add concept of a "filter"

internal/processing/osc-message-filter.go

@@ -0,0 +1,71 @@
+package processing
+
+import (
+	"context"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/jwetzell/osc-go"
+)
+
+type OSCMessageFilter struct {
+	config  ProcessorConfig
+	Address *regexp.Regexp
+}
+
+func (o *OSCMessageFilter) Process(ctx context.Context, payload any) (any, error) {
+
+	payloadMessage, ok := payload.(osc.OSCMessage)
+
+	if !ok {
+		return nil, fmt.Errorf("osc.message.filter can only operate on OSCMessage payloads")
+	}
+
+	if !o.Address.MatchString(payloadMessage.Address) {
+		return nil, nil
+	}
+
+	return payloadMessage, nil
+}
+
+func (o *OSCMessageFilter) Type() string {
+	return o.config.Type
+}
+
+func init() {
+	RegisterProcessor(ProcessorRegistration{
+		Type: "osc.message.filter",
+		New: func(config ProcessorConfig) (Processor, error) {
+			params := config.Params
+			address, ok := params["address"]
+
+			if !ok {
+				return nil, fmt.Errorf("osc.message.filter requires an address parameter")
+			}
+
+			addressString, ok := address.(string)
+
+			if !ok {
+				return nil, fmt.Errorf("osc.message.filter address must be a string")
+			}
+
+			addressPattern := strings.ReplaceAll(addressString, "?", ".")
+			addressPattern = strings.ReplaceAll(addressPattern, "*", "[^/]*")
+			addressPattern = strings.ReplaceAll(addressPattern, "[!", "[^")
+			addressPattern = strings.ReplaceAll(addressPattern, "{", "(")
+			addressPattern = strings.ReplaceAll(addressPattern, "}", ")")
+			addressPattern = strings.ReplaceAll(addressPattern, ",", "|")
+
+			fmt.Println(addressPattern)
+
+			addressPatternRegexp, err := regexp.Compile(fmt.Sprintf("^%s$", addressPattern))
+
+			if err != nil {
+				return nil, err
+			}
+
+			return &OSCMessageFilter{config: config, Address: addressPatternRegexp}, nil
+		},
+	})
+}