docs: link-import in anleitung, changelog und screenshots

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,21 @@ die Versionierung [Semantic Versioning](https://semver.org/lang/de/).
 
 ## [Unreleased]
 
+### Hinzugefügt
+
+- **Set aus einem Link übernehmen**, für alle Hersteller: Amazon, idealo,
+  geizhals, Hersteller-Shops, Brickfact oder Merlins Bricks. Bricktrack liest
+  Produktdaten (schema.org, Open Graph, bei Amazon die Produktseite) und, wenn
+  die Seite blockt, den Link selbst. Lego wird über Rebrickable ergänzt,
+  BlueBrixx und Cobi über Merlins Bricks. Das Ergebnis füllt das Formular vor,
+  das Bild wird beim Speichern lokal abgelegt.
+
+### Sicherheit
+
+- Abrufe im Auftrag eines Nutzers gehen nur an öffentliche Adressen: Jede
+  Adresse wird vor dem Verbindungsaufbau geprüft, Weiterleitungen ebenso,
+  Größe und Zeit sind begrenzt.
+
 ## [0.4.0] - 2026-10-25
 
 Ein neues Gesicht: Bricktrack sieht jetzt aus wie das, was es verwaltet.

CLAUDE.md

@@ -63,6 +63,8 @@ Bild-URLs, die der Nutzer selbst hinterlegt hat.
 | `src/lib/reminder-job.ts`, `src/lib/mailer.ts` | Versand und Zeitplan |
 | `src/lib/export.ts` | Export und Import des gesamten Bestands |
 | `src/lib/money.ts`, `src/lib/format.ts` | Cent-Umrechnung, dd.MM.yyyy |
+| `src/lib/link-import.ts` | Set-Daten aus Link und Seite lesen (rein, testbar) |
+| `src/lib/safe-fetch.ts`, `src/lib/net-guard.ts` | Abruf fremder URLs nur an oeffentliche Adressen |
 | `src/lib/design.ts`, `src/app/designs.css` | Designs: Namen und Cookie bzw. Tokens je `data-design` |
 | `src/components/brick/` | Noppen, Logo, Platzhalter fuer Sets ohne Bild |
 
@@ -195,7 +197,9 @@ Session.
    nichts preis ausser den Wunschlisten-Daten - keine Nutzernamen,
    keine Sammlungsdaten, keine IDs anderer Objekte.
 4. Externe API-Aufrufe (Rebrickable, ab Phase 2) laufen ausschliesslich
-   serverseitig.
+   serverseitig. URLs, die ein Nutzer eingibt (Link-Import, Bild-Uebernahme),
+   werden nur ueber `safeFetch` abgerufen - nie mit `fetch` direkt, sonst
+   erreicht der Server auch Geraete im Heimnetz.
 5. Session-Cookies: `httpOnly`, `secure`, `sameSite=lax`.
    Rate-Limiting auf den Login-Endpunkten.
 6. Der Export enthaelt **keine** Konten, Passwoerter oder Passkeys - und

docs/ANLEITUNG.md

@@ -306,8 +306,35 @@ gib ihnen sprechende Namen.
 
 ## 11. Import und Scanner
 
-Sets von Hand einzutippen ist der langsame Weg. Für Lego gibt es zwei
+Sets von Hand einzutippen ist der langsame Weg. Es gibt drei schnellere.
-schnellere.
+
+### Aus einem Link übernehmen – für alle Hersteller
+
+Auf **Katalog → Set anlegen** steht das Feld „Aus einem Link übernehmen".
+Dort passt jeder Link zu einem Set hinein: Amazon, idealo, geizhals, der Shop
+des Herstellers oder eine Set-Datenbank wie
+[Brickfact](https://brickfact.com) (Lego) und
+[Merlins Bricks](https://www.merlinsbricks.com) (BlueBrixx, Cobi und viele
+mehr). „Übernehmen" füllt das Formular darunter aus – **gespeichert wird erst,
+wenn du „Set anlegen" drückst**. Ein Blick auf Name und Nummer lohnt sich,
+denn Shops schreiben gern das halbe Sortiment in den Titel.
+
+Was dabei passiert:
+
+1. Bricktrack liest die Seite und übernimmt Name, Setnummer, EAN, Bild,
+   Teile und Jahr, soweit sie dort stehen.
+2. Manche Shops lassen sich nicht abfragen. Dann reicht oft schon der Link
+   selbst: In `amazon.de/LEGO-60398-Familienhaus-…` stecken Hersteller,
+   Nummer und Name.
+3. Mit Hersteller und Nummer ergänzt Bricktrack den Rest: Lego über
+   Rebrickable (mit API-Key), BlueBrixx und Cobi über Merlins Bricks.
+
+Das Bild wird beim Speichern lokal abgelegt, die Quelle steht in den Notizen.
+Gibt es den Hersteller noch nicht, wird er angelegt. Steht das Set schon im
+Katalog, kommt statt des Formulars ein Link zum vorhandenen Eintrag.
+
+> Bricktrack ruft dafür nur öffentliche Adressen ab. Links ins eigene Netz –
+> Router, NAS, andere Container – werden abgewiesen.
 
