I've created a private messaging app where users login and can view their private messages. The problem that I am having is that is only shows the message list of one logged in user at a time. So let's say User A is logged in, it will show the chat list of user A. But then User B logs in, then both User A and User B will see the chat list of User B.
This is my server side call to fetch chats by user id:
Im using express for the backend
io.on('connection', socket => {
socket.on('findAllChatsByUserId', (userId) => {
socket.userId = userId
socket.join(socket.userId)
ChatModel.aggregate([{$match: {$or:[{senderId: userId},{receiver: userId}]}}, {$group: {_id: '$chatId', 'data': {$last: '$$ROOT'}}}]).exec(function(error, data) {
if (error) {
return error
} else {
data.sort(function (a, b) {
return b.data.date - a.data.date;
});
io.to(socket.userId).emit('findAllChatsByUserId', data);
}
})
})
});
And on the client side I do:
I am using VueJs on the FE
mounted () {
this.loading = true
this.socket.emit('findAllChatsByUserId', this.getUserId) // this calls the socket to get the chats for the given user Id
this.loading = false
},
I tried creating rooms by userId to make sure that only the data for a given user ID is passed in but it seems like only one user can use the socket at a time. I thought the rooms would solve this issue for me. Do I have to create a separate socket for each user? If so, how do I do that? I've followed the socket.io private messaging tutorial but they use 2 users talking to each other to explain the problem.
So I ended up solving this by doing:
io.to(socket.id).emit('findAllChatsByUserId', data);
instead of:
io.to(socket.userId).emit('findAllChatsByUserId', data);
So you use the "to" attribute to make sure the data you're sending is going to a particular socket, and you can find your specific socket by just calling socket.id (you don't have to set this, it gets set on its own. And the data will get emitted to whomever is on that specific socket.
Related
onUserJoined provides UID which is then used to set up remote video.
in live stream feature when there are two hosts streaming in one channel and if another audience joins later then how can that audience tell which uid is for which host.
Note that onUserJoined does call in random order.
https://docs.agora.io/en/All/API%20Reference/java/classio_1_1agora_1_1rtc_1_1_i_rtc_channel_event_handler.html#a65fd197a39824219aedc2cba81296e82
Use case:
2 hosts already streaming in one channel. 1 of the host is original host and another is a co-host(got invited into the channel)
an audience joins the channel. onUserJoined callback is triggered twice and given the remote UID. That audience now needs to know who is the original host and related his UID and who is the co-host and his related UID.
You basically Answered your self
LIVE_BROADCASTING profile: This callback notifies the app when the host joins the channel. If other hosts are already in the channel, the SDK also reports to the app on the existing hosts. We recommend having at most 17 hosts in a channel.
I finally found a solution for that issue by informing all users that will enter the channel after the Orignal Host by the uid of the orignal host
and you can do this by using sendStreamMessage() function
First joinChannelSuccess triggers after original host login
which will return uid of the original host - and we will save it in a variable.
Then, use sendStreamMessage() to send this uid for all new users
and that by using this function which will be called when userJoined triggers
check this code
int _orignalHost = 'the uid';
_addListener() {
_engine.setEventHandler(RtcEngineEventHandler(
**joinChannelSuccess:** (channel, uid, elapsed) {
setState(() {
isJoined = true;
});
},
**userJoined:** (uid, elapsed) {
remoteUids.add(uid);
setState(() {});
},
// this trriger when you recive the mesage
**streamMessage:** (int uid, int streamId, Uint8List data) {
// save it in _orignalHost variable for the audince
},
streamMessageError:
(int uid, int streamId, ErrorCode error, int missed, int cached) {
},
));
}
Future<void> _onNewUserJoin() async {
try {
var streamId = await _engine
.createDataStreamWithConfig(DataStreamConfig(false, false));
if (streamId != null) {
await _engine.sendStreamMessage(
streamId, Uint8List.fromList(utf8.encode(_orignalHost)));
}
_controller.clear();
} catch (e) {
}
}
you can check full code for StreamMessage:
https://github.com/AgoraIO/Agora-Flutter-SDK/blob/master/example/lib/examples/advanced/stream_message/stream_message.dart
Also, You can check this for more info (anoter solution)
https://docs.agora.io/en/Real-time-Messaging/faq/audience_event?platform=Android
I have a simple VoxImplant scenario which creates a standalone conference and calls its participants:
require(Modules.Conference);
VoxEngine.addEventListener(AppEvents.Started, () => {
let conf = VoxEngine.createConference();
let { users } = JSON.parse(VoxEngine.customData());
users.forEach((username) => {
let call = VoxEngine.callUser({username: username, callerid: "root", displayName: "Whatever" });
call.addEventListener(CallEvents.Connected, (e) => { VoxEngine.sendMediaBetween(conf, e.call); });
});
});
I use StartScenarios endpoint to initiate the conference.
