I am building a messenger system. since it is an async server, the user send message not in order in which it makes the message record stored not in order, i am wondering what I can do without delaying the send time.
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TL;DR
I'm listening to Firestore changes using a snapshot. Snapshots documents are from cache. How can I indicate whether a DocumentSnapshot has delivered or not? Is there any flag which can indicate it?
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I'm developing a chat application, and I want to implement a "message not delivered" icon next to the message, same as WhatsApp does (on no network connection).
I'm using Firestore to collect my messages, and I'm listening to updates using a snapshot. Since I'm using Firestore snapshot, I'm getting my messages from the cache, while the cache itself updates on every change (which is pretty cool).
My issue is that I cannot indicate whether each message was delivered successfully or not.
A good use case is a user, with no network connection, that is sending a message, then closes the app, and re-opens it (without any network, cached only). I need to indicate to them that the last message has still not been delivered.
The flag document.metadata.hasPendingWrites indicates whether the document was delivered or not.
I need to implement push notifications for my asp.net core project.For a news service
it needs to work in such a manner that if the user is not online while a message is being sent out, then the message will arrive at the client when they are online thenext time.
All the articles I can find about this, are all slightly vague about this case, and just emphasises the "real-time" communication.
So would it be possible to have push notifications that could that wiht signalr?
it needs to work in such a manner that if the user is not online while a message is being sent out, then the message will arrive at the client when they are online thenext time.
To achieve your above requirement, you can try:
mapping user to the connection id(s) and persist that mapping, which would help find/get new connection id(s) based on user name or email etc readable info after user connect/reconnect to hub, then you can send unread message/data to specific user by specifying connection id(s).
Note: you can also send a message to a specific user by passing the user identifier to the User function in a hub method, please refer to this doc: https://learn.microsoft.com/en-us/aspnet/core/signalr/groups?view=aspnetcore-5.0#users-in-signalr
for unread messages, as #SamiKuhmonen mentioned, you can store/persist those messages in somewhere, and if you want to persist information after restarts or you would host hub on multi-servers/instances, in-memory store is not a good approach. You can try to store messages in database etc permanent, external storage.
define and use a flag to indicates if the message has been seen by user. After client received a message, then invoke a hub method to update that flag or delete that message from the store.
Im using inoic with cordova-plugin-fcm
There's any way to handle when user dismiss a notification, because I need to do store some data when a notification arrives.
tks for any help.
There are two types of messages that you can send with FCM:
notification messages, which are primarily meant to be displayed to the user.
data messages, which are handled by your application code.
If you send a notification messages, then your code can handle the message while the app is active. But if your app is not active, the message is handled by the system and displayed to the user. Your code is not invoked in this case.
If you send a data message, it is always handled by your code. For your use-case, these sound like the better match.
I'm trying to understand what I will need to build on my server for Push notifications to work successfully.
My thoughts were:
The phone sends the notify URL to my server
The server stores the information in a Database
A separate process or PHP script will query the database and open continuous looping process for each device. (Each socket will be querying a 3rd party API)
When there is a change detected in the API for that device a push notification will be sent to the device's notify url.
Is this the right method on what needs to be done. Isn't this going to eat up server resources or is it the expected outcome of Push a push notifications server?
I've produced a simple diagram on all this below:
First of all, let's separate the process in the main stages needed for PUSH.
Device subscription.
Send the PUSH
Process the notification on device.
Subscription
For the subscription, your device (more specifically, your App) must call the PUSH api,for enabling PUSH notifications. This call to the push API will give you a URL that uniquely identify the device where your application is installed and running. You should store this URL on your database, the same way you store a user's email, or a user's phone number. No special black magic here. You only use it when you need to send a communication to a user.
Send the PUSH
For the push stuff, the same approach as for email, or SMS messaging here: "One does not simply make an infinite loop and send a message if any change is detected". What you have to do is, just send the PUSH message when your application needs to. So you have the user to which you want to send a message, instead of opening a SMTP connection to send ane mail, just build the PUSH XML Message and call the URL associated with that user. Some things to consider here are:
Network reliability (you need to retry if you can't connect to the server).
Response error code-handling (you don't need to retry if the server tells you that the phone has uninstalled your application, for example).
Scalability. You don't want to send a PUSH message from your PHP code, because you don't know how long it will take for the task to be completed. You have to make this thing asynchronously. So just queue up all the push messages, you can create a separate process (windows service, nodeJS service, cron job, daemon, etc.) to send the PUSH, handle retries and errors and clean the queue.
Process the notification on Device
So now that you are this far, you need to handle the notification on the phone. It depends on the type of PUSH notification that you are sending:
Tile. You will update the image, text and counter of the application tile, if the user has put your application to the start screen. On client side you need nothing to so, as all these parameters are part of your PUSH request.
Toast. This one requires a title, text (limited to some 35 characters more or less) and a relative URL inside of your APP. Your application will be launched (like when you click on a Toast notification from Twitter, for example) using the URI that you specify in the payload. So a bit of data can be already injected here. You may/or may not make a request to your server for new data. It is up to you.
Raw. This one is pretty much silent. Is not seen by the user if your APP is not running. As you might guess, this kind of PUSH is useful to live update your running APP, instead of continuously polling your server, wasting user battery and bandwidth and wasting your server resources. You can send anything (raw bytes or strings) up to the max size of the payload allowed my Microsoft.
If yo have any more questions, don't hesitate to ask.
Bottom line: separate the PUSH sending, make it async, don't you ever forget that...
Your PHP script that continually pings the database for changes...THAT is what will eat up your system resources. Push notifications go hand in hand with Event Driven Programming. This means that ideally, your code shouldn't continuously ping your DB. Rather, when something happens (ie, an "event"), THEN your code does something...like contact your phone via push notification.
Your steps for push notifications are more or less correct, but are incomplete. Step 4: the server contacts the client via the notify url (which you have). Step 5 is that the client then contacts the server to actually pull down the information it needs. That is: The new information is not provided to the client via the notify url. Once the client has its new information, then the program continues as normal (populates a list, downloads skynet, etc.)
Your third step is very wasteful and not practical if your app is installed on more than a few devices.
Instead, each device should be subscribed to types of server updates it cares about. Your server's DB will have a mapping from each type of update you support to the list of notification channel URLs of devices that care about this update type.
When your server detects an update of type X, it would send a notification to all devices subscribed to that type of update.
I've posted this in Firebase's google group but haven't received an answer so I thought I would try here.
Let me outline my current scenario
I have a global messages bucket that stores messages by room. So path messages/room_1/ would store a prioritized list of messages for room 1.
I want to stream the latest messages for all rooms so that I can send push notifications to offline users. So essentially I want to listen to the /messages path from a ruby or python backed server and send notifications to offline users.
My problem is that when I initially start listening to the /messages path I get the entire set of data, which can be millions of messages. After the initial bulk load, I get new incoming messages in real time. Is there any way to skip that initial bulk load of data and just get new messages from the start of the streaming connection?
Fyi, I'm using examples from this page: https://www.firebase.com/blog/2014-03-24-streaming-for-firebase-rest-api.html