initial commit

2025-07-20 17:11:22 +02:00 · 2024-01-13 14:55:03 +01:00
parent d1c918f43d
commit 87b90f8015
11 changed files with 743 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,2 @@
+.bin/
+./scratch-link4linux
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -0,0 +1,16 @@
+linters:
+  disable-all: true
+  # Enable specific linter
+  # https://golangci-lint.run/usage/linters/#enabled-by-default
+  enable:
+    - gofmt
+    - gosec
+    - govet
+    - goimports
+    - misspell
+    - unconvert
+    - unparam
+    - goconst
+    - gocritic
+    - gochecknoinits
+    - gochecknoinits
--- a/13
+++ b/13
@@ -0,0 +1,13 @@
+
+init:
+	go install golang.org/x/tools/cmd/goimports@v0.17.0
+	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b ./bin v1.55.2
+
+fmt:
+	goimports -w .
+
+test:
+	go test -v ./...
+
+lint:
+	./bin/golangci-lint run ./...
--- a/README.md
+++ b/README.md
@@ -0,0 +1,15 @@
+# Scratch-link for Linux
+
+>**Note:** This repositiory is in early stage and not all features are yet implemented.
+
+This project is a linux implementation of the [Scratch Link](https://github.com/scratchfoundation/scratch-link).
+
+## How to run
+
+Make sure [golang](https://go.dev/doc/install) is installed in you machine.
+
+Open a terminal navigate to the project directory, then run the following command:
+
+```bash
+go run .
+```
--- a/go.mod
+++ b/go.mod
@@ -0,0 +1,23 @@
+module github.com/lucarin91/scratch-link4linux
+
+go 1.21.0
+
+require (
+	github.com/google/uuid v1.5.0
+	github.com/rs/zerolog v1.31.0
+	golang.org/x/net v0.20.0
+	tinygo.org/x/bluetooth v0.8.0
+)
+
+require (
+	github.com/fatih/structs v1.1.0 // indirect
+	github.com/go-ole/go-ole v1.2.6 // indirect
+	github.com/godbus/dbus/v5 v5.1.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/muka/go-bluetooth v0.0.0-20221213043340-85dc80edc4e1 // indirect
+	github.com/saltosystems/winrt-go v0.0.0-20230921082907-2ab5b7d431e1 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/tinygo-org/cbgo v0.0.4 // indirect
+	golang.org/x/sys v0.16.0 // indirect
+)
--- a/go.sum
+++ b/go.sum
@@ -0,0 +1,87 @@
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
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+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/fatih/structs v1.1.0 h1:Q7juDM0QtcnhCpeyLGQKyg4TOIghuNXrkL32pHAUMxo=
+github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
+github.com/go-ole/go-ole v1.2.6 h1:/Fpf6oFPoeFik9ty7siob0G6Ke8QvQEuVcuChpwXzpY=
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+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
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--- a/jsonrpc/jsonrpc.go
+++ b/jsonrpc/jsonrpc.go
@@ -0,0 +1,145 @@
+/*
+Simple implementation of JSONRPC 2.0.
+*/
+package jsonrpc
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"sync/atomic"
+
+	"github.com/rs/zerolog/log"
+	"golang.org/x/net/websocket"
+)
+
+var MsgID int64 = 0
+
+type Msg struct {
+	ID      int64           `json:"id"`
+	Jsonrpc string          `json:"jsonrpc"`
+	Method  string          `json:"method"`
+	Params  json.RawMessage `json:"params"`
+}
+
+type Result struct {
+	ID       int64       `json:"id"`
+	Jsonrpc  string      `json:"jsonrpc"`
+	Result   interface{} `json:"result"`
+	Encoding string      `json:"encoding,omitempty"`
+}
+
+type Error struct {
+	ID      int64  `json:"id"`
+	Jsonrpc string `json:"jsonrpc"`
+	Error   string `json:"error"`
+}
+
+func NewMsg(method string, params interface{}) Msg {
+	buff, err := json.Marshal(params)
+	if err != nil {
+		panic(err)
+	}
+	return Msg{
+		ID:      atomic.AddInt64(&MsgID, 1),
+		Jsonrpc: "2.0",
+		Method:  method,
+		Params:  json.RawMessage(buff),
+	}
+}
+
+func (m Msg) RespondBytes(buf []byte) Result {
+	return Result{
+		ID:       m.ID,
+		Jsonrpc:  "2.0",
+		Encoding: "base64",
+		Result:   base64.StdEncoding.EncodeToString(buf),
+	}
+}
+
+func (m Msg) Respond(data interface{}) Result {
+	return Result{
+		ID:      m.ID,
+		Jsonrpc: "2.0",
+		Result:  data,
+	}
+}
+
+func (m Msg) Error(err string) Error {
+	return Error{
+		ID:      m.ID,
