寫入及回應 Pub/Sub 訊息

區域 ID

REGION_ID 是 Google 根據您在建立應用程式時選取的地區所指派的簡寫代碼。雖然某些區域 ID 可能看起來與常用的國家/地區代碼相似，但此代碼並非對應國家/地區或省份。如果是 2020 年 2 月後建立的應用程式，App Engine 網址會包含 REGION_ID.r。如果是在此日期之前建立的現有應用程式，網址中則可選擇加入地區 ID。

進一步瞭解區域 ID。

Pub/Sub 在應用程式之間提供可靠的多對多非同步訊息傳遞功能。發布者應用程式能將訊息傳送到「主題」，而其他應用程式只要訂閱該主題後就能收到訊息。

本文件說明如何使用 Cloud 用戶端程式庫，在 App Engine 應用程式中傳送及接收 Pub/Sub 訊息。

事前準備

複製範例應用程式

將範例應用程式複製到您的本機電腦，然後前往 pubsub 目錄：

Go

git clone https://github.com/GoogleCloudPlatform/golang-samples.git
cd golang-samples/appengine_flexible/pubsub

Java

git clone https://github.com/GoogleCloudPlatform/java-docs-samples
cd java-docs-samples/flexible/java-11/pubsub/

Node.js

git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples
cd nodejs-docs-samples/appengine/pubsub

PHP

git clone https://github.com/GoogleCloudPlatform/php-docs-samples.git
cd php-docs-samples/pubsub

Python

git clone https://github.com/GoogleCloudPlatform/python-docs-samples
cd python-docs-samples/appengine/flexible/pubsub

Ruby

git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples
cd ruby-docs-samples/appengine/flexible/pubsub/

.NET

git clone  https://github.com/GoogleCloudPlatform/dotnet-docs-samples
cd dotnet-docs-samples/appengine/flexible/Pubsub/Pubsub.Sample

建立主題和訂閱

建立主題和訂閱，其中包括指定 Pub/Sub 伺服器傳送要求的目的地端點：

Go

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

Java

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

Node.js

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

PHP

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

Python

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

Ruby

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

.NET

# Configure the topic
gcloud pubsub topics create YOUR_TOPIC_NAME

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

以私密的隨機憑證取代 YOUR_TOKEN。推送端點會使用這個憑證來驗證要求。

如要使用具備驗證機制的 Pub/Sub，請建立另一個訂閱項目：

# Configure the push subscription
gcloud pubsub subscriptions create YOUR_SUBSCRIPTION_NAME \
    --topic=YOUR_TOPIC_NAME \
    --push-auth-service-account=YOUR-SERVICE-ACCOUNT-EMAIL\
    --push-auth-token-audience=OPTIONAL_AUDIENCE_OVERRIDE\
    --push-endpoint=https://YOUR_PROJECT_ID.REGION_ID.r.appspot.com/push-handlers/receive_messages?token=YOUR_TOKEN \
    --ack-deadline=10

# Your service agent
# `service-{PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com` needs to have the
# `iam.serviceAccountTokenCreator` role.
PUBSUB_SERVICE_ACCOUNT="service-${PROJECT_NUMBER}@gcp-sa-pubsub.iam.gserviceaccount.com"
gcloud projects add-iam-policy-binding ${PROJECT_ID} \
    --member="serviceAccount:${PUBSUB_SERVICE_ACCOUNT}"\
    --role='roles/iam.serviceAccountTokenCreator'

將 YOUR-SERVICE-ACCOUNT-EMAIL 替換為服務帳戶的電子郵件地址。

設定環境變數

Go

編輯 app.yaml 檔案，為您的主題和驗證憑證設定環境變數：

env_variables:
  PUBSUB_TOPIC: your-topic
  # This token is used to verify that requests originate from your
  # application. It can be any sufficiently random string.
  PUBSUB_VERIFICATION_TOKEN: your-token

Java

編輯 app.yaml 檔案，為您的主題和驗證憑證設定環境變數：

env_variables:
  PUBSUB_TOPIC: <your-topic-name>
  # This token is used to verify that requests originate from your
  # application. It can be any sufficiently random string.
  PUBSUB_VERIFICATION_TOKEN: <your-verification-token>

