private/protocol: Loosen endpoint validation to allow customer specify port number

CHANGELOG_PENDING.md

@@ -1,6 +1,8 @@
 ### SDK Features
 
 ### SDK Enhancements
+* `private/protocol`: Loosen endpoint validation to allow customer specify port number ([#3730](https://github.com/aws/aws-sdk-go/pull/3730))
+    * Updates SDK's endpoint validation of the hostname to allow ports to be specified.
 * `service/s3/s3manager`: Add ETag field to UploadOutput ([#3733](https://github.com/aws/aws-sdk-go/pull/3733))
   * Adds the ETag field to the Uploader's UploadOutput return value.
   * Fixes [#2764](https://github.com/aws/aws-sdk-go/issues/2764)

private/protocol/host.go

@@ -1,9 +1,10 @@
 package protocol
 
 import (
-	"strings"
-
 	"github.com/aws/aws-sdk-go/aws/request"
+	"net"
+	"strconv"
+	"strings"
 )
 
 // ValidateEndpointHostHandler is a request handler that will validate the
@@ -22,8 +23,26 @@ var ValidateEndpointHostHandler = request.NamedHandler{
 // 3986 host. Returns error if the host is not valid.
 func ValidateEndpointHost(opName, host string) error {
 	paramErrs := request.ErrInvalidParams{Context: opName}
-	labels := strings.Split(host, ".")
 
+	var hostname string
+	var port string
+	var err error
+
+	if strings.Contains(host, ":") {
+		hostname, port, err = net.SplitHostPort(host)
+
+		if err != nil {
+			paramErrs.Add(request.NewErrParamFormat("endpoint", err.Error(), host))
+		}
+
+		if !ValidPortNumber(port) {
+			paramErrs.Add(request.NewErrParamFormat("endpoint port number", "[0-65535]", port))
+		}
+	} else {
+		hostname = host
+	}
+
+	labels := strings.Split(hostname, ".")
 	for i, label := range labels {
 		if i == len(labels)-1 && len(label) == 0 {
 			// Allow trailing dot for FQDN hosts.
@@ -36,7 +55,11 @@ func ValidateEndpointHost(opName, host string) error {
 		}
 	}
 
-	if len(host) > 255 {
+	if len(hostname) == 0 {
+		paramErrs.Add(request.NewErrParamMinLen("endpoint host", 1))
+	}
+
+	if len(hostname) > 255 {
 		paramErrs.Add(request.NewErrParamMaxLen(
 			"endpoint host", 255, host,
 		))
@@ -66,3 +89,16 @@ func ValidHostLabel(label string) bool {
 
 	return true
 }
+
+// ValidPortNumber return if the port is valid RFC 3986 port
+func ValidPortNumber(port string) bool {
+	i, err := strconv.Atoi(port)
+	if err != nil {
+		return false
+	}
+
+	if i < 0 || i > 65535 {
+		return false
+	}
+	return true
+}

private/protocol/host_test.go

@@ -7,6 +7,28 @@ import (
 	"testing"
 )
 
+func TestValidPortNumber(t *testing.T) {
+	cases := []struct {
+		Input string
+		Valid bool
+	}{
+		{Input: "123", Valid: true},
+		{Input: "123.0", Valid: false},
+		{Input: "-123", Valid: false},
+		{Input: "65536", Valid: false},
+		{Input: "0", Valid: true},
+	}
+	for i, c := range cases {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			valid := ValidPortNumber(c.Input)
+			if e, a := c.Valid, valid; e != a {
+				t.Errorf("expect valid %v, got %v", e, a)
+			}
+		})
+	}
+
+}
+
 func TestValidHostLabel(t *testing.T) {
 	cases := []struct {
 		Input string
@@ -50,6 +72,10 @@ func TestValidateEndpointHostHandler(t *testing.T) {
 			Input: "123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456",
 			Valid: false,
 		},
+		"valid host with port number":         {Input: "abd.123:1234", Valid: true},
+		"valid host with invalid port number": {Input: "abc.123:99999", Valid: false},
+		"empty host with port number":         {Input: ":1234", Valid: false},
+		"valid host with empty port number":   {Input: "abc.123:", Valid: false},
 	}
 
 	for name, c := range cases {