0904

internal/template/minify.go

@@ -0,0 +1,119 @@
+// Copyright 2022 E99p1ant. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package template
+
+import (
+	"bytes"
+	"embed"
+	"io/fs"
+	"path/filepath"
+	"regexp"
+
+	"github.com/flamego/template"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"github.com/tdewolff/minify/v2"
+	"github.com/tdewolff/minify/v2/css"
+	"github.com/tdewolff/minify/v2/html"
+	"github.com/tdewolff/minify/v2/js"
+)
+
+var _ template.FileSystem = (*FileSystem)(nil)
+
+type file struct {
+	name string
+	data []byte
+	ext  string
+}
+
+func (f *file) Name() string          { return f.name }
+func (f *file) Data() ([]byte, error) { return f.data, nil }
+func (f *file) Ext() string           { return f.ext }
+
+type FileSystem struct {
+	files []template.File
+}
+
+func (fs *FileSystem) Files() []template.File { return fs.files }
+
+// getExt returns the extension of given name, prefixed with the dot (".").
+// 必须用 filepath.Ext：取最后一个点之后的部分。
+// 旧的 strings.Index 实现会把 "foo.bar.html" 的扩展名误判为 ".bar.html"，
+// 导致模板名截取错误（如 "foo" 丢失子目录结构）。
+func getExt(name string) string {
+	return filepath.Ext(name)
+}
+
+func Minify(embedFS embed.FS, dir string, allowedExtensions []string) (*FileSystem, error) {
+	var beforeSize, afterSize int64
+
+	var files []template.File
+	m := minify.New()
+	m.AddFunc("text/html", html.Minify)
+	m.AddFunc("text/css", css.Minify)
+	m.AddFuncRegexp(regexp.MustCompile(`^(application|text)/(x-)?(java|ecma)script$`), js.Minify)
+
+	err := fs.WalkDir(embedFS, dir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+
+		relpath, err := filepath.Rel(dir, path)
+		if err != nil {
+			return errors.Wrap(err, "get relative path")
+		}
+
+		ext := getExt(relpath)
+		for _, allowed := range allowedExtensions {
+			if ext != allowed {
+				continue
+			}
+
+			data, err := embedFS.ReadFile(path)
+			if err != nil {
+				return errors.Wrap(err, "read")
+			}
+			beforeSize += int64(len(data))
+
+			var buf bytes.Buffer
+			switch filepath.Ext(path) {
+			case ".html":
+				if err := html.Minify(m, &buf, bytes.NewReader(data), nil); err != nil {
+					return errors.Wrap(err, "minify html")
+				}
+			default:
+				buf = *bytes.NewBuffer(data)
+			}
+			afterSize += int64(buf.Len())
+
+			name := filepath.ToSlash(relpath[:len(relpath)-len(ext)])
+			files = append(files,
+				&file{
+					name: name,
+					data: buf.Bytes(),
+					ext:  ext,
+				},
+			)
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, errors.Wrap(err, "walk")
+	}
+
+	logrus.WithFields(logrus.Fields{
+		"before_size": beforeSize,
+		"after_size":  afterSize,
+		"ratio":       float64(afterSize) / float64(beforeSize),
+	}).Info("Minify succeeded")
+
+	return &FileSystem{
+		files: files,
+	}, nil
+}