WebSocket Example

This example shows how simple it is to use CloudEvents over a websocket connection. The code here shows backend communication from two server side processes, and also between a browser and a server process.

Running the Example

This simple project consists of a server and a client. The server receives CloudEvents from the client over a local websocket connection.

To get started, first install dependencies.

npm install

Server

The server opens a websocket and waits for incoming connections. It expects that any messages it receives will be a CloudEvent. When received, it reads the data field, expecting a zip code. It then fetches the current weather for that zip code and responds with a CloudEvent containing the body of the Weather API response as the event data.

You will need to change one line in the server.js file and provide your Open Weather API key. You can also create a environment variable OPEN_WEATHER_API_KEY and store your key there.

To start the server, run node server.js.

Client

Upon start, the client prompts a user for a zip code, then sends a CloudEvent over a websocket to the server with the provided zip code as the event data. The server fetches the current weather for that zip code and returns it as a CloudEvent. The client extracts the data and prints the current weather to the console.

To start the client, run node client.js

Browser

Open the index.html file in your browser and provide a zip code in the provided form field. The browser will send the zip code in the data field of a CloudEvent over a websocket. When it receives a response from the server it prints the weather, or an error message, to the screen.

To terminate the client or server, type CTL-C.