How do I provide real time update in nodejs? - node.js

I am working on an e-commerce site. There are times where a product would no longer be available but the user would have added it to the cart or added to their saved items. How do I implement the feature such that if the product has been updated, the user would be notified as soon as possible?
I thought about doing a cron job that would check the status of the product if it still available or has been recently updated. But I do not know if that is feasible. I am open to better ideas
Thanks
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What you are trying to achieve falls into real-time updates category and technically there would be more than one option to achieve this.
The chosen solution would depend on your application architecture and requirements. Meanwhile, I can suggest looking into Ably SDK for Node.js which can offer a good starter.
Here down a sample implementation where on the back-end you will be publishing messages upon item's stock reaching its limit:
// create client
var client = new Ably.Realtime('your-api-key');
// get appropriate channel
var channel = client.channels.get('product');
// publish a named (may be the product type in your case) message (you can set the quantity as the message payload
channel.publish('some-product-type', 0);
On the subscriber side, which would be your web client, you can subscribe to messages and update your UI accordingly:
// create client using same API key
var client = new Ably.Realtime('your-api-key');
// get product channel
var channel = client.channels.get('product');
// subscribe to messages and update your UI
channel.subscribe(function (message) {
const productName = message.name;
const updatedQuantity = message.data;
// update your UI or perform whatever action
});

Did a live betting app once and of course live updates are the most important part.
I suggest taking a look into websockets. The idea is pretty straight forward. On backend you emit an event let's say itemGotDisabled and on frontend you just connect to your websocket and listen to events.
You can create a custom component that will handle the logic related to webscoket events in order to have a cleaner and more organized code an you can do any type of logic you want to updated to component as easy as yourFEWebsocketInstance.onmessage = (event) => {}.
Of course it's not the only way and I am sure there are packages that implements this in an even more easy to understand and straight forward way.

Related

Shopify Webhook Real Time changing

is there an api on shopify where I can see real time when data changes ? Maybe I have a node server and I use sockets to see when anyone has bought anything from my shop that I get a notification via nodejs on my backend. is it possible ? a few websites has this, they offers you to sell on their site and you can see real time changes data when anything was bought
Yes, you can subscribe to multiple Webhooks to get notified when a change occurs on your shop. Using the REST Admin API, available webhook event topics include:
orders/create: occurs whenever an order is created / someone buys from your shop.
orders/paid: occurs whenever an order is paid.
orders/fulfilled: occurs whenever an order is fulfilled.
orders/cancelled: occurs whenever an order is cancelled.
Use the /admin/api/2023-01/webhooks.json endpoint to subscribe to a webhook:
// Node.js - Session is built by the OAuth process
const webhook = new shopify.rest.Webhook({session: session});
webhook.topic = "orders/create";
webhook.address = "https://example.hostname.com/";
// format you want to receive the event data in
webhook.format = "json"; // or XML
// fields you want to receive
webhook.fields = [
"id",
"note"
];
await webhook.save({
update: true,
});
You can also use the GraphQL Admin API for the same purpose.

Is it possible to add a new tag to all current registrations efficiently?

I currently have 160k active registered devices on my notification hub. Each one has a set of tags. I have added a new feature in my application and the user can turn notification on/off for this feature. We currently manage the on/off state by registering a tag. We would like to deploy this feature with everyone on by default, which means we would need to add this tag to every registration. Is it possible to do this efficiently? My current solution is taking way too long:
var result = await HubClient.GetAllRegistrationsAsync(currentToken, 100);
foreach(var r in result)
{
//get installationId from tags
var id = ...;
var installation = await HubClient.GetInstallationAsync(id);
installation.Tags.Add("newtag");
await HubClient.CreateOrUpdateInstallationAsync(installation);
}
This is taking way too long and even resulting in QuotaExceededExceptions. Is there a more efficient way of doing this? Is it possible to avoid the GetInstallationAsync call? Possibly getting all Installations directly, instead of going through the Registrations? How about updating the tags through the Registration without going through the Installation?
The short answer to your question is "no".
Does your app register its push token each time the user starts a session? If so maybe the best approach is to add the tag when each user launches the new version of the app for the first time.
Do you also have a server that keeps track of all the push registrations and user preferences? You could also update your table of all the user preferences with the new default setting, if the new feature does not depend on the user having the latest build of the mobile app.

