The OGC’s 131st member meeting took place at the Auditorium della Tecnica Centro Congressi in Rome, Italy, from March 3-6, 2025. The event was a wonderful oportuinity to discuss about lattest technologies like AI, Data Analysis, 3D, Digital Twins, tools for tracking provenance or increasing data trust or even the Metaverse, all of it applied to domain of the geospatial data.
Citizen science also had a place at this OGC meeting, with a specific session dedicated to it, where many experts in the field shared their latest research, concerns and achievements. The more4nature project was well represented by a presentation given by Núria Julià (CREAF) in collaboration with the CitiObs project.
The presentation explored the GANXET tool: a Webhook implementation for Websub. In short, GANXET is a software component that helps applications recieve automatic notifications when new data is available on the web, using a standard called WebSub. It enables real-time, secure, and automated data notifications for applications that work with sensor observations, without requiring constant manual data requests.
WebSub is a recommendation from the W3C, an organization that defines many web standards. It allows one system (the publisher) to notify other systems (the subscribers) whenever information changes, instead of making them check repeatedly. A third component, called a hub, manages subscriptions and sends updates. A webhook is the key idea behind this process: it is a way for one system to send a message to another system automatically when something happens. This message is sent using standard web communication (HTTP).
GANXET is a webhook implementation created for the SensorThings API (STA) WebSub extension. In simple terms, it acts as a messenger between the WebSub hub, which sends updates, and the web application, which wants to receive and display those updates.
GANXET runs on a server and uses two types of communication:
- HTTP, to subscribe or unsubscribe to data updates and to receive notifications from the hub.
- WebSockets, to instantly forward those updates to the web application in real time.
It also includes security checks, ensuring that messages truly come from the hub and have not been altered. GANXET can handle multiple users and multiple subscriptions at the same time, making it scalable and efficient.
