Initial scaffolding from plume.chat

README.md

@@ -1,2 +1,21 @@
 # draw
-Real-time collaborative whiteboard on the web
+
+draw is a tiny in-memory collaborative whiteboard. It's built on...
+
+- [Gorilla WebSocket](https://github.com/gorilla/websocket) for initiating and managing WebSocket connections
+- [Torus](https://github.com/thesephist/torus) as a light frontend UI library
+- My own [blocks.css](https://thesephist.github.io/blocks.css/) to add some spice to the UI design
+
+## Deploy
+
+Deployment is managed by systemd. Copy the `draw.service` file to `/etc/systemd/system/draw.service` and update:
+
+- replace `draw-user` with your Linux user
+- replace `/home/draw-user/draw` with your working directory (path to repository or a copy of `static/`)
+
+Then start draw as a service:
+
+```sh
+systemctl daemon-reload # reload systemd script
+systemctl start draw   # start draw server as a service
+```

cmd/draw.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/thesephist/draw/pkg/draw"
+)
+
+func main() {
+	fmt.Println("Starting draw server...")
+
+	draw.StartServer()
+}

cmd/plume.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/thesephist/draw/pkg/draw"
+)
+
+func main() {
+	fmt.Println("Starting draw server...")
+
+	draw.StartServer()
+}

draw.service

@@ -0,0 +1,28 @@
+[Unit]
+Description=draw server
+ConditionPathExists=/home/draw-user/draw/draw
+After=network.target
+
+[Service]
+Type=simple
+User=draw-user
+LimitNOFILE=256
+
+Restart=on-failure
+RestartSec=10
+StartLimitIntervalSec=60
+
+WorkingDirectory=/home/draw-user/draw/
+ExecStart=/home/draw-user/draw/draw
+
+# make sure log directory exists and owned by syslog
+PermissionsStartOnly=true
+ExecStartPre=/bin/mkdir -p /var/log/draw
+ExecStartPre=/bin/chown syslog:adm /var/log/draw
+ExecStartPre=/bin/chmod 755 /var/log/draw
+StandardOutput=syslog
+StandardError=syslog
+SyslogIdentifier=draw
+
+[Install]
+WantedBy=multi-user.target

go.mod

@@ -0,0 +1,11 @@
+module github.com/thesephist/plume
+
+go 1.13
+
+require (
+	github.com/google/uuid v1.1.1 // indirect
+	github.com/gorilla/mux v1.7.3
+	github.com/gorilla/websocket v1.4.1
+	github.com/mailgun/mailgun-go/v3 v3.6.3 // indirect
+	golang.org/x/time v0.0.0-20191024005414-555d28b269f0
+)

go.sum

@@ -0,0 +1,24 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/facebookgo/ensure v0.0.0-20160127193407-b4ab57deab51 h1:0JZ+dUmQeA8IIVUMzysrX4/AKuQwWhV2dYQuPZdvdSQ=
+github.com/facebookgo/ensure v0.0.0-20160127193407-b4ab57deab51/go.mod h1:Yg+htXGokKKdzcwhuNDwVvN+uBxDGXJ7G/VN1d8fa64=
+github.com/facebookgo/stack v0.0.0-20160209184415-751773369052 h1:JWuenKqqX8nojtoVVWjGfOF9635RETekkoH6Cc9SX0A=
+github.com/facebookgo/stack v0.0.0-20160209184415-751773369052/go.mod h1:UbMTZqLaRiH3MsBH8va0n7s1pQYcu3uTb8G4tygF4Zg=
+github.com/facebookgo/subset v0.0.0-20150612182917-8dac2c3c4870 h1:E2s37DuLxFhQDg5gKsWoLBOB0n+ZW8s599zru8FJ2/Y=
+github.com/facebookgo/subset v0.0.0-20150612182917-8dac2c3c4870/go.mod h1:5tD+neXqOorC30/tWg0LCSkrqj/AR6gu8yY8/fpw1q0=
+github.com/go-chi/chi v4.0.0+incompatible h1:SiLLEDyAkqNnw+T/uDTf3aFB9T4FTrwMpuYrgaRcnW4=
+github.com/go-chi/chi v4.0.0+incompatible/go.mod h1:eB3wogJHnLi3x/kFX2A+IbTBlXxmMeXJVKy9tTv1XzQ=
+github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
+github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/mux v1.7.3 h1:gnP5JzjVOuiZD07fKKToCAOjS0yOpj/qPETTXCCS6hw=
+github.com/gorilla/mux v1.7.3/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
+github.com/gorilla/websocket v1.4.1 h1:q7AeDBpnBk8AogcD4DSag/Ukw/KV+YhzLj2bP5HvKCM=
+github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/mailgun/mailgun-go/v3 v3.6.3 h1:dkPP10w15Igt0uM313CStG9+gd/XqdiqO0862zNAXbs=
+github.com/mailgun/mailgun-go/v3 v3.6.3/go.mod h1:ZjVnH8S0dR2BLjvkZc/rxwerdcirzlA12LQDuGAadR0=
+github.com/mailru/easyjson v0.0.0-20180823135443-60711f1a8329 h1:2gxZ0XQIU/5z3Z3bUBu+FXuk2pFbkN6tcwi/pjyaDic=
+github.com/mailru/easyjson v0.0.0-20180823135443-60711f1a8329/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+golang.org/x/time v0.0.0-20191024005414-555d28b269f0 h1:/5xXl8Y5W96D+TtHSlonuFqGHIWVuyCkGJLwGh9JJFs=
+golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=

