Minify html on-the-fly before sending it to users

pkg/httpx/html_minify.go

@@ -0,0 +1,42 @@
+package httpx
+
+import (
+	"io"
+	"regexp"
+
+	"github.com/tdewolff/minify"
+	"github.com/tdewolff/minify/css"
+	"github.com/tdewolff/minify/html"
+	"github.com/tdewolff/minify/js"
+	"github.com/tdewolff/minify/svg"
+)
+
+// minifier holds the minfier used for all html minification
+//
+// NOTE(twiesing): We can't use an init function for this, because otherwise initialization order is incorrect.
+var minifier = (func() *minify.M {
+	m := minify.New()
+	m.AddFunc("text/html", html.Minify)
+	m.AddFunc("text/css", css.Minify)
+	m.AddFunc("image/svg+xml", svg.Minify)
+	m.AddFuncRegexp(regexp.MustCompile("^(application|text)/(x-)?(java|ecma)script$"), js.Minify)
+	return m
+})()
+
+// MinifyHTMLWriter wraps the given io.Writer to minify the given html instead.
+// The writer must be closed explicitly.
+//
+// Specific environments may chose to disable http minification, in which case MinifyHTMLWriter becomes the identity function.
+func MinifyHTMLWriter(dest io.Writer) io.WriteCloser {
+	return minifier.Writer("text/html", dest)
+}
+
+// MinifyHTML minifies the html source.
+// If an error occurs, returns the unmodified source instead.
+func MinifyHTML(source []byte) []byte {
+	result, err := minifier.Bytes("text/html", source)
+	if err != nil {
+		return source
+	}
+	return result
+}