编写和响应 Pub/Sub 消息

区域 ID

REGION_ID 是 Google 根据您在创建应用时选择的区域分配的缩写代码。此代码不对应于国家/地区或省，尽管某些区域 ID 可能类似于常用国家/地区代码和省代码。对于 2020 年 2 月以后创建的应用，REGION_ID.r 包含在 App Engine 网址中。对于在此日期之前创建的现有应用，网址中的区域 ID 是可选的。

详细了解区域 ID。

确定

Go Java Node.js PHP Python Ruby

Pub/Sub 可在应用之间提供可靠的多对多异步消息传递服务。发布者应用可以向某一主题发送消息，其他应用可以订阅该主题以接收消息。

本文档介绍了如何使用 Cloud 客户端库在 App Engine 应用中发送和接收 Pub/Sub 消息。

前提条件

• 按照相关说明为您选择的运行时构建应用以设置您的环境和项目，并了解如何设计 App Engine 应用的结构。
• 记下并保存项目 ID，因为您需要用它来运行本文档中所述的示例应用。
• 创建服务账号和服务账号密钥以用于您的应用。

• Enable the Google Cloud Pub/Sub API.

  Enable the API

克隆示例应用

将示例应用复制到本地机器，然后导航到 pubsub 目录：

Go

git clone https://github.com/GoogleCloudPlatform/golang-samples.git
cd golang-samples/appengine/go11x/pubsub/authenicated_push

Java

此运行时没有可用示例。

请注意，柔性环境中提供 Java 8 和 Java 11/17 演示版应用。

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/standard_python3/pubsub

Ruby

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

创建主题和订阅

创建主题和订阅，并在订阅中指定 Pub/Sub 服务器应发送请求的目标端点：

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

用随机密钥令牌替换 YOUR_TOKEN。推送端点使用它来验证请求。

如需将 Pub/Sub 与身份验证搭配使用，请创建另一个订阅：

# 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'

将 YOUR-SERVICE-ACCOUNT-EMAIL 替换为您的服务账号电子邮件地址。

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

用随机密钥令牌替换 YOUR_TOKEN。推送端点使用它来验证请求。

如需将 Pub/Sub 与身份验证搭配使用，请创建另一个订阅：

# 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'

将 YOUR-SERVICE-ACCOUNT-EMAIL 替换为您的服务账号电子邮件地址。

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

用随机密钥令牌替换 YOUR_TOKEN。推送端点使用它来验证请求。

如需将 Pub/Sub 与身份验证搭配使用，请创建另一个订阅：

# 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'

将 YOUR-SERVICE-ACCOUNT-EMAIL 替换为您的服务账号电子邮件地址。

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

用随机密钥令牌替换 YOUR_TOKEN。推送端点使用它来验证请求。

如需将 Pub/Sub 与身份验证搭配使用，请创建另一个订阅：

# 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'

将 YOUR-SERVICE-ACCOUNT-EMAIL 替换为您的服务账号电子邮件地址。

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

用随机密钥令牌替换 YOUR_TOKEN。推送端点使用它来验证请求。

如需将 Pub/Sub 与身份验证搭配使用，请创建另一个订阅：

# 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'

将 YOUR-SERVICE-ACCOUNT-EMAIL 替换为您的服务账号电子邮件地址。

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

用随机密钥令牌替换 YOUR_TOKEN。推送端点使用它来验证请求。

如需将 Pub/Sub 与身份验证搭配使用，请创建另一个订阅：

# 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'

将 YOUR-SERVICE-ACCOUNT-EMAIL 替换为您的服务账号电子邮件地址。

设置环境变量

Go

修改 app.yaml 文件，以为您的主题和验证令牌设置环境变量：

# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

runtime: go121
env_variables:
    # This token is used to verify that requests originate from your
    # application. It can be any sufficiently random string.
    PUBSUB_VERIFICATION_TOKEN: check123

Java

修改 app.yaml 文件，以为您的主题和验证令牌设置环境变量：

env_variables:
  PUBSUB_TOPIC: <your-topic-name>
  PUBSUB_VERIFICATION_TOKEN: <your-verification-token>

Node.js

修改 app.yaml 文件，以为您的主题和验证令牌设置环境变量：

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

修改 index.php 文件，为您的主题和订阅设置环境变量：

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

Python

修改 app.yaml 文件，为您的项目 ID、主题和验证令牌设置环境变量：

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_VERIFICATION_TOKEN>'

Ruby

修改 app.standard.yaml 文件，为您的项目 ID、主题和验证令牌设置环境变量：

env_variables:
    PUBSUB_TOPIC: gaeflex_net_pubsub_auth_push_1
    # This token is used to verify that requests originate from your
    # application. It can be any sufficiently random string.
    PUBSUB_VERIFICATION_TOKEN: abc123

