[IMPROVED] URL parsing allowing to skip scheme and default port

nats.go

@@ -297,6 +297,9 @@ const (
 
 	// NUID size
 	nuidSize = 22
+
+	// Default port used if none is specified in given URL(s)
+	defaultPortString = "4222"
 )
 
 // A Conn represents a bare connection to a nats-server.
@@ -942,9 +945,27 @@ func (nc *Conn) setupServerPool() error {
 
 // addURLToPool adds an entry to the server pool
 func (nc *Conn) addURLToPool(sURL string, implicit bool) error {
-	u, err := url.Parse(sURL)
-	if err != nil {
-		return err
+	if !strings.Contains(sURL, "://") {
+		sURL = "nats://" + sURL
+	}
+	var (
+		u   *url.URL
+		err error
+	)
+	for i := 0; i < 2; i++ {
+		u, err = url.Parse(sURL)
+		if err != nil {
+			return err
+		}
+		if u.Port() != "" {
+			break
+		}
+		// In case given URL is of the form "localhost:", just add
+		// the port number at the end, otherwise, add ":4222".
+		if sURL[len(sURL)-1] != ':' {
+			sURL += ":"
+		}
+		sURL += defaultPortString
 	}
 	s := &srv{url: u, isImplicit: implicit}
 	nc.srvPool = append(nc.srvPool, s)
@@ -1179,7 +1200,8 @@ func (nc *Conn) checkForSecure() error {
 	if o.Secure && !nc.info.TLSRequired {
 		return ErrSecureConnWanted
 	} else if nc.info.TLSRequired && !o.Secure {
-		return ErrSecureConnRequired
+		// Switch to Secure since server needs TLS.
+		o.Secure = true
 	}
 
 	// Need to rewrap with bufio

nats_test.go

@@ -223,6 +223,50 @@ var testServers = []string{
 	"nats://localhost:1228",
 }
 
+func TestSimplifiedURLs(t *testing.T) {
+	opts := GetDefaultOptions()
+	opts.NoRandomize = true
+	opts.Servers = []string{
+		"nats://host1:1234",
+		"nats://host2:",
+		"nats://host3",
+		"host4:1234",
+		"host5:",
+		"host6",
+		"nats://[1:2:3:4]:1234",
+		"nats://[5:6:7:8]:",
+		"nats://[9:10:11:12]",
+		"[13:14:15:16]:",
+		"[17:18:19:20]:1234",
+	}
+
+	// We expect the result in the server pool to be:
+	expected := []string{
+		"nats://host1:1234",
+		"nats://host2:4222",
+		"nats://host3:4222",
+		"nats://host4:1234",
+		"nats://host5:4222",
+		"nats://host6:4222",
+		"nats://[1:2:3:4]:1234",
+		"nats://[5:6:7:8]:4222",
+		"nats://[9:10:11:12]:4222",
+		"nats://[13:14:15:16]:4222",
+		"nats://[17:18:19:20]:1234",
+	}
+
+	nc := &Conn{Opts: opts}
+	if err := nc.setupServerPool(); err != nil {
+		t.Fatalf("Problem setting up Server Pool: %v\n", err)
+	}
+	// Check server pool directly
+	for i, u := range nc.srvPool {
+		if u.url.String() != expected[i] {
+			t.Fatalf("Expected url %q, got %q", expected[i], u.url.String())
+		}
+	}
+}
+
 func TestServersRandomize(t *testing.T) {
 	opts := GetDefaultOptions()
 	opts.Servers = testServers

test/conn_test.go

@@ -165,14 +165,12 @@ func TestServerSecureConnections(t *testing.T) {
 
 	nc.Close()
 
-	// Server required, but not requested.
+	// Server required, but not specified in Connect(), should switch automatically
 	nc, err = nats.Connect(secureURL)
-	if err == nil || nc != nil || err != nats.ErrSecureConnRequired {
-		if nc != nil {
-			nc.Close()
-		}
-		t.Fatal("Should have failed to create secure (TLS) connection")
+	if err != nil {
+		t.Fatalf("Failed to create secure (TLS) connection: %v", err)
 	}
+	nc.Close()
 
 	// Test flag mismatch
 	// Wanted but not available..
@@ -1983,3 +1981,50 @@ func TestReceiveInfoWithEmptyConnectURLs(t *testing.T) {
 	nc.Close()
 	wg.Wait()
 }
+
+func TestConnectWithSimplifiedURLs(t *testing.T) {
+	urls := []string{
+		"nats://127.0.0.1:4222",
+		"nats://127.0.0.1:",
+		"nats://127.0.0.1",
+		"127.0.0.1:",
+		"127.0.0.1",
+	}
+
+	connect := func(t *testing.T, url string) {
+		t.Helper()
+		nc, err := nats.Connect(url)
+		if err != nil {
+			t.Fatalf("URL %q expected to connect, got %v", url, err)
+		}
+		nc.Close()
+	}
+
+	// Start a server that listens on default port 4222.
+	s := RunDefaultServer()
+	defer s.Shutdown()
+
+	// Try for every connection in the urls array.
+	for _, u := range urls {
+		connect(t, u)
+	}
+
+	s.Shutdown()
+
+	// Use this to build the options for us...
+	s, opts := RunServerWithConfig("configs/tls.conf")
+	s.Shutdown()
+	// Now change listen port to 4222 and remove auth
+	opts.Port = 4222
+	opts.Username = ""
+	opts.Password = ""
+	// and restart the server
+	s = RunServerWithOptions(*opts)
+	defer s.Shutdown()
+
+	// Test again against a server that wants TLS and check
+	// that we automatically switch to Secure.
+	for _, u := range urls {
+		connect(t, u)
+	}
+}