> For the complete documentation index, see [llms.txt](https://docs.bloxroute.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bloxroute.com/eth/streams/working-with-streams/handling-the-notification.md). # Handling the Notification To process a new notification, call the function **`get_next_subscription_notification_by_id`**, passing in the subscription\_id returned from the **`subscribe`** command as a parameter. After subscribing to a stream, your application receives a notification for each published event (for example, a new transaction or block). This section explains how to **handle stream notifications** using the supported protocols: **WebSocket** and **gRPC**. Both approaches are covered below. ### WebSocket For WebSocket subscriptions, notifications are delivered over the established WebSocket connection. Each notification includes the `subscription_id` returned by the initial `subscribe` call. To process a notification, listen for incoming messages and match the message `id` with the corresponding `subscription_id`. #### **Examples** {% tabs %} {% tab title="Gateway-API" %} Handling the transaction notification from a Gateway Stream in Python (line 8 handles the notification): ```python import asyncio, json, ssl, websockets async def main(): try: ws_uri = "ws://127.0.0.1:28333/ws", auth_key = "YOUR_AUTHORIZATION_HEADER" async with websockets.connect( ws_uri, header=["Authorization:{}".format(auth_key)], ) as websocket: subscription_request = json.dumps({"id": 1, "method": "subscribe", "params": ["newTxs", {"include": ["tx_hash"]}]}) await websocket.send(subscription_request) response = await websocket.recv() subscription_id = json.loads(response)['result'] while True: response = await websocket.recv() response = json.loads(response) if response['id'] == subscription_id: print(response) # or process it generally except Exception as e: print(f'Connection failed, Reason: {e}') if __name__ == '__main__': asyncio.run(main()) ``` {% endtab %} {% tab title="Cloud-API (Enterprise)" %} Handling the transaction notification from a Cloud-API Stream in Python (version 3.7 or higher): ```python import asyncio, json, ssl, websockets async def main(): try: auth_key = "YOUR_AUTHORIZATION_HEADER" async with websockets.connect( 'wss://virginia.eth.blxrbdn.com/ws', header=["Authorization:{}".format(auth_key)], sslopt={"cert_reqs": ssl.CERT_NONE}, ) as websocket: subscription_request = json.dumps({"id": 1, "method": "subscribe", "params": ["newTxs", {"include": ["tx_hash"]}]}) await websocket.send(subscription_request) subscription_id = None while True: response = await websocket.recv() response_json = json.loads(response) if response_json.get('id') == 1: subscription_id = response_json.get('result') else: print(response_json) # or process it generally except Exception as e: print(f'Connection failed, Reason: {e}') finally: if subscription_id is not None: try: unsubscription_request = json.dumps({"id": 2, "method": "unsubscribe", "params": [subscription_id]}) await websocket.send(unsubscription_request) except Exception as e: print(f'Unsubscription failed, Reason: {e}') if __name__ == '__main__': asyncio.run(main()) ``` {% endtab %} {% tab title="Cloud-API (non-Enterprise)" %} Handling the transaction notification from a Cloud-API Stream in Python (version 3.7 or higher): ```python import asyncio, json, ssl, websockets async def main(): try: auth_key = "YOUR_AUTHORIZATION_HEADER" async with websockets.connect( 'wss://api.blxrbdn.com/ws', header=["Authorization:{}".format(auth_key)], sslopt={"cert_reqs": ssl.CERT_NONE}, ) as websocket: subscription_request = json.dumps({"id": 1, "method": "subscribe", "params": ["newTxs", {"include": ["tx_hash"]}]}) await websocket.send(subscription_request) subscription_id = None while True: response = await websocket.recv() response_json = json.loads(response) if response_json.get('id') == 1: subscription_id = response_json.get('result') else: print(response_json) # or process it generally except Exception as e: print(f'Connection failed, Reason: {e}') finally: if subscription_id is not None: try: unsubscription_request = json.dumps({"id": 2, "method": "unsubscribe", "params": [subscription_id]}) await websocket.send(unsubscription_request) except Exception as e: print(f'Unsubscription failed, Reason: {e}') if __name__ == '__main__': asyncio.run(main()) ``` {% endtab %} {% endtabs %} ### gRPC For gRPC subscriptions, notifications are received by calling `Recv()` on the stream object returned by the subscription request. Each call to `Recv()` blocks until a new event is available or an error occurs. #### **Example** {% tabs %} {% tab title="Gateway-API" %} Subscribing to Gateway Stream in Go using gRPC (ex: `NewTxs` stream): ```go package main import ( "context" "fmt" "time" pb "github.com/bloXroute-Labs/gateway/v2/protobuf" "google.golang.org/grpc" "google.golang.org/grpc/credentials" ) type blxrCredentials struct { authorization string } func (bc blxrCredentials) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) { return map[string]string{ "authorization": bc.authorization, }, nil } func (bc blxrCredentials) RequireTransportSecurity() bool { return false } func main() { // gRPC server default values gatewayHostIP := "localhost" gatewayGRPCPort := 5001 // this will use localhost CA to verify the certificate creds := credentials.NewClientTLSFromCert(nil, "") // Open gRPC connection to Gateway. conn, _ := grpc.Dial( fmt.Sprintf("%v:%v", gatewayHostIP, gatewayGRPCPort), grpc.WithTransportCredentials(creds), grpc.WithPerRPCCredentials(blxrCredentials{authorization: ""}), // for the best networking performance between gateway and a client // we recommend to use following dial configuration: grpc.WithWriteBufferSize(0), grpc.WithInitialConnWindowSize(128*1024), ) // Use the Gateway client connection interface. client := pb.NewGatewayClient(conn) // create context and defer cancel of context callContext, cancel := context.WithTimeout(context.Background(), 24*time.Hour) defer cancel() // Create a subscription using the stream-specific method and request. stream, _ := client.NewTxs(callContext, &pb.TxsRequest{Filters: "", Includes: ""}) for { subscriptionNotification, err := stream.Recv() if err == nil { fmt.Println(subscriptionNotification) // or process it generally } } } ``` {% endtab %} {% endtabs %} --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.bloxroute.com/eth/streams/working-with-streams/handling-the-notification.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.