Node.js

編輯 app.yaml 檔案，為您的主題和驗證憑證設定環境變數：

env_variables:
  PUBSUB_TOPIC: YOUR_TOPIC_NAME
  # This token is used to verify that requests originate from your
  # application. It can be any sufficiently random string.
  PUBSUB_VERIFICATION_TOKEN: YOUR_VERIFICATION_TOKEN

PHP

編輯 index.php 檔案，為您的主題和訂閱項目設定環境變數：

$container->set('topic', 'php-example-topic');
$container->set('subscription', 'php-example-subscription');

Python

編輯 app.yaml 檔案，為您的專案 ID、主題和驗證憑證設定環境變數：

env_variables:
    PUBSUB_TOPIC: your-topic
    # This token is used to verify that requests originate from your
    # application. It can be any sufficiently random string.
    PUBSUB_VERIFICATION_TOKEN: 1234abc

Ruby

編輯 app.yaml 檔案，為您的專案 ID、主題和驗證憑證設定環境變數：

env_variables:
    PUBSUB_TOPIC: <pubsub-topic-name>
    # This token is used to verify that requests originate from your
    # application. It can be any sufficiently random string.
    PUBSUB_VERIFICATION_TOKEN: <verification-token>

.NET

編輯 app.yaml 檔案，為您的主題和驗證憑證設定環境變數：

runtime: aspnetcore
env: flex

runtime_config:
  operating_system: ubuntu22

env_variables:
  TEST_PROJECT_ID: your-project-id
  TEST_VERIFICATION_TOKEN: your-token
  TEST_TOPIC_ID: your-topic
  TEST_SUBSCRIPTION_ID: your-sub
  TEST_AUTH_SUBSCRIPTION_ID: your-auth-sub
  TEST_SERVICE_ACCOUNT_EMAIL: your-service-account-email

審查程式碼

此範例應用程式使用 Pub/Sub 用戶端程式庫。

Go

此範例應用程式會使用您在 app.yaml 檔案 (PUBSUB_TOPIC 和 PUBSUB_VERIFICATION_TOKEN) 中設定的環境變數進行設定。

此執行個體收到的訊息會儲存在一個配量中：

messages   []string

pushHandler 函式會接收已推送的訊息、驗證權杖，並將訊息加入至 messages 配量：


func pushHandler(w http.ResponseWriter, r *http.Request) {
	// Verify the token.
	if r.URL.Query().Get("token") != token {
		http.Error(w, "Bad token", http.StatusBadRequest)
		return
	}
	msg := &pushRequest{}
	if err := json.NewDecoder(r.Body).Decode(msg); err != nil {
		http.Error(w, fmt.Sprintf("Could not decode body: %v", err), http.StatusBadRequest)
		return
	}

	messagesMu.Lock()
	defer messagesMu.Unlock()
	// Limit to ten.
	messages = append(messages, string(msg.Message.Data))
	if len(messages) > maxMessages {
		messages = messages[len(messages)-maxMessages:]
	}
}

publishHandler 函式會將新訊息發布至主題。


func publishHandler(w http.ResponseWriter, r *http.Request) {
	ctx := context.Background()

	msg := &pubsub.Message{
		Data: []byte(r.FormValue("payload")),
	}

	if _, err := topic.Publish(ctx, msg).Get(ctx); err != nil {
		http.Error(w, fmt.Sprintf("Could not publish message: %v", err), 500)
		return
	}

	fmt.Fprint(w, "Message published.")
}

Java

範例應用程式會使用您在 app.yaml 檔案中設定的值來設定環境變數。推送要求處理常式會使用這些值，確認要求是來自 Pub/Sub 和可信任的來源：

String pubsubVerificationToken = System.getenv("PUBSUB_VERIFICATION_TOKEN");

範例應用程式會維護一個 Cloud Datastore 資料庫執行個體，以便儲存訊息。PubSubPush Servlet 可接收已推送的訊息，並將訊息新增至 messageRepository 資料庫執行個體：

11/17 版

@WebServlet(value = "/pubsub/push")
@MultipartConfig()
public class PubSubPush extends HttpServlet {

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    String pubsubVerificationToken = System.getenv("PUBSUB_VERIFICATION_TOKEN");
    // Do not process message if request token does not match pubsubVerificationToken
    if (pubsubVerificationToken == null
        || pubsubVerificationToken.compareTo(req.getParameter("token")) != 0) {
      resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
      return;
    }
    // parse message object from "message" field in the request body json
    // decode message data from base64
    Message message = getMessage(req);
    try {
      messageRepository.save(message);
      // 200, 201, 204, 102 status codes are interpreted as success by the Pub/Sub system
      resp.setStatus(HttpServletResponse.SC_OK);
    } catch (Exception e) {
      System.out.println(e);
      resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
    }
  }

