在Golang中一对一聊天

I want to create one to one chat in revel framework but it gives error. Firstly work in revel chat according to demo but refreshing page did not work so I tried this method and dont know how to handle single chat.

Here is an error:

app server.go:2848: http: panic serving 127.0.0.1:50420: interface conversion: interface is nil, not io.Writer goroutine 166 [running]: net/http.(*conn).serve.func1(0xc4201d03c0)

my go code is where I handle ws root,single user chat need to db connection to. I'm using posgres for it

package main

import (
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

var clients = make(map[*websocket.Conn]bool) // connected clients
var broadcast = make(chan Message)           // broadcast channel

// Configure the upgrader
var upgrader = websocket.Upgrader{
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

// Define our message object
type Message struct {
    Email    string `json:"email"`
    Username string `json:"username"`
    Message  string `json:"message"`
    Created  string `json:"created"`
}

func main() {
    // Create a simple file server
    fs := http.FileServer(http.Dir("public"))
    http.Handle("/", fs)

    // Configure websocket route
    http.HandleFunc("/ws", handleConnections)

    // Start listening for incoming chat messages
    go handleMessages()

    // Start the server on localhost port 8000 and log any errors
    log.Println("http server started on :8090")
    err := http.ListenAndServe(":8090", nil)
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

func handleConnections(w http.ResponseWriter, r *http.Request) {
    // Upgrade initial GET request to a websocket
    ws, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Fatal(err)
    }
    // Make sure we close the connection when the function returns
    defer ws.Close()

    // Register our new client
    clients[ws] = true

    for {
        var msg Message
        // Read in a new message as JSON and map it to a Message object
        err := ws.ReadJSON(&msg)
        if err != nil {
            log.Printf("error: %v", err)
            delete(clients, ws)
            break
        }
        // Send the newly received message to the broadcast channel
        broadcast <- msg
    }
}

func handleMessages() {
    for {
        // Grab the next message from the broadcast channel
        msg := <-broadcast
        // Send it out to every client that is currently connected
        for client := range clients {
            err := client.WriteJSON(msg)
            if err != nil {
                log.Printf("error: %v", err)
                client.Close()
                delete(clients, client)
            }
        }
    }
}