 ### Lego-Import über die Setnummer
 

src/app/(app)/katalog/actions.ts

@@ -5,8 +5,10 @@ import { and, eq, ne } from 'drizzle-orm';
 import { db } from '@/db';
 import { instruction, photo, set } from '@/db/schema';
 import { actionData, actionError, actionOk, formToObject, parseForm, type ActionResult } from '@/lib/action-result';
+import { env } from '@/env';
+import { safeFetch, SafeFetchError } from '@/lib/safe-fetch';
 import { requireUser } from '@/lib/session';
-import { deleteStoredFile, storeImage, storePdf, UploadError } from '@/lib/uploads';
+import { deleteStoredFile, storeImage, storeImageBytes, storePdf, UploadError } from '@/lib/uploads';
 import { optionalText, optionalUrl, setSchema } from '@/lib/validation';
 import { z } from 'zod';
 
@@ -20,6 +22,23 @@ function revalidateSet(id?: string) {
   if (id) revalidatePath(`/katalog/${id}`);
 }
 
+async function cacheRemoteImage(url: string, setId: string): Promise<string | null> {
+  try {
+    const response = await safeFetch(url, {
+      accept: 'image/webp,image/png,image/jpeg;q=0.9,*/*;q=0.5',
+      maxBytes: env.MAX_UPLOAD_BYTES,
+    });
+    if (response.status !== 200) return null;
+    return (await storeImageBytes(response.body, 'set-image', setId)).filePath;
+  } catch (error) {
+    if (error instanceof SafeFetchError || error instanceof UploadError) {
+      console.error('[katalog] Bild konnte nicht übernommen werden', url, error.message);
+      return null;
+    }
+    throw error;
+  }
+}
+
 function fileFrom(formData: FormData, field: string): File | null {
   const value = formData.get(field);
   return value instanceof File && value.size > 0 ? value : null;
@@ -60,12 +79,17 @@ export async function createSet(formData: FormData): Promise<ActionResult<{ id:
       if (error instanceof UploadError) return actionError(error.message);
       throw error;
     }
+  } else if (formData.get('cacheImage') === 'on' && parsed.data.imageUrl) {
+    // A picture found by the link import is kept locally, like the Lego
+    // import does. If that fails, the URL stays as the fallback.
+    imagePath = await cacheRemoteImage(parsed.data.imageUrl, id);
   }
 
   db.insert(set)
     .values({
       id,
       ...parsed.data,
+      imageUrl: imagePath ? null : parsed.data.imageUrl,
       imagePath,
       createdAt: now(),
       updatedAt: now(),

