Deploy an application built to connect to SAP HANA Express Edition, on App engine of the Google Cloud Platform (GCP)

1. Run the following commands.

mkdir ruby-odata cd ruby-odata/ touch config.ru touch app.rb touch Gemfile mkdir views touch views/products.slim
2. Copy following code to file app.rb

```
#!/usr/bin/env ruby
require ‘ruby_odata’
require ‘sinatra’
require ‘slim’

  set :bind, '0.0.0.0'
  $headers = ['PRODUCTID', 'CATEGORYID', 'LINEID', 'PRODUCTNAME', 'PRODUCTDESCRIPTION', 'CATEGORYNAME', 'CATEGORYDESCRIPTION', 'LINENAME', 'LINEDESCRIPTION', 'DISCONTINUED', 'CAPACITY', 'SCREENSIZE']

  def retrieveProductData
    src = OData::Service.new "http://<YOUR_HOSTNAME>:8090/ODataTutorial/product.xsodata", { :username => "<YOUR_USERNAME>", :password=> "<YOUR_PASSWORD>" }

    # Querying, pull all products  from service 'src'
    src.products
    products = src.execute
    # Generate an 2d array that contains products data
    productData = products.map do |p|
      # 'p.send h' calls method p."h", e.g. p.PRODUCTID when h == "PRODUCTID"
      $headers.collect {|h| p.send h}
    end
    return productData
  end

  get '/' do
    @data = retrieveProductData
    @headers = $headers
    slim :products
  end

```

1. Copy following code to file views/products.slim

     doctype html
     html
       head
         title HANA Express OData Service Example
       body
         h1 Show data from Table 'Products'
   
         table border="1px"
           thead
             tr
             - @headers.each do |header|
               th = header
           tbody
           - @data.each do |row|
             tr
             - row.each do |cell|
               td = cell
   

2. Copy the below code to the Gemfile file in the directory.
   ```
   source “https://rubygems.org”

   gem "sinatra"
   gem "slim"
   gem "ruby_odata"
   

   ```

3. Run the following commands at the root of the project directory.

   ```
   ~ruby-odata$bundle install
   # This command should generate ‘Gemfile.lock’ file, which is needed in deploying
   ~ruby-odata$ruby app.rb
   (dev_appserver.py does not support Ruby currently)

   ```

4. Browse the application at http://localhost:4567.
   The results should look like below.