How to upload a file in ruby on rails?

Question

I’m very new in ruby on rails. I’m stuck with a problem. I want to make a file upload functionality through which I can upload any kind of file (text,image etc.). My controller file is (upload_controller.rb):

class UploadController < ApplicationController
def index
    render :file => 'app\views\upload\uploadfile.html.erb'
end
def uploadFile
    post = DataFile.save(params[:upload])
    render :text => "File has been uploaded successfully"
end
end

My Model file is (data_file.rb):

class DataFile < ActiveRecord::Base
    attr_accessor :upload
  def self.save(upload)
    name = upload['datafile'].original_filename
    directory = 'public/data'
    # create the file path
    path = File.join(directory,name)
    # write the file
    File.open(path, "wp") { |f| f.write(upload['datafile'].read)}
  end
end

My View file is (uploadfile.html.erb):

<h1>File Upload</h1>
<%= form_tag({:action => 'uploadFile'}, :multipart => true) do %>
<p><label for="upload_file">Select File</label>
<%= file_field 'upload', 'datafile' %></p>
<%= submit_tag "Upload" %>
<% end %>

Now when I try to upload image then I'm getting error "invalid access mode wp" in model file. When I change File.open(path, "wp") to File.open(path, "w") in model file this give error "'\x89' from ASCII-8BIT to UTF-8". For .txt file, It works fine. I'm using ruby 1.9.3 and rails 3.2.6

Answer 1

Thank you for example, I study rails too!

It works in rails 3.1

My code:

Routes
resources :images do
      collection { post :upload_image }
    end

Controller

class ImagesController < ApplicationController
  def index
    @car = Car.find(params[:car_id])
    @images = @car.images.order("order_id")
  end

  def upload_image   
    DataFile.save_file(params[:upload])
    redirect_to images_path(:car_id => params[:car_id])
  end

View index.html.erb

<h1>File Upload</h1>
  <%= form_tag({:action => 'upload_image', :car_id => @car.id}, :multipart => true) do %>
    <p><label for="upload_file">Select File</label>
    <%= file_field 'upload', 'datafile' %></p>
    <%= submit_tag "Upload" %>
  <% end %>

  <% @images.each do |image| %>
     <%= image.id %><br/>
     <%= image.name %>
  <% end %>

Model

class DataFile < ActiveRecord::Base
    attr_accessor :upload

  def self.save_file(upload)   

    file_name = upload['datafile'].original_filename  if  (upload['datafile'] !='')    
    file = upload['datafile'].read    

    file_type = file_name.split('.').last
    new_name_file = Time.now.to_i
    name_folder = new_name_file
    new_file_name_with_type = "#{new_name_file}." + file_type

    image_root = "#{RAILS_CAR_IMAGES}"


    Dir.mkdir(image_root + "#{name_folder}");
      File.open(image_root + "#{name_folder}/" + new_file_name_with_type, "wb")  do |f|  
        f.write(file) 
      end

  end
end

Answer 2

The reason for the issue is encoding problems. It seems that you are reading the file in ASCII-8BIT mode and writing it in UTF-8 which means a conversion needs to take place. And conversion from ASCII-8BIT to UTF-8 isn't straight forward. Alternatively, you can specify binary mode for both reading and writing the files.

upload_file = File.new(<original file>, "rb").read

and

File.open(<final uploaded file>, "wb") {|f| f.write(upload_file) }