代码审核

示例应用使用 Pub/Sub 客户端库。

Go

示例应用使用您在 app.yaml 文件（PUBSUB_TOPIC 和 PUBSUB_VERIFICATION_TOKEN）中设置的环境变量进行配置。

此实例接收的消息存储在切片中：

messages   []string

注意：本教程使用实例级全局变量 messages 来存储从 Pub/Sub 接收的消息。在生产环境中，应将其转换为外部存储解决方案，例如 Firestore。

receiveMessagesHandler 函数接收推送的消息，验证令牌，并将消息添加到 messages 切片：

// receiveMessagesHandler validates authentication token and caches the Pub/Sub
// message received.
func (a *app) receiveMessagesHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
		return
	}

	// Verify that the request originates from the application.
	// a.pubsubVerificationToken = os.Getenv("PUBSUB_VERIFICATION_TOKEN")
	if token, ok := r.URL.Query()["token"]; !ok || len(token) != 1 || token[0] != a.pubsubVerificationToken {
		http.Error(w, "Bad token", http.StatusBadRequest)
		return
	}

	// Get the Cloud Pub/Sub-generated JWT in the "Authorization" header.
	authHeader := r.Header.Get("Authorization")
	if authHeader == "" || len(strings.Split(authHeader, " ")) != 2 {
		http.Error(w, "Missing Authorization header", http.StatusBadRequest)
		return
	}
	token := strings.Split(authHeader, " ")[1]
	// Verify and decode the JWT.
	// If you don't need to control the HTTP client used you can use the
	// convenience method idtoken.Validate instead of creating a Validator.
	v, err := idtoken.NewValidator(r.Context(), option.WithHTTPClient(a.defaultHTTPClient))
	if err != nil {
		http.Error(w, "Unable to create Validator", http.StatusBadRequest)
		return
	}
	// Please change http://example.com to match with the value you are
	// providing while creating the subscription.
	payload, err := v.Validate(r.Context(), token, "http://example.com")
	if err != nil {
		http.Error(w, fmt.Sprintf("Invalid Token: %v", err), http.StatusBadRequest)
		return
	}
	if payload.Issuer != "accounts.google.com" && payload.Issuer != "https://accounts.google.com" {
		http.Error(w, "Wrong Issuer", http.StatusBadRequest)
		return
	}

	// IMPORTANT: you should validate claim details not covered by signature
	// and audience verification above, including:
	//   - Ensure that `payload.Claims["email"]` is equal to the expected service
	//     account set up in the push subscription settings.
	//   - Ensure that `payload.Claims["email_verified"]` is set to true.
	if payload.Claims["email"] != "[e-mail]" || payload.Claims["email_verified"] != true {
		http.Error(w, "Unexpected email identity", http.StatusBadRequest)
		return
	}

	var pr pushRequest
	if err := json.NewDecoder(r.Body).Decode(&pr); err != nil {
		http.Error(w, fmt.Sprintf("Could not decode body: %v", err), http.StatusBadRequest)
		return
	}

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

	fmt.Fprint(w, "OK")
}

Java

此运行时没有可用示例。

请注意，柔性环境中不提供 Java 8 演示版应用。

Node.js

示例应用使用您在 app.yaml 文件中设置的值来配置环境变量。推送请求处理程序使用这些值来确认请求来自 Pub/Sub 且来源可信：

// 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);

示例应用维护一个全局列表以存储此实例接收的消息：

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

注意：本教程使用实例级全局变量 messages 来存储从 Pub/Sub 接收的消息。在生产环境中，应将其转换为外部存储解决方案，例如 Firestore。

此方法接收推送的消息并将其添加到 messages 全局列表中：

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();
});

此方法与 App Engine Web 应用交互，以发布新消息并显示收到的消息：

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

示例应用使用您在 app.yaml 文件中设置的值来配置环境变量。推送请求处理程序使用这些值来确认请求来自 Pub/Sub 且来源可信：

runtime: php81

handlers:
- url: /pubsub\.js
  static_files: pubsub.js
  upload: pubsub\.js

示例应用维护一个全局列表以存储此实例接收的消息：

$messages = [];

注意：本教程使用实例级全局变量 $messages 来存储从 Pub/Sub 接收的消息。在生产环境中，应将其转换为外部存储解决方案，例如 Firestore。

pull 方法从您创建的主题中检索消息，并将消息添加到消息列表中：

// 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 方法向主题发布新消息：

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

示例应用使用您在 app.yaml 文件中设置的值来配置环境变量。推送请求处理程序使用这些值来确认请求来自 Pub/Sub 且来源可信：

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

示例应用维护一个全局列表以存储此实例接收的消息：

MESSAGES = []

注意：本教程使用实例级全局变量 MESSAGES 来存储从 Pub/Sub 接收的消息。在生产环境中，应将其转换为外部存储解决方案，例如 Firestore。

receive_messages_handler() 方法会接收推送的消息并将其添加到 MESSAGES 全局列表中：

@app.route("/pubsub/push", methods=["POST"])
def receive_pubsub_messages_handler():
    # Verify that the request originates from the application.
    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() 方法与 App Engine Web 应用交互，以发布新消息并显示收到的消息：

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

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

    # Consider initializing the publisher client outside this function
    # for better latency performance.
    publisher = pubsub_v1.PublisherClient()
    topic_path = publisher.topic_path(
        app.config["GOOGLE_CLOUD_PROJECT"], app.config["PUBSUB_TOPIC"]
    )
    future = publisher.publish(topic_path, data)
    future.result()
    return "OK", 200