Azure Notification Hub Sending thousands of notifications and getting back results from each

We're setting up Push Notifications for our app. We are creating a console app now that will determine which users to send to, and then send them to said users. What's not obvious to us at this point is how do we know when each one of them completed? Or didn't complete? There's not a lot of documentation provided by Microsoft (big surprise there) and whatever documentation there is doesn't really explain how to read the responses.
For instance, here's an example snippet of what we think we need to implement, because we could have thousands of people receiving a notification at one time, we would want them to run parallel and not block UI.
public async Task GenerateNotifications()
{
NotificationHubClient hub = NotificationHubClient.CreateClientFromConnectionString(AppHelper.AzureNotificationHubConnectionString, "myhub");
List<Task<NotificationOutcome>> notificaitonTasks = new List<Task<NotificationOutcome>>();
for (int i = 0; i < 10; i++)
{
var notification = new
{
aps = new
{
alert = string.Format("Awesome Notification {0}", i),
sound = "default"
}
};
string notificationJSON = JsonConvert.SerializeObject(notification);
notificaitonTasks.Add(hub.SendAppleNativeNotificationAsync(notificationJSON, "mytag"));
}
await Task.WhenAll(notificaitonTasks);
}
This makes sense to us, we use the WhenAll method to execute all the tasks on parralel threads. But then is there a way to know what happens with EACH task that gets run? For instance, the ContinueWith method seems to do what we want, except we think that this will only run after ALL the tasks are completed, and not after each one (please correct me if I'm wrong).
So, is there a way to read each response of a WhenAll call? If no, is there a better way to do what we are trying to do? I will supply any other information needed, please just ask.
You can use per message Telemetry feature to get the result of each notification sent. You will need to however upgrade to Standard Tier to do that. See link
Per Message Telemetry
Per Message Telemetry Blog
On a side note you can use NotificationOutcome.Result property by using the EnableTestSend property as shown in the link EnableTestSend property(Search for Debug Failed notifications). This will only send the notification to 10 devices that matches your condition. This is primarily used for debugging purpose

How to detect when bot was added to conversation and other events?

I am testing a bot that I am building using the Bot Framework. The emulator for local testing that Microsoft created has several events that can be provided to the bot to solicit a response.
I looked at the GitHub samples provided for Node.js here, but I can not find any example that responds to the different events within the Bot Framework Emulator.
The states are:
Bot Added to Conversation
Bot Removed from Conversation
User Added to Conversation
User Removed from Conversation
End of Conversation
Ping
Delete User Data
The API also does not make it clear how to achieve any of these actions.
Does anyone have any insight on where I should be looking for a example, or the API entries that I should be using?
In response to one of the answers, I did try code -
.onDefault(function (session) { console.log(session.message.type); }
But it only ever display "message" if a message was sent by the user.
The incoming message.type field will have "BotAddedToConversation" etc.
For the Node SDK, the botConnectorBot is able to trigger custom listeners on events using the on() handler.
Example
var builder = require('botbuilder');
var bot = new builder.BotConnectorBot({ appId: 'APPID', appSecret: 'APPSECRET' });
bot.on('DeleteUserData', function(message) {
// Handle Deleting User Data
});
More information can be found here.
You are also able to configure some standard messages using the configure() method.
Example
bot.configure({
userWelcomeMessage: "Hello... Welcome to the group.",
goodbyeMessage: "Goodbye..."
});
More information on what can be configured through options is located here.
Concerns
This is not part of the question, as the question was to identify how to listen to these events. But as a general concern, the event listener does not return a session object. It is unclear how to act once you handle the event.

