dialing + consts

index.go

@@ -67,3 +67,36 @@ func (m *Multiaddr) Decapsulate(o *Multiaddr) (*Multiaddr, error) {
 	}
 	return NewMultiaddr(s1[:i])
 }
+
+func (m *Multiaddr) DialArgs() (string, string, error) {
+	if !m.IsThinWaist() {
+		return "", "", fmt.Errorf("%s is not a 'thin waist' address.", m)
+	}
+
+	str, err := m.String()
+	if err != nil {
+		return "", "", err
+	}
+
+	parts := strings.Split(str, "/")[1:]
+	network := parts[2]
+	host := strings.Join([]string{parts[1], parts[3]}, ":")
+	return network, host, nil
+}
+
+func (m *Multiaddr) IsThinWaist() bool {
+	p, err := m.Protocols()
+	if err != nil {
+		return false
+	}
+
+	if p[0].Code != P_IP4 && p[0].Code != P_IP6 {
+		return false
+	}
+
+	if p[1].Code != P_TCP && p[1].Code != P_UDP {
+		return false
+	}
+
+	return true
+}

multiaddr_test.go

@@ -107,3 +107,23 @@ func TestEncapsulate(t *testing.T) {
 		t.Error("decapsulate /ip4 failed.", "/", s)
 	}
 }
+
+func TestDialArgs(t *testing.T) {
+	m, err := NewMultiaddr("/ip4/127.0.0.1/udp/1234")
+	if err != nil {
+		t.Fatal("failed to construct", "/ip4/127.0.0.1/udp/1234")
+	}
+
+	nw, host, err := m.DialArgs()
+	if err != nil {
+		t.Fatal("failed to get dial args", "/ip4/127.0.0.1/udp/1234", err)
+	}
+
+	if nw != "udp" {
+		t.Error("failed to get udp network Dial Arg")
+	}
+
+	if host != "127.0.0.1:1234" {
+		t.Error("failed to get host:port Dial Arg")
+	}
+}

protocols.go

@@ -11,14 +11,23 @@ type Protocol struct {
 // 2. ensuring errors in the csv don't screw up code.
 // 3. changing a number has to happen in two places.
 
+const (
+	P_IP4  = 4
+	P_TCP  = 6
+	P_UDP  = 17
+	P_DCCP = 33
+	P_IP6  = 41
+	P_SCTP = 132
+)
+
 var Protocols = []*Protocol{
-	&Protocol{4, 32, "ip4"},
-	&Protocol{6, 16, "tcp"},
-	&Protocol{17, 16, "udp"},
-	&Protocol{33, 16, "dccp"},
-	&Protocol{41, 128, "ip6"},
+	&Protocol{P_IP4, 32, "ip4"},
+	&Protocol{P_TCP, 16, "tcp"},
+	&Protocol{P_UDP, 16, "udp"},
+	&Protocol{P_DCCP, 16, "dccp"},
+	&Protocol{P_IP6, 128, "ip6"},
 	// these require varint:
-	&Protocol{132, 16, "sctp"},
+	&Protocol{P_SCTP, 16, "sctp"},
 	// {480, 0, "http"},
 	// {443, 0, "https"},
 }