simple_attach: A Ruby repository from copremesis

#Simple Attach

###Chapter 1. start new rails instance

rails new simple_attach

create controller

rails g upload

create simple form root/app/views/upload/index.html.erb

<form method=POST action= '/upload' enctype="multipart/form-data">
  <input name="upload[file]" type=file /> <br>
  <input type=submit value=upload>
</form>

create routes root/config/routes.rb

SimpleAttach::Application.routes.draw do
  root 'upload#index'
  post '/upload' => 'upload#attach'
end

process file root/app/controllers/index.rb

  def attach
    #simplest form of attachment
    uploaded_io = params[:upload][:file]
    File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'wb') do |file|
      file.write(uploaded_io.read)
    end
    #something happens here like book keeping or conversion etc
    redirect_to :root
  end

modify upload page to list files

inside upload#index controller:

  @files = `ls #{Rails.root.join('public','uploads')}`.split(/\n/)

inside view:

<% @files.each do |file| %>
<%= file %> <br>
<% end %>

example use:

###Chapter 2.

Adding bootstrap to the project.

I made a copy of the application layout file and named it bootstrap.rb

<!DOCTYPE html>
<html>
<head>
  <title>SimpleAttach</title>
  <%= stylesheet_link_tag    "application", media: "all", "data-turbolinks-track" => true %>
  <%= javascript_include_tag "application", "data-turbolinks-track" => true %>
  <%= csrf_meta_tags %>


  <!-- Latest compiled and minified CSS -->
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">

  <!-- Optional theme -->
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap-theme.min.css">
  <!-- Latest compiled and minified JavaScript -->
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>

</head>
<body>

<%= yield %>

</body>
</html>

The markup for the upload view now becomes:

<form method=POST action= '/upload' enctype="multipart/form-data">
    <div class='container'>
      <div class="row">
        <div class="col-md-6">
          <input name="authenticity_token" value="<%= form_authenticity_token %>" type="hidden">
          <input name="files[]" type=file multiple/> 
        </div>
        <div class="col-md-6">
          <input type=submit value=upload>
        </div>
      </div>
    </div>
</form>

When setting this up I skipped over the authenticity_token to get a working application ... here's the line i commented before inside the application controller.

  protect_from_forgery with: :exception

Also the to handle multiple files renamed the field name for files as such:

  <input name="files[]" type=file multiple/>

The controller that handles this has now become:

Inside the index controller I add this to use the bootstrap layout.

    render :layout => 'bootstrap'

and to handle multiple files we now have:

  def attach
    #simplest form of attachment
    (params[:files] || []).each {|uploaded_io|
      File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'wb') do |file|
        file.write(uploaded_io.read)
      end
    }
    #something happens here like book keeping or conversion etc
    redirect_to :root
  end

New look and tests performed

###Chapter 3. Do we need a database to attach files? This was the primary reason for my need to abandon applications that center around a database -- hence the use of backticks vs sql queries

    @files = `ls #{Rails.root.join('public','uploads')}`.split(/\n/)

Which keeps this light and thin Also if I need to migrate this from one system dev->stage->production to another there's no database to align with a file system. The file system is the database.

If anything we now are at a place where we should write tests and refactor as the code is becoming complex.

###Chapter 4.

Lets get ajaxy and do some HTML5 or something cool like drag and drop

so we can add slew of files all at once ... possbile use cases:

a car dealer
a web designer
real estate agent
golf coach
music major

we don't want to drag or type out 100's of files when we can select them all using the file explorer then upload them in one swoop with a progress bar status I think that is good for today's standards

###Chapter 6.

Blocking I/O will kill mobile. We must have an invisible fast backend system to maximize the power of our handheld device.

optimize

backgroundjob
redis/resque

###Chapter 7. mime types

Now that we've transfered 1's & 0's from somwhere to our mother ship server lets now do something with these files:

render drawings ... build a montage ... create an animation etc ...

copremesis/simple_attach