版本 8

@WebServlet(value = "/pubsub/push")
public class PubSubPush extends HttpServlet {

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    String pubsubVerificationToken = System.getenv("PUBSUB_VERIFICATION_TOKEN");
    // Do not process message if request token does not match pubsubVerificationToken
    if (req.getParameter("token").compareTo(pubsubVerificationToken) != 0) {
      resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
      return;
    }
    // parse message object from "message" field in the request body json
    // decode message data from base64
    Message message = getMessage(req);
    try {
      messageRepository.save(message);
      // 200, 201, 204, 102 status codes are interpreted as success by the Pub/Sub system
      resp.setStatus(HttpServletResponse.SC_OK);
    } catch (Exception e) {
      resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
    }
  }

PubSubPublish Servlet 會與 App Engine 網頁應用程式互動，以發布新訊息並顯示收到的訊息：

@WebServlet(name = "Publish with PubSub", value = "/pubsub/publish")
public class PubSubPublish extends HttpServlet {

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    Publisher publisher = this.publisher;
    try {
      String topicId = System.getenv("PUBSUB_TOPIC");
      // create a publisher on the topic
      if (publisher == null) {
        publisher = Publisher.newBuilder(
            ProjectTopicName.of(ServiceOptions.getDefaultProjectId(), topicId))
            .build();
      }
      // construct a pubsub message from the payload
      final String payload = req.getParameter("payload");
      PubsubMessage pubsubMessage =
          PubsubMessage.newBuilder().setData(ByteString.copyFromUtf8(payload)).build();

      publisher.publish(pubsubMessage);
      // redirect to home page
      resp.sendRedirect("/");
    } catch (Exception e) {
      resp.sendError(HttpStatus.SC_INTERNAL_SERVER_ERROR, e.getMessage());
    }
  }

Node.js

範例應用程式會使用您在 app.yaml 檔案中設定的值來設定環境變數。推送要求處理常式會使用這些值，確認要求是來自 Pub/Sub 和可信任的來源：

// The following environment variables are set by the `app.yaml` file when
// running on App Engine, but will need to be manually set when running locally.
var PUBSUB_VERIFICATION_TOKEN = process.env.PUBSUB_VERIFICATION_TOKEN;
var pubsub = gcloud.pubsub({
    projectId: process.env.GOOGLE_CLOUD_PROJECT
});
var topic = pubsub.topic(process.env.PUBSUB_TOPIC);

範例應用程式會維護一份全域清單，以便儲存此執行個體收到的訊息：

// List of all messages received by this instance
var messages = [];

這個方法可接收已推送的訊息，並將這些訊息新增至 messages 全域清單：

app.post('/pubsub/push', jsonBodyParser, (req, res) => {
  if (req.query.token !== PUBSUB_VERIFICATION_TOKEN) {
    res.status(400).send();
    return;
  }

  // The message is a unicode string encoded in base64.
  const message = Buffer.from(req.body.message.data, 'base64').toString(
    'utf-8'
  );

  messages.push(message);

  res.status(200).send();
});

此方法會與 App Engine 網路應用程式互動，以發佈新訊息並顯示收到的訊息：

app.get('/', (req, res) => {
  res.render('index', {messages, tokens, claims});
});

app.post('/', formBodyParser, async (req, res, next) => {
  if (!req.body.payload) {
    res.status(400).send('Missing payload');
    return;
  }

  const data = Buffer.from(req.body.payload);
  try {
    const messageId = await topic.publishMessage({data});
    res.status(200).send(`Message ${messageId} sent.`);
  } catch (error) {
    next(error);
  }
});

