wip

2026-04-23 21:56:59 +02:00
commit 7a11b5bbbf
17 changed files with 1710 additions and 0 deletions
@@ -0,0 +1,282 @@
+package caldav
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"path"
+	"strings"
+	"time"
+
+	ical "github.com/emersion/go-ical"
+	"github.com/emersion/go-webdav"
+	"github.com/emersion/go-webdav/caldav"
+	"github.com/yourusername/caldav-server/internal/auth"
+	"github.com/yourusername/caldav-server/internal/config"
+	"github.com/yourusername/caldav-server/internal/store"
+)
+
+// Backend implements caldav.Backend using a filesystem store.
+type Backend struct {
+	cfg    *config.Config
+	store  *store.Store
+	logger *slog.Logger
+}
+
+// NewBackend creates a CalDAV backend.
+func NewBackend(cfg *config.Config, st *store.Store, logger *slog.Logger) *Backend {
+	return &Backend{cfg: cfg, store: st, logger: logger}
+}
+
+// NewHandler returns an http.Handler for the /cal/ prefix.
+func NewHandler(cfg *config.Config, st *store.Store, logger *slog.Logger) http.Handler {
+	b := NewBackend(cfg, st, logger)
+	return &caldav.Handler{Backend: b}
+}
+
+// -------- caldav.Backend interface --------
+
+func (b *Backend) CurrentUserPrincipal(ctx context.Context) (string, error) {
+	p := auth.FromContext(ctx)
+	if p == nil {
+		return "", webdav.NewHTTPError(http.StatusUnauthorized, fmt.Errorf("not authenticated"))
+	}
+	return principalPath(p.Username), nil
+}
+
+func (b *Backend) CalendarHomeSetPath(ctx context.Context) (string, error) {
+	p := auth.FromContext(ctx)
+	if p == nil {
+		return "", webdav.NewHTTPError(http.StatusUnauthorized, fmt.Errorf("not authenticated"))
+	}
+	return calHomePath(p.Username), nil
+}
+
+func (b *Backend) ListCalendars(ctx context.Context) ([]caldav.Calendar, error) {
+	p := auth.FromContext(ctx)
+	if p == nil {
+		return nil, webdav.NewHTTPError(http.StatusUnauthorized, fmt.Errorf("not authenticated"))
+	}
+
+	user, ok := b.cfg.Users[p.Username]
+	if !ok {
+		return nil, fmt.Errorf("user not found")
+	}
+
+	var cals []caldav.Calendar
+	for _, name := range user.Calendars {
+		if err := b.store.EnsureCollection(p.Username, "cal-"+name); err != nil {
+			b.logger.Warn("ensuring calendar directory", "calendar", name, "error", err)
+			continue
+		}
+		cals = append(cals, b.calendarMeta(p.Username, name))
+	}
+
+	// Also include any extra calendars that exist on disk but aren't in config
+	disk, _ := b.store.ListCollections(p.Username)
+	configured := make(map[string]bool)
+	for _, n := range user.Calendars {
+		configured["cal-"+n] = true
+	}
+	for _, dir := range disk {
+		if strings.HasPrefix(dir, "cal-") && !configured[dir] {
+			name := strings.TrimPrefix(dir, "cal-")
+			cals = append(cals, b.calendarMeta(p.Username, name))
+		}
+	}
+
+	return cals, nil
+}
+
+func (b *Backend) GetCalendar(ctx context.Context, calPath string) (*caldav.Calendar, error) {
+	user, name, err := b.parseCalPath(ctx, calPath)
+	if err != nil {
+		return nil, err
+	}
+	if _, err := b.store.GetCollection(user, "cal-"+name); err != nil {
+		return nil, webdav.NewHTTPError(http.StatusNotFound, err)
+	}
+	cal := b.calendarMeta(user, name)
+	return &cal, nil
+}
+
+func (b *Backend) GetCalendarObject(ctx context.Context, objPath string, req *caldav.CalendarCompRequest) (*caldav.CalendarObject, error) {
+	user, calName, objID, err := b.parseObjPath(ctx, objPath)
+	if err != nil {
+		return nil, err
+	}
+
+	data, err := b.store.GetObject(user, "cal-"+calName, objID)
+	if err != nil {
+		return nil, webdav.NewHTTPError(http.StatusNotFound, err)
+	}
+
+	return b.decodeObject(objPath, data)
+}
+
+func (b *Backend) ListCalendarObjects(ctx context.Context, calPath string, req *caldav.CalendarCompRequest) ([]caldav.CalendarObject, error) {
+	user, calName, err := b.parseCalPath(ctx, calPath)
+	if err != nil {
+		return nil, err
+	}
+
+	ids, err := b.store.ListObjects(user, "cal-"+calName)
+	if err != nil {
+		return nil, err
+	}
+
+	var objs []caldav.CalendarObject
+	for _, id := range ids {
+		data, err := b.store.GetObject(user, "cal-"+calName, id)
+		if err != nil {
+			continue
+		}
+		obj, err := b.decodeObject(calObjectPath(user, calName, id), data)
+		if err != nil {
+			b.logger.Warn("decoding calendar object", "id", id, "error", err)
+			continue
+		}
+		objs = append(objs, *obj)
+	}
+	return objs, nil
+}
+
+func (b *Backend) QueryCalendarObjects(ctx context.Context, calPath string, query *caldav.CalendarQuery) ([]caldav.CalendarObject, error) {
+	// List all and filter – sufficient for small collections.