src/app/(app)/katalog/link-actions.ts

@@ -0,0 +1,225 @@
+'use server';
+
+import { and, eq } from 'drizzle-orm';
+import { z } from 'zod';
+import { db } from '@/db';
+import { manufacturer, set } from '@/db/schema';
+import { actionData, actionError, type ActionResult } from '@/lib/action-result';
+import {
+  cleanSetName,
+  hintsFromHtml,
+  hintsFromUrl,
+  mergeHints,
+  sourceLabel,
+  type LinkHints,
+} from '@/lib/link-import';
+import { fetchMinifigCount, fetchSet, isRebrickableEnabled, RebrickableError } from '@/lib/rebrickable';
+import { safeFetch, SafeFetchError } from '@/lib/safe-fetch';
+import { requireUser } from '@/lib/session';
+import { uniqueSlug } from '@/lib/slug';
+
+/**
+ * "Aus einem Link übernehmen": reads a set out of a shop, price-comparison or
+ * database link and returns a draft for the form. Nothing is saved here except
+ * a missing manufacturer - the form needs it to be selectable.
+ *
+ * Amazon, idealo and geizhals usually refuse requests from a server; then the
+ * link itself (brand, number, words in the address) is the starting point,
+ * and Rebrickable (Lego) or Merlins Bricks (BlueBrixx, Cobi) fill in the rest.
+ */
+
+export type LinkPreview = {
+  manufacturerId: string | null;
+  manufacturerName: string | null;
+  setNumber: string;
+  name: string;
+  year: number | null;
+  pieceCount: number | null;
+  minifigCount: number | null;
+  ean: string;
+  imageUrl: string;
+  sourceUrl: string;
+  /** Where the data came from, for the confirmation message. */
+  sources: string[];
+  /** The shop did not let us read the page; only the address was used. */
+  pageBlocked: boolean;
+  /** The set is already in the catalog. */
+  existingSetId: string | null;
+};
+
+const inputSchema = z.object({
+  url: z
+    .string()
+    .trim()
+    .min(1, 'Bitte einen Link einfügen.')
+    .max(2000, 'Der Link ist zu lang.')
+    .url('Das ist kein gültiger Link.')
+    .refine((value) => /^https?:\/\//i.test(value), 'Nur http- und https-Links.'),
+});
+
+/** Manufacturer website for the ones we create on the fly. */
+const WEBSITES: Record<string, string> = {
+  Lego: 'https://www.lego.com/de-de',
+  Playmobil: 'https://www.playmobil.de',
+  Cobi: 'https://cobi.pl',
+  BlueBrixx: 'https://www.bluebrixx.com',
+  'Mega Bloks': 'https://www.megabrands.com',
+};
+
+/** Merlins Bricks keys its set pages by a brand prefix. */
+const MERLIN_PREFIX: Record<string, string> = { BlueBrixx: 'bb', Cobi: 'cobi' };
+
+function key(value: string): string {
+  return value.toLowerCase().replace(/[^a-z0-9]/g, '');
+}
+
+function ensureManufacturer(name: string): string {
+  const rows = db
+    .select({ id: manufacturer.id, name: manufacturer.name, slug: manufacturer.slug })
+    .from(manufacturer)
+    .all();
+
+  const match = rows.find((row) => key(row.name) === key(name) || row.slug === key(name));
+  if (match) return match.id;
+
+  const id = crypto.randomUUID();
+  const now = new Date();
+  db.insert(manufacturer)
+    .values({
+      id,
+      name,
+      slug: uniqueSlug(name, rows.map((row) => row.slug)),
+      website: WEBSITES[name] ?? null,
+      createdAt: now,
+      updatedAt: now,
+    })
+    .run();
+  return id;
+}
+
+async function readPage(url: URL): Promise<{ hints: LinkHints | null; finalUrl: URL; blocked: boolean }> {
+  const response = await safeFetch(url);
+  const finalUrl = new URL(response.url);
+  const isHtml = /html|xml/i.test(response.contentType);
+
+  if (response.status !== 200 || !isHtml) return { hints: null, finalUrl, blocked: true };
+  return { hints: hintsFromHtml(response.body.toString('utf8'), finalUrl), finalUrl, blocked: false };
+}
+
+async function fromRebrickable(setNumber: string): Promise<(LinkHints & { minifigCount?: number }) | null> {
+  if (!isRebrickableEnabled()) return null;
+  try {
+    const remote = await fetchSet(setNumber);
+    if (!remote) return null;
+    const minifigs = await fetchMinifigCount(remote.setNumber);
+    return {
+      name: remote.name,
+      year: remote.year ?? undefined,
+      pieceCount: remote.pieceCount ?? undefined,
+      imageUrl: remote.imageUrl ?? undefined,
+      minifigCount: minifigs ?? undefined,
+    };
+  } catch (error) {