PHP

範例應用程式會使用您在 app.yaml 檔案中指定的值來設定環境變數。推送要求處理常式會使用這些值，確認要求是來自 Pub/Sub 和可信任的來源：

runtime: php
env: flex

範例應用程式會維護一份全域清單，以便儲存此執行個體收到的訊息：

$messages = [];

pull 方法會從您建立的主題中擷取訊息，並將訊息加到訊息清單中：

// get PULL pubsub messages
$pubsub = new PubSubClient([
    'projectId' => $projectId,
]);
$subscription = $pubsub->subscription($subscriptionName);
$pullMessages = [];
foreach ($subscription->pull(['returnImmediately' => true]) as $pullMessage) {
    $pullMessages[] = $pullMessage;
    $messages[] = $pullMessage->data();
}
// acknowledge PULL messages
if ($pullMessages) {
    $subscription->acknowledgeBatch($pullMessages);
}

publish 方法會將新訊息發布到主題：

if ($message = (string) $request->getBody()) {
    // Publish the pubsub message to the topic
    $pubsub = new PubSubClient([
        'projectId' => $projectId,
    ]);
    $topic = $pubsub->topic($topicName);
    $topic->publish(['data' => $message]);
    return $response->withStatus(204);
}

Python

範例應用程式會使用您在 app.yaml 檔案中指定的值來設定環境變數。推送要求處理常式會使用這些值，確認要求是來自 Pub/Sub 和可信任的來源：

app.config['PUBSUB_VERIFICATION_TOKEN'] = \
    os.environ['PUBSUB_VERIFICATION_TOKEN']
app.config['PUBSUB_TOPIC'] = os.environ['PUBSUB_TOPIC']

範例應用程式會維護一份全域清單，以便儲存此執行個體收到的訊息：

MESSAGES = []

pubsub_push() 方法可接收已推送的訊息，並將訊息加入 MESSAGES 全域清單：

@app.route("/pubsub/push", methods=["POST"])
def pubsub_push():
    if request.args.get("token", "") != current_app.config["PUBSUB_VERIFICATION_TOKEN"]:
        return "Invalid request", 400

    envelope = json.loads(request.data.decode("utf-8"))
    payload = base64.b64decode(envelope["message"]["data"])

    MESSAGES.append(payload)

    # Returning any 2xx status indicates successful receipt of the message.
    return "OK", 200

index() 方法會與 App Engine 網頁應用程式互動，以發布新訊息並顯示收到的訊息：

@app.route("/", methods=["GET", "POST"])
def index():
    if request.method == "GET":
        return render_template("index.html", messages=MESSAGES)

    data = request.form.get("payload", "Example payload").encode("utf-8")

    # publisher = pubsub_v1.PublisherClient()
    topic_path = publisher.topic_path(
        current_app.config["PROJECT"], current_app.config["PUBSUB_TOPIC"]
    )

    publisher.publish(topic_path, data=data)

    return "OK", 200

Ruby

範例應用程式會使用您在 app.yaml 檔案中指定的值來設定環境變數。推送要求處理常式會使用這些值，確認要求是來自 Pub/Sub 和可信任的來源：

topic = pubsub.topic ENV["PUBSUB_TOPIC"]
PUBSUB_VERIFICATION_TOKEN = ENV["PUBSUB_VERIFICATION_TOKEN"]

範例應用程式會維護一份全域清單，以便儲存此執行個體收到的訊息：

# List of all messages received by this instance
messages = []

這個方法可接收已推送的訊息，並將這些訊息新增至 messages 全域清單：

post "/pubsub/push" do
  halt 400 if params[:token] != PUBSUB_VERIFICATION_TOKEN

  message = JSON.parse request.body.read
  payload = Base64.decode64 message["message"]["data"]

  messages.push payload
end

此方法會與 App Engine 網路應用程式互動，以發佈新訊息並顯示收到的訊息：

get "/" do
  @claims = claims
  @messages = messages

  slim :index
end

post "/publish" do
  topic.publish params[:payload]

  redirect "/", 303
end

.NET

[HttpGet]
[HttpPost]
public async Task<IActionResult> IndexAsync(MessageForm messageForm)
{
    var model = new MessageList();
    if (!_options.HasGoodProjectId())
    {
        model.MissingProjectId = true;
        return View(model);
    }
    if (!string.IsNullOrEmpty(messageForm.Message))
    {
        // Publish the message.
        var pubsubMessage = new PubsubMessage()
        {
            Data = ByteString.CopyFromUtf8(messageForm.Message)
        };
        pubsubMessage.Attributes["token"] = _options.VerificationToken;
        await _publisher.PublishAsync(pubsubMessage);
        model.PublishedMessage = messageForm.Message;
    }
    // Render the current list of messages.
    model.Messages = s_receivedMessages.ToArray();
    model.AuthMessages = s_authenticatedMessages.ToArray();
    return View(model);
}

