go.tools/{cmd/present,playground/socket}: add orighost flag to handle the web origin more flexible

Also fixes the following nits;
- literal IPv6 address handling
- URL host component handling in the case of a wildcard listen
- URL port component handling in the case of no port component in origin

Fixes golang/go#8096.

LGTM=dan.kortschak, adg
R=adg, golang-codereviews, dan.kortschak
CC=golang-codereviews
https://golang.org/cl/102770046

1 files changed, 7 insertions, 1 deletions

diff --git a/playground/socket/socket.go b/playground/socket/socket.go
index 51c2a49ee..4d84cf096 100644
--- a/playground/socket/socket.go
+++ b/playground/socket/socket.go
@@ -22,6 +22,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -84,7 +85,12 @@ func handshake(c *websocket.Config, req *http.Request) error {
 		log.Println("bad websocket origin:", err)
 		return websocket.ErrBadWebSocketOrigin
 	}
-	ok := c.Origin.Scheme == o.Scheme && c.Origin.Host == o.Host
+	_, port, err := net.SplitHostPort(c.Origin.Host)
+	if err != nil {
+		log.Println("bad websocket origin:", err)
+		return websocket.ErrBadWebSocketOrigin
+	}
+	ok := c.Origin.Scheme == o.Scheme && (c.Origin.Host == o.Host || c.Origin.Host == net.JoinHostPort(o.Host, port))
 	if !ok {
 		log.Println("bad websocket origin:", o)
 		return websocket.ErrBadWebSocketOrigin