/
broker.go
268 lines (226 loc) · 4.6 KB
/
broker.go
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// Package broker provides a go-micro/broker handler
package broker
import (
"encoding/json"
"io/ioutil"
"net/http"
"net/url"
"strings"
"sync"
"time"
"github.com/gorilla/websocket"
"github.com/micro/go-micro/api/handler"
"github.com/micro/go-micro/broker"
"github.com/micro/go-micro/util/log"
)
const (
Handler = "broker"
pingTime = (readDeadline * 9) / 10
readLimit = 16384
readDeadline = 60 * time.Second
writeDeadline = 10 * time.Second
)
type brokerHandler struct {
opts handler.Options
u websocket.Upgrader
}
type conn struct {
b broker.Broker
cType string
topic string
queue string
exit chan bool
sync.Mutex
ws *websocket.Conn
}
var (
once sync.Once
contentType = "text/plain"
)
func checkOrigin(r *http.Request) bool {
origin := r.Header["Origin"]
if len(origin) == 0 {
return true
}
u, err := url.Parse(origin[0])
if err != nil {
return false
}
return u.Host == r.Host
}
func (c *conn) close() {
select {
case <-c.exit:
return
default:
close(c.exit)
}
}
func (c *conn) readLoop() {
defer func() {
c.close()
c.ws.Close()
}()
// set read limit/deadline
c.ws.SetReadLimit(readLimit)
c.ws.SetReadDeadline(time.Now().Add(readDeadline))
// set close handler
ch := c.ws.CloseHandler()
c.ws.SetCloseHandler(func(code int, text string) error {
err := ch(code, text)
c.close()
return err
})
// set pong handler
c.ws.SetPongHandler(func(string) error {
c.ws.SetReadDeadline(time.Now().Add(readDeadline))
return nil
})
for {
_, message, err := c.ws.ReadMessage()
if err != nil {
return
}
c.b.Publish(c.topic, &broker.Message{
Header: map[string]string{"Content-Type": c.cType},
Body: message,
})
}
}
func (c *conn) write(mType int, data []byte) error {
c.Lock()
c.ws.SetWriteDeadline(time.Now().Add(writeDeadline))
err := c.ws.WriteMessage(mType, data)
c.Unlock()
return err
}
func (c *conn) writeLoop() {
ticker := time.NewTicker(pingTime)
var opts []broker.SubscribeOption
if len(c.queue) > 0 {
opts = append(opts, broker.Queue(c.queue))
}
subscriber, err := c.b.Subscribe(c.topic, func(p broker.Event) error {
b, err := json.Marshal(p.Message())
if err != nil {
return nil
}
return c.write(websocket.TextMessage, b)
}, opts...)
defer func() {
subscriber.Unsubscribe()
ticker.Stop()
c.ws.Close()
}()
if err != nil {
log.Log(err.Error())
return
}
for {
select {
case <-ticker.C:
if err := c.write(websocket.PingMessage, []byte{}); err != nil {
return
}
case <-c.exit:
return
}
}
}
func (b *brokerHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
br := b.opts.Service.Client().Options().Broker
// Setup the broker
once.Do(func() {
br.Init()
br.Connect()
})
// Parse
r.ParseForm()
topic := r.Form.Get("topic")
// Can't do anything without a topic
if len(topic) == 0 {
http.Error(w, "Topic not specified", 400)
return
}
// Post assumed to be Publish
if r.Method == "POST" {
// Create a broker message
msg := &broker.Message{
Header: make(map[string]string),
}
// Set header
for k, v := range r.Header {
msg.Header[k] = strings.Join(v, ", ")
}
// Read body
b, err := ioutil.ReadAll(r.Body)
if err != nil {
http.Error(w, err.Error(), 500)
return
}
// Set body
msg.Body = b
// Publish
br.Publish(topic, msg)
return
}
// now back to our regularly scheduled programming
if r.Method != "GET" {
http.Error(w, "Method not allowed", 405)
return
}
queue := r.Form.Get("queue")
ws, err := b.u.Upgrade(w, r, nil)
if err != nil {
log.Log(err.Error())
return
}
cType := r.Header.Get("Content-Type")
if len(cType) == 0 {
cType = contentType
}
c := &conn{
b: br,
cType: cType,
topic: topic,
queue: queue,
exit: make(chan bool),
ws: ws,
}
go c.writeLoop()
c.readLoop()
}
func (b *brokerHandler) String() string {
return "broker"
}
func NewHandler(opts ...handler.Option) handler.Handler {
return &brokerHandler{
u: websocket.Upgrader{
CheckOrigin: func(r *http.Request) bool {
return true
},
ReadBufferSize: 1024,
WriteBufferSize: 1024,
},
opts: handler.NewOptions(opts...),
}
}
func WithCors(cors map[string]bool, opts ...handler.Option) handler.Handler {
return &brokerHandler{
u: websocket.Upgrader{
CheckOrigin: func(r *http.Request) bool {
if origin := r.Header.Get("Origin"); cors[origin] {
return true
} else if len(origin) > 0 && cors["*"] {
return true
} else if checkOrigin(r) {
return true
}
return false
},
ReadBufferSize: 1024,
WriteBufferSize: 1024,
},
opts: handler.NewOptions(opts...),
}
}