Books: broken-book repair flow + simplify password change

When a book fails to open, a '!' button appears next to it in the list.
Clicking it prompts for the original file; the file is re-encrypted with
the current key and replaces the broken ciphertext on the server while
keeping all metadata, progress, highlights and bookmarks intact.

- Add POST /books/<pk>/replace-data/ endpoint (updates data only)
- Add _evictCachedBook() to clear IndexedDB cache for a single book
- Replace complex client-side re-encryption on password change with a
  simple confirm() warning that books will need to be re-uploaded

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

books/urls.py

@@ -6,6 +6,7 @@ urlpatterns = [
     path('upload/', views.upload_book, name='upload_book'),
     path('<int:pk>/data/', views.get_book_data, name='get_book_data'),
     path('<int:pk>/delete/', views.delete_book, name='delete_book'),
+    path('<int:pk>/replace-data/', views.replace_book_data, name='replace_book_data'),
     path('<int:pk>/rekey/', views.rekey_book, name='rekey_book'),
     path('<int:pk>/progress/', views.save_progress, name='save_book_progress'),
     path('<int:pk>/highlights/', views.book_highlights, name='book_highlights'),

books/views.py

@@ -94,6 +94,35 @@ def get_book_data(request, pk):
     return JsonResponse({'data_ct': book.data_ct, 'data_iv': book.data_iv})
 
 
+@csrf_exempt
+@require_http_methods(['POST'])
+def replace_book_data(request, pk):
+    err = _require_auth(request)
+    if err:
+        return err
+
+    try:
+        book = EBook.objects.get(pk=pk, user=request.user)
+    except EBook.DoesNotExist:
+        return JsonResponse({'error': 'not found'}, status=404)
+
+    try:
+        body = json.loads(request.body)
+    except (json.JSONDecodeError, ValueError):
+        return JsonResponse({'error': 'invalid JSON'}, status=400)
+
+    data_ct = body.get('data_ct', '')
+    data_iv = body.get('data_iv', '')
+
+    if not all([data_ct, data_iv]):
+        return JsonResponse({'error': 'data_ct and data_iv required'}, status=400)
+
+    book.data_ct = data_ct
+    book.data_iv = data_iv
+    book.save(update_fields=['data_ct', 'data_iv'])
+    return JsonResponse({'ok': True})
+
+
 @csrf_exempt
 @require_http_methods(['POST'])
 def rekey_book(request, pk):

static/js/app.js

@@ -2720,6 +2720,18 @@ async function _setCachedBook(bookId, data_ct, data_iv) {
   } catch {}
 }
 
+async function _evictCachedBook(bookId) {
+  try {
+    const db = await _openBookCacheDb();
+    await new Promise((resolve) => {
+      const tx = db.transaction(_BOOK_CACHE_STORE, 'readwrite');
+      tx.objectStore(_BOOK_CACHE_STORE).delete(bookId);
+      tx.oncomplete = resolve;
+      tx.onerror    = resolve;
+    });
+  } catch {}
+}
+
 async function _evictBookCache(bookList) {
   try {
     const db = await _openBookCacheDb();
@@ -2838,6 +2850,54 @@ async function loadBookList() {
   }
 }
 
