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package main
import (
"context"
"encoding/json"
"log"
"net/http"
"os"
"os/signal"
"strconv"
"syscall"
"time"
_ "net/http/pprof"
"github.com/centrifugal/centrifuge"
)
type clientMessage struct {
Timestamp int64 `json:"timestamp"`
Input string `json:"input"`
}
func handleLog(e centrifuge.LogEntry) {
log.Printf("%s: %v", e.Message, e.Fields)
}
func authMiddleware(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
newCtx := centrifuge.SetCredentials(ctx, ¢rifuge.Credentials{
UserID: "42",
})
r = r.WithContext(newCtx)
h.ServeHTTP(w, r)
})
}
func waitExitSignal(n *centrifuge.Node) {
sigCh := make(chan os.Signal, 1)
done := make(chan bool, 1)
signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
go func() {
<-sigCh
_ = n.Shutdown(context.Background())
done <- true
}()
<-done
}
const (
exampleChannel = "chat:index"
historySize = 3000
historyTTL = 5 * time.Minute
)
// Check whether channel is allowed for subscribing. In real case permission
// check will probably be more complex than in this example.
func channelSubscribeAllowed(channel string) bool {
return channel == exampleChannel
}
func main() {
cfg := centrifuge.DefaultConfig
cfg.LogLevel = centrifuge.LogLevelInfo
cfg.LogHandler = handleLog
node, _ := centrifuge.New(cfg)
broker, _ := centrifuge.NewMemoryBroker(node, centrifuge.MemoryBrokerConfig{
HistoryMetaTTL: 120 * time.Second,
})
node.SetBroker(broker)
node.OnConnect(func(client *centrifuge.Client) {
go func() {
time.Sleep(time.Second)
client.Disconnect(centrifuge.DisconnectForceReconnect)
}()
transport := client.Transport()
log.Printf("user %s connected via %s with protocol: %s", client.UserID(), transport.Name(), transport.Protocol())
client.OnSubscribe(func(e centrifuge.SubscribeEvent, cb centrifuge.SubscribeCallback) {
log.Printf("user %s subscribes on %s", client.UserID(), e.Channel)
if !channelSubscribeAllowed(e.Channel) {
cb(centrifuge.SubscribeReply{}, centrifuge.ErrorPermissionDenied)
return
}
cb(centrifuge.SubscribeReply{
Options: centrifuge.SubscribeOptions{
Position: true,
},
}, nil)
})
client.OnHistory(func(e centrifuge.HistoryEvent, cb centrifuge.HistoryCallback) {
if !client.IsSubscribed(e.Channel) {
cb(centrifuge.HistoryReply{}, centrifuge.ErrorPermissionDenied)
return
}
cb(centrifuge.HistoryReply{}, nil)
})
client.OnUnsubscribe(func(e centrifuge.UnsubscribeEvent) {
log.Printf("user %s unsubscribed from %s", client.UserID(), e.Channel)
})
client.OnPublish(func(e centrifuge.PublishEvent, cb centrifuge.PublishCallback) {
log.Printf("user %s publishes into channel %s: %s", client.UserID(), e.Channel, string(e.Data))
if !client.IsSubscribed(e.Channel) {
cb(centrifuge.PublishReply{}, centrifuge.ErrorPermissionDenied)
return
}
var msg clientMessage
err := json.Unmarshal(e.Data, &msg)
if err != nil {
cb(centrifuge.PublishReply{}, centrifuge.ErrorBadRequest)
return
}
msg.Timestamp = time.Now().Unix()
data, _ := json.Marshal(msg)
result, err := node.Publish(
e.Channel, data,
centrifuge.WithHistory(historySize, historyTTL),
centrifuge.WithClientInfo(e.ClientInfo),
)
cb(centrifuge.PublishReply{Result: &result}, err)
})
client.OnDisconnect(func(e centrifuge.DisconnectEvent) {
log.Printf("user %s disconnected, disconnect: %s", client.UserID(), e.Disconnect)
})
})
if err := node.Run(); err != nil {
log.Fatal(err)
}
go func() {
// Publish to channel periodically.
i := 1
for {
time.Sleep(200 * time.Millisecond)
_, err := node.Publish(
"chat:index",
[]byte(`{"input": "Publish from server `+strconv.Itoa(i)+`"}`),
centrifuge.WithHistory(historySize, historyTTL),
)
if err != nil {
log.Printf("error publishing to personal channel: %s", err)
}
i++
}
}()
websocketHandler := centrifuge.NewWebsocketHandler(node, centrifuge.WebsocketConfig{
ReadBufferSize: 1024,
UseWriteBufferPool: true,
})
http.Handle("/connection/websocket", authMiddleware(websocketHandler))
http.Handle("/", http.FileServer(http.Dir("./")))
go func() {
if err := http.ListenAndServe(":8000", nil); err != nil {
log.Fatal(err)
}
}()
waitExitSignal(node)
log.Println("bye!")
}
|
