Add minifier package

minifier/minifier.go

@@ -0,0 +1,89 @@
+// Copyright (c) 2018, Janoš Guljaš <[email protected]>
+// All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package minifier
+
+import (
+	"io"
+	"net/http"
+	"regexp"
+
+	"github.com/tdewolff/minify"
+	"github.com/tdewolff/minify/css"
+	"github.com/tdewolff/minify/html"
+	"github.com/tdewolff/minify/js"
+	"github.com/tdewolff/minify/json"
+	"github.com/tdewolff/minify/svg"
+	"github.com/tdewolff/minify/xml"
+)
+
+var minifier = minify.New()
+
+func init() {
+	htmlMinify := &html.Minifier{
+		KeepWhitespace: true,
+	}
+	minifier.AddFunc("text/css", css.Minify)
+	minifier.Add("text/html", htmlMinify)
+	minifier.Add("text/x-template", htmlMinify)
+	minifier.AddFunc("text/javascript", js.Minify)
+	minifier.AddFunc("application/javascript", js.Minify)
+	minifier.AddFunc("application/x-javascript", js.Minify)
+	minifier.AddFunc("image/svg+xml", svg.Minify)
+	minifier.AddFuncRegexp(regexp.MustCompile("[/+]json$"), json.Minify)
+	minifier.AddFuncRegexp(regexp.MustCompile("[/+]xml$"), xml.Minify)
+}
+
+// LogFunc defines the function that is used by NewHandler
+// to log error messages from minifier.
+type LogFunc func(format string, a ...interface{})
+
+// NewHandler returns a minifer http handler that implements common http.Hander
+// related interfaces and uses a common configuration for github.com/tdewolff/minify.
+func NewHandler(h http.Handler, logFunc LogFunc) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		mw := &minifyResponseWriter{mw: minifier.ResponseWriter(w, r), w: w}
+		h.ServeHTTP(mw, r)
+		if err := mw.Close(); err != nil && err != minify.ErrNotExist && logFunc != nil {
+			logFunc("minifier %q: %v", r.URL.String(), err)
+		}
+	})
+}
+
+type minifyResponseWriter struct {
+	mw http.ResponseWriter
+	w  http.ResponseWriter
+}
+
+func (w *minifyResponseWriter) Header() http.Header {
+	return w.mw.Header()
+}
+
+func (w *minifyResponseWriter) CloseNotify() <-chan bool {
+	return w.w.(http.CloseNotifier).CloseNotify()
+}
+
+func (w *minifyResponseWriter) Flush() {
+	w.w.(http.Flusher).Flush()
+}
+
+func (w *minifyResponseWriter) Write(b []byte) (int, error) {
+	return w.mw.Write(b)
+}
+
+func (w *minifyResponseWriter) WriteHeader(s int) {
+	w.mw.WriteHeader(s)
+}
+
+func (w *minifyResponseWriter) Push(target string, opts *http.PushOptions) error {
+	return w.w.(http.Pusher).Push(target, opts)
+}
+
+func (w *minifyResponseWriter) Close() error {
+	if c, ok := w.mw.(io.Closer); ok {
+		return c.Close()
+	}
+	return nil
+}