+		Jsonrpc: "2.0",
+		Error:   err,
+	}
+}
+
+func (m Msg) DebugParams() map[string]interface{} {
+	var out map[string]interface{}
+	err := json.Unmarshal(m.Params, &out)
+	if err != nil {
+		panic(err)
+	}
+	return out
+}
+
+func WsSend[T Msg | Error | Result](c *websocket.Conn, data T) error {
+	buff, err := json.Marshal(data)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = c.Write(buff)
+	if err != nil {
+		return fmt.Errorf("ws write error: %w", err)
+	}
+
+	return nil
+}
+
+func WsReadLoop(c *websocket.Conn) <-chan Msg {
+	out := make(chan Msg, 100)
+
+	go func() {
+		defer close(out)
+		for {
+			msg, err := wsRead(c)
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			if err != nil {
+				log.Warn().Err(err).Msg("read loop error, ignore")
+				return
+			}
+			out <- msg
+		}
+	}()
+
+	return out
+}
+
+func wsRead(c *websocket.Conn) (Msg, error) {
+	buff := make([]byte, 512)
+	var msg Msg
+	for {
+		n, err := c.Read(buff)
+		if err != nil {
+			return msg, fmt.Errorf("ws read: %w", err)
+		}
+		if n >= 512 {
+			panic("too big")
+		}
+
+		err = json.Unmarshal(buff[:n], &msg)
+		if err != nil {
+			return msg, fmt.Errorf("ws read error: %w", err)
+		}
+		if len(msg.Method) == 0 {
+			// ignore response messages
+			continue
+		}
+
+		return msg, nil
+	}
+}
--- a/main.go
+++ b/main.go
@@ -0,0 +1,51 @@
+package main
+
+import (
+	"flag"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"tinygo.org/x/bluetooth"
+
+	"github.com/lucarin91/scratch-link4linux/scratchlink"
+)
+
+func setLogger(debug bool) {
+	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stdout})
+	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+	if debug {
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+	} else {
+		zerolog.SetGlobalLevel(zerolog.InfoLevel)
+	}
+}
+
+func main() {
+	debug := flag.Bool("debug", false, "sets log level to debug")
+	flag.Parse()
+
+	setLogger(*debug)
+
+	var adapter = bluetooth.DefaultAdapter
+	if err := adapter.Enable(); err != nil {
+		log.Fatal().Err(err).Msgf("BLE cannot be enabled")
+	}
+
+	http.Handle("/scratch/ble", scratchlink.GetHandler(adapter))
+
+	server := &http.Server{
+		Addr:              ":20111",
+		ReadHeaderTimeout: 3 * time.Second,
+	}
+
+	log.Info().Msgf("Starting scratch server on %q", server.Addr)
+
+	err := server.ListenAndServe()
+	if err != nil {
+		log.Fatal().Err(err).Msg("server stopped")
+	}
+}
--- a/scratchlink/ble.go
+++ b/scratchlink/ble.go
@@ -0,0 +1,92 @@
+package scratchlink
+
+import (
+	"encoding/base64"
+
+	"github.com/google/uuid"
+	"github.com/rs/zerolog/log"
+	"golang.org/x/net/websocket"
+	"tinygo.org/x/bluetooth"
+
+	"github.com/lucarin91/scratch-link4linux/jsonrpc"
+)
+
+func matchDevice(device bluetooth.ScanResult, filters []DiscoverFilter) bool {
+	//TODO: implement match device
+
+	for _, filter := range filters {
+		if len(filter.Name) != 0 && filter.Name != device.LocalName() {
+			return false
+		}
+
+		for _, service := range filter.Services {
+			if !device.HasServiceUUID(bluetooth.NewUUID(service)) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+func getDeviceCharacteristic(device bluetooth.Device, serviceID, characteristicID bluetooth.UUID) (bluetooth.DeviceCharacteristic, error) {
+	services, err := device.DiscoverServices([]bluetooth.UUID{serviceID})
+	if err != nil {
+		return bluetooth.DeviceCharacteristic{}, err
+	}
+
+	chars, err := services[0].DiscoverCharacteristics([]bluetooth.UUID{characteristicID})
+	if err != nil {
+		return bluetooth.DeviceCharacteristic{}, err
+	}
+
+	return chars[0], nil
+}
+
+func notificationCallback(c *websocket.Conn, serviceID, characteristicID uuid.UUID) func(buf []byte) {
+	return func(buf []byte) {
+		_ = jsonrpc.WsSend(c, jsonrpc.NewMsg("characteristicDidChange", UpdateParams{
+			ServiceID:        serviceID,
+			CharacteristicID: characteristicID,
+			Message:          base64.StdEncoding.EncodeToString(buf),
+			Encoding:         "base64",
+		}))
+	}
+}
+
+func startAsyncScan(adapter *bluetooth.Adapter, filter []DiscoverFilter) <-chan Device {
+	// Stop previus scan (if any).
