Base64 encode SVG's too, to avoid things like '%' breaking.

README.md

@@ -1,2 +1,65 @@
+# Stream Deck plugin library for Go
+
 [![Go Reference](https://pkg.go.dev/badge/github.com/tardisx/streamdeck-plugin.svg)](https://pkg.go.dev/github.com/tardisx/streamdeck-plugin)
 
+You can find fully-formed examples using this library in
+[streamdeck-plugin-examples](https://github.com/tardisx/streamdeck-plugin-examples)
+
+## Basic usage
+
+```go
+package main
+
+import (
+	"fmt"
+	"log/slog"
+	"time"
+
+	"github.com/tardisx/streamdeck-plugin"
+	"github.com/tardisx/streamdeck-plugin/events"
+)
+
+// keep track of instances we've seen
+var contexts = map[string]bool{}
+
+func main() {
+	slog.Info("Starting up")
+	c := streamdeck.New()
+
+	slog.Info("Registering handlers")
+	c.RegisterHandler(func(e events.ERWillAppear) {
+		slog.Info(fmt.Sprintf("action %s appeared, context %s", e.Action, e.Context))
+		contexts[e.Context] = true
+	})
+	c.RegisterHandler(func(e events.ERWillDisappear) {
+		slog.Info(fmt.Sprintf("action %s disappeared, context %s", e.Action, e.Context))
+		delete(contexts, e.Context)
+	})
+	c.RegisterHandler(func(e events.ERKeyDown) {
+		slog.Info(fmt.Sprintf("action %s appeared, context %s", e.Action, e.Context))
+	})
+
+	slog.Info("Connecting web socket")
+	err := c.Connect()
+	if err != nil {
+		panic(err)
+	}
+
+	// update the title once a second, for all "seen" contexts
+	go func() {
+		for {
+			for context := range contexts {
+				c.Send(events.NewESSetTitle(
+					context,
+					time.Now().Format(time.Kitchen),
+					events.EventTargetBoth,
+					0))
+			}
+			time.Sleep(time.Second)
+		}
+	}()
+
+	slog.Info("waiting for the end")
+	c.WaitForPluginExit()
+}
+```

events/events_received.go

@@ -1,10 +1,27 @@
-package streamdeck
+package events
 
 import (
 	"encoding/json"
 	"reflect"
 )
 
+// ValidEventType returns a boolean indicating whether or not
+// this is a valid event type
+func ValidEventType(t reflect.Type) bool {
+	for i := range receivedEventTypeMap {
+		if receivedEventTypeMap[i] == t {
+			return true
+		}
+	}
+	return false
+}
+
+// TypeForEvent returns the type for a particular event type string
+func TypeForEvent(e string) (reflect.Type, bool) {
+	t, ok := receivedEventTypeMap[e]
+	return t, ok
+}
+
 var receivedEventTypeMap = map[string]reflect.Type{}
 
 func init() {

events/events_send.go

@@ -1,26 +1,22 @@
-package streamdeck
+package events
 
 import (
-	"bytes"
-	"encoding/base64"
 	"encoding/json"
-	"image"
-	"image/png"
 )
 
 type EventTarget int
 
-const EventTargetBoth = 0
+const EventTargetBoth = EventTarget(0)
-const EventTargetHardware = 1
+const EventTargetHardware = EventTarget(1)
-const EventTargetSoftware = 2
+const EventTargetSoftware = EventTarget(2)
 
 type ESCommon struct {
-	Event   string `json:"event"`
+	Event   string `json:"event"`   // name of this event type
-	Context string `json:"context"`
+	Context string `json:"context"` // A value to Identify the instance's action or Property Inspector. This value is received by the Property Inspector as a parameter of the connectElgatoStreamDeckSocket function.
 }
 
 type ESCommonNoContext struct {
-	Event string `json:"event"`
+	Event string `json:"event"` // name of this event type
 }
 
 type ESOpenMessage struct {
@@ -162,12 +158,12 @@ type ESSetImage struct {
 }
 
 type ESSetImagePayload struct {
-	Image  string      `json:"title"`
+	Image  string      `json:"image"`
 	Target EventTarget `json:"target"`
-	State  int         `json:"state"`
+	State  *int        `json:"state,omitempty"`
 }
 
-func NewESSetImagePayload(context string, imageBase64 string, target EventTarget, state int) ESSetImage {
+func NewESSetImage(context string, imageBase64 string, target EventTarget, state *int) ESSetImage {
 	return ESSetImage{
 		ESCommon: ESCommon{
 			Event:   "setImage",
@@ -286,13 +282,13 @@ type ESSetStatePayload struct {
 	State int `json:"state"`
 }
 
