SignalR Core call function when connection is established












0















When my client successfully connects to the hub, I want the client to immediately join a group. I have a method in my hub to do that, I just need an event handler for when the connection is established, just like 



connection.start().done(

    function () {

        connection.invoke('JoinGroup', 'GroupName');

    });


in SignalR for plain ASP.Net.



Can I do that or do I have to set a timer to do it after x seconds after the start(); call was made?



Edit:



I found out I can do 



connection.start(

    function (){

            connection.invoke('JoinGroup', 'GroupName');

    }

);


but it tells me that it Cannot send data if the connection is not in the 'Connected' State.



what do?






signalr.client asp.net-core-signalr







share|improve this question



























    0















    When my client successfully connects to the hub, I want the client to immediately join a group. I have a method in my hub to do that, I just need an event handler for when the connection is established, just like 



    connection.start().done(
    
    function () {
    
        connection.invoke('JoinGroup', 'GroupName');
    
    });


    in SignalR for plain ASP.Net.



    Can I do that or do I have to set a timer to do it after x seconds after the start(); call was made?



    Edit:



    I found out I can do 



    connection.start(
    
    function (){
    
            connection.invoke('JoinGroup', 'GroupName');
    
    }
    
);


    but it tells me that it Cannot send data if the connection is not in the 'Connected' State.



    what do?






    signalr.client asp.net-core-signalr







    share|improve this question

























      0












      0








      0








      When my client successfully connects to the hub, I want the client to immediately join a group. I have a method in my hub to do that, I just need an event handler for when the connection is established, just like 



      connection.start().done(
      
    function () {
      
        connection.invoke('JoinGroup', 'GroupName');
      
    });


      in SignalR for plain ASP.Net.



      Can I do that or do I have to set a timer to do it after x seconds after the start(); call was made?



      Edit:



      I found out I can do 



      connection.start(
      
    function (){
      
            connection.invoke('JoinGroup', 'GroupName');
      
    }
      
);


      but it tells me that it Cannot send data if the connection is not in the 'Connected' State.



      what do?






      signalr.client asp.net-core-signalr







      share|improve this question














      When my client successfully connects to the hub, I want the client to immediately join a group. I have a method in my hub to do that, I just need an event handler for when the connection is established, just like 



      connection.start().done(
      
    function () {
      
        connection.invoke('JoinGroup', 'GroupName');
      
    });


      in SignalR for plain ASP.Net.



      Can I do that or do I have to set a timer to do it after x seconds after the start(); call was made?



      Edit:



      I found out I can do 



      connection.start(
      
    function (){
      
            connection.invoke('JoinGroup', 'GroupName');
      
    }
      
);


      but it tells me that it Cannot send data if the connection is not in the 'Connected' State.



      what do?






      signalr.client asp.net-core-signalr




      signalr.client asp.net-core-signalr






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 21 '18 at 13:13









      lennyylennyy

      154118




      154118
























          1 Answer
          1






          active

          oldest

          votes


















          2














          SignalR is notoriously difficult due to version mismatches etc.



          Please see the following article: https://docs.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio



          In it, there's a section that specifies how to start (and wait for connection to be established):



          var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();
          
connection.start().then(() => {
          
  //try some stuff here :)
          
})
          
.catch(function (err) {
          
  //failed to connect
          
  return console.error(err.toString());
          
});


          The javascript client uses promises that have to be resolved/rejected before you can use it.
          The other option is to wrap inside async method and await the call (not sure if this will work correctly). Such as:



          await connection.start();
          
//connection should be started now. beware of exceptions though





          share|improve this answer
























          • I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

            – lennyy
            Nov 21 '18 at 13:41






          • 1





            Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

            – Neal
            Nov 21 '18 at 13:44











          • It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

            – lennyy
            Nov 21 '18 at 13:45






          • 1





            Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

            – Neal
            Nov 21 '18 at 13:46






          • 1





            "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

            – Neal
            Nov 21 '18 at 14:30











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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          2














          SignalR is notoriously difficult due to version mismatches etc.



          Please see the following article: https://docs.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio



          In it, there's a section that specifies how to start (and wait for connection to be established):



          var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();
          
connection.start().then(() => {
          
  //try some stuff here :)
          
})
          
.catch(function (err) {
          
  //failed to connect
          
  return console.error(err.toString());
          
});


          The javascript client uses promises that have to be resolved/rejected before you can use it.
          The other option is to wrap inside async method and await the call (not sure if this will work correctly). Such as:



          await connection.start();
          
//connection should be started now. beware of exceptions though





          share|improve this answer
























          • I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

            – lennyy
            Nov 21 '18 at 13:41






          • 1





            Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

            – Neal
            Nov 21 '18 at 13:44











          • It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

            – lennyy
            Nov 21 '18 at 13:45






          • 1





            Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

            – Neal
            Nov 21 '18 at 13:46






          • 1





            "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

            – Neal
            Nov 21 '18 at 14:30
















          2














          SignalR is notoriously difficult due to version mismatches etc.



