fix1

internal/blobfs/blobfs.go

@@ -0,0 +1,161 @@
+package blobfs
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"mime"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type Meta struct {
+	Name        string `json:"name"`
+	Size        int64  `json:"size"`
+	ContentType string `json:"contentType"`
+	SHA256      string `json:"sha256"`
+}
+
+type Store interface {
+	Save(ctx context.Context, id int64, filename string, r io.Reader) (Meta, error)
+	Open(ctx context.Context, id int64) (io.ReadSeekCloser, Meta, error)
+	Stat(ctx context.Context, id int64) (Meta, bool, error)
+	Delete(ctx context.Context, id int64) error
+}
+
+type FS struct{ root string }
+
+func New(root string) *FS { return &FS{root: root} }
+
+func (fs *FS) dir(id int64) string      { return filepath.Join(fs.root, "files", fmt.Sprintf("%d", id)) }
+func (fs *FS) metaPath(id int64) string { return filepath.Join(fs.dir(id), "meta.json") }
+func (fs *FS) blobPath(id int64, name string) string {
+	return filepath.Join(fs.dir(id), "blob"+safeExt(name))
+}
+
+func safeExt(name string) string {
+	ext := filepath.Ext(name)
+	if len(ext) > 16 { // unrealistisch lange Exts beschneiden
+		ext = ext[:16]
+	}
+	return ext
+}
+
+func (fs *FS) Save(_ context.Context, id int64, filename string, r io.Reader) (Meta, error) {
+	if strings.TrimSpace(filename) == "" {
+		return Meta{}, errors.New("filename required")
+	}
+	if err := os.MkdirAll(fs.dir(id), 0o755); err != nil {
+		return Meta{}, err
+	}
+	tmp := filepath.Join(fs.dir(id), "blob.tmp")
+	out, err := os.Create(tmp)
+	if err != nil {
+		return Meta{}, err
+	}
+	defer out.Close()
+
+	hasher := sha256.New()
+	tee := io.TeeReader(r, hasher)
+
+	// Content-Type sniffen: ersten 512 Bytes puffern
+	buf := make([]byte, 512)
+	n, _ := io.ReadFull(tee, buf)
+	if n > 0 {
+		if _, err := out.Write(buf[:n]); err != nil {
+			return Meta{}, err
+		}
+	}
+	// Rest kopieren
+	size := int64(n)
+	written, err := io.Copy(out, tee)
+	if err != nil {
+		return Meta{}, err
+	}
+	size += written
+
+	// Hash
+	sum := hex.EncodeToString(hasher.Sum(nil))
+
+	ct := http.DetectContentType(buf[:n])
+	if ct == "application/octet-stream" {
+		// Versuch über Dateiendung
+		if ext := filepath.Ext(filename); ext != "" {
+			if byExt := mime.TypeByExtension(ext); byExt != "" {
+				ct = byExt
+			}
+		}
+	}
+
+	// finaler Ort
+	final := fs.blobPath(id, filename)
+	if err := os.Rename(tmp, final); err != nil {
+		return Meta{}, err
+	}
+
+	meta := Meta{Name: filename, Size: size, ContentType: ct, SHA256: sum}
+	if err := writeJSON(fs.metaPath(id), meta); err != nil {
+		return Meta{}, err
+	}
+
+	return meta, nil
+}
+
+func (fs *FS) Open(_ context.Context, id int64) (io.ReadSeekCloser, Meta, error) {
+	meta, ok, err := fs.Stat(context.Background(), id)
+	if err != nil {
+		return nil, Meta{}, err
+	}
+	if !ok {
+		return nil, Meta{}, os.ErrNotExist
+	}
+	f, err := os.Open(fs.blobPath(id, meta.Name))
+	return f, meta, err
+}
+
+func (fs *FS) Stat(_ context.Context, id int64) (Meta, bool, error) {
+	b, err := os.ReadFile(fs.metaPath(id))
+	if err != nil {
+		if os.IsNotExist(err) {
+			return Meta{}, false, nil
+		}
+		return Meta{}, false, err
+	}
+	var m Meta
+	if err := json.Unmarshal(b, &m); err != nil {
+		return Meta{}, false, err
+	}
+	// Größe aus FS gegenprüfen (falls manipuliert)
+	info, err := os.Stat(fs.blobPath(id, m.Name))
+	if err == nil {
+		m.Size = info.Size()
+	}
+	return m, true, nil
+}
+
+func (fs *FS) Delete(_ context.Context, id int64) error {
+	return os.RemoveAll(fs.dir(id))
+}
+
+func writeJSON(path string, v any) error {
+	tmp := path + ".tmp"
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return err
+	}
+	f, err := os.Create(tmp)
+	if err != nil {
+		return err
+	}
+	if err := json.NewEncoder(f).Encode(v); err != nil {
+		f.Close()
+		return err
+	}
+	f.Close()
+	return os.Rename(tmp, path)
+}