Create a Tiny World Python Application using the Flask framework, to consume OData services to connect to SAP HANA, Express Edition.

Note:
The tutorial assumes you have a local Unix machine. Please use equivalent commands if running a Windows Environment.

Open terminal and create a directory.

    ~$ mkdir TinyWorldFlaskApp
    ~$ cd TinyWorldFlaskApp/

Run the following commands.

    ~TinyWorldFlaskApp$ touch main.py
    ~TinyWorldFlaskApp$ touch requirements.txt
    ~TinyWorldFlaskApp$ mkdir templates
    ~TinyWorldFlaskApp$ mkdir static
    ~TinyWorldFlaskApp$ cd templates
    ~TinyWorldFlaskApp/templates$ touch odata.html
    ~$ cd ..

Copy the below code to the file main.py in this directory and edit the code to change IP Address, OData Service Name and Credentials:

        from flask import Flask, render_template, request
        from pyslet.odata2.client import Client
        from pyslet.http.auth import BasicCredentials
        from pyslet.http.client import Client as http
        from pyslet.http.client import ClientRequest

        app = Flask(__name__)

        @app.route('/odata')
        def hello():
            products = testClient()
            return render_template('odata.html', products=products)

        # Edit the below code to use the IP address, URL, table name, column names as per the table exposed in the Odata service
        # This example assumes you have the table as mentioned in the prerequisite OData tutorial.
        def testClient():
            c = MyAuthenticatedClient('http://<YOUR_HOST_NAME>:8090/ODataTutorial/product.xsodata')
            products = c.feeds['Product'].OpenCollection()
            productNames = []
            for p in products.iteritems():
                c1 = p['PRODUCTID'].value
                c2 = p['CATEGORYID'].value
                c3 = p['LINEID'].value
                c4 = p['PRODUCTNAME'].value
                c5 = p['PRODUCTDESCRIPTION'].value
                c6 = p['CATEGORYNAME'].value
                c7 = p['CATEGORYDESCRIPTION'].value
                c8 = p['LINENAME'].value
                c9 = p['LINEDESCRIPTION'].value
                c10 = p['DISCONTINUED'].value
                c11 = p['CAPACITY'].value
                c12 = p['SCREENSIZE'].value
                productNames.append((c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12))

            return productNames

        #Overridden Class to handle HTTP authentication
        class MyAuthenticatedClient(Client):

            def process_request(self, request):
                # Edit the code below to add required credentials to access the OData service.
                if (self.credentials is not None and not request.has_header("Authorization")):
                    credentials = BasicCredentials()
                    credentials.userid = "<YOUR_USERNAME>"
                    credentials.password = "<YOUR_PASSWORD>"
                    request.set_header('Authorization', str(credentials))
                    super(MyAuthenticatedClient, self).process_request(request)

        if __name__ == '__main__':
          app.run(host='0.0.0.0', port=80)

Copy the below code to the requirements.txt file in the directory.

        Flask==0.12.1
        pyslet

Copy the following code to the file odata.html under the templates directory.

  Hello World From HANA Express through OData!
  </br>
  </br>

  <!-- Edit the below code to use the column names as per the table exposed in the Odata service
   This example assumes you have the table as mentioned in the prerequisite OData tutorial. -->

  <table style="width:100%">
    <tr>
      <th>PRODUCT ID</th>
      <th>CATEGORY ID</th>
      <th>LINE ID</th>
      <th>PRODUCT NAME</th>
      <th>PRODUCT DESCRIPTION</th>
      <th>CATEGORY NAME</th>
      <th>CATEGORY DESCRIPTION</th>
      <th>LINE NAME</th>
      <th>LINE DESCRIPTION</th>
      <th>DISCONTINUED</th>
      <th>CAPACITY</th>
      <th>SCREEN SIZE</th>
    </tr>
    {% for p in products:%}
        <tr>
          <td> {{ p[0] }}</td>
          <td> {{ p[1] }}</td>
          <td> {{ p[2] }}</td>
          <td> {{ p[3] }}</td>
          <td> {{ p[4] }}</td>
          <td> {{ p[5] }}</td>
          <td> {{ p[6] }}</td>
          <td> {{ p[7] }}</td>
          <td> {{ p[8] }}</td>
          <td> {{ p[9] }}</td>
          <td> {{ p[10] }}</td>
          <td> {{ p[11] }}</td>
        </tr>
    {% endfor %}
  </table>

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

    ~TinyWorldFlaskApp$ pip install virtualenv
    ~TinyWorldFlaskApp$ virtualenv env
    ~TinyWorldFlaskApp$ source env/bin/activate
    ~TinyWorldFlaskApp$ pip install -r requirements.txt
    ~TinyWorldFlaskApp$ python main.py

Browse the application at http://localhost:8080/odata.
The results would look like below.

You now have a working Python/Flask application connecting to SAP HANA, Express Edition using OData services.