add a SetQuicHeaders function to h2quic.Server

fixes #156

protocol/version.go

@@ -3,6 +3,7 @@ package protocol
 import (
 	"bytes"
 	"encoding/binary"
+	"strconv"
 )
 
 // VersionNumber is a version number as int
@@ -16,6 +17,9 @@ var SupportedVersions = []VersionNumber{
 // SupportedVersionsAsTags is needed for the SHLO crypto message
 var SupportedVersionsAsTags []byte
 
+// SupportedVersionsAsString is needed for the Alt-Scv HTTP header
+var SupportedVersionsAsString string
+
 // VersionNumberToTag maps version numbers ('32') to tags ('Q032')
 func VersionNumberToTag(vn VersionNumber) uint32 {
 	v := uint32(vn)
@@ -45,4 +49,11 @@ func init() {
 		b.Write(s)
 	}
 	SupportedVersionsAsTags = b.Bytes()
+
+	for i := len(SupportedVersions) - 1; i >= 0; i-- {
+		SupportedVersionsAsString += strconv.Itoa(int(SupportedVersions[i]))
+		if i != 0 {
+			SupportedVersionsAsString += ","
+		}
+	}
 }

protocol/version_test.go

@@ -22,6 +22,10 @@ var _ = Describe("Version", func() {
 		Expect(protocol.SupportedVersionsAsTags).To(Equal([]byte("Q030Q031Q032Q033")))
 	})
 
+	It("has proper version list", func() {
+		Expect(protocol.SupportedVersionsAsString).To(Equal("33,32,31,30"))
+	})
+
 	It("recognizes supported versions", func() {
 		Expect(protocol.IsSupportedVersion(0)).To(BeFalse())
 		Expect(protocol.IsSupportedVersion(protocol.SupportedVersions[0])).To(BeTrue())