Authenticating with a User and Password

For this example, start the server using:

nats-server --user myname --pass password

You can encrypt passwords to pass to nats-server using the simple NATS CLI tool:

nats server passwd

? Enter password [? for help] **********************
? Reenter password [? for help] **********************

$2a$11$qbtrnb0mSG2eV55xoyPqHOZx/lLBlryHRhU3LK2oOPFRwGF/5rtGK

and use the hashed password in the server config. The client still uses the plain text version.

The code uses localhost:4222 so that you can start the server on your machine to try them out.

Connecting with a User/Password

When logging in with a password nats-server will take either a plain text password or an encrypted password.

Go

// Set a user and plain text password
nc, err := nats.Connect("127.0.0.1", nats.UserInfo("myname", "password"))
if err != nil {
    log.Fatal(err)
}
defer nc.Close()

// Do something with the connection

Java

Options options = new Options.Builder()
    .server("nats://localhost:4222")
    .userInfo("myname","password") // Set a user and plain text password
    .build();
Connection nc = Nats.connect(options);

// Do something with the connection

nc.close();

JavaScript

 const nc = await connect({
      port: ns.port,
      user: "byname",
      pass: "password",
});

Python

nc = NATS()

await nc.connect(servers=["nats://myname:[email protected]:4222"])

# Do something with the connection.

C#

// dotnet add package NATS.Net
using NATS.Net;
using NATS.Client.Core;

await using var client = new NatsClient(new NatsOpts
{
    Url = "nats://localhost:4222",
    AuthOpts = new NatsAuthOpts
    {
        Username = "myname",
        Password = "password",
    }
});

Ruby

require 'nats/client'

NATS.start(servers:["nats://myname:[email protected]:4222"], name: "my-connection") do |nc|
   nc.on_error do |e|
    puts "Error: #{e}"
  end

   nc.on_reconnect do
    puts "Got reconnected to #{nc.connected_server}"
  end

  nc.on_disconnect do |reason|
    puts "Got disconnected! #{reason}"
  end

  nc.close
end

C

natsConnection      *conn      = NULL;
natsOptions         *opts      = NULL;
natsStatus          s          = NATS_OK;

s = natsOptions_Create(&opts);
if (s == NATS_OK)
    s = natsOptions_SetUserInfo(opts, "myname", "password");
if (s == NATS_OK)
    s = natsConnection_Connect(&conn, opts);

(...)

// Destroy objects that were created
natsConnection_Destroy(conn);
natsOptions_Destroy(opts);

Connecting with a User/Password in the URL

Most clients make it easy to pass the user name and password by accepting them in the URL for the server. This standard format is:

nats://user:password@server:port

Using this format, you can connect to a server using authentication as easily as you connected with a URL:

Go

// Set a user and plain text password
nc, err := nats.Connect("myname:[email protected]")
if err != nil {
    log.Fatal(err)
}
defer nc.Close()

// Do something with the connection

Java

Connection nc = Nats.connect("nats://myname:password@localhost:4222");

// Do something with the connection

nc.close();

JavaScript

// JavaScript clients don't support username/password in urls use `user` and `pass` options.

Python

nc = NATS()

await nc.connect(servers=["nats://myname:[email protected]:4222"])

# Do something with the connection.

C#

// dotnet add package NATS.Net
using NATS.Net;
using NATS.Client.Core;

await using var nc = new NatsClient(new NatsOpts
{
    // .NET client doesn't support username/password in URLs
    // use `Username` and `Password` options.
    Url = "nats://demo.nats.io:4222",
    AuthOpts = new NatsAuthOpts
    {
        Username = "myname",
        Password = "password",
    }
});

Ruby

require 'nats/client'

NATS.start(servers:["nats://myname:[email protected]:4222"], name: "my-connection") do |nc|
   nc.on_error do |e|
    puts "Error: #{e}"
  end

   nc.on_reconnect do
    puts "Got reconnected to #{nc.connected_server}"
  end

  nc.on_disconnect do |reason|
    puts "Got disconnected! #{reason}"
  end

  nc.close
end

C

natsConnection      *conn      = NULL;
natsOptions         *opts      = NULL;
natsStatus          s          = NATS_OK;

s = natsOptions_Create(&opts);
if (s == NATS_OK)
    s = natsOptions_SetURL(opts, "nats://myname:[email protected]:4222");
if (s == NATS_OK)
    s = natsConnection_Connect(&conn, opts);

(...)

// Destroy objects that were created
natsConnection_Destroy(conn);
natsOptions_Destroy(opts);