Use embed package for CSS bundles instead of generated files

ui/static/static.go

@@ -5,32 +5,48 @@
 package static // import "miniflux.app/ui/static"
 
 import (
+	"bytes"
 	"crypto/sha256"
 	"embed"
 	"fmt"
+
+	"github.com/tdewolff/minify/v2"
+	"github.com/tdewolff/minify/v2/css"
+)
+
+// Static assets.
+var (
+	StylesheetBundleChecksums map[string]string
+	StylesheetBundles         map[string][]byte
 )
 
 //go:embed bin/*
 var binaryFiles embed.FS
 
+//go:embed css/*.css
+var stylesheetFiles embed.FS
+
 var binaryFileChecksums map[string]string
 
-func init() {
+// CalculateBinaryFileChecksums generates hash of embed binary files.
+func CalculateBinaryFileChecksums() error {
 	binaryFileChecksums = make(map[string]string)
 
 	dirEntries, err := binaryFiles.ReadDir("bin")
 	if err != nil {
-		panic(err)
+		return err
 	}
 
 	for _, dirEntry := range dirEntries {
 		data, err := LoadBinaryFile(dirEntry.Name())
 		if err != nil {
-			panic(err)
+			return err
 		}
 
 		binaryFileChecksums[dirEntry.Name()] = fmt.Sprintf("%x", sha256.Sum256(data))
 	}
+
+	return nil
 }
 
 // LoadBinaryFile loads an embed binary file.
@@ -45,3 +61,44 @@ func GetBinaryFileChecksum(filename string) (string, error) {
 	}
 	return binaryFileChecksums[filename], nil
 }
+
+// GenerateStylesheetsBundles creates CSS bundles.
+func GenerateStylesheetsBundles() error {
+	var bundles = map[string][]string{
+		"light_serif":       {"css/light.css", "css/serif.css", "css/common.css"},
+		"light_sans_serif":  {"css/light.css", "css/sans_serif.css", "css/common.css"},
+		"dark_serif":        {"css/dark.css", "css/serif.css", "css/common.css"},
+		"dark_sans_serif":   {"css/dark.css", "css/sans_serif.css", "css/common.css"},
+		"system_serif":      {"css/system.css", "css/serif.css", "css/common.css"},
+		"system_sans_serif": {"css/system.css", "css/sans_serif.css", "css/common.css"},
+	}
+
+	StylesheetBundles = make(map[string][]byte)
+	StylesheetBundleChecksums = make(map[string]string)
+
+	minifier := minify.New()
+	minifier.AddFunc("text/css", css.Minify)
+
+	for bundle, srcFiles := range bundles {
+		var buffer bytes.Buffer
+
+		for _, srcFile := range srcFiles {
+			fileData, err := stylesheetFiles.ReadFile(srcFile)
+			if err != nil {
+				return err
+			}
+
+			buffer.Write(fileData)
+		}
+
+		minifiedData, err := minifier.Bytes("text/css", buffer.Bytes())
+		if err != nil {
+			return err
+		}
+
+		StylesheetBundles[bundle] = minifiedData
+		StylesheetBundleChecksums[bundle] = fmt.Sprintf("%x", sha256.Sum256(minifiedData))
+	}
+
+	return nil
+}

ui/static_stylesheet.go

@@ -29,7 +29,7 @@ func (h *handler) showStylesheet(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	etag, found := static.StylesheetsChecksums[filename]
+	etag, found := static.StylesheetBundleChecksums[filename]
 	if !found {
 		html.NotFound(w, r)
 		return
@@ -37,7 +37,7 @@ func (h *handler) showStylesheet(w http.ResponseWriter, r *http.Request) {
 
 	response.New(w, r).WithCaching(etag, 48*time.Hour, func(b *response.Builder) {
 		b.WithHeader("Content-Type", "text/css; charset=utf-8")
-		b.WithBody(static.Stylesheets[filename])
+		b.WithBody(static.StylesheetBundles[filename])
 		b.Write()
 	})
 }

ui/view/view.go

@@ -40,7 +40,7 @@ func New(tpl *template.Engine, r *http.Request, sess *session.Session) *View {
 	b.params["flashMessage"] = sess.FlashMessage(request.FlashMessage(r))
 	b.params["flashErrorMessage"] = sess.FlashErrorMessage(request.FlashErrorMessage(r))
 	b.params["theme"] = theme
-	b.params["theme_checksum"] = static.StylesheetsChecksums[theme]
+	b.params["theme_checksum"] = static.StylesheetBundleChecksums[theme]
 	b.params["app_js_checksum"] = static.JavascriptsChecksums["app"]
 	b.params["sw_js_checksum"] = static.JavascriptsChecksums["service-worker"]
 	return b