Build a GPS Routing API with Python Flask

Create a free Distance Matrix API using Flask with a Selenium Bot deployed on Heroku

Photo by Samantha Gollnick / Unsplash

My first project using GPS routing was 4 years ago.

I wanted to optimise a transport plan for 1,200 truck deliveries/month covering 50 stores from a Cross-Docking platform.

I have built a Transportation Route Optimization tool using Excel-VBA — mainly for transport plan design using distance collected from Google Maps API.

This was my first experience using an API; Google Maps API was free with a limit of 10,000 requests per day.

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What about now?

A few years later, Google changed its billing policy, so you have to pay from the first request.

If you have never subscribed to the Google Cloud Platform (GCP) service you can have 200$ free credits after setting up a credit card.

But what if

you need to get several thousand distances?
you don’t care if it takes a long time?
you don’t feel confident about using your personal card (or cannot get a company credit card) for non-personal projects?

This article will show you a solution built with a Flask API using a Selenium bot connected to Google Map WebPage.

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You can find the full code uploaded in this repository: Github

How does it work?

Before starting to read this part, please forget everything you know about how to put in production a fast, efficient and stable code that ensures quick response with limited resources.

This will be simple, quick and dirty, with no intention of being a scalable solution.

The performance will be way lower than if you directly query the official Google API — but here it’s free :)

The whole solution as a three-icon loop in black line art with the traffic labelled in navy on the arrows rather than in — Full Process to get the distance between two cities in your Google Sheet — (Image by Author)

Build your API

Let us do it in three steps

Build a Selenium Bot that will query the distance from City A to City B on the Google Maps Website
Set up your Flask API that will receive the request and return a distance
Deploy your code on Heroku

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You can find the full code in this Github repository: Link

Set up your Selenium Bot

Set ChromeDriver options to ensure the highest speed of execution
Input Environment Variables that will be created in your Heroku instance

Write your distance scrapper

Google Maps link to get the distance from "Paris, France" to "Marseille, France"https://www.google.fr/maps/dir/Paris,France/Marseille, France/data=!4m2!4m1!3e0"/data=!4m2!4m1!3e0" is added to ensure that you take the road transportation distance

Set up your Flask API

Your API link to get the distance from "Paris, France" to "Marseille, France"http://xxx-xxx.herokuapp.com/distance/Paris,France/Marseille,France(replace xxx-xxx by your Heroku app name)<fr> = Paris,France<to> = Marseille, France

Deploy your API

I will skip details on how to create and deploy an app on Heroku. You can find links to Medium articles explaining detailed steps to create your Heroku instance at the end of the article.

Prepare files for deployment on Heroku

Prepare requirements.txt file with a listing of libraries needed with pip freeze

(env) C:\Users\yourprojectfolder> pip freeze > requirements.txt

Create ProcFile to launch your web app

(env) C:\Users\yourprojectfolder> echo web: gunicorn -t 120 -b :$PORT app:app > ProcfileP.S: Please make sure that your app name is "app" and your python script is named "app.py"