+const _brokenBooks = new Set();
+
+function markBookBroken(bookId) {
+  _brokenBooks.add(bookId);
+  const item = document.querySelector(`.book-item[data-book-id="${bookId}"]`);
+  if (!item) return;
+  if (!item.querySelector('.book-broken-btn')) {
+    const btn = document.createElement('button');
+    btn.className = 'btn btn-sm btn-danger book-broken-btn';
+    btn.title = 'Buch konnte nicht geöffnet werden — Datei erneut hochladen';
+    btn.textContent = '!';
+    btn.onclick = () => repairBook(bookId);
+    item.querySelector('.book-item-actions').prepend(btn);
+  }
+}
+
+function repairBook(bookId) {
+  const input = document.createElement('input');
+  input.type = 'file';
+  input.accept = '.epub,.pdf';
+  input.onchange = async () => {
+    const file = input.files[0];
+    if (!file) return;
+    const item = document.querySelector(`.book-item[data-book-id="${bookId}"]`);
+    const btn = item?.querySelector('.book-broken-btn');
+    if (btn) btn.textContent = '…';
+    try {
+      const key = await getOrCreateEncKey();
+      const buf = await file.arrayBuffer();
+      const enc = await encryptBytes(key, buf);
+      const res = await fetch(`/books/${bookId}/replace-data/`, {
+        method: 'POST',
+        headers: {'Content-Type': 'application/json', 'X-CSRFToken': getCsrfToken()},
+        body: JSON.stringify({data_ct: enc.ciphertext, data_iv: enc.iv}),
+      });
+      if (!(await res.json()).ok) throw new Error('Server error');
+      await _evictCachedBook(bookId);
+      _brokenBooks.delete(bookId);
+      if (btn) btn.remove();
+      openBook(bookId);
+    } catch (e) {
+      if (btn) btn.textContent = '!';
+      alert('Reparatur fehlgeschlagen: ' + e.message);
+    }
+  };
+  input.click();
+}
+
 function renderBookList(books) {
   const listEl = $('book-list');
   if (!listEl) return;
@@ -2845,13 +2905,15 @@ function renderBookList(books) {
   for (const b of books) {
     const pct = Math.round((b.scroll_fraction || 0) * 100);
     const keyWarning = b.keyOk === false ? '<span title="Wrong encryption key — import the correct key to open this book" style="color:var(--accent,#e63946);margin-left:4px;">⚠️ wrong key</span>' : '';
-    html += `<div class="book-item">
+    const broken = _brokenBooks.has(b.id);
+    html += `<div class="book-item" data-book-id="${b.id}">
       <div class="book-item-info">
         <strong class="book-title">${escapeHtml(b.title)}${keyWarning}</strong>
         <span class="muted book-author">${escapeHtml(b.author)}</span>
         ${pct > 0 ? `<span class="muted book-progress">${pct}% read</span>` : ''}
       </div>
       <div class="book-item-actions">
+        ${broken ? `<button class="btn btn-sm btn-danger book-broken-btn" title="Buch konnte nicht geöffnet werden — Datei erneut hochladen" onclick="repairBook(${b.id})">!</button>` : ''}
         <button class="btn btn-sm" onclick="openBook(${b.id})"${b.keyOk === false ? ' disabled title="Import the correct encryption key first"' : ''}>Open</button>
         <button class="btn btn-sm btn-danger" onclick="deleteBook(${b.id})">Delete</button>
       </div>
@@ -3352,7 +3414,7 @@ async function openBook(bookId) {
 
   } catch (e) {
     overlay.style.display = 'none';
-    alert(`Failed to open book: ${e.message}`);
+    markBookBroken(bookId);
   }
 }
 

