CODEWITHSUNDEEP
javascriptnode.jsredis
gsmaker
gsmaker

Reputation: 593

How to make asynchronous Redis subscriber call

I have a Redis server into AWS ElastiCache. Publishing message into the Redis channel. And trying to get the message by subscribing. I am using Javascript sample like below.

const redis = require("redis");

const subscriber = redis.createClient();

let messageCount = 0;

subscriber.on("message", function(channel, message) {
  messageCount += 1;

  console.log("Subscriber received message in channel '" + channel + "': " + message);

  if (messageCount === 2) {
    subscriber.unsubscribe();
    subscriber.quit();
  }
});

subscriber.subscribe("my_channel");

So far I understand as a JS novice, above sample is a synchronous call.

Now I would like to make the subscriber message call as asynchronous may be like below:

await subscriber.onAsync('message').then(function(channel, message){
  console.log(JSON.stringify(message)); 
}).catch(function(e){
    console.log(e);
});

Basically I am going to use this asynchronous call into AWS Lambda.

I am Googling continuously, but still no luck. If there is any similar Q/A, please share me.

Thanks.

Upvotes: 1

Views: 1195

Answers (1)

gsmaker
gsmaker

Reputation: 593

I have fixed my issue by creating a function to get message from Redis channel and call the function as asynchronous. Let me share the code if it help others.

Here is the function

function getMessage(client) {
    return new Promise(function(resolve) {
        client.on('message', function(channel, message) {
            resolve(message);
        });
    });
}

Here the calling part after channel subscription.

// Subscribe channel
client.subscribe('my_channel');
console.log("Subscribed");

// Get feed message from channel
feedMsg = await getMessage(client);
console.log("Message received");

Thanks.

Upvotes: 1

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