在本機執行範例

在本機執行應用程式範例時，您可以使用 Google Cloud CLI 提供驗證以使用 Google Cloud API。假設您是根據必備條件一節中的指示來設定環境，那麼您應該已經執行可提供這項驗證的 gcloud init 指令。

Go

在啟動應用程式前設定環境變數：

export GOOGLE_CLOUD_PROJECT=[your-project-id]
export PUBSUB_VERIFICATION_TOKEN=[your-token]
export PUBSUB_TOPIC=[your-topic]
go run pubsub.go

Java

mvn clean package

在啟動應用程式前設定環境變數：

export PUBSUB_VERIFICATION_TOKEN=[your-verification-token]
export PUBSUB_TOPIC=[your-topic]
mvn jetty:run

Node.js

在啟動應用程式前設定環境變數：

export GOOGLE_CLOUD_PROJECT=[your-project-id]
export PUBSUB_VERIFICATION_TOKEN=[your-verification-token]
export PUBSUB_TOPIC=[your-topic]
npm install
npm start

PHP

使用 Composer 安裝相依項目：

composer install

接著設定環境變數，然後啟動應用程式：

export GOOGLE_CLOUD_PROJECT=[your-project-id]
export PUBSUB_VERIFICATION_TOKEN=[your-verification-token]
export PUBSUB_TOPIC=[your-topic]
php -S localhost:8080

Python

安裝依附元件，建議在虛擬環境中安裝。

Mac OS / Linux

  1. 建立獨立的 Python 環境：
    python3 -m venv env
source env/bin/activate
  2. 如果您目前所在的目錄並未包含範例程式碼，請前往包含 hello_world 範例程式碼的目錄。接著安裝依附元件：
    cd YOUR_SAMPLE_CODE_DIR
pip install -r requirements.txt

Windows

請使用 PowerShell 執行 Python 套件。

  1. 尋找已安裝的 PowerShell。
  2. 以滑鼠右鍵按一下 PowerShell 的捷徑，然後以系統管理員的身分啟動 PowerShell。
  3. 建立隔離的 Python 環境。
    python -m venv env
.\env\Scripts\activate
  4. 前往專案目錄，並安裝依附元件。如果您不在包含範例程式碼的目錄中，請前往包含 hello_world 範例程式碼的目錄。接著，安裝依附元件：
    cd YOUR_SAMPLE_CODE_DIR
pip install -r requirements.txt

接著設定環境變數，然後啟動應用程式：

export GOOGLE_CLOUD_PROJECT=[your-project-id]
export PUBSUB_VERIFICATION_TOKEN=[your-verification-token]
export PUBSUB_TOPIC=[your-topic]
python main.py

Ruby

安裝依附元件：

bundle install

接著設定環境變數，然後啟動應用程式：

export GOOGLE_CLOUD_PROJECT=[your-project-id]
export PUBSUB_VERIFICATION_TOKEN=[your-verification-token]
export PUBSUB_TOPIC=[your-topic]
bundle exec ruby app.rb -p 8080

.NET

在應用程式的根目錄中執行下列指令：

    dotnet restore
    dotnet run

在網路瀏覽器中輸入 http://localhost:5000/。如要關閉網路伺服器，請在終端機視窗中按下 Ctrl+C 鍵。

模擬推播通知

應用程式可在本機傳送訊息，但是無法在本機接收推送訊息。不過您可以向本機的推送通知端點提出 HTTP 要求，就能模擬推送訊息。範例包含 sample_message.json 檔案。

Go

您可以使用 curl 或 httpie 用戶端傳送 HTTP POST 要求：

curl -H "Content-Type: application/json" -i --data @sample_message.json "localhost:8080/push-handlers/receive_messages?token=[your-token]"

或

http POST ":8080/push-handlers/receive_messages?token=[your-token]" < sample_message.json

回應：

HTTP/1.1 200 OK
Date: Tue, 13 Nov 2018 16:04:18 GMT
Content-Length: 0

完成要求後，您可以重新整理 localhost:8080，並在已接收訊息的清單中查看訊息。

Java

您可以使用 curl 或 httpie 用戶端傳送 HTTP POST 要求：

curl -H "Content-Type: application/json" -i --data @sample_message.json "localhost:8080/push-handlers/receive_messages?token=[your-token]"

或

http POST ":8080/push-handlers/receive_messages?token=[your-token]" < sample_message.json

回應：

HTTP/1.1 200 OK
Date: Wed, 26 Apr 2017 00:03:28 GMT
Content-Length: 0
Server: Jetty(9.3.8.v20160314)