The calls arrive, users can answer them and hear each other. But what if they decline and decide to join later? I can see callConference methods in SDKs but they require conferenceId, how can I get it? Conference object doesn't seem to have id property, neither do ConferenceParameters.
VoxImplant conference sample has create_conference endpoint which inserts a record into a database and returns primary key but it seems to be unused.
Should use StartConference endpoint instead of StartScenario, it has conference_name parameter. Generate and pass conference name there, and pass the same name to callConference in order to join a running conference.
After a connection to the socket.io server a socket.id is given for the connection. When the socket connection has not been used after some time a new socket id is generated.
I have read a lot of tutorials that do a "hello world" connection that just gets you connected, but, there is not much literature on messaging peer-to-peer/group. The docs give a 3 line paragraph on rooms/namespaces and every question related to this is just given a link to the same 3 line paragraph.
I understand that you can create and object/array of chats(in this example). For this example, let's say it is an object. That Object looks something like this:
const connections = {
"randomSocketID1": {
recipient: "Mom",
messages: [Array of Objects]
//more information
}
}
I then send a message to randomSocketID1 --> 'Hello'. Then next day I want to send another message to "Mom". Is that socketID going to be the same OR AT LEAST will "randomSocketID1" be updated under the hood, to its updated ID(which sounds improbable)? Is the regeneration of the socketID a product of garbage collection or a socket/engine/websocket protocol?
thanks for any clarification
So I was still unable to find an actual answer to this and by the 0 responses i see that no one knows. So what I have done in order to make sure that user and socket id are maintained is whenever a user enters the component that connects to the socketio server an automatic 'update-user' is emitted and the back end then just finds the user and assigns it the value.
So I have something like this:
chat.component.ts:
ngOnInit(){
this.socket.emit('update-user', 'Ctfrancia');
}
then in the back end:
const users = {};
io.on('connection', socket => {
socket.on('update-user', user => {
if (user in users) users[user] = socket.id;
else users[user] = socket.id
});
});
I've got an observable data service (UserService) that returns the currently logged in user. I followed this tutorial - https://coryrylan.com/blog/angular-observable-data-services, which describes using a BehaviorSubject to return a default currentUser immediately, then emit the real currentUser once it's loaded or altered. The service is basically like this...
private _currentUser: BehaviorSubject<User> = new BehaviorSubject(new User());
public currentUser: Observable<User> = this._currentUser.asObservable();
constructor(private http: Http) {}
loadUser() { // app.component onInit and login component call this
return this.http.get('someapi.com/getcurrentuser')
.map(response => <User>this.extractData(response))
.do(
(user) => {
this.dataStore.currentUser = user;
this._currentUser.next(Object.assign(new User(), this.dataStore).currentUser);
},
(error) => this.handleError(error)
)
.catch(error -> this.handleError(error));
}
I'm having problems whenever a user hits F5 to reload the entire spa. When a consuming component subscribes to the currentUser on the UserService, it immediately receives a default user while the UserService waits for an api call to receive the actual user. The moment that api call finishes, the real user is emitted by UserService and all the subscribers get the real user. The first value emitted by the BehaviorSubject, however, is the default value and it always has an id of "undefined", so we can't make our next api call yet. In fact, when the real user comes through and I CAN make a valid call using the user.id, the chained subscription never happens and I don't get the values out of the response.