templates/accounts/settings.html

@@ -143,101 +143,9 @@ async function _getOrCreateEncKey() {
   return key;
 }
 
-function _hexToBytes(hex) {
+document.getElementById('pw-change-form')?.addEventListener('submit', function(e) {
-  const buf = new Uint8Array(hex.length / 2);
+  const ok = confirm('Nach dem Ändern des Passworts können alle hochgeladenen Bücher nicht mehr geöffnet werden und müssen erneut hochgeladen werden. Fortfahren?');
-  for (let i = 0; i < buf.length; i++) buf[i] = parseInt(hex.slice(i*2, i*2+2), 16);
+  if (!ok) e.preventDefault();
-  return buf;
-}
-
-async function _pbkdf2Key(password, username) {
-  const enc = new TextEncoder();
-  const mat = await crypto.subtle.importKey('raw', enc.encode(password), 'PBKDF2', false, ['deriveKey']);
-  return crypto.subtle.deriveKey(
-    {name: 'PBKDF2', salt: enc.encode('diora:' + username), iterations: 200000, hash: 'SHA-256'},
-    mat, {name: 'AES-GCM', length: 256}, true, ['encrypt', 'decrypt']
-  );
-}
-
-async function _reEncrypt(oldKey, newKey, iv, ct) {
-  const plain = await crypto.subtle.decrypt({name: 'AES-GCM', iv: _hexToBytes(iv)}, oldKey, _base64ToBytes(ct));
-  const newIv = crypto.getRandomValues(new Uint8Array(12));
-  const newCt = await crypto.subtle.encrypt({name: 'AES-GCM', iv: newIv}, newKey, plain);
-  return {iv: _bytesToHex(newIv), ct: _bytesToBase64(newCt)};
-}
-
-document.getElementById('pw-change-form')?.addEventListener('submit', async function(e) {
-  e.preventDefault();
-  const form = this;
-  const statusEl = document.getElementById('pw-change-status');
-  const oldPw = form.old_password.value;
-  const newPw = form.new_password1.value;
-  const userId = {{ request.user.id }};
-  const username = '{{ request.user.username }}';
-  const storageKey = `diora_enc_key_${userId}`;
-
-  statusEl.textContent = 'Passwort prüfen…';
-  try {
-    // Validate old password server-side before touching any keys
-    const checkResp = await fetch('/accounts/check-password/', {
-      method: 'POST',
-      headers: {'Content-Type': 'application/json', 'X-CSRFToken': getCsrfToken()},
-      body: JSON.stringify({password: oldPw}),
-    }).then(r => r.json());
-    if (!checkResp.ok) {
-      statusEl.textContent = 'Fehler: Altes Passwort ist falsch.';
-      return;
-    }
-
-    // Use the key currently in localStorage as the old key (source of truth for decryption)
-    const stored = localStorage.getItem(storageKey);
-    let oldKey;
-    if (stored) {
-      oldKey = await crypto.subtle.importKey('raw', _base64ToBytes(stored), {name: 'AES-GCM'}, false, ['decrypt']);
-    }
-
-    const newKey = await _pbkdf2Key(newPw, username);
-
-    // Re-encrypt all books (only if we have a key to decrypt with)
-    statusEl.textContent = 'Bücherliste laden…';
-    const books = oldKey ? await fetch('/books/').then(r => r.json()) : [];
-
-    for (let i = 0; i < books.length; i++) {
-      const book = books[i];
-      statusEl.textContent = `Buch ${i + 1} / ${books.length} neu verschlüsseln…`;
-
-      const newMeta = await _reEncrypt(oldKey, newKey, book.meta_iv, book.meta_ct);
-      const data    = await fetch(`/books/${book.id}/data/`).then(r => r.json());
-      const newData = await _reEncrypt(oldKey, newKey, data.data_iv, data.data_ct);
-
-      await fetch(`/books/${book.id}/rekey/`, {
-        method: 'POST',
-        headers: {'Content-Type': 'application/json', 'X-CSRFToken': getCsrfToken()},
-        body: JSON.stringify({meta_ct: newMeta.ct, meta_iv: newMeta.iv, data_ct: newData.ct, data_iv: newData.iv}),
-      });
-
-      // Re-encrypt highlights and bookmarks if they exist
-      for (const endpoint of ['highlights', 'bookmarks']) {
-        const resp = await fetch(`/books/${book.id}/${endpoint}/`).then(r => r.json());
-        if (resp.ct) {
-          const reenc = await _reEncrypt(oldKey, newKey, resp.iv, resp.ct);
-          await fetch(`/books/${book.id}/${endpoint}/`, {
-            method: 'POST',
-            headers: {'Content-Type': 'application/json', 'X-CSRFToken': getCsrfToken()},
-            body: JSON.stringify({ct: reenc.ct, iv: reenc.iv}),
-          });
-        }
-      }
-    }
-
-    // Update localStorage key
-    const newRaw = new Uint8Array(await crypto.subtle.exportKey('raw', newKey));
-    localStorage.setItem(storageKey, _bytesToBase64(newRaw));
-
-    statusEl.textContent = 'Passwort ändern…';
-    form.submit();
-  } catch (err) {
-    statusEl.textContent = 'Fehler: ' + err.message;
-  }
 });
 
 async function uploadBackground(input) {