main: add CORS support

cors.go

@@ -20,24 +20,37 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
+	"strings"
 )
 
 type CORSInfo map[string]bool
 
-func newCORSInfo(origins []string) (*CORSInfo, error) {
-	// Construct a lookup of all origins.
+// CORSInfo implements the flag.Value interface to allow users to define a list of CORS origins
+func (ci *CORSInfo) Set(s string) error {
 	m := make(map[string]bool)
-	for _, v := range origins {
+	for _, v := range strings.Split(s, ",") {
+		v = strings.TrimSpace(v)
+		if v == "" {
+			continue
+		}
 		if v != "*" {
 			if _, err := url.Parse(v); err != nil {
-				return nil, fmt.Errorf("Invalid CORS origin: %s", err)
+				return fmt.Errorf("Invalid CORS origin: %s", err)
 			}
 		}
 		m[v] = true
-	}
 
-	info := CORSInfo(m)
-	return &info, nil
+	}
+	*ci = CORSInfo(m)
+	return nil
+}
+
+func (ci *CORSInfo) String() string {
+	o := make([]string, 0)
+	for k, _ := range *ci {
+		o = append(o, k)
+	}
+	return strings.Join(o, ",")
 }
 
 // OriginAllowed determines whether the server will allow a given CORS origin.

main.go

@@ -40,6 +40,7 @@ var (
 
 	peers     = &etcdhttp.Peers{}
 	addrs     = &Addrs{}
+	cors      = &CORSInfo{}
 	proxyFlag = new(ProxyFlag)
 
 	proxyFlagValues = []string{
@@ -52,6 +53,7 @@ var (
 func init() {
 	flag.Var(peers, "peers", "your peers")
 	flag.Var(addrs, "bind-addr", "List of HTTP service addresses (e.g., '127.0.0.1:4001,10.0.0.1:8080')")
+	flag.Var(cors, "cors", "Comma-separated white list of origins for CORS (cross-origin resource sharing).")
 	flag.Var(proxyFlag, "proxy", fmt.Sprintf("Valid values include %s", strings.Join(proxyFlagValues, ", ")))
 	peers.Set("0x1=localhost:8080")
 	addrs.Set("127.0.0.1:4001")
@@ -156,8 +158,14 @@ func startEtcd() {
 	}
 	s.Start()
 
-	ch := etcdhttp.NewClientHandler(s, *peers, *timeout)
-	ph := etcdhttp.NewPeerHandler(s)
+	ch := &CORSHandler{
+		Handler: etcdhttp.NewClientHandler(s, *peers, *timeout),
+		Info:    cors,
+	}
+	ph := &CORSHandler{
+		Handler: etcdhttp.NewPeerHandler(s),
+		Info:    cors,
+	}
 
 	// Start the peer server in a goroutine
 	go func() {
@@ -181,6 +189,10 @@ func startProxy() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	ph = &CORSHandler{
+		Handler: ph,
+		Info:    cors,
+	}
 
 	if string(*proxyFlag) == proxyFlagValueReadonly {
 		ph = proxy.NewReadonlyHandler(ph)