Scrape and Show

You can use one line of Bash code to scrape a web page and show the data you're tracking in Home Assistant or Node-RED

- Pete Metcalfe

Many home automation solutions provide a central dashboard that serves as a nerve center for the Internet of Things (IoT) environment. From the dashboard, you can monitor and manage light levels, thermostat temperatures, and all the other settings the system controls. Some users don’t realize that the dashboard can also provide information from beyond your home network. In other words, you can use the tools of the home automation environment to fetch information from the Internet and display it in a handy at-a-glance view along with your IoT settings.

For instance, you might have personal or hobby topics that you check periodically. These personal data points might be the wave height at a local surf spot, the insect levels at a favorite camping area, or the best time of go fishing. You probably know exactly where to find this information, however, it still requires several steps to start up a web browser, click on a bookmark, and scan the page for the desired data – which might just consist of a single number or a couple of words.

In this article, I will look at how to scrape these hobby data points from web pages with just a single line of Bash code and display the results in the dashboards of two home IoT packages, Home Assistant [1] and Node-RED [2].

Getting Started

Several different automation solutions offer web-scraping tools. For example, Python has the Beautiful Soup [3] library, Home Assistant has the Scrape [4] sensor, and Node-RED has the scrape-it [5] flow. These web-scraping tools are all very usable, but unfortunately they require a detailed knowledge of the HTML/ Document Object Model for the requested page.