-func NewESSetState(context string, state int) ESSetImage {
+func NewESSetState(context string, state int) ESSetState {
-	return ESSetImage{
+	return ESSetState{
 		ESCommon: ESCommon{
 			Event:   "setState",
 			Context: context,
 		},
-		Payload: ESSetImagePayload{
+		Payload: ESSetStatePayload{
 			State: state,
 		},
 	}
@@ -362,24 +358,3 @@ func NewESSendToPlugin(context string, action string, payload json.RawMessage) E
 		Payload: payload,
 	}
 }
-
-/// --------- helpers ----------
-
-// Turns an image.Image into a string suitable for delivering
-// via a ESSetImage struct
-func ImageToPayload(i image.Image) string {
-
-	out := bytes.Buffer{}
-	b64 := base64.NewEncoder(base64.RawStdEncoding, &out)
-	err := png.Encode(b64, i)
-	if err != nil {
-		panic(err)
-	}
-	return "data:image/png;base64," + out.String()
-}
-
-// Turns an image.Image into a string suitable for delivering
-// via a ESSetImage struct
-func SVGToPayload(context string, svg string) string {
-	return "data:image/svg+xml;charset=utf8," + svg
-}

streamdeck.go

@@ -1,3 +1,5 @@
+// Package streamdeck interfaces with the Stream Deck plugin API,
+// allowing you to create go-based plugins for the platform.
 package streamdeck
 
 import (
@@ -8,21 +10,16 @@ import (
 	"io"
 	"reflect"
 
+	"github.com/tardisx/streamdeck-plugin/events"
+
 	"github.com/gorilla/websocket"
 )
 
+// these are automatically populated by parseFlags
 var flagPort int
 var flagEvent, flagInfo string
 var UUID string // the UUID this plugin is assigned
 
-func init() {
-	flag.IntVar(&flagPort, "port", 0, "streamdeck sdk port")
-	flag.StringVar(&flagEvent, "registerEvent", "", "streamdeck sdk register event")
-	flag.StringVar(&flagInfo, "info", "", "streamdeck application info")
-	flag.StringVar(&UUID, "pluginUUID", "", "uuid")
-	flag.Parse()
-}
-
 type logger interface {
 	Info(string, ...any)
 	Error(string, ...any)
@@ -35,11 +32,6 @@ func (nl nullLogger) Info(string, ...any)  {}
 func (nl nullLogger) Error(string, ...any) {}
 func (nl nullLogger) Debug(string, ...any) {}
 
-type EventHandler struct {
-	MsgType string
-	Handler func()
-}
-
 type Connection struct {
 	ws       *websocket.Conn
 	logger   logger
@@ -48,9 +40,7 @@ type Connection struct {
 }
 
 // New creates a new struct for communication with the streamdeck
-// plugin API. The command line flags required for the API to
+// plugin API. The websocket will not connect until Connect is called.
-// communicate with your plugin have already been parsed.
-// The websocket will not connect until Connect is called.
 func New() Connection {
 	return Connection{
 		handlers: make(map[reflect.Type]reflect.Value),
@@ -67,6 +57,16 @@ func NewWithLogger(l logger) Connection {
 	return c
 }
 
+// parseFlags parses the command line flags to get the values provided
+// by the Stream Deck plugin API.
+func parseFlags() {
+	flag.IntVar(&flagPort, "port", 0, "streamdeck sdk port")
+	flag.StringVar(&flagEvent, "registerEvent", "", "streamdeck sdk register event")
+	flag.StringVar(&flagInfo, "info", "", "streamdeck application info")
+	flag.StringVar(&UUID, "pluginUUID", "", "uuid")
+	flag.Parse()
+}
+
 // Connect connects the plugin to the Stream Deck API via the websocket.
 // Once connected, events will be passed to handlers you have registered.
 // Handlers should thus be registered via RegisterHandler before calling
@@ -75,14 +75,15 @@ func NewWithLogger(l logger) Connection {
 // then call WaitForPluginExit to block until the connection is closed.
 func (conn *Connection) Connect() error {
 
+	parseFlags()
 	c, _, err := websocket.DefaultDialer.Dial(fmt.Sprintf("ws://localhost:%d", flagPort), nil)
 	if err != nil {
 		return err
 	}
 
 	conn.ws = c
-	msg := ESOpenMessage{
+	msg := events.ESOpenMessage{
-		ESCommonNoContext: ESCommonNoContext{
+		ESCommonNoContext: events.ESCommonNoContext{
 			Event: flagEvent,
 		},
 		UUID: UUID,
@@ -103,8 +104,8 @@ func (conn *Connection) Connect() error {
 
 // WaitForPluginExit waits until the Stream Deck API closes
 // the websocket connection.
-func (c *Connection) WaitForPluginExit() {
+func (conn *Connection) WaitForPluginExit() {
-	<-c.done
+	<-conn.done
 }
 