+	_ = adapter.StopScan()
+
+	devices := make(chan Device, 10)
+
+	go func() {
+		defer close(devices)
+
+		err := adapter.Scan(func(adapter *bluetooth.Adapter, device bluetooth.ScanResult) {
+			if len(device.LocalName()) == 0 {
+				return
+			}
+
+			log.Debug().
+				Str("name", device.LocalName()).
+				Str("address", device.Address.String()).
+				Int16("RSSI", device.RSSI).
+				Msg("found device")
+
+			if !matchDevice(device, filter) {
+				return
+			}
+
+			devices <- Device{
+				PeripheralID: device.Address.String(),
+				Name:         device.LocalName(),
+				RSSI:         device.RSSI,
+			}
+		})
+		if err != nil {
+			log.Error().Err(err).Msg("scan error")
+		}
+	}()
+
+	return devices
+}
--- a/scratchlink/handler.go
+++ b/scratchlink/handler.go
@@ -0,0 +1,198 @@
+package scratchlink
+
+import (
+	"encoding/base64"
+
+	"github.com/lucarin91/scratch-link4linux/jsonrpc"
+	"github.com/rs/zerolog/log"
+	"golang.org/x/net/websocket"
+	"tinygo.org/x/bluetooth"
+)
+
+func GetHandler(adapter *bluetooth.Adapter) websocket.Handler {
+	return websocket.Handler(func(c *websocket.Conn) {
+		log.Info().Msgf("client connected from %q", c.RemoteAddr())
+
+		var DEVICE *bluetooth.Device
+
+		msgs := jsonrpc.WsReadLoop(c)
+
+		for msg := range msgs {
+			log.Debug().Msgf("get message: %v", msg)
+
+			switch msg.Method {
+			case "getVersion":
+				_ = jsonrpc.WsSend(c, msg.Respond(map[string]string{"protocol": "1.3"}))
+
+			case "discover":
+				params, err := DiscoverParamsFromJSON(msg.Params)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				devices := startAsyncScan(adapter, params.Filters)
+				go func() {
+					for device := range devices {
+						_ = jsonrpc.WsSend(c, jsonrpc.NewMsg("didDiscoverPeripheral", device))
+					}
+				}()
+
+				_ = jsonrpc.WsSend(c, msg.Respond(nil))
+
+			case "connect":
+				params, err := ConnectParamsFromJSON(msg.Params)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				_ = adapter.StopScan()
+
+				mac := bluetooth.Address{}
+				mac.Set(params.PeripheralID)
+				DEVICE, err = adapter.Connect(mac, bluetooth.ConnectionParams{
+					ConnectionTimeout: 0,
+					MinInterval:       0,
+					MaxInterval:       0,
+				})
+				if err != nil {
+					log.Error().Msgf("ble connect error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				_ = jsonrpc.WsSend(c, msg.Respond(nil))
+
+			case "startNotifications":
+				params, err := NotificationsParamsFromJSON(msg.Params)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+				log.Debug().Msgf("startNotifications params: %+v", params)
+
+				char, err := getDeviceCharacteristic(*DEVICE, bluetooth.NewUUID(params.ServiceID), bluetooth.NewUUID(params.CharacteristicID))
+				if err != nil {
+					log.Error().Msgf("get device characteristic error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				err = char.EnableNotifications(notificationCallback(c, params.CharacteristicID, params.CharacteristicID))
+				if err != nil {
+					log.Error().Msgf("enable notification error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				_ = jsonrpc.WsSend(c, msg.Respond(nil))
+
+			case "write":
+				params, err := UpdateParamsFromJSON(msg.Params)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+				log.Debug().Msgf("write params: %+v", params)
+
+				if params.Encoding != "base64" {
+					log.Error().Msgf("encoding format %q not supported", params.Encoding)
+					continue
+				}
+
+				services, err := DEVICE.DiscoverServices([]bluetooth.UUID{bluetooth.NewUUID(params.ServiceID)})
+				if err != nil {
+					log.Error().Msgf("discover service error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				chars, err := services[0].DiscoverCharacteristics([]bluetooth.UUID{bluetooth.NewUUID(params.CharacteristicID)})
+				if err != nil {
+					log.Error().Msgf("discovert characteristics error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+				char := chars[0]
+
+				buf, err := base64.StdEncoding.DecodeString(params.Message)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				// TODO: handle params.WithResponse
+				n, err := char.WriteWithoutResponse(buf)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				_ = jsonrpc.WsSend(c, msg.Respond(n))