pkg/draw/client.go

@@ -0,0 +1,56 @@
+package draw
+
+// Client represents an abstract client of a chat room
+type Client struct {
+	User      User
+	Room      *Room
+	OnMessage func(Message)
+
+	receiver chan Message
+}
+
+// Send sends a new message to the room to which the client
+// cl belongs, under the client user's name.
+func (cl *Client) Send(text string) error {
+	if cl.Room == nil {
+		return Error{"client is not in a room yet"}
+	}
+
+	cl.Room.Broadcast(Message{
+		Type: msgText,
+		User: cl.User,
+		Text: text,
+	})
+
+	return nil
+}
+
+// Leave lets the client leave the room and cleans up.
+func (cl *Client) Leave() error {
+	if cl.Room == nil {
+		return Error{"client is not in a room yet"}
+	}
+
+	delete(cl.Room.clientReceivers, cl)
+	close(cl.receiver)
+	cl.Room = nil
+
+	return nil
+}
+
+// StartListening enters an indefinite loop listening
+// for new messages for the client and responds with cl.OnMessage.
+func (cl *Client) StartListening() {
+	for {
+		msg, open := <-cl.receiver
+		if !open {
+			return
+		}
+
+		if cl.OnMessage == nil {
+			continue
+		}
+
+		cl.OnMessage(msg)
+	}
+}

pkg/draw/err.go

@@ -0,0 +1,11 @@
+package draw
+
+// Error represents any error originating
+// from unexpected states in the draw server.
+type Error struct {
+	reason string
+}
+
+func (err Error) Error() string {
+	return err.reason
+}

pkg/draw/message.go

@@ -0,0 +1,30 @@
+package draw
+
+const (
+	// msgHello is used to first connect and request authentication
+	msgHello = iota
+	// msgText is used for all normal text messages
+	msgText
+
+	// msgAuth represents an attempt to authenticate with a token
+	msgAuth
+	// msgAuthAck is sent by the server to approve authentication attempt
+	msgAuthAck
+	// msgAuthRst is sent by the server to reject authentication attemp
+	msgAuthRst
+
+	// msgMayNotEnter is sent by the server to reject entry attempt, usually
+	// means the username is taken
+	msgMayNotEnter
+
+	// In the future, we can support things like presence
+	// by using additional codes like MsgTypingStart/Stop
+)
+
+// Message represents any atomic communication between a draw client
+// and server.
+type Message struct {
+	Type int    `json:"type"`
+	User User   `json:"user"`
+	Text string `json:"text"`
+}

pkg/draw/room.go

@@ -0,0 +1,61 @@
+package draw
+
+import (
+	"strings"
+)
+
+// Room represents a collection of draw clients all
+// sending each other messages.
+type Room struct {
+	Sender chan<- Message
+	// map of usernames to emails
+	verifiedNames   map[string]string
+	clientReceivers map[*Client]chan Message
+}
+
+// NewRoom allocates, creates, and returns a new Room
+// ready to be used
+func NewRoom() *Room {
+	return &Room{
+		Sender:          make(chan Message),
+		verifiedNames:   make(map[string]string),
+		clientReceivers: make(map[*Client]chan Message),
+	}
+}
+
+// Enter creates a new Client for a given user ready
+// to be used
+func (rm *Room) Enter(u User) *Client {
+	receiver := make(chan Message)
+	client := Client{
+		User:     u,
+		Room:     rm,
+		receiver: receiver,
+	}
+
+	rm.verifiedNames[strings.ToLower(u.Name)] = u.Email
+	rm.clientReceivers[&client] = receiver
+	go client.StartListening()
+
+	return &client
+}
+
+// CanEnter reports whether a user should be allowed in a room.
+// A user may not enter a room if another user with a different email
+// but a matching username is already inside.
+func (rm *Room) CanEnter(u User) bool {
+	existingEmail, prs := rm.verifiedNames[strings.ToLower(u.Name)]
+	if prs {
+		return u.Email == existingEmail
+	}
+
+	return true
+}
+
+// Broadcast sends a new Message to every client
+// in the Room
+func (rm *Room) Broadcast(msg Message) {
+	for _, receiver := range rm.clientReceivers {
+		receiver <- msg
+	}
+}