Use Dash to Build to Web Apps on Hacker News Data

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

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

Connecting to Hacker News Data

Connecting to Hacker News 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.

Connecting to HackerNews

The HackerNews API (powered by Firebase) is a public API that requires no authentication. You can connect and query data immediately without any credentials.

After setting the following connection properties, you are ready to connect:

• AuthScheme: Set this to None.

Example connection string:

Profile=C:\profiles\HackerNews.apip;AuthScheme=None

After installing the CData Hacker News Connector, follow the procedure below to install the other required modules and start accessing Hacker News 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 Hacker News 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.api as mod
import plotly.graph_objs as go

You can now connect with a connection string. Use the connect function for the CData Hacker News Connector to create a connection for working with Hacker News data.

cnxn = mod.connect("Profile=C:\profiles\HackerNews.apip;AuthScheme=None")

Execute SQL to Hacker News

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 ,  FROM TopStories WHERE  = ''", 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-apiedataplot'

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 Hacker News data and configure the app layout.

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

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='Hacker News TopStories 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 Hacker News data.

python api-dash.py

Free Trial & More Information

Download a free, 30-day trial of the CData API Driver for Python to start building Python apps with connectivity to Hacker News 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.api as mod
import plotly.graph_objs as go

cnxn = mod.connect("Profile=C:\profiles\HackerNews.apip;AuthScheme=None")

df = pd.read_sql("SELECT ,  FROM TopStories WHERE  = ''", cnxn)
app_name = 'dash-apidataplot'

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., y=df., name='')

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='Hacker News TopStories Data', barmode='stack')
		})
], className="container")

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