add artnet packet filter

internal/processor/artnet-packet-filter.go

@@ -0,0 +1,52 @@
+package processor
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jwetzell/artnet-go"
+	"github.com/jwetzell/showbridge-go/internal/config"
+)
+
+type ArtNetPacketFilter struct {
+	config config.ProcessorConfig
+	OpCode uint16
+}
+
+func (apf *ArtNetPacketFilter) Process(ctx context.Context, payload any) (any, error) {
+	payloadPacket, ok := payload.(artnet.ArtNetPacket)
+
+	if !ok {
+		return nil, fmt.Errorf("artnet.packet.filter processor only accepts an ArtNetPacket")
+	}
+
+	if payloadPacket.GetOpCode() != apf.OpCode {
+		return nil, nil
+	}
+
+	return payloadPacket, nil
+}
+
+func (apf *ArtNetPacketFilter) Type() string {
+	return apf.config.Type
+}
+
+func init() {
+	RegisterProcessor(ProcessorRegistration{
+		Type: "artnet.packet.filter",
+		New: func(config config.ProcessorConfig) (Processor, error) {
+			params := config.Params
+
+			opCode, ok := params["opCode"]
+			if !ok {
+				return nil, fmt.Errorf("artnet.packet.filter requires an opCode parameter")
+			}
+			opCodeNum, ok := opCode.(float64)
+			if !ok {
+				return nil, fmt.Errorf("artnet.packet.filter opCode must be a number")
+			}
+
+			return &ArtNetPacketFilter{config: config, OpCode: uint16(opCodeNum)}, nil
+		},
+	})
+}