Is there any way to use our own server for storage of data generated using PUBNUB api? [duplicate]

I'm looking to develop a chat application with Pubnub where I want to make sure all the chat messages that are send is been stored in the database and also want to send messages in chat.
I found out that I can use the Parse with pubnub to provide storage options, But I'm not sure how to setup those two in a way where the messages and images send in the chat are been stored in the database.
Anyone have done this before with pubnub and parse? Are there any other easy options available to use with pubnub instead of using parse?
Sutha,
What you are seeking is not a trivial solution unless you are talking about a limited number of end users. So I wouldn't say there are no "easy" solutions, but there are solutions.
The reason is your server would need to listen (subscribe) to every chat channel that is active and store the messages being sent into your database. Imagine your app scaling to 1 million users (doesn't even need to get that big, but that number should help you realize how this can get tricky to scale where several server instances are listening to channels in a non-overlapping manner or with overlap but using a server queue implementation and de-duping messages).
That said, yes, there are PubNub customers that have implemented such a solution - Parse not being the key to making this happen, by the way.
You have three basic options for implementing this:
Implement a solution that will allow many instances of your server to subscribe to all of the channels as they become active and store the messages as they come in. There are a lot of details to making this happen so if you are not up to this then this is not likely where you want to go.
There is a way to monitor all channels that become active or inactive with PubNub Presence webhooks (enable Presence on your keys). You would use this to keep a list of all channels that your server would use to pull history (enable Storage & Playback on your keys) from in an on-demand (not completely realtime) fashion.
For every channel that goes active or inactive, your server will receive these events via the REST call (and endpoint that you implement on your server - your Parse server in this case):
channel active: record "start chat" timetoken in your Parse db
channel inactive: record "end chat" timetoken in your Parse db
the inactive event is the kickoff for a process that uses start/end timetokens that you recorded for that channel to get history from for channel from PubNub: pubnub.history({channel: channelName, start:startTT, end:endTT})
you will need to iterate on this history call until you receive < 100 messages (100 is the max number of messages you can retrieve at a time)
as you retrieve these messages you will save them to your Parse db
New Presence Webhooks have been added:
We now have webhooks for all presence events: join, leave, timeout, state-change.
Finally, you could just save each message to Parse db on success of every pubnub.publish call. I am not a Parse expert and barely know all of its capabilities but I believe they have some sort or store local then sync to cloud db option (like StackMob when that was a product), but even if not, you will save msg to Parse cloud db directly.
The code would look something like this (not complete, likely errors, figure it out or ask PubNub support for details) in your JavaScript client (on the browser).
var pubnub = PUBNUB({
publish_key : your_pub_key,
subscribe_key : your_sub_key
});
var msg = ... // get the message form your UI text box or whatever
pubnub.publish({
// this is some variable you set up when you enter a chat room
channel: chat_channel,
message: msg
callback: function(event){
// DISCLAIMER: code pulled from [Parse example][4]
// but there are some object creation details
// left out here and msg object is not
// fully fleshed out in this sample code
var ChatMessage = Parse.Object.extend("ChatMessage");
var chatMsg = new ChatMessage();
chatMsg.set("message", msg);
chatMsg.set("user", uuid);
chatMsg.set("channel", chat_channel);
chatMsg.set("timetoken", event[2]);
// this ChatMessage object can be
// whatever you want it to be
chatMsg.save();
}
error: function (error) {
// Handle error here, like retry until success, for example
console.log(JSON.stringify(error));
}
});
You might even just store the entire set of publishes (on both ends of the conversation) based on time interval, number of publishes or size of total data but be careful because either user could exit the chat and the browser without notice and you will fail to save. So the per publish save is probably best practice if a bit noisy.
I hope you find one of these techniques as a means to get started in the right direction. There are details left out so I expect you will have follow up questions.
Just some other links that might be helpful:
http://blog.parse.com/learn/building-a-killer-webrtc-video-chat-app-using-pubnub-parse/
http://www.pubnub.com/blog/realtime-collaboration-sync-parse-api-pubnub/
https://www.pubnub.com/knowledge-base/discussion/293/how-do-i-publish-a-message-from-parse
And we have a PubNub Parse SDK, too. :)

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