+
+			case "read":
+				params, err := ReadParamsFromJSON(msg.Params)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+				log.Debug().Msgf("read params: %+v", params)
+
+				char, err := getDeviceCharacteristic(*DEVICE, bluetooth.NewUUID(params.ServiceID), bluetooth.NewUUID(params.CharacteristicID))
+				if err != nil {
+					log.Error().Msgf("get device characteristic error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				if params.StartNotifications {
+					err = char.EnableNotifications(notificationCallback(c, params.CharacteristicID, params.CharacteristicID))
+					if err != nil {
+						log.Error().Msgf("enable notification error: %s", err)
+						_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+						continue
+					}
+				}
+
+				buf := make([]byte, 512)
+				n, err := char.Read(buf)
+				if err != nil {
+					log.Error().Msgf("read characteristic error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				_ = jsonrpc.WsSend(c, msg.RespondBytes(buf[:n]))
+
+			case "stopNotifications":
+				params, err := NotificationsParamsFromJSON(msg.Params)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+				log.Debug().Msgf("stopNotifications params: %+v", params)
+
+				char, err := getDeviceCharacteristic(*DEVICE, bluetooth.NewUUID(params.ServiceID), bluetooth.NewUUID(params.CharacteristicID))
+				if err != nil {
+					log.Error().Msgf("get device characteristic error: %s", err)
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				err = char.EnableNotifications(nil)
+				if err != nil {
+					_ = jsonrpc.WsSend(c, msg.Error(err.Error()))
+					continue
+				}
+
+				_ = jsonrpc.WsSend(c, msg.Respond(nil))
+
+			default:
+				log.Error().Msgf("unknown command '%s' with params: %+v", msg.Method, msg.DebugParams())
+			}
+		}
+
+		log.Info().Msgf("client disconnected from %q", c.RemoteAddr())
+	})
+}
--- a/scratchlink/types.go
+++ b/scratchlink/types.go
@@ -0,0 +1,101 @@
+package scratchlink
+
+import (
+	"encoding/json"
+
+	"github.com/google/uuid"
+)
+
+type Device struct {
+	PeripheralID string `json:"peripheralId"`
+	Name         string `json:"name"`
+	RSSI         int16  `json:"rssi"`
+}
+
+type DiscoverParams struct {
+	Filters []DiscoverFilter `json:"filters"`
+}
+
+func DiscoverParamsFromJSON(j json.RawMessage) (DiscoverParams, error) {
+	var params DiscoverParams
+
+	err := json.Unmarshal(j, &params)
+	if err != nil {
+		return DiscoverParams{}, err
+	}
+
+	return params, nil
+}
+
+type DiscoverFilter struct {
+	Name       string      `json:"name"`
+	NamePrefix string      `json:"namePrefix"`
+	Services   []uuid.UUID `json:"services"`
+}
+
+type ConnectParams struct {
+	PeripheralID string `json:"peripheralId"`
+}
+
+func ConnectParamsFromJSON(j json.RawMessage) (ConnectParams, error) {
+	var params ConnectParams
+
+	err := json.Unmarshal(j, &params)
+	if err != nil {
+		return ConnectParams{}, err
+	}
+
+	return params, nil
+}
+
+type NotificationsParams struct {
+	ServiceID        uuid.UUID `json:"serviceId"`
+	CharacteristicID uuid.UUID `json:"characteristicId"`
+}
+
+func NotificationsParamsFromJSON(j json.RawMessage) (NotificationsParams, error) {
+	var params NotificationsParams
+
+	err := json.Unmarshal(j, &params)
+	if err != nil {
+		return NotificationsParams{}, err
+	}
+
+	return params, nil
+}
+
+type UpdateParams struct {
+	ServiceID        uuid.UUID `json:"serviceId"`
+	CharacteristicID uuid.UUID `json:"characteristicId"`
+	Message          string    `json:"message"`
+	Encoding         string    `json:"encoding,omitempty"`
+	WithResponse     bool      `json:"withResponse"`
+}
+
+func UpdateParamsFromJSON(j json.RawMessage) (UpdateParams, error) {
+	var params UpdateParams
+
+	err := json.Unmarshal(j, &params)
+	if err != nil {
+		return UpdateParams{}, err
+	}
+
+	return params, nil
+}
+
+type ReadParams struct {
+	ServiceID          uuid.UUID `json:"serviceId"`
+	CharacteristicID   uuid.UUID `json:"characteristicId"`
+	StartNotifications bool      `json:"startNotifications"`
+}
+
+func ReadParamsFromJSON(j json.RawMessage) (ReadParams, error) {
+	var params ReadParams
+
+	err := json.Unmarshal(j, &params)
+	if err != nil {
+		return ReadParams{}, err
+	}
+
+	return params, nil
+}