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Feature #859

Uploading Raw Files into Database With Ruby on Rails

Added by Daniel Curtis almost 4 years ago. Updated over 3 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Target version:
Start date:
10/16/2016
Due date:
% Done:

100%

Estimated time:
0.50 h
Spent time:

Description

This is a simple guide for setting up a simple file upload to database with Ruby on Rails.

  • Create the new Ruby on Rails web application:
    rails new uploadr
    
  • Change into the message_app directory:
    cd uploadr
    
  • Start the rails development web server locally:
    bundle exec rails s
    
    • NOTE: The development web server bind the IP address to the localhost by default, so accessing it over the network will not work. To allow network access to the development web server:
      bundle exec rails s -b 0.0.0.0
      

Document Scaffold

  • Generate the scaffold model, view, and controller code for the document.
    bundle exec rails generate scaffold document filename:string content_type:string file_contents:binary
    
  • Edit the route config:
    vi config/routes.rb
    
    • And add the default route to the app:
      Uploadr::Application.routes.draw do
        resources :documents
        root :to => 'documents#index'
      end
      
  • Edit the form view:
    vi app/view/documents/_form.html.erb
    
    • And remove the unneeded form div tags, leaving the following:
        <div class="field">
          <%= f.file_field :file %>
        </div>
        <div class="actions">
          <%= f.submit %>
        </div>
      
  • Edit the document controller:
    vi app/controllers/documents_controller.rb
    
    • And the following right b+efore the final end+ statement to allow file as a parameter so you can use it in the model:
      def document_params
        params.require(:document).permit(:file)
      end
      
  • Next edit the document model:
    vi app/models/document.rb
    
    • And add the following to update the model to read and save the file
        def initialize(params = {})
          file = params.delete(:file)
          super
          if file
            self.filename = sanitize_filename(file.original_filename)
            self.content_type = file.content_type
            self.file_contents = file.read
          end
        end
      
        private
        def sanitize_filename(filename)
          return File.basename(filename)
        end
      

Showing the Document

  • Edit the document controller again:
    vi app/controllers/documents_controller.rb
    
    • And modify the show method to send the raw file for viewing:
      def show
        send_data(@document.file_contents,
                  type: @document.content_type,
                  filename: @document.filename)
      end
      

File Size Validation

  • Edit the document model again:
    vi app/controllers/documents_controller.rb
    
    • And modify the file using the following code:
      validate :max_file_size
      
      def initialize(params = {})
        # File is now an instance variable so it can be validated.
        @file = params.delete(:file)
        super
        if @file
          self.filename = sanitize_filename(@file.original_filename)
          self.content_type = @file.content_type
          self.file_contents = @file.read
        end
      end
      
      NUM_BYTES = 1048576 # 1MB
      def max_file_size
        if (@file.size.to_f / NUM_BYTES) > 1
          errors.add(:file, 'File size cannot be over #{NUM_BYTES} bytes.')
        end
      end
      

Resources

History

#1 Updated by Daniel Curtis almost 4 years ago

  • % Done changed from 0 to 100
  • Status changed from New to Resolved

#2 Updated by Daniel Curtis almost 4 years ago

  • Description updated (diff)

#3 Updated by Daniel Curtis almost 4 years ago

  • Description updated (diff)

#4 Updated by Daniel Curtis over 3 years ago

  • Status changed from Resolved to Closed

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