How do clients connect to a SignalR Hub and send messages?

Question

Utpal Vishwas · Answer

1. Client Connects to the SignalR Hub
Clients use the 
SignalR client library to establish a connection to the hub endpoint exposed by the server.The connection is built using the hub URL, then started asynchronously.
Example (JavaScript client):
// Create a connection to the hub endpoint
const connection = new signalR.HubConnectionBuilder()
    .withUrl("/chatHub")     // URL of the hub on the server
    .build();
// Start the connection
connection.start()
    .then(() =andgt; console.log("Connected to SignalR Hub!"))
    .catch(err =andgt; console.error("Connection error: ", err));
2. Listening for Server Messages
Clients can register handlers for messages (methods) that the server will call.This is done using .on("methodName", callback).
connection.on("ReceiveMessage", (user, message) =andgt; {
    console.log(`${user}: ${message}`);
    // You could also update your UI here to show the message
});
3. Sending Messages to the Server
Once connected, clients can invoke methods on the 
server hub using .invoke("MethodName", args...).These method names correspond to public methods defined in your Hub class on the server.
function sendMessage() {
    const user = "Alice";
    const message = "Hello from client!";
    connection.invoke("SendMessage", user, message)
        .catch(err =andgt; console.error(err.toString()));
}
Summary of the Flow
Step
What happens
1. Create connection
Build connection with HubConnectionBuilder
2. Start connection
Connect asynchronously with connection.start()
3. Register handlers
Use connection.on() to handle server messages
4. Send messages
Use connection.invoke() to call server hub methods
and

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How do clients connect to a SignalR Hub and send messages?

Utpal Vishwas

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1 Answers

1. Client Connects to the SignalR Hub

Example (JavaScript client):

2. Listening for Server Messages

3. Sending Messages to the Server

Summary of the Flow

Liked By

Step	What happens
1. Create connection	Build connection with `HubConnectionBuilder`
2. Start connection	Connect asynchronously with `connection.start()`
3. Register handlers	Use `connection.on()` to handle server messages
4. Send messages	Use `connection.invoke()` to call server hub methods