refactor: rename file to conform to standards

common/custom-event.go

@@ -0,0 +1,82 @@
+// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package common
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+type stringWriter interface {
+	io.Writer
+	writeString(string) (int, error)
+}
+
+type stringWrapper struct {
+	io.Writer
+}
+
+func (w stringWrapper) writeString(str string) (int, error) {
+	return w.Writer.Write([]byte(str))
+}
+
+func checkWriter(writer io.Writer) stringWriter {
+	if w, ok := writer.(stringWriter); ok {
+		return w
+	} else {
+		return stringWrapper{writer}
+	}
+}
+
+// Server-Sent Events
+// W3C Working Draft 29 October 2009
+// http://www.w3.org/TR/2009/WD-eventsource-20091029/
+
+var contentType = []string{"text/event-stream"}
+var noCache = []string{"no-cache"}
+
+var fieldReplacer = strings.NewReplacer(
+	"\n", "\\n",
+	"\r", "\\r")
+
+var dataReplacer = strings.NewReplacer(
+	"\n", "\ndata:",
+	"\r", "\\r")
+
+type CustomEvent struct {
+	Event string
+	Id    string
+	Retry uint
+	Data  interface{}
+}
+
+func encode(writer io.Writer, event CustomEvent) error {
+	w := checkWriter(writer)
+	return writeData(w, event.Data)
+}
+
+func writeData(w stringWriter, data interface{}) error {
+	dataReplacer.WriteString(w, fmt.Sprint(data))
+	if strings.HasPrefix(data.(string), "data") {
+		w.writeString("\n\n")
+	}
+	return nil
+}
+
+func (r CustomEvent) Render(w http.ResponseWriter) error {
+	r.WriteContentType(w)
+	return encode(w, r)
+}
+
+func (r CustomEvent) WriteContentType(w http.ResponseWriter) {
+	header := w.Header()
+	header["Content-Type"] = contentType
+
+	if _, exist := header["Cache-Control"]; !exist {
+		header["Cache-Control"] = noCache
+	}
+}