Replace gorilla with melody for websocket API (#1205)

vendor/gopkg.in/olahol/melody.v1/README.md

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+# melody
+
+[![Build Status](https://travis-ci.org/olahol/melody.svg)](https://travis-ci.org/olahol/melody)
+[![Coverage Status](https://img.shields.io/coveralls/olahol/melody.svg?style=flat)](https://coveralls.io/r/olahol/melody)
+[![GoDoc](https://godoc.org/github.com/olahol/melody?status.svg)](https://godoc.org/github.com/olahol/melody)
+
+> :notes: Minimalist websocket framework for Go.
+
+Melody is websocket framework based on [github.com/gorilla/websocket](https://github.com/gorilla/websocket)
+that abstracts away the tedious parts of handling websockets. It gets out of
+your way so you can write real-time apps. Features include:
+
+* [x] Clear and easy interface similar to `net/http` or Gin.
+* [x] A simple way to broadcast to all or selected connected sessions.
+* [x] Message buffers making concurrent writing safe.
+* [x] Automatic handling of ping/pong and session timeouts.
+* [x] Store data on sessions.
+
+## Install
+
+```bash
+go get gopkg.in/olahol/melody.v1
+```
+
+## [Example: chat](https://github.com/olahol/melody/tree/master/examples/chat)
+
+[![Chat](https://cdn.rawgit.com/olahol/melody/master/examples/chat/demo.gif "Demo")](https://github.com/olahol/melody/tree/master/examples/chat)
+
+Using [Gin](https://github.com/gin-gonic/gin):
+```go
+package main
+
+import (
+	"github.com/gin-gonic/gin"
+	"gopkg.in/olahol/melody.v1"
+	"net/http"
+)
+
+func main() {
+	r := gin.Default()
+	m := melody.New()
+
+	r.GET("/", func(c *gin.Context) {
+		http.ServeFile(c.Writer, c.Request, "index.html")
+	})
+
+	r.GET("/ws", func(c *gin.Context) {
+		m.HandleRequest(c.Writer, c.Request)
+	})
+
+	m.HandleMessage(func(s *melody.Session, msg []byte) {
+		m.Broadcast(msg)
+	})
+
+	r.Run(":5000")
+}
+```
+
+Using [Echo](https://github.com/labstack/echo):
+```go
+package main
+
+import (
+	"github.com/labstack/echo"
+	"github.com/labstack/echo/engine/standard"
+	"github.com/labstack/echo/middleware"
+	"gopkg.in/olahol/melody.v1"
+	"net/http"
+)
+
+func main() {
+	e := echo.New()
+	m := melody.New()
+
+	e.Use(middleware.Logger())
+	e.Use(middleware.Recover())
+
+	e.GET("/", func(c echo.Context) error {
+		http.ServeFile(c.Response().(*standard.Response).ResponseWriter, c.Request().(*standard.Request).Request, "index.html")
+		return nil
+	})
+
+	e.GET("/ws", func(c echo.Context) error {
+		m.HandleRequest(c.Response().(*standard.Response).ResponseWriter, c.Request().(*standard.Request).Request)
+		return nil
+	})
+
+	m.HandleMessage(func(s *melody.Session, msg []byte) {
+		m.Broadcast(msg)
+	})
+
+	e.Run(standard.New(":5000"))
+}
+```
+
+## [Example: gophers](https://github.com/olahol/melody/tree/master/examples/gophers)
+
+[![Gophers](https://cdn.rawgit.com/olahol/melody/master/examples/gophers/demo.gif "Demo")](https://github.com/olahol/melody/tree/master/examples/gophers)
+
+```go
+package main
+
+import (
+	"github.com/gin-gonic/gin"
+	"gopkg.in/olahol/melody.v1"
+	"net/http"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+type GopherInfo struct {
+	ID, X, Y string
+}
+
+func main() {
+	router := gin.Default()
+	mrouter := melody.New()
+	gophers := make(map[*melody.Session]*GopherInfo)
+	lock := new(sync.Mutex)
+	counter := 0
+
+	router.GET("/", func(c *gin.Context) {
+		http.ServeFile(c.Writer, c.Request, "index.html")
+	})
+
+	router.GET("/ws", func(c *gin.Context) {
+		mrouter.HandleRequest(c.Writer, c.Request)
+	})
+
+	mrouter.HandleConnect(func(s *melody.Session) {
+		lock.Lock()
+		for _, info := range gophers {
+			s.Write([]byte("set " + info.ID + " " + info.X + " " + info.Y))
+		}
+		gophers[s] = &GopherInfo{strconv.Itoa(counter), "0", "0"}
+		s.Write([]byte("iam " + gophers[s].ID))
+		counter += 1
+		lock.Unlock()
+	})
+
+	mrouter.HandleDisconnect(func(s *melody.Session) {
+		lock.Lock()
+		mrouter.BroadcastOthers([]byte("dis "+gophers[s].ID), s)
+		delete(gophers, s)
+		lock.Unlock()
+	})
+
+	mrouter.HandleMessage(func(s *melody.Session, msg []byte) {
+		p := strings.Split(string(msg), " ")
+		lock.Lock()
+		info := gophers[s]
+		if len(p) == 2 {
+			info.X = p[0]
+			info.Y = p[1]
+			mrouter.BroadcastOthers([]byte("set "+info.ID+" "+info.X+" "+info.Y), s)
+		}
+		lock.Unlock()
+	})
+
+	router.Run(":5000")
+}
+```
+
+### [More examples](https://github.com/olahol/melody/tree/master/examples)
+
+## [Documentation](https://godoc.org/github.com/olahol/melody)
+
+## Contributors
+
+* Ola Holmström (@olahol)
+* Shogo Iwano (@shiwano)
+* Matt Caldwell (@mattcaldwell)
+* Heikki Uljas (@huljas)
+* Robbie Trencheny (@robbiet480)
+* yangjinecho (@yangjinecho)
+
+## FAQ
+
+If you are getting a `403` when trying  to connect to your websocket you can [change allow all origin hosts](http://godoc.org/github.com/gorilla/websocket#hdr-Origin_Considerations):
+
+```go
+m := melody.New()
+m.Upgrader.CheckOrigin = func(r *http.Request) bool { return true }
+```