Ruby

示例应用使用您在 app.standard.yaml 文件中设置的值来配置环境变量。推送请求处理程序使用这些值来确认请求来自 Pub/Sub 且来源可信：

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

示例应用维护一个全局列表以存储此实例接收的消息：

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

此方法接收推送的消息并将其添加到 messages 全局列表中：

注意：本教程使用实例级全局变量 messages 来存储从 Pub/Sub 接收的消息。在生产环境中，应将其转换为外部存储解决方案，例如 Firestore。

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

此方法与 App Engine 网络应用交互，以发布新消息并显示收到的消息：

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

  slim :index
end

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

  redirect "/", 303
end

在本地运行示例

在本地运行时，您可以借助 Google Cloud CLI 提供身份验证以使用 Google Cloud API。假设您按照前提条件中的说明设置了环境，那么您已经运行了 gcloud init 命令，该命令可提供此身份验证。

Go

在启动应用之前设置环境变量：

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

Java

在启动应用之前设置环境变量：

export PUBSUB_VERIFICATION_TOKEN=[your-verification-token]
export PUBSUB_TOPIC=[your-topic]

如需在本地运行您的应用，请使用您的常用开发工具。

Node.js

在启动应用之前设置环境变量：

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 安装依赖项：

composer install

然后在启动应用之前设置环境变量：

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

Python

安装依赖项（最好在虚拟环境中）。

Mac OS/Linux

1. 创建一个独立的 Python 环境：

   python3 -m venv env
   source env/bin/activate

2. 如果您当前不在包含示例代码的目录中，则导航到包含 hello_world 示例代码的目录。然后安装依赖项：

   cd YOUR_SAMPLE_CODE_DIR
   pip install -r requirements.txt

Windows

使用 Powershell 运行 Python 包。

1. 找到已安装的 Powershell。
2. 右键点击 Powershell 的快捷方式，并以管理员身份启动。
3. 创建一个独立的 Python 环境。

   python -m venv env
   .\env\Scripts\activate

4. 导航到项目目录并安装依赖项。如果您当前不在包含示例代码的目录中，则导航到包含 hello_world 示例代码的目录。然后安装依赖项：

   cd YOUR_SAMPLE_CODE_DIR
   pip install -r requirements.txt

然后在启动应用之前设置环境变量：

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

Ruby

安装依赖项：

bundle install

然后在启动应用之前设置环境变量：

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

模拟推送通知

应用可以在本地发送消息，但无法在本地接收推送消息。但是，您可以向本地推送通知端点发送 HTTP 请求来模拟推送消息。该示例包含文件 sample_message.json。

Go

您可以使用 curl 或 httpie 客户端发送 HTTP POST 请求：

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

响应：

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

请求完成后，您可以刷新 localhost:8080 并在收到的消息列表中查看该消息。

Java

您可以使用 curl 或 httpie 客户端发送 HTTP POST 请求：

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

请求完成后，您可以刷新 localhost:8080 并在收到的消息列表中查看该消息。

Node.js

您可以使用 curl 或 httpie 客户端发送 HTTP POST 请求：

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

响应：

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

请求完成后，您可以刷新 localhost:8080 并在收到的消息列表中查看该消息。

PHP

您可以使用 curl 或 httpie 客户端发送 HTTP POST 请求：

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

请求完成后，您可以刷新 localhost:8080 并在收到的消息列表中查看该消息。

Python

您可以使用 curl 或 httpie 客户端发送 HTTP POST 请求：

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

响应：

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

请求完成后，您可以刷新 localhost:8080 并在收到的消息列表中查看该消息。

Ruby

您可以使用 curl 或 httpie 客户端发送 HTTP POST 请求：

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

响应：

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!

请求完成后，您可以刷新 localhost:8080 并在收到的消息列表中查看该消息。

在 App Engine 上运行

如需使用 gcloud 命令行工具将演示版应用部署到 App Engine，请执行以下操作：

Go

从 app.yaml 文件所在的目录运行以下命令：

gcloud app deploy

Java

从 app.yaml 文件所在的目录运行 gcloud 命令：

gcloud app deploy

如需使用 Maven 部署应用，请运行以下命令：

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

将 PROJECT_ID 替换为您的 Google Cloud 项目的 ID。 如果您的 pom.xml 文件已经指定了您的项目 ID，则您无需在运行的命令中添加 -Dapp.deploy.projectId 属性。

Node.js

从 app.yaml 文件所在的目录运行以下命令：

gcloud app deploy

PHP

从 app.yaml 文件所在的目录运行以下命令：

gcloud app deploy

Python

从 app.yaml 文件所在的目录运行以下命令：

gcloud app deploy

Ruby

从 app.yaml 文件所在的目录运行以下命令：

gcloud app deploy app.standard.yaml

您现在可以通过 https://PROJECT_ID.REGION_ID.r.appspot.com 访问该应用。您可以使用表单提交消息，但无法保证您的哪个应用实例会收到通知。您可以发送多条消息并刷新页面，以查看收到的消息。