xmpp.js Documentation

Fast authentication (based on XEP-0484) is included and enabled by default in @xmpp/client.

By default, the authentication token is stored only in memory. This means fast authentication will only be available starting from the first reconnection after the initial login. To enable fast authentication across restarts or sessions, you must provide custom functions to store, retrieve, and remove the token from a persistent storage mechanism (like a database or secure storage).

If fast authentication fails (e.g., the token is missing or invalid), the client will automatically fall back to regular authentication.

import { xmpp } from "@xmpp/client";

const client = xmpp({
  // ... client configuration
});

// Implement persistent storage for fast authentication tokens
client.fast.fetchToken = async () => {
  const value = await secureStorage.get("token")
  return JSON.parse(value);
}

client.fast.saveToken = async (token) => {
  await secureStorage.set("token", JSON.stringify(token));
}

client.fast.removeToken = async () => {
  await secureStorage.del("token");
}

Instead of a static object, you can provide an asynchronous function to the credentials option. This function is called every time authentication occurs (including reconnections), allowing for dynamic credential retrieval or interactive user input.

The function signature is async function(authenticate, mechanisms):

• authenticate: A function to call to complete the authentication process. It accepts credentials (an object with username and password) and the selected mechanism string.
• mechanisms: An array of available SASL mechanisms provided by the server.

Common use cases include:

• Prompting the user for credentials at runtime.
• Fetching credentials from a secure database.
• Debugging authentication flows.
• Implementing specific requirements for a particular SASL mechanism.

import { xmpp } from "@xmpp/client";

const client = xmpp({ credentials: onAuthenticate });

async function onAuthenticate(authenticate, mechanisms) {
  console.debug("authenticate", mechanisms);
  const credentials = {
    username: await prompt("enter username"),
    password: await prompt("enter password"),
  };
  console.debug("authenticating");
  await authenticate(credentials, mechanisms[0]);
  console.debug("authenticated");
}