Initial commit

README.md

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+# midi-hid
+
+This software allows mapping and translating of MIDI commands to HID inputs on Linux.

controller.go

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+package main
+
+import (
+	"log"
+	"gitlab.com/gomidi/midi/v2"
+)
+
+type Controller struct {
+	midiInput *MidiInput
+	mappings []Mapping
+	abortChan chan interface{}
+}
+
+func NewController(portName string) (*Controller, error) {
+	midiInput, err := NewMidiInput(portName)
+	if err != nil {
+		return nil, err
+	}
+
+	abortChan := make(chan interface{})
+
+	controller := &Controller{midiInput, nil, abortChan}
+
+	go func() {
+		for {
+			select {
+			case midiMessage := <-midiInput.Messages:
+				controller.update(midiMessage)
+			case <-abortChan:
+				return
+			}
+		}
+	}()
+
+	return controller, nil
+}
+
+func (c *Controller) AddMapping(mapping Mapping) {
+	c.mappings = append(c.mappings, mapping)
+}
+
+func (c Controller) Stop() {
+	c.midiInput.Stop()
+	c.abortChan <- struct{}{}
+}
+
+func (c Controller) update(msg midi.Message) {
+	for _, mapping := range c.mappings {
+		if mapping.Is(msg) {
+			log.Println("Mapping triggered!\n")
+		}
+	}
+}

go.mod

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+module datalore/midi-hid
+
+go 1.24.5
+
+require gitlab.com/gomidi/midi/v2 v2.3.16

go.sum

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+gitlab.com/gomidi/midi/v2 v2.3.16 h1:yufWSENyjnJ4LFQa9BerzUm4E4aLfTyzw5nmnCteO0c=
+gitlab.com/gomidi/midi/v2 v2.3.16/go.mod h1:jDpP4O4skYi+7iVwt6Zyp18bd2M4hkjtMuw2cmgKgfw=

main.go

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+package main
+
+import (
+	"log"
+	"time"
+
+	"gitlab.com/gomidi/midi/v2"
+)
+
+func must[T any](obj T, err error) T {
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return obj
+}
+
+func main() {
+	defer midi.CloseDriver()
+
+	midiInput := must(NewMidiInput("DJControl Inpulse 500 MIDI 1"))
+
+	time.Sleep(time.Second * 20)
+	midiInput.Stop()
+}

mapping.go

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+package main
+
+import (
+	"gitlab.com/gomidi/midi/v2"
+)
+
+type Mapping interface {
+	Is(midi.Message) bool
+}
+
+type ButtonMapping struct {
+	midiChannel uint8
+	midiKey uint8
+}
+
+func (m ButtonMapping) Is(msg midi.Message) bool {
+	var channel, key uint8
+
+	switch {
+	case msg.GetNoteOn(&channel, &key, nil), msg.GetNoteOff(&channel, &key, nil):
+		return (m.midiChannel == channel && m.midiKey == key)
+	default:
+		return false
+	}
+}
+
+type ControlMapping struct {
+	midiChannel uint8
+	midiController uint8
+}
+
+func (m ControlMapping) Is(msg midi.Message) bool {
+	var channel, controller uint8
+
+	if msg.GetControlChange(&channel, &controller, nil) {
+		return (m.midiChannel == channel && m.midiController == controller)
+	} else {
+		return false
+	}
+}

midi.go

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+package main
+
+import (
+	"gitlab.com/gomidi/midi/v2"
+	"gitlab.com/gomidi/midi/v2/drivers"
+	_ "gitlab.com/gomidi/midi/v2/drivers/rtmididrv"
+)
+
+type MidiInput struct {
+	input drivers.In
+	Messages chan midi.Message
+	Stop func()
+}
+
+func NewMidiInput(portName string) (*MidiInput, error) {
+	input, err := midi.FindInPort(portName)
+	if err != nil {
+		return nil, err
+	}
+
+	messages := make(chan midi.Message)
+
+	midiListener := func(msg midi.Message, timestampMs int32) {
+		if msg.IsOneOf(midi.NoteOnMsg, midi.NoteOffMsg, midi.ControlChangeMsg) {
+			messages <- msg
+		}
+	}
+
+	stopFunc, err := midi.ListenTo(input, midiListener, midi.UseSysEx())
+	if err != nil {
+		return nil, err
+	}
+
+	return &MidiInput{input, messages, stopFunc}, nil
+}