feat: caching headers

internal/components/page/page.go

@@ -0,0 +1,88 @@
+package page
+
+import (
+	"bytes"
+	"compress/flate"
+	"context"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"log/slog"
+	"regexp"
+	"strings"
+
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/images"
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/translate"
+	"github.com/studio-b12/gowebdav"
+)
+
+var titleRGX = regexp.MustCompile(`(?m)^#\s+(.+)$`)
+
+var (
+	ErrMalFormedInput = errors.New("mal formed input")
+	ErrNotFound       = errors.New("not found")
+)
+
+func (s *Service) getPageHeaders(ctx context.Context, uid string) (page PageHeader, err error) {
+	info, err := s.fs.ReadDir(uid)
+	if gowebdav.IsErrNotFound(err) { // try private
+		err = ErrNotFound
+	}
+	if err != nil {
+		return
+	}
+
+	lang := translate.Language(ctx)
+
+	var coverImage *gowebdav.File
+	var contentMD *gowebdav.File
+
+	for _, f := range info {
+		file := f.(gowebdav.File)
+
+		if strings.HasPrefix(file.ContentType(), "image/") {
+			coverImage = &file
+		}
+
+		parts := strings.Split(file.Name(), ".")
+
+		// fallback content
+		if contentMD == nil && len(parts) == 2 && parts[1] == "md" {
+			contentMD = &file
+		}
+		// language content
+		if len(parts) == 3 && parts[1] == lang && parts[2] == "md" {
+			contentMD = &file
+		}
+	}
+
+	slog.Debug("loaded page infos", "cover", coverImage, "content", contentMD)
+
+	content, err := s.fs.Read(contentMD.Path())
+	if err != nil {
+		return
+	}
+
+	title := titleRGX.FindStringSubmatch(string(content))
+	if len(title) < 2 {
+		err = fmt.Errorf("%w: no matches for title", ErrMalFormedInput)
+		return
+	}
+
+	page.UID = uid
+	page.Title = title[1]
+	page.CoverImageUID, err = images.UIDFromPath(coverImage.Path())
+
+	return
+}
+
+func getImageUID(path string) string {
+	var b bytes.Buffer
+	// NewWriter with NoDict (nil) creates a raw DEFLATE compressor
+	zw, _ := flate.NewWriter(&b, flate.BestCompression)
+
+	zw.Write([]byte(path))
+	zw.Close() // Essential to flush the final bits
+
+	return base64.RawURLEncoding.EncodeToString(b.Bytes())
+}