicController. So add the following code to the PublicController.

def uploading
   # creating an object for the Image class
   @image = Image.new
   # get the file_type that have been uploaded
   file_type = params[:image][:uploaded_image].content_type

   # check the file type for images
   if file_type == 'image/jpeg' || file_type == 'image/jpg' || file_type == 'image/png' || file_type == 'image/gif' || file_type == 'image/bmp'

      # as per the file type give the images name
      case file_type
         when "image/jpeg"
            file_name = "pic_#{Time.now.strftime("%Y%m%d%H%M%S")}.jpg"
         when "image/png"
            file_name = "pic_#{Time.now.strftime("%Y%m%d%H%M%S")}.png"
         when "image/gif"
            file_name = "pic_#{Time.now.strftime("%Y%m%d%H%M%S")}.gif"
         when "image/bmp"
            file_name = "pic_#{Time.now.strftime("%Y%m%d%H%M%S")}.bmp"
      end
 
      # give the file path for image
      file_path = File.join(Rails.root, 'public', 'images', 'upload_images', file_name)

      # copy the image from the uploaded one to file_path
      File.open(file_path, 'wb') do |f|
            f.write params[:image][:uploaded_image].read
      end

      #
      @image.image_name = file_name
      @image.image_type = file_type

      # save the image
      @image.save
      #redirect to /uploadimage
      redirect_to uploadimage_path
   else
      # get all the images from the database
      @images = Image.all
      # add an error
      @image.errors.add(:image, "should be in jpeg/bmp/png/gif format")
      render 'upload_image'
   end
end

     For showing the error message in the time of uploading, we have placed “” code in the  ‘app\views\public\upload_image.html.erb’. So we need to create “_error_img_messages.html.erb” file in “app\views\shared\”. Then place the following code in it.

prohibited the uploading process…

         
There were problems with the following fields:
      

     In the ‘app\views\public\upload_image.html.erb’, we have shown a remove link against to each uploaded image. For this we need to create another action in PublicController. Please add the following code to PublicController.

def remove_image
   #get the image from db by image id
   image = Image.find(params[:id])
   # get the image path
   img_path = File.join(Rails.root, 'public', 'images', 'upload_images', image.image_name)
   # delete the image file
   File.delete(img_path)
   # delete record from the database
   image.destroy

   redirect_to uploadimage_path
end

After that we have to modify the routes.rb with the following code.

resources :public, :only => [:upload_image, :uploading, :remove_image]
 
# define the routes
match '/uploadimage', :to => 'public#upload_image'
match '/uploadingimage', :to => 'public#uploading'
match '/removeimage/:id', :to => 'public#remove_image'

Now your application is ready to upload and remove image using rails3.