Start cameradar server to communicate with GUI

server/adaptor/websocket/gorillaFactory.go

@@ -0,0 +1,132 @@
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package websocket
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/EtixLabs/cameradar/server/adaptor"
+
+	gorilla "github.com/gorilla/websocket"
+	"github.com/pkg/errors"
+)
+
+// GorillaFactory is a websocket Factory using Gorilla websocket client
+type GorillaFactory struct {
+	readLimit           int64
+	pingInterval        time.Duration
+	pongWait            time.Duration
+	writeChanBufferSize uint
+	upgrader            gorilla.Upgrader
+}
+
+// NewGorillaFactory instantiates and returns a Gorilla Factory
+func NewGorillaFactory(options ...func(*GorillaFactory)) *GorillaFactory {
+	gf := &GorillaFactory{
+		// readLimit: default to 1MB
+		readLimit:    1024 * 1024,
+		pingInterval: 5 * time.Second,
+		pongWait:     10 * time.Second,
+
+		// allow about 1 frame per grid cell to be buffered (grids contain about ~16 cameras)
+		// NOTE: this should be about the same size as the number of subcriptions the client has
+		writeChanBufferSize: 20,
+
+		// default upgrader: don't check requests origin
+		upgrader: gorilla.Upgrader{
+			CheckOrigin: func(r *http.Request) bool { return true },
+		},
+	}
+	// apply the options to the struct
+	for _, option := range options {
+		option(gf)
+	}
+	return gf
+}
+
+// NewIncomingWebSocket instantiates a Gorilla websocket from an http incoming connection
+func (gf *GorillaFactory) NewIncomingWebSocket(w http.ResponseWriter, req *http.Request) (adaptor.WebSocket, error) {
+	fmt.Printf("new ws connection from %v\n", req.RemoteAddr)
+
+	// create WS connection
+	conn, err := gf.upgrader.Upgrade(w, req, nil)
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot upgrade ws connection")
+	}
+
+	g := &Gorilla{
+		conn:        conn,
+		accessToken: req.Header.Get("Sec-WebSocket-Protocol"),
+
+		input:  make(chan interface{}),
+		output: make(chan interface{}, gf.writeChanBufferSize),
+	}
+
+	go g.pingAndWrite(gf.pingInterval)
+	go g.read(gf.readLimit, gf.pongWait)
+
+	return g, nil
+}
+
+// NewWebSocket attemps to connect to a ws server using Gorilla library
+func (gf *GorillaFactory) NewWebSocket(url string) (adaptor.WebSocket, error) {
+	fmt.Printf("opening new ws connection to %v\n", url)
+
+	// create WS connection
+	conn, _, err := gorilla.DefaultDialer.Dial(url, nil)
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot open ws connection")
+	}
+
+	g := &Gorilla{
+		conn: conn,
+
+		input:  make(chan interface{}),
+		output: make(chan interface{}, gf.writeChanBufferSize),
+	}
+
+	go g.pingAndWrite(gf.pingInterval)
+	go g.read(gf.readLimit, gf.pongWait)
+
+	return g, nil
+}
+
+// SetReadLimit sets the maximum size read from an incoming message
+func SetReadLimit(limit int64) func(gf *GorillaFactory) {
+	return func(gf *GorillaFactory) {
+		gf.readLimit = limit
+	}
+}
+
+// SetPingInterval sets the interval between pings
+func SetPingInterval(interval time.Duration) func(gf *GorillaFactory) {
+	return func(gf *GorillaFactory) {
+		gf.pingInterval = interval
+	}
+}
+
+// SetPongWait sets the time before read should timeout if no pong is received
+func SetPongWait(pongWait time.Duration) func(gf *GorillaFactory) {
+	return func(gf *GorillaFactory) {
+		gf.pongWait = pongWait
+	}
+}
+
+// SetWriteChanBufferSize sets the buffer size of the write channel
+func SetWriteChanBufferSize(size uint) func(gf *GorillaFactory) {
+	return func(gf *GorillaFactory) {
+		gf.writeChanBufferSize = size
+	}
+}