完成要求後，您可以重新整理 localhost:8080，並在已接收訊息的清單中查看訊息。

Node.js

您可以使用 curl 或 httpie 用戶端傳送 HTTP POST 要求：

curl -H "Content-Type: application/json" -i --data @sample_message.json "localhost:8080/push-handlers/receive_messages?token=[your-token]"

或

http POST ":8080/push-handlers/receive_messages?token=[your-token]" < sample_message.json

回應：

HTTP/1.1 200 OK
Connection: keep-alive
Date: Mon, 31 Aug 2015 22:19:50 GMT
Transfer-Encoding: chunked
X-Powered-By: Express

完成要求後，您可以重新整理 localhost:8080，並在已接收訊息的清單中查看訊息。

PHP

您可以使用 curl 或 httpie 用戶端傳送 HTTP POST 要求：

curl -i --data @sample_message.json "localhost:4567/push-handlers/receive_messages?token=[your-token]"

或

http POST ":4567/push-handlers/receive_messages?token=[your-token]" < sample_message.json

完成要求後，您可以重新整理 localhost:8080，並在收到的訊息的清單中查看訊息。

Python

您可以使用 curl 或 httpie 用戶端傳送 HTTP POST 要求：

curl -H "Content-Type: application/json" -i --data @sample_message.json "localhost:8080/pubsub/push?token=[your-token]"

或

http POST ":8080/pubsub/push?token=[your-token]" < sample_message.json

回應：

HTTP/1.0 200 OK
Content-Length: 2
Content-Type: text/html; charset=utf-8
Date: Mon, 10 Aug 2015 17:52:03 GMT
Server: Werkzeug/0.10.4 Python/2.7.10

OK

完成要求後，您可以重新整理 localhost:8080，並在已接收訊息的清單中查看訊息。

Ruby

您可以使用 curl 或 httpie 用戶端傳送 HTTP POST 要求：

curl -i --data @sample_message.json "localhost:4567/push-handlers/receive_messages?token=[your-token]"

或

http POST ":4567/push-handlers/receive_messages?token=[your-token]" < sample_message.json

回應：

HTTP/1.1 200 OK
Content-Type: text/html;charset=utf-8
Content-Length: 13
X-Xss-Protection: 1; mode=block
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
Server: WEBrick/1.3.1 (Ruby/2.3.0/2015-12-25)
Date: Wed, 20 Apr 2016 20:56:23 GMT
Connection: Keep-Alive

Hello, World!

完成要求後，您可以重新整理 localhost:8080，並在已接收訊息的清單中查看訊息。

.NET

如要發出 HTTP POST 要求：

Get-Content -Raw .\sample_message.json | Invoke-WebRequest -Uri
http://localhost:5000/Push?token=your-secret-token -Method POST -ContentType
'text/json' -OutFile out.txt

完成要求後，您可以重新整理 localhost:5000，並在已接收訊息的清單中查看訊息。

在 App Engine 上執行

如要使用 gcloud 指令列工具將示範應用程式部署至 App Engine，請按照下列步驟操作：

Go

請在 app.yaml 檔案所在的目錄中執行下列指令：

gcloud app deploy

Java

如要使用 Maven 部署應用程式，請執行下列指令：

mvn package appengine:deploy -Dapp.deploy.projectId=PROJECT_ID

將 PROJECT_ID 替換為您的 Google Cloud 專案 ID。如果 pom.xml 檔案已指定專案 ID，您就不需要在執行的指令中加入 -Dapp.deploy.projectId 屬性。

Node.js

請在 app.yaml 檔案所在的目錄中執行下列指令：

gcloud app deploy

PHP

請在 app.yaml 檔案所在的目錄中執行下列指令：

gcloud app deploy

Python

請在 app.yaml 檔案所在的目錄中執行下列指令：

gcloud app deploy

Ruby

請在 app.yaml 檔案所在的目錄中執行下列指令：

gcloud app deploy app.yaml

.NET

請在 app.yaml 檔案所在的目錄中執行下列指令：

gcloud app deploy

您現在可以前往 https://PROJECT_ID.REGION_ID.r.appspot.com 存取應用程式，且可使用表單提交訊息，但系統無法保證應用程式的哪個執行個體會收到通知。此外，您也可以傳送多則訊息、重新整理頁面以查看收到的訊息。