adding ipv6 support because i like ipv6

net/dualstack.go

@@ -0,0 +1,40 @@
+package net
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"sync"
+)
+
+type DualStackHTTPServer struct {
+    Handler http.Handler
+}
+
+func (s *DualStackHTTPServer) ListenAndServe(ipv4 string, ipv6 string, port int) error {
+    v4Listener, err := net.Listen("tcp4", fmt.Sprintf("%s:%d", ipv4, port))
+    if err != nil {
+        return fmt.Errorf("IPv4 listen: %v", err)
+    }
+
+    v6Listener, err := net.Listen("tcp6", fmt.Sprintf("[%s]:%d", ipv6, port))
+    if err != nil {
+        v4Listener.Close()
+        return fmt.Errorf("IPv6 listen: %v", err)
+    }
+
+    srv := &http.Server{ Handler: s.Handler }
+
+    var wg sync.WaitGroup
+    errs := make(chan error, 2)
+
+    for _, listener := range []net.Listener{v4Listener, v6Listener} {
+        wg.Add(1)
+        go func(l net.Listener) {
+            defer wg.Done()
+            errs <- srv.Serve(l)
+        }(listener)
+    }
+
+    return <-errs
+}