+	all, err := b.ListCalendarObjects(ctx, calPath, &query.CompRequest)
+	if err != nil {
+		return nil, err
+	}
+	return caldav.Filter(query, all)
+}
+
+func (b *Backend) CreateCalendar(ctx context.Context, calendar *caldav.Calendar) error {
+	p := auth.FromContext(ctx)
+	if p == nil {
+		return webdav.NewHTTPError(http.StatusUnauthorized, fmt.Errorf("not authenticated"))
+	}
+	// Derive collection name from the trailing path segment.
+	name := path.Base(strings.TrimSuffix(calendar.Path, "/"))
+	return b.store.EnsureCollection(p.Username, "cal-"+name)
+}
+
+func (b *Backend) DeleteCalendar(ctx context.Context, calPath string) error {
+	user, name, err := b.parseCalPath(ctx, calPath)
+	if err != nil {
+		return err
+	}
+	return b.store.DeleteCollection(user, "cal-"+name)
+}
+
+func (b *Backend) PutCalendarObject(ctx context.Context, objPath string, calendar *ical.Calendar, opts *caldav.PutCalendarObjectOptions) (*caldav.CalendarObject, error) {
+	user, calName, objID, err := b.parseObjPath(ctx, objPath)
+	if err != nil {
+		return nil, err
+	}
+
+	var buf strings.Builder
+	enc := ical.NewEncoder(&buf)
+	if err := enc.Encode(calendar); err != nil {
+		return nil, fmt.Errorf("encoding calendar: %w", err)
+	}
+
+	data := []byte(buf.String())
+	if err := b.store.PutObject(user, "cal-"+calName, objID, data); err != nil {
+		return nil, fmt.Errorf("storing calendar object: %w", err)
+	}
+
+	return b.decodeObject(objPath, data)
+}
+
+func (b *Backend) DeleteCalendarObject(ctx context.Context, objPath string) error {
+	user, calName, objID, err := b.parseObjPath(ctx, objPath)
+	if err != nil {
+		return err
+	}
+	if err := b.store.DeleteObject(user, "cal-"+calName, objID); err != nil {
+		return webdav.NewHTTPError(http.StatusNotFound, err)
+	}
+	return nil
+}
+
+// -------- helpers --------
+
+func (b *Backend) calendarMeta(user, name string) caldav.Calendar {
+	return caldav.Calendar{
+		Path:                  calHomePath(user) + name + "/",
+		Name:                  name,
+		Description:           fmt.Sprintf("%s's %s calendar", user, name),
+		SupportedComponentSet: []string{"VEVENT", "VTODO", "VJOURNAL"},
+		MaxResourceSize:       10 * 1024 * 1024, // 10 MiB
+	}
+}
+
+func (b *Backend) decodeObject(objPath string, data []byte) (*caldav.CalendarObject, error) {
+	cal, err := ical.NewDecoder(strings.NewReader(string(data))).Decode()
+	if err != nil {
+		return nil, fmt.Errorf("decoding ical: %w", err)
+	}
+
+	etag := fmt.Sprintf(`"%x"`, hashBytes(data))
+
+	return &caldav.CalendarObject{
+		Path:          objPath,
+		ModTime:       time.Now(),
+		ContentLength: int64(len(data)),
+		ETag:          etag,
+		Data:          cal,
+	}, nil
+}
+
+func (b *Backend) parseCalPath(ctx context.Context, calPath string) (user, calName string, err error) {
+	p := auth.FromContext(ctx)
+	if p == nil {
+		return "", "", webdav.NewHTTPError(http.StatusUnauthorized, fmt.Errorf("not authenticated"))
+	}
+	user = p.Username
+	parts := strings.Split(strings.Trim(calPath, "/"), "/")
+	// expected: cal/<user>/<calname>/
+	if len(parts) < 3 {
+		return "", "", webdav.NewHTTPError(http.StatusBadRequest, fmt.Errorf("invalid calendar path"))
+	}
+	calName = parts[2]
+	return user, calName, nil
+}
+
+func (b *Backend) parseObjPath(ctx context.Context, objPath string) (user, calName, objID string, err error) {
+	p := auth.FromContext(ctx)
+	if p == nil {
+		return "", "", "", webdav.NewHTTPError(http.StatusUnauthorized, fmt.Errorf("not authenticated"))
+	}
+	user = p.Username
+	parts := strings.Split(strings.Trim(objPath, "/"), "/")
+	// expected: cal/<user>/<calname>/<objid>
+	if len(parts) < 4 {
+		return "", "", "", webdav.NewHTTPError(http.StatusBadRequest, fmt.Errorf("invalid object path"))
+	}
+	calName = parts[2]
+	objID = path.Base(objPath)
+	return user, calName, objID, nil
+}
+
+func principalPath(user string) string {
+	return fmt.Sprintf("/principals/%s/", user)
+}
+
+func calHomePath(user string) string {
+	return fmt.Sprintf("/cal/%s/", user)
+}
+
+func calObjectPath(user, calName, objID string) string {
+	return fmt.Sprintf("/cal/%s/%s/%s", user, calName, objID)
+}
+
+func hashBytes(data []byte) uint64 {
+	var h uint64 = 14695981039346656037
+	for _, b := range data {
+		h ^= uint64(b)
+		h *= 1099511628211
+	}
+	return h
+}