Use Dash to Build to Web Apps on SAP Netweaver Gateway Data

The rich ecosystem of Python modules lets you get to work quickly and integrate your systems more effectively. With the CData Python Connector for SAP Netweaver Gateway, the pandas module, and the Dash framework, you can build SAP Netweaver Gateway-connected web applications for SAP Netweaver Gateway data. This article shows how to connect to SAP Netweaver Gateway with the CData Connector and use pandas and Dash to build a simple web app for visualizing SAP Netweaver Gateway data.

With built-in, optimized data processing, the CData Python Connector offers unmatched performance for interacting with live SAP Netweaver Gateway data in Python. When you issue complex SQL queries from SAP Netweaver Gateway, the driver pushes supported SQL operations, like filters and aggregations, directly to SAP Netweaver Gateway and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations).

Connecting to SAP Netweaver Gateway Data

Connecting to SAP Netweaver Gateway data looks just like connecting to any relational data source. Create a connection string using the required connection properties. For this article, you will pass the connection string as a parameter to the create_engine function.

SAP Gateway allows both basic and OAuth 2.0 authentication. You can use basic authentication to connect to your own account, or you can use OAuth to enable other users to retrieve data from your service with their accounts. In addition to authenticating, set the following connection properties to access SAP Gateway tables.

• Url: Set this to the URL of your environment, or to the full URL of the service. For example, the full URL might appear as: https://sapes5.sapdevcenter.com/sap/opu/odata/IWBEP/GWSAMPLE_BASIC/. In this example, the environment URL would just be: https://sapes5.sapdevcenter.com.
• Namespace: Set the appropriate Service Namespace. In the example above, IWBEP is the namespace. It is optional if the full URL to the service is specified.
• Service: Set this to the service you want to retrieve data from. In the example above, the service is GWSAMPLE_BASIC. It is not required if the full URL is specified.

Authenticate via Basic Authentication

In basic authentication, you use your login credentials to connect. Set the following properties:

• User: This is the username you use to log in to SAP Gateway.
• Password: This is the password you use to log in to SAP Gateway.

Authenticate via OAuth Authentication

You can connect to SAP Gateway using the embedded OAuth connectivity (without setting any additional authentication connection properties). When you connect, the OAuth endpoint opens in your browser. Log in and grant permissions to complete the OAuth process. See the OAuth section in the online Help documentation for more information on other OAuth authentication flows.

After installing the CData SAP Netweaver Gateway Connector, follow the procedure below to install the other required modules and start accessing SAP Netweaver Gateway through Python objects.

Install Required Modules

Use the pip utility to install the required modules and frameworks:

pip install pandas
pip install dash
pip install dash-daq

Visualize SAP Netweaver Gateway Data in Python

Once the required modules and frameworks are installed, we are ready to build our web app. Code snippets follow, but the full source code is available at the end of the article.

First, be sure to import the modules (including the CData Connector) with the following:

import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import cdata.sapgateway as mod
import plotly.graph_objs as go

You can now connect with a connection string. Use the connect function for the CData SAP Netweaver Gateway Connector to create a connection for working with SAP Netweaver Gateway data.

cnxn = mod.connect("User=user;Password=password;URL=https://sapes5.sapdevcenter.com/sap/opu/odata/IWBEP/GWSAMPLE_BASIC/;InitiateOAuth=GETANDREFRESH;OAuthSettingsLocation=/PATH/TO/OAuthSettings.txt")")

Execute SQL to SAP Netweaver Gateway

Use the read_sql function from pandas to execute any SQL statement and store the result set in a DataFrame.

df = pd.read_sql("SELECT ProductID, Quantity FROM SalesOrderLineItems WHERE Quantity = '15'", cnxn)

Configure the Web App

With the query results stored in a DataFrame, we can begin configuring the web app, assigning a name, stylesheet, and title.

app_name = 'dash-sapgatewayedataplot'

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.title = 'CData + Dash'

Configure the Layout

The next step is to create a bar graph based on our SAP Netweaver Gateway data and configure the app layout.

trace = go.Bar(x=df.ProductID, y=df.Quantity, name='ProductID')

app.layout = html.Div(children=[html.H1("CData Extension + Dash", style={'textAlign': 'center'}),
	dcc.Graph(
		id='example-graph',
		figure={
			'data': [trace],
			'layout':
			go.Layout(title='SAP Netweaver Gateway SalesOrderLineItems Data', barmode='stack')
		})
], className="container")

Set the App to Run

With the connection, app, and layout configured, we are ready to run the app. The last lines of Python code follow.

if __name__ == '__main__':
    app.run_server(debug=True)

Now, use Python to run the web app and a browser to view the SAP Netweaver Gateway data.

python sapgateway-dash.py

Free Trial & More Information

Download a free, 30-day trial of the CData Python Connector for SAP Netweaver Gateway to start building Python apps with connectivity to SAP Netweaver Gateway data. Reach out to our Support Team if you have any questions.

Full Source Code

import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import cdata.sapgateway as mod
import plotly.graph_objs as go

cnxn = mod.connect("User=user;Password=password;URL=https://sapes5.sapdevcenter.com/sap/opu/odata/IWBEP/GWSAMPLE_BASIC/;InitiateOAuth=GETANDREFRESH;OAuthSettingsLocation=/PATH/TO/OAuthSettings.txt")

df = pd.read_sql("SELECT ProductID, Quantity FROM SalesOrderLineItems WHERE Quantity = '15'", cnxn)
app_name = 'dash-sapgatewaydataplot'

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.title = 'CData + Dash'
trace = go.Bar(x=df.ProductID, y=df.Quantity, name='ProductID')

app.layout = html.Div(children=[html.H1("CData Extension + Dash", style={'textAlign': 'center'}),
	dcc.Graph(
		id='example-graph',
		figure={
			'data': [trace],
			'layout':
			go.Layout(title='SAP Netweaver Gateway SalesOrderLineItems Data', barmode='stack')
		})
], className="container")

if __name__ == '__main__':
    app.run_server(debug=True)