clipper/backend/server/server.go

package server

import (
	"math/rand"
	"sync"
	"time"

	"github.com/gorilla/websocket"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
)

type Options struct {
	BindAddr string
	Timeout  time.Duration
}

type messageSinkStore struct {
	sinks map[*websocket.Conn]*MessageSink
	mu    sync.Mutex
}

func (ss *messageSinkStore) Put(conn *websocket.Conn, s *MessageSink) {
	ss.mu.Lock()
	defer ss.mu.Unlock()

	ss.sinks[conn] = s
}

func (ss *messageSinkStore) Get(conn *websocket.Conn) (*MessageSink, bool) {
	ss.mu.Lock()
	defer ss.mu.Unlock()

	s, ok := ss.sinks[conn]
	return s, ok
}

var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")

func randSeq(n int) string {
	b := make([]rune, n)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}
	return string(b)
}

func Start(opts Options) error {
	e := echo.New()
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	h := handler{
		messageSinks: &messageSinkStore{
			sinks: make(map[*websocket.Conn]*MessageSink),
		},
	}

	// websockets provide their own custom CORS handler, so don't add further
	// middleware here.
	e.GET("/api/websocket", h.upgradeWebsocket)

	api := e.Group("/api")
	api.Use(middleware.TimeoutWithConfig(middleware.TimeoutConfig{Timeout: opts.Timeout}))
	api.Use(middleware.CORSWithConfig(middleware.CORSConfig{
		AllowOrigins: []string{"http://localhost:3000"},
		AllowHeaders: []string{echo.HeaderOrigin, echo.HeaderContentType, echo.HeaderAccept},
	}))

	api.GET("/media_sets/:id", h.getMediaSet)
	api.GET("/media_sets/:id/peaks", h.getPeaks)
	api.GET("/media_sets/:id/thumbnails", h.getThumbnails)
	api.GET("/media_sets/:id/video", h.getVideo)

	return e.Start(opts.BindAddr)
}