Connect to Pulsar cluster using WebSocket API

This example shows how to use the WebSocket API to connect to a Pulsar cluster and then produce and consume messages to and from the Pulsar cluster.

Prerequisites

• Get the service URL.
• Get a service account token.

Steps

1. Connect to the Pulsar cluster.

   import websocket, base64, json
   
   # TOPIC = 'ws://CLUSTER_HOST:9090/ws/v2/consumer/persistent/public/default/test/sub'
   TOPIC = 'wss://CLUSTER_HOST:9443/ws/v2/consumer/persistent/public/default/test/sub'
   token = "YOUR_TOKEN"
   header = ["Authorization:Bearer" + token]
   ws = websocket.create_connection(TOPIC, header=header)
   while True:
     msg = json.loads(ws.recv())
     if not msg: break
     print("Received: {} - payload: {}".format(msg, base64.b64decode(msg['payload'])))
     # Acknowledge successful processing
     ws.send(json.dumps({'messageId' : msg['messageId']}))
   
   ws.close()
   

   Replace the CLUSTER_HOST parameter with the domain name of the cluster.

2. Create a consumer and use the consumer to consume messages.

   import websocket, base64, json
   
   # TOPIC = 'ws://CLUSTER_HOST:9090/ws/v2/consumer/persistent/public/default/test/sub'
   TOPIC = 'wss://CLUSTER_HOST:9443/ws/v2/consumer/persistent/public/default/test/sub'
   token = "YOUR_TOKEN"
   header = ["Authorization:Bearer " + token]
   ws = websocket.create_connection(TOPIC, header=header)
   while True:
     msg = json.loads(ws.recv())
     if not msg: break
     print("Received: {} - payload: {}".format(msg, base64.b64decode(msg['payload'])))
     # Acknowledge successful processing
     ws.send(json.dumps({'messageId' : msg['messageId']}))
   
   ws.close()
   

3. Create a producer and use the producer to produce messages.

   import websocket, base64, json
   
   # TOPIC = 'ws://CLUSTER_HOST:9090/ws/v2/producer/persistent/public/default/test'
   TOPIC = 'wss://CLUSTER_HOST:9443/ws/v2/producer/persistent/public/default/test'
   
   token = "YOUR_TOKEN"
   
   header = ["Authorization:Bearer " + token]
   
   ws = websocket.create_connection(TOPIC, header=header)
   
   # Send one message as JSON
   ws.send(json.dumps({
   'payload' : base64.b64encode('Hello World'),
   'properties': {
     'key1' : 'VALUE1',
     'key2' : 'VALUE2'
   },
   'context' : 5
   }))
   
   response =  json.loads(ws.recv())
   if response['result'] == 'ok':
     print('Message published successfully')
   else:
     print('Failed to publish message:', response)
   ws.close()