          Please see the following article: https://docs.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio



          In it, there's a section that specifies how to start (and wait for connection to be established):



          var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();
          
connection.start().then(() => {
          
  //try some stuff here :)
          
})
          
.catch(function (err) {
          
  //failed to connect
          
  return console.error(err.toString());
          
});


          The javascript client uses promises that have to be resolved/rejected before you can use it.
          The other option is to wrap inside async method and await the call (not sure if this will work correctly). Such as:



          await connection.start();
          
//connection should be started now. beware of exceptions though





          share|improve this answer
























          • I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

            – lennyy
            Nov 21 '18 at 13:41






          • 1





            Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

            – Neal
            Nov 21 '18 at 13:44











          • It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

            – lennyy
            Nov 21 '18 at 13:45






          • 1





            Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

            – Neal
            Nov 21 '18 at 13:46






          • 1





            "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

            – Neal
            Nov 21 '18 at 14:30














          2












          2








          2







          SignalR is notoriously difficult due to version mismatches etc.



          Please see the following article: https://docs.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio



          In it, there's a section that specifies how to start (and wait for connection to be established):



          var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();
          
connection.start().then(() => {
          
  //try some stuff here :)
          
})
          
.catch(function (err) {
          
  //failed to connect
          
  return console.error(err.toString());
          
});


          The javascript client uses promises that have to be resolved/rejected before you can use it.
          The other option is to wrap inside async method and await the call (not sure if this will work correctly). Such as:



          await connection.start();
          
//connection should be started now. beware of exceptions though





          share|improve this answer













          SignalR is notoriously difficult due to version mismatches etc.



          Please see the following article: https://docs.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio



          In it, there's a section that specifies how to start (and wait for connection to be established):



          var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();
          
connection.start().then(() => {
          
  //try some stuff here :)
          
})
          
.catch(function (err) {
          
  //failed to connect
          
  return console.error(err.toString());
          
});


          The javascript client uses promises that have to be resolved/rejected before you can use it.
          The other option is to wrap inside async method and await the call (not sure if this will work correctly). Such as:



          await connection.start();
          
//connection should be started now. beware of exceptions though






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 21 '18 at 13:29









          NealNeal

          293111




          293111













          • I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

            – lennyy
            Nov 21 '18 at 13:41






          • 1





            Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

            – Neal
            Nov 21 '18 at 13:44











          • It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

            – lennyy
            Nov 21 '18 at 13:45






          • 1





            Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

            – Neal
            Nov 21 '18 at 13:46






          • 1





            "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

            – Neal
            Nov 21 '18 at 14:30



















          • I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

            – lennyy
            Nov 21 '18 at 13:41






          • 1





            Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

            – Neal
            Nov 21 '18 at 13:44











          • It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

            – lennyy
            Nov 21 '18 at 13:45






          • 1





            Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

            – Neal
            Nov 21 '18 at 13:46






          • 1





            "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

            – Neal
            Nov 21 '18 at 14:30

















          I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

          – lennyy
          Nov 21 '18 at 13:41





          I tried await connection.start() but it told me that's only for async functions. I'll try the then. thanks for the quick reply.

          – lennyy
          Nov 21 '18 at 13:41




          1




          1





          Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

          – Neal
          Nov 21 '18 at 13:44





          Yeah that's correct, it has to be inside an async function(){} :-). No problem. Good luck!

          – Neal
          Nov 21 '18 at 13:44













          It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

          – lennyy
          Nov 21 '18 at 13:45





          It's still saying Cannot send data if the connection is not in the 'Connected' State. but it does recieve method calls sent to the client group it's supposed to join. I guess that's good enough.

          – lennyy
          Nov 21 '18 at 13:45




          1




          1





          Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

          – Neal
          Nov 21 '18 at 13:46





          Check out in the hub, there are two methods called OnConnected and OnDisconnected that you can override from inherited hub for troubleshooting.

          – Neal
          Nov 21 '18 at 13:46




          1




          1





          "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

          – Neal
          Nov 21 '18 at 14:30





          "Experience is simply the name we give our mistakes" - Oscar Wilde. :-) So, I suspect that the client that's failing to connect you get some error before it stating failed to negotiate (or something to that effect) The answer is to enable something called CORS. Basic example here: stackoverflow.com/questions/48185985/… I recommend you look into the CORS stuff for ASP core and setup a policy only whitelisting your domain.

          – Neal
          Nov 21 '18 at 14:30




















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