fileUploader example with ruby-grape

fileUploader.ru

#!/usr/bin/env rackup
# encoding: UTF-8

=begin
# start application
$ mkdir files
$ ./fileUploader.ru

# upload
$ curl localhost:9292/files -F comment="hello,world" -F "body=@example.txt;type=image/jpg"
#=> Content-Type: application/json
{"id":"d20f7400-81f6-0133-570b-7831c1cfdb38"}

# download body
$ curl localhost:9292/files/d20f7400-81f6-0133-570b-7831c1cfdb38
#=> Content-Type: image/jpg
(bytes)

# download comment
$ curl localhost:9292/files/d20f7400-81f6-0133-570b-7831c1cfdb38/comment
#=> Content-Type: text/plain
hello,world

# delete content
$ curl localhost:9292/files/d20f7400-81f6-0133-570b-7831c1cfdb38 -X DELETE
{"state":"deleted"}

=end

require 'grape'
require 'uuid'
require 'yaml/store'
require 'pp'

module FileStore
  class << self
    @@me = nil
    def me
      unless @@me
        filename = 'files/contents.yaml'
        File.write(filename, {files:{}}.to_yaml) unless File.exist?(filename)
        @@me = YAML::Store.new(filename)
      end
      @@me
    end

    def find(id)
      me.transaction do
        me[:files][id]
      end
    end

    def store(body, comment)
      id = UUID.generate
      File.write("files/#{id}", body.tempfile.read)
      me.transaction do
        me[:files][id] = {comment:comment, name:body.filename, type:body.type}
      end
      id
    end

    def destroy(id)
      me.transaction do
        if me[:files].delete(id)
          File.unlink("files/#{id}")
          true
        else
          false
        end
      end
    end

  end
end


class FileStreamer
  def initialize(file_path)
    @file_path = file_path
  end

  def each(&blk)
    File.open(@file_path, 'rb') do |file|
      file.each(10, &blk)
    end
  end
end


class FileUploader < Grape::API
  content_type :txt,  'text/plain'
  content_type :json, 'application/json'
  format :json
  default_format :json

  resource :files do

    params do
      requires :comment,  type: String
      requires :body,     type: File
    end
    post '' do
      id = FileStore.store(params.body, params.comment)
      status 201
      {id:id}
    end

    params do
      requires :id, type: String
    end
    get ':id' do
      obj = FileStore.find(params[:id])
      unless obj
        status 404
        return {error: '404 not found.'}
      end
      status 200
      content_type obj[:type]
      file FileStreamer.new("files/#{params.id}")
    end

    params do
      requires :id, type: String
    end
    get ':id/comment' do
      obj = FileStore.find(params[:id])
      unless obj
        status 404
        return {error: '404 not found.'}
      end
      status 200
      content_type 'text/plain'
      body obj[:comment]
    end

    params do
      requires :id, type: String
    end
    delete ':id' do
      if FileStore.destroy(params.id)
        status 200
        return {state:'deleted'}
      else
        status 404
        return {error: '404 not found.'}
      end
    end
  end
end

run FileUploader