p2p/host: expose multistream function matching and add semver func

p2p/host/basic/basic_host.go

@@ -156,6 +156,17 @@ func (h *BasicHost) SetStreamHandler(pid protocol.ID, handler inet.StreamHandler
 	})
 }
 
+// SetStreamHandlerMatch sets the protocol handler on the Host's Mux
+// using a matching function to do protocol comparisons
+func (h *BasicHost) SetStreamHandlerMatch(pid protocol.ID, m func(string) bool, handler inet.StreamHandler) {
+	h.Mux().AddHandlerWithFunc(string(pid), m, func(p string, rwc io.ReadWriteCloser) error {
+		is := rwc.(inet.Stream)
+		is.SetProtocol(p)
+		handler(is)
+		return nil
+	})
+}
+
 // RemoveStreamHandler returns ..
 func (h *BasicHost) RemoveStreamHandler(pid protocol.ID) {
 	h.Mux().RemoveHandler(string(pid))

p2p/host/host.go

@@ -48,6 +48,10 @@ type Host interface {
 	// (Threadsafe)
 	SetStreamHandler(pid protocol.ID, handler inet.StreamHandler)
 
+	// SetStreamHandlerMatch sets the protocol handler on the Host's Mux
+	// using a matching function for protocol selection.
+	SetStreamHandlerMatch(protocol.ID, func(string) bool, inet.StreamHandler)
+
 	// RemoveStreamHandler removes a handler on the mux that was set by
 	// SetStreamHandler
 	RemoveStreamHandler(pid protocol.ID)

p2p/host/match.go

+package host
+
+import (
+	"strings"
+
+	semver "github.com/coreos/go-semver/semver"
+)
+
+func MultistreamSemverMatcher(base string) (func(string) bool, error) {
+	parts := strings.Split(base, "/")
+	vers, err := semver.NewVersion(parts[len(parts)-1])
+	if err != nil {
+		return nil, err
+	}
+
+	return func(check string) bool {
+		chparts := strings.Split(check, "/")
+		if len(chparts) != len(parts) {
+			return false
+		}
+
+		for i, v := range chparts[:len(chparts)-1] {
+			if parts[i] != v {
+				return false
+			}
+		}
+
+		chvers, err := semver.NewVersion(chparts[len(chparts)-1])
+		if err != nil {
+			return false
+		}
+
+		return vers.Major == chvers.Major && vers.Minor >= chvers.Minor
+	}, nil
+}

p2p/host/match_test.go

+package host
+
+import (
+	"testing"
+)
+
+func TestSemverMatching(t *testing.T) {
+	m, err := MultistreamSemverMatcher("/testing/4.3.5")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cases := map[string]bool{
+		"/testing/4.3.0":   true,
+		"/testing/4.3.7":   true,
+		"/testing/4.3.5":   true,
+		"/testing/4.2.7":   true,
+		"/testing/4.0.0":   true,
+		"/testing/5.0.0":   false,
+		"/cars/dogs/4.3.5": false,
+		"/foo/1.0.0":       false,
+		"":                 false,
+		"dogs":             false,
+		"/foo":             false,
+		"/foo/1.1.1.1":     false,
+	}
+
+	for p, ok := range cases {
+		if m(p) != ok {
+			t.Fatalf("expected %s to be %t", p, ok)
+		}
+	}
+}

p2p/host/routed/routed.go

@@ -110,6 +110,10 @@ func (rh *RoutedHost) SetStreamHandler(pid protocol.ID, handler inet.StreamHandl
 	rh.host.SetStreamHandler(pid, handler)
 }
 
+func (rh *RoutedHost) SetStreamHandlerMatch(pid protocol.ID, m func(string) bool, handler inet.StreamHandler) {
+	rh.host.SetStreamHandlerMatch(pid, m, handler)
+}
+
 func (rh *RoutedHost) RemoveStreamHandler(pid protocol.ID) {
 	rh.host.RemoveStreamHandler(pid)
 }
@@ -125,3 +129,5 @@ func (rh *RoutedHost) Close() error {
 func (rh *RoutedHost) GetBandwidthReporter() metrics.Reporter {
 	return rh.host.GetBandwidthReporter()
 }
+
+var _ (host.Host) = (*RoutedHost)(nil)