Iniciar uma conexão WebSocket com o Azure Web PubSub
Artigo
Os clientes se conectam ao serviço Azure Web PubSub usando o protocolo WebSocket padrão. Você pode usar idiomas que tenham suporte ao cliente WebSocket para escrever um cliente para o serviço. Neste artigo, você verá vários exemplos de cliente WebSocket em idiomas diferentes.
Autorização
O Web PubSub usa um JSON Web Token (JWT) para validar e autorizar clientes. Os clientes podem colocar o access_token token no parâmetro de consulta ou colocá-lo no Authorization cabeçalho ao se conectar ao serviço.
Normalmente, o cliente se comunica com seu servidor de aplicativos primeiro, para obter a URL do serviço e o token. Em seguida, o cliente abre a conexão WebSocket para o serviço usando a URL e o token que recebe.
O portal também fornece uma ferramenta para gerar a URL do cliente com o token dinamicamente. Esta ferramenta pode ser útil para fazer um teste rápido.
Nota
Certifique-se de incluir apenas as funções necessárias quando estiver gerando o token.
Nas seções a seguir, para simplificar o fluxo de trabalho de exemplo, usamos essa URL gerada temporariamente do portal para o cliente se conectar. Usamos <Client_URL_From_Portal> para representar o valor. O token gerado expira em 60 minutos por padrão, então não se esqueça de regenerar um quando o token expirar.
O serviço suporta dois tipos de clientes WebSocket: um é o cliente WebSocket simples e o outro é o cliente PubSub WebSocket. Aqui mostramos como esses dois tipos de clientes se conectam ao serviço. Para obter mais informações sobre esses clientes, consulte Protocolos de cliente WebSocket para Azure Web PubSub.
<script>
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
let ws = new WebSocket("<Client_URL_From_Portal>");
ws.onopen = () => {
// Do things when the WebSocket connection is established
};
ws.onmessage = event => {
// Do things when messages are received.
};
</script>
const WebSocket = require('ws');
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
const client = new WebSocket("<Client_URL_From_Portal>");
client.on('open', () => {
// Do things when the WebSocket connection is established
});
client.on('message', msg => {
// Do things when messages are received.
});
import asyncio
import websockets
async def hello():
# Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
uri = '<Client_URL_From_Portal>'
async with websockets.connect(uri) as ws:
while True:
await ws.send('hello')
greeting = await ws.recv()
print(greeting)
asyncio.get_event_loop().run_until_complete(hello())
using System;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using Websocket.Client;
namespace subscriber
{
class Program
{
static async Task Main(string[] args)
{
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
using (var client = new WebsocketClient(new Uri("<Client_URL_From_Portal>")))
{
// Disable the auto disconnect and reconnect because the sample would like the client to stay online even if no data comes in
client.ReconnectTimeout = null;
client.MessageReceived.Subscribe(msg => Console.WriteLine($"Message received: {msg}"));
await client.Start();
Console.WriteLine("Connected.");
Console.Read();
}
}
}
}
package client;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.WebSocket;
import java.util.concurrent.CompletionStage;
/**
* A simple WebSocket Client.
*
*/
public final class SimpleClient {
private SimpleClient() {
}
/**
* Starts a simple WebSocket connection.
* @param args The arguments of the program.
*/
public static void main(String[] args) throws Exception {
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
WebSocket ws = HttpClient.newHttpClient().newWebSocketBuilder()
.buildAsync(URI.create("<Client_URL_From_Portal>"), new WebSocketClient()).join();
System.in.read();
}
private static final class WebSocketClient implements WebSocket.Listener {
private WebSocketClient() {
}
@Override
public void onOpen(WebSocket webSocket) {
System.out.println("onOpen using subprotocol " + webSocket.getSubprotocol());
WebSocket.Listener.super.onOpen(webSocket);
}
@Override
public CompletionStage<?> onText(WebSocket webSocket, CharSequence data, boolean last) {
System.out.println("onText received " + data);
return WebSocket.Listener.super.onText(webSocket, data, last);
}
@Override
public void onError(WebSocket webSocket, Throwable error) {
System.out.println("Bad day! " + webSocket.toString());
WebSocket.Listener.super.onError(webSocket, error);
}
}
}
<script>
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
let ws = new WebSocket("<Client_URL_From_Portal>", 'json.webpubsub.azure.v1');
ws.onopen = () => {
// Do things when the WebSocket connection is established
};
ws.onmessage = event => {
// Do things when messages are received.
};
</script>
const WebSocket = require('ws');
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
const client = new WebSocket("<Client_URL_From_Portal>", "json.webpubsub.azure.v1");
client.on('open', () => {
// Do things when the WebSocket connection is established
});
client.on('message', msg => {
// Do things when messages are received.
});
import asyncio
import websockets
async def join_group():
# Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
uri = '<Client_URL_From_Portal>'
async with websockets.connect(uri, subprotocols=['json.webpubsub.azure.v1']) as ws:
await ws.send('{"type":"joinGroup","ackId":1,"group":"group1"}')
return await ws.recv()
print(asyncio.get_event_loop().run_until_complete(join_group()))
using System;
using System.IO;
using System.Net.WebSockets;
using System.Text;
using System.Threading.Tasks;
namespace subscriber
{
class Program
{
static async Task Main(string[] args)
{
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
using (var client = new WebsocketClient(new Uri("<Client_URL_From_Portal>"), () =>
{
var inner = new ClientWebSocket();
inner.Options.AddSubProtocol("json.webpubsub.azure.v1");
return inner;
}))
{
// Disable the auto disconnect and reconnect because the sample would like the client to stay online even if no data comes in
client.ReconnectTimeout = null;
client.MessageReceived.Subscribe(msg => Console.WriteLine($"Message received: {msg}"));
await client.Start();
Console.WriteLine("Connected.");
Console.Read();
}
}
}
}
package client;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.WebSocket;
import java.util.concurrent.CompletionStage;
/**
* A PubSub WebSocket Client.
*
*/
public final class SubprotocolClient {
private SubprotocolClient() {
}
/**
* Starts a PubSub WebSocket connection.
* @param args The arguments of the program.
*/
public static void main(String[] args) throws Exception {
// Don't forget to replace this <Client_URL_From_Portal> with the value fetched from the portal
WebSocket ws = HttpClient.newHttpClient().newWebSocketBuilder().subprotocols("json.webpubsub.azure.v1")
.buildAsync(URI.create("<Client_URL_From_Portal>"), new WebSocketClient()).join();
ws.sendText("{\"type\":\"joinGroup\",\"ackId\":1,\"group\":\"group1\"}", true);
System.in.read();
}
private static final class WebSocketClient implements WebSocket.Listener {
private WebSocketClient() {
}
@Override
public void onOpen(WebSocket webSocket) {
System.out.println("onOpen using subprotocol " + webSocket.getSubprotocol());
WebSocket.Listener.super.onOpen(webSocket);
}
@Override
public CompletionStage<?> onText(WebSocket webSocket, CharSequence data, boolean last) {
System.out.println("onText received " + data);
return WebSocket.Listener.super.onText(webSocket, data, last);
}
@Override
public void onError(WebSocket webSocket, Throwable error) {
System.out.println("Bad day! " + webSocket.toString());
WebSocket.Listener.super.onError(webSocket, error);
}
}
}
Próximos passos
Neste artigo, você aprendeu como se conectar ao serviço usando a URL gerada a partir do portal. Para ver como os clientes se comunicam com o servidor de aplicativos para obter a URL em aplicativos do mundo real, leia estes tutoriais e confira os exemplos.