 // RegisterHandler registers a function to be called for a particular event. The
@@ -114,7 +115,7 @@ func (c *Connection) WaitForPluginExit() {
 // function per event type. This function will panic if the wrong kind of
 // function is passed in, or if you try to register more than one for a single
 // event type.
-func (r *Connection) RegisterHandler(handler any) {
+func (conn *Connection) RegisterHandler(handler any) {
 	hType := reflect.TypeOf(handler)
 	if hType.Kind() != reflect.Func {
 		panic("handler must be a function")
@@ -127,27 +128,20 @@ func (r *Connection) RegisterHandler(handler any) {
 	argType := hType.In(0)
 
 	// check its a valid one (one that matches an event type)
-	valid := false
+	if !events.ValidEventType(argType) {
-	for i := range receivedEventTypeMap {
-		if receivedEventTypeMap[i] == argType {
-			valid = true
-			break
-		}
-	}
-	if !valid {
 		panic("you cannot register a handler with this argument type")
 	}
 
-	_, alreadyExists := r.handlers[argType]
+	_, alreadyExists := conn.handlers[argType]
 	if alreadyExists {
 		panic("handler for " + argType.Name() + " already exists")
 	}
 
-	r.handlers[argType] = reflect.ValueOf(handler)
+	conn.handlers[argType] = reflect.ValueOf(handler)
 }
 
 // Send sends a message to the API. It should be one of the
-// ES* structs, such as ESOpenURL.
+// events.ES* structs, such as events.ESOpenURL.
 func (conn *Connection) Send(e any) error {
 	b, _ := json.Marshal(e)
 	conn.logger.Debug(fmt.Sprintf("sending: %s", string(b)))
@@ -185,14 +179,14 @@ func (conn *Connection) reader() {
 
 		b := bytes.Buffer{}
 		r = io.TeeReader(r, &b)
-		base := ERBase{}
+		base := events.ERBase{}
 		err = json.NewDecoder(r).Decode(&base)
 		if err != nil {
 			conn.logger.Error("cannot decode: " + err.Error())
 			continue
 		}
 
-		t, ok := receivedEventTypeMap[base.Event]
+		t, ok := events.TypeForEvent(base.Event)
 		if !ok {
 			conn.logger.Error(fmt.Sprintf("no type registered for event '%s'", base.Event))
 			continue

streamdesk_test.go

@@ -2,6 +2,8 @@ package streamdeck
 
 import (
 	"testing"
+
+	"github.com/tardisx/streamdeck-plugin/events"
 )
 
 type testLogger struct {
@@ -16,10 +18,10 @@ func TestReflection(t *testing.T) {
 
 	c := NewWithLogger(testLogger{t: t})
 	// incoming
-	in := ERDidReceiveSettingsPayload{}
+	in := events.ERDidReceiveSettingsPayload{}
 
 	ranHandler := false
-	c.RegisterHandler(func(event ERDidReceiveSettingsPayload) {
+	c.RegisterHandler(func(event events.ERDidReceiveSettingsPayload) {
 		ranHandler = true
 	})
 
@@ -52,13 +54,14 @@ func TestUmmarshal(t *testing.T) {
 }`)
 
 	c := NewWithLogger(testLogger{t: t})
-	keyUp, err := c.unmarshalToConcrete(receivedEventTypeMap["keyUp"], b)
+	e, _ := events.TypeForEvent("keyUp")
+	keyUp, err := c.unmarshalToConcrete(e, b)
 
 	if err != nil {
 		t.Error(err)
 	}
 
-	realKeyUp, ok := keyUp.(ERKeyUp)
+	realKeyUp, ok := keyUp.(events.ERKeyUp)
 	if !ok {
 		t.Errorf("wrong type (is %T)", keyUp)
 	}

tools/tools.go

@@ -0,0 +1,29 @@
+// Package tools provides some helper functions to assist with
+// creating Stream Deck plugins
+package tools
+
+import (
+	"bytes"
+	"encoding/base64"
+	"image"
+	"image/png"
+)
+
+// Turns an image.Image into a string suitable for delivering
+// via an events.ESSetImage struct
+func ImageToPayload(i image.Image) string {
+
+	out := bytes.Buffer{}
+	b64 := base64.NewEncoder(base64.RawStdEncoding, &out)
+	err := png.Encode(b64, i)
+	if err != nil {
+		panic(err)
+	}
+	return "data:image/png;base64," + out.String()
+}
+
+// SVGToPayload create the string necessary to send an SVG
+// via a ESSetImage struct
+func SVGToPayload(svg string) string {
+	return "data:image/svg+xml;charset=utf8;base64," + base64.StdEncoding.EncodeToString([]byte(svg))
+}