added option add Access-Control-Allow-Origin header

config.go

@@ -16,7 +16,8 @@ const (
 	defaultLogFile  = "lightningTip.log"
 	defaultLogLevel = "debug"
 
-	defaultRESTHost = "localhost:8081"
+	defaultRESTHost     = "localhost:8081"
+	defaultAccessDomain = ""
 
 	defaultTipExpiry = 3600
 
@@ -31,7 +32,8 @@ type config struct {
 	LogFile  string `long:"logfile" Description:"Log file location"`
 	LogLevel string `long:"loglevel" Description:"Log level: debug, info, warning, error"`
 
-	RESTHost string `long:"resthost" Description:"Host for the rest interface of LightningTip"`
+	RESTHost     string `long:"resthost" Description:"Host for the rest interface of LightningTip"`
+	AccessDomain string `long:"accessdomain" Description:"The domain you are using LightningTip from"`
 
 	TipExpiry int64 `long:"tipexpiry" Description:"Invoice expiry time in seconds"`
 
@@ -51,7 +53,8 @@ func initConfig() {
 		LogFile:  defaultLogFile,
 		LogLevel: defaultLogLevel,
 
-		RESTHost: defaultRESTHost,
+		RESTHost:     defaultRESTHost,
+		AccessDomain: defaultAccessDomain,
 
 		TipExpiry: defaultTipExpiry,
 

lightningtip.go

@@ -68,12 +68,12 @@ func main() {
 
 		eventSrv = eventsource.NewServer()
 
-		http.HandleFunc("/", notFoundHandler)
+		http.Handle("/", handleHeaders(notFoundHandler))
-		http.HandleFunc("/getinvoice", getInvoiceHandler)
+		http.Handle("/getinvoice", handleHeaders(getInvoiceHandler))
-		http.HandleFunc("/eventsource", eventSrv.Handler(eventChannel))
+		http.Handle("/eventsource", handleHeaders(eventSrv.Handler(eventChannel)))
 
 		// Alternative for browsers which don't support EventSource (Internet Explorer and Edge)
-		http.HandleFunc("/invoicesettled", invoiceSettledHandler)
+		http.Handle("/invoicesettled", handleHeaders(invoiceSettledHandler))
 
 		log.Debug("Starting ticker to clear expired invoices")
 
@@ -255,6 +255,16 @@ func notFoundHandler(writer http.ResponseWriter, request *http.Request) {
 	writeError(writer, "Not found")
 }
 
+func handleHeaders(handler func(w http.ResponseWriter, r *http.Request)) http.Handler {
+	return http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
+		if cfg.AccessDomain != "" {
+			writer.Header().Add("Access-Control-Allow-Origin", cfg.AccessDomain)
+		}
+
+		handler(writer, request)
+	})
+}
+
 func writeError(writer http.ResponseWriter, message string) {
 	writer.WriteHeader(http.StatusBadRequest)