关闭WebSocket连接错误

Question

Hello I'm using websockets on my node.js server in order to stablish WebRTC connections. But when I end the connection the node server console gives me the following error:

        conn.otherName = null;
                       ^

TypeError: Cannot set property 'otherName' of undefined

Other name is the name of the other Peer and I'ts setted up in the connection like this: case "offer": //for ex. UserA wants to call UserB console.log("Sending offer to: ", data.name);

        //if UserB exists then send him offer details 
        var conn = users[data.name]; 

        if(conn != null) { 
           //setting that UserA connected with UserB 
           connection.otherName = data.name; 

           sendTo(conn, { 
              type: "offer", 
              offer: data.offer, 
              name: connection.name 
           }); 
        } 

        break;

     case "answer": 
        console.log("Sending answer to: ", data.name); 
        //for ex. UserB answers UserA 
        var conn = users[data.name]; 

        if(conn != null) { 
           connection.otherName = data.name; 
           sendTo(conn, { 
              type: "answer", 
              answer: data.answer 
           });
        } 

Afterwards I'm closing the connection like this:

connection.on("close", function() { 

  if(connection.name) { 
     delete users[connection.name]; 

     if(connection.otherName) { 
        console.log("Disconnecting from ", connection.otherName); 
        var conn = users[connection.otherName]; 
        conn.otherName = null;  

        if(conn != null) { 
           sendTo(conn, { 
              type: "leave" 
          }); 
        }  
     } 
  } 
});

How can I change it to be able to close the connection without crashing my node server?

Answer 1

Stopping it from breaking is quite simple with some defensive code, change this

var conn = users[connection.otherName]; 
conn.otherName = null;  

to this

if (connection.otherName) {
    var conn = users[connection.otherName]; 
    if (conn) 
         conn.otherName = null;  

    if(conn != null) { 
// The connection is closed, trying to send at this point isn't a good idea
           sendTo(conn, { 
              type: "leave" 
          }); 
        }  
    }

It doesn't address why users[connection.otherName] is returning undefined (that's an exercise for you), but it will stop it crashing