Remove magic numbers

input_file.go

@@ -61,7 +61,7 @@ func (i *FileInput) emit() {
 		buf := scanner.Bytes()
 		meta := payloadMeta(buf)
 
-		if meta[0][0] == '1' && lastTime != 0 {
+		if meta[0][0] == RequestPayload && lastTime != 0 {
 			ts, _ := strconv.ParseInt(string(meta[2]), 10, 64)
 			timeDiff := ts - lastTime
 

input_raw_test.go

@@ -72,12 +72,12 @@ func TestInputRAW100Expect(t *testing.T) {
 	// We will use it to get content of raw HTTP request
 	testOutput := NewTestOutput(func(data []byte) {
 		switch data[0] {
-		case '1':
+		case RequestPayload:
 			if strings.Contains(string(data), "Expect: 100-continue") {
 				t.Error("Should not contain 100-continue header")
 			}
 			wg.Done()
-		case '2':
+		case ResponsePayload:
 			wg.Done()
 		}
 	})

protocol.go

@@ -8,9 +8,9 @@ import (
 )
 
 const (
-	RequestPayload = 1 << iota
-	ResponsePayload
-	ReplayedResponsePayload
+	RequestPayload = '1'
+	ResponsePayload = '2'
+	ReplayedResponsePayload = '3'
 )
 
 func uuid() []byte {
@@ -43,26 +43,18 @@ func payloadScanner(data []byte, atEOF bool) (advance int, token []byte, err err
 
 
 // Timing is request start or round-trip time, depending on payloadType
-func payloadHeader(payloadType int, uuid []byte, timing int64) (header []byte) {
+func payloadHeader(payloadType byte, uuid []byte, timing int64) (header []byte) {
 	sTime := strconv.FormatInt(timing, 10)
 
 	//Example:
 	//  3 f45590522cd1838b4a0d5c5aab80b77929dea3b3 1231\n
 	// `+ 1` indicates space characters or end of line
 	header = make([]byte, 1+1+len(uuid)+1+len(sTime)+1)
+	header[0] = payloadType
 	header[1] = ' '
 	header[2+len(uuid)] = ' '
 	header[len(header)-1] = '\n'
 
-	switch payloadType {
-	case RequestPayload:
-		header[0] = '1'
-	case ResponsePayload:
-		header[0] = '2'
-	case ReplayedResponsePayload:
-		header[0] = '3'
-	}
-
 	copy(header[2:], uuid)
 	copy(header[3+len(uuid):], sTime)
 
@@ -81,7 +73,7 @@ func payloadMeta(payload []byte) [][]byte {
 
 func isOriginPayload(payload []byte) bool {
 	switch payload[0] {
-	case '1', '2':
+	case RequestPayload, ResponsePayload:
 		return true
 	default:
 		return false
@@ -89,5 +81,5 @@ func isOriginPayload(payload []byte) bool {
 }
 
 func isRequestPayload(payload []byte) bool {
-	return payload[0] == '1'
+	return payload[0] == RequestPayload
 }