// Copyright 2016 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

//

// http://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.

'use strict';

// [START functions_pubsub_setup]

const {PubSub} = require('@google-cloud/pubsub');

// Instantiates a client

const pubsub = new PubSub();

// [END functions_pubsub_setup]

// [START functions_pubsub_publish]

/**

* Publishes a message to a Cloud Pub/Sub Topic.

*

* @example

* gcloud functions call publish --data '{"topic":"[YOUR_TOPIC_NAME]","message":"Hello, world!"}'

*

* - Replace `[YOUR_TOPIC_NAME]` with your Cloud Pub/Sub topic name.

*

* @param {object} req Cloud Function request context.

* @param {object} req.body The request body.

* @param {string} req.body.topic Topic name on which to publish.

* @param {string} req.body.message Message to publish.

* @param {object} res Cloud Function response context.

*/

exports.publish = async (req, res) => {

if (!req.body.topic || !req.body.message) {

res

.status(500)

.send(

'Missing parameter(s); include "topic" and "subscription" properties in your request.'

);

return;

}

console.log(`Publishing message to topic ${req.body.topic}`);

// References an existing topic

const topic = pubsub.topic(req.body.topic);

const messageObject = {

data: {

message: req.body.message,

},

};

const messageBuffer = Buffer.from(JSON.stringify(messageObject), 'utf8');

// Publishes a message

try {

await topic.publish(messageBuffer);

res.status(200).send('Message published.');

} catch (err) {

console.error(err);

res.status(500).send(err);

return Promise.reject(err);

}

};

// [END functions_pubsub_publish]

// [START functions_pubsub_subscribe]

/**

* Triggered from a message on a Cloud Pub/Sub topic.

*

* @param {object} pubsubMessage The Cloud Pub/Sub Message object.

* @param {string} pubsubMessage.data The "data" property of the Cloud Pub/Sub Message.

*/

exports.subscribe = (pubsubMessage) => {

// Print out the data from Pub/Sub, to prove that it worked

console.log(Buffer.from(pubsubMessage.data, 'base64').toString());

};

// [END functions_pubsub_subscribe]