#Upload files with carrierwave and Sinatra example

This repo contains code for a very simple sinatra application that uses, carrierwave gem to upload files. Follow the following steps to create your own app that uses carrierwave or browse the code.

This Project is based on https://github.com/codetrotters/sinatra-starter, so view that repositories readme on how to run this app.

###Step 1 - Add Carriwewave to Gemfile

/src/Gemfile

gem 'carrierwave'

###Step 2 - Install Carrierwave with bundle

$ bundle install

###Step 3 - Require Carrierwave

Require carrierwave on /src/app.rb

...
require "carrierwave"
require "carrierwave/orm/activerecord"
...

###Step 4 - Create Carrierwave configuration

Add this code somewhere after requiring carrierwave on /src/app.rb

...

#Configure Carrierwave
CarrierWave.configure do |config|
  config.root = File.dirname(__FILE__) + "/public"
end

...

###Step 5 - Create Carrierwave uploader

Create a file called src/uploader/images_uploader.rb or similar and the following code

class ImagesUploader < CarrierWave::Uploader::Base
  storage :file
end

An uploader contains all the information needed to upload a file, there are several options that we can set. The storage option means that we are going to save the file to the filesystem

Other options exist manage thumbnails, and where to store the uploaded files ( defaults to /public/uploads/ )

###Step 6 - Create a model to store the image

Create an ActiveRecord Model to hold our image information

In a file called src/models/image.rb

class Image < ActiveRecord::Base

end

###Step 7 - Create table on the database

Create the database a table to hold the image information

Using your webrowser access TeamPostgreSql on this address http://localhost:8082/teampostgresql

Create a new table with the name images. Remember that tables names must be in plural and matching an Activerecord Model.

Use the following columns

Column	Type	Primary Key	Not Null
id	serial	Y	N/A
image	text	N	Y
caption	text	N	Y

The image column is where we will be storing the path to the image on the filesystem. You can add as many columns as you want.

##Step 8 - Associate the model with the uploader

Change the file called src/models/image.rb to look like this. This adds a new method to the model called image that returns an image object with usefull properties to manage the upload. This method maps to the image column on our table.

require 'uploader/images_uploader'

class Images < ActiveRecord::Base
  mount_uploader :image, ImagesUploader
end

##Step 9 - Create a form

Create a view file with a form with an input of type file. Make sure the form has the method POST and the enctype multipart/form-data

For Example:

<form method='POST' action='/' enctype="multipart/form-data">
  <input type='file' name='file' class='form-control'>
  <button type='submit'> Add</button>
</form>

The codes contains such a form on views/index.erb

##Step 10 - Create a form

Add a route somewhere on the routes folder, to recieve the file, upload it to public/uploads and save the record.

We have this code on src/default.rb

  post "/" do

      #Create new Image Model
      img = Image.new

      #Save the data from the request
      img.file    = params[:file] #carrierwave will upload the file automatically
      img.caption = "This is the caption" #Or recieve it from params

      #Save
      img.save!

      #Redirect to view
      redirect to("/")

  end

##Step 11 - Use .image on the model, to get the url of the image

/src/routes/default.rb

get "/" do
   #Get an instance of an Image
	@image = Image.find( 1 )
	erb :index
end

/src/views/index.erb

<img src='<%= @image.image.url %>' />