Notes/connection_manager.go

package main

import (
	// External
	"github.com/google/uuid"
	"github.com/gorilla/websocket"

	// Standard
	"log"
	"net/http"
)

type WsConnection struct {
	ConnectionManager *ConnectionManager
	UUID string
	Conn *websocket.Conn
	Pruned bool
}
type ConnectionManager struct {
	connections map[string]*WsConnection
	broadcastQueue chan interface{}
	sendQueue chan SendRequest
}
type SendRequest struct {
	WsConn *WsConnection
	Msg interface{}
}

func validateOrigin(r *http.Request) bool {// {{{
	/*
	host := r.Header.Get("X-Forwarded-Host")
	if host == "" {
		components := strings.Split(r.Host, ":")
		host = components[0]
	}
	*/
	return true
}// }}}

var (
	upgrader = websocket.Upgrader{
		ReadBufferSize:  1024,
		WriteBufferSize: 1024,

		// CheckOrigin is to match DOMAIN constant.
		// Use X-Forwarded-Server if behind proxy.
		CheckOrigin: validateOrigin,
	}
)

func NewConnectionManager() (cm ConnectionManager) {// {{{
	cm.connections = make(map[string]*WsConnection)
	cm.sendQueue = make(chan SendRequest, 65536)
	cm.broadcastQueue = make(chan interface{}, 65536)
	return
}// }}}

// NewConnection creates a new connection, which is assigned a UUIDv4 for
// identification. This is then put into the connection collection.
func (cm *ConnectionManager) NewConnection(w http.ResponseWriter, r *http.Request) (*WsConnection, error) {// {{{
	var err error
	wsConn := WsConnection{
		UUID: uuid.NewString(),
		ConnectionManager: cm,
	}
	wsConn.Conn, err = upgrader.Upgrade(w, r, nil)
	if err != nil {
		return nil, err
	}

	// Keep track of all connections.
	cm.connections[wsConn.UUID] = &wsConn

	// Successfully upgraded to a websocket connection.
	log.Printf("[%s] Connection from %s", wsConn.UUID, r.RemoteAddr)

	go cm.ReadLoop(&wsConn)

	return &wsConn, nil
}// }}}

// Prune closes an deletes connections. If this happened to be non-fatal, the
// user will just have to reconnect.
func (cm *ConnectionManager) Prune(wsConn *WsConnection, err error) {// {{{
	if false {
		log.Printf("[%s] pruning connection [%s]\n", wsConn.UUID, err)
	}
	wsConn.Conn.Close()
	wsConn.Pruned = true
	delete(cm.connections, wsConn.UUID)
}// }}}
func (cm *ConnectionManager) ReadLoop(wsConn *WsConnection) {// {{{
	var data []byte
	var ok   bool

	for {
		if data, ok = cm.Read(wsConn); !ok {
			break
		}

		log.Printf("%s\n", data)

		//cm.Send(wsConn, response)
	}
}// }}}
func (cm *ConnectionManager) Read(wsConn *WsConnection) ([]byte, bool) {// {{{
	var err error
	var requestData []byte
	_, requestData, err = wsConn.Conn.ReadMessage()
	if err != nil {
		cm.Prune(wsConn, err)
		return nil, false
	}
	return requestData, true
}// }}}
func (cm *ConnectionManager) Send(wsConn *WsConnection, msg interface{}) {// {{{
	wsConn.Conn.WriteJSON(msg)
}// }}}
func (cm *ConnectionManager) Broadcast(msg interface{}) {// {{{
	cm.broadcastQueue <- msg
}// }}}

func (cm *ConnectionManager) BroadcastLoop() {// {{{
	for {
		msg := <-cm.broadcastQueue
		for _, wsConn := range cm.connections {
			cm.Send(wsConn, msg)
		}
	}
}// }}}

// vim: foldmethod=marker