I know I'm doing something stupid, but I haven't figured out exactly what yet. I just stumbled across concatMap, but I'm not sure how to use it. While I pursue that, I'd like to know why the below code doesn't work. I particularly want to know why the subscribe never fires, even after the real user comes in, just to help my newbie understanding of Observables.
this.userService.currentUser
.flatMap((user) => {
this.user = user;
// Need to NOT call this if the user does not have an id!!!
this.someOtherService.getSomethingElse(user.id); // user.id is always undefined the first time
})
.subscribe((somethingElse) => {
// This never gets called, even after the real user is emitted by the UserService
// and I see the getSomethingElse() call above get executed with a valid user.id
this.somethingElse = somethingElse;
});
If you want to ignore user instances that do not have an id, use the filter operator:
import 'rxjs/add/operator/filter';
this.userService.currentUser
.filter((user) => Boolean(user.id))
.flatMap((user) => {
this.user = user;
this.someOtherService.getSomethingElse(user.id);
})
.subscribe((somethingElse) => {
this.somethingElse = somethingElse;
});
Regarding "why the subscribe never fires", it's likely due to an error arising from the undefined id. You only pass a next function to subscribe, so any errors will be unhandled. And if an error occurs, the observable will terminate and will unsubscribe any subscribers - as that is how observables behave - so any subsequent users with defined id properties will not be received.
I am using Meteor and the Twitter API for a project. I want to get information on a user from Twitter. I wrote a function that for example returns only the location of a user from Twitter. I believe this is the proper way to do a request on Meteor. Here it is :
Meteor.methods({getTwitterLocation: function (username) {
Meteor.http.get("https://api.twitter.com/1/users/show.json?screen_name="+ username +"&include_entities=true", function(error, result) {
if (result.statusCode === 200) {
var respJson = JSON.parse(result.content);
console.log(respJson.location);
console.log("location works");
return (respJson.location)
}else {
return ( "Unknown user ")
}
});
}});
Now this function will log what's in the console on my Git Bash. I get someones Location by doing a Meteor.call. But I want to post what that function returns on a page. In my case, I want to post in on a user's profile. This doesn't work. But the console.log(respJson.location) returns the location in my Git Bash but it won't display anything on the profile page. This is what I did on my profile page:
profile.js :
Template.profile.getLocation= function(){
return Meteor.call("getTwitterLocation","BillGates");
}
profile.html :
<template name="profile">
from {{getLocation}}
</template>
With that I get "Seattle, WA" and " "location works" on my Git Bash but nothing on the profile page. If anyone knows what I can do, that'd be really appreciated. Thanks.
Firstly when data is returned from the server you need to use a synchronous call, as the callback will return the data when the server already thinks the meteor method has completed. (the callback will be fired at a later time, when the data is returned from the server, by which time the meteor client would have already got a response)
var result = Meteor.http.get("https://api.twitter.com/1/users/show.json?screen_name="+ username +"&include_entities=true");
if (result.statusCode === 200) {
var respJson = JSON.parse(result.content);
console.log(respJson.location);
console.log("location works");
return (respJson.location)
}else {
return ( "Unknown user ")
}
The second is you need to use a Session hash to return the data from the template. This is because it will take time to get the response and the getLocation would expect an instant result (without a callback). At the moment client side javascript can't use synchronous api calls like on the server.
Template.profile.getLocation= function(){
return Session.get("twitterlocation");
}
Use the template created event to fire the meteor call:
Template.profile.created = function() {
Meteor.call("getTwitterLocation","BillGates", function(err,result) {
if(result && !err) {
Session.set("twitterlocation", result);
}
else
{
Session.set("twitterlocation", "Error");
}
});
});
Update:
Twitter has since updated its API to 1.1 a few modifications are required:
You now need to swap over to the 1.1 api by using 1.1 instead of 1. In addition you need to OAuth your requests. See https://dev.twitter.com/docs/auth/authorizing-request. Below contains sample data but you need to get proper keys
var authkey = "OAuth oauth_consumer_key="xvz1evFS4wEEPTGEFPHBog",
oauth_nonce="kYjzVBB8Y0ZFabxSWbWovY3uYSQ2pTgmZeNu2VS4cg",
oauth_signature="tnnArxj06cWHq44gCs1OSKk%2FjLY%3D",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp=""+(new Date().getTime()/1000).toFixed(0)+"",
oauth_token="370773112-GmHxMAgYyLbNEtIKZeRNFsMKPR9EyMZeS9weJAEb",
oauth_version="1.0"";
Be sure to remove the newlines, I've wrapped it to make it easy to read.
var result = Meteor.http.get("https://api.twitter.com/1.1/users/show.json?screen_name="+ username +"&include_entities=true",{headers:{Authorization : authkey});
If you find this a bit troublesome it might be easier to just use a package like https://github.com/Sewdn/meteor-twitter-api via meteorite to OAuth your requests for you.