+    if (error instanceof RebrickableError) return null;
+    throw error;
+  }
+}
+
+async function fromMerlinsBricks(brand: string, setNumber: string): Promise<LinkHints | null> {
+  const prefix = MERLIN_PREFIX[brand];
+  if (!prefix || !/^[\w-]+$/.test(setNumber)) return null;
+  try {
+    const page = await readPage(new URL(`https://www.merlinsbricks.com/sets/${prefix}-${setNumber}/`));
+    return page.hints;
+  } catch {
+    return null;
+  }
+}
+
+export async function previewSetFromLink(input: unknown): Promise<ActionResult<LinkPreview>> {
+  await requireUser();
+
+  const parsed = inputSchema.safeParse(input);
+  if (!parsed.success) return actionError(parsed.error.issues[0]?.message ?? 'Ungültiger Link.');
+
+  const url = new URL(parsed.data.url);
+  const sources: string[] = [];
+
+  // 1. The page itself, if it lets us in. A short link (amzn.eu/...) still
+  //    tells us where it leads, even when the target then refuses.
+  let pageHints: LinkHints | null = null;
+  let finalUrl = url;
+  let pageBlocked = true;
+  try {
+    const page = await readPage(url);
+    pageHints = page.hints;
+    finalUrl = page.finalUrl;
+    pageBlocked = page.blocked;
+  } catch (error) {
+    if (!(error instanceof SafeFetchError)) throw error;
+    if (/intern/i.test(error.message)) return actionError(error.message);
+  }
+  if (pageHints) sources.push(sourceLabel(finalUrl));
+
+  // 2. The address.
+  const addressHints = mergeHints(hintsFromUrl(finalUrl), hintsFromUrl(url));
+  if (!pageHints || pageBlocked) sources.push(`Link (${sourceLabel(finalUrl)})`);
+
+  let hints = mergeHints(pageHints, addressHints);
+  let minifigCount: number | null = null;
+
+  // 3. A set database for the brand.
+  if (hints.manufacturer === 'Lego' && hints.setNumber) {
+    const remote = await fromRebrickable(hints.setNumber);
+    if (remote) {
+      // The shop's German name beats Rebrickable's English one; Rebrickable's
+      // facts and clean picture beat the shop's.
+      hints = mergeHints({ name: pageHints?.name ?? addressHints.name, ean: hints.ean }, remote, hints);
+      minifigCount = remote.minifigCount ?? null;
+      sources.push('Rebrickable');
+    }
+  } else if (hints.manufacturer && hints.setNumber && !/merlinsbricks\./.test(finalUrl.hostname)) {
+    const merlin = await fromMerlinsBricks(hints.manufacturer, hints.setNumber);
+    if (merlin) {
+      hints = mergeHints(hints, merlin);
+      sources.push('Merlins Bricks');
+    }
+  }
+
+  if (!hints.name && !hints.setNumber) {
+    return actionError(
+      pageBlocked
+        ? `${sourceLabel(finalUrl)} lässt keine Abfrage zu, und der Link selbst verrät nichts über das Set. Versuch es mit einem anderen Link oder trag das Set von Hand ein.`
+        : 'Auf der Seite stehen keine Produktdaten, mit denen sich etwas anfangen lässt.',
+    );
+  }
+
+  const manufacturerName = hints.manufacturer ?? null;
+  const manufacturerId = manufacturerName ? ensureManufacturer(manufacturerName) : null;
+  const setNumber = hints.setNumber ?? '';
+
+  const existing =
+    manufacturerId && setNumber
+      ? db
+          .select({ id: set.id })
+          .from(set)
+          .where(and(eq(set.manufacturerId, manufacturerId), eq(set.setNumber, setNumber)))
+          .get()
+      : undefined;
+
+  return actionData({
+    manufacturerId,
+    manufacturerName,
+    setNumber,
+    name: hints.name ? cleanSetName(hints.name, manufacturerName ?? undefined, setNumber) : '',
+    year: hints.year ?? null,
+    pieceCount: hints.pieceCount ?? null,
+    minifigCount,
+    ean: hints.ean ?? '',
+    imageUrl: hints.imageUrl ?? '',
+    sourceUrl: url.toString(),
+    sources,
+    pageBlocked,
+    existingSetId: existing?.id ?? null,
+  });
+}

src/app/(app)/katalog/neu/page.tsx

@@ -1,7 +1,7 @@
 import type { Metadata } from 'next';
 import Link from 'next/link';
+import { NewSetEntry } from '@/components/katalog/link-import';
 import { RebrickableImport } from '@/components/katalog/rebrickable-import';
-import { SetForm } from '@/components/katalog/set-form';
 import { Button } from '@/components/ui/button';
 import { listManufacturers, listThemes } from '@/lib/queries/master-data';
 import { isRebrickableEnabled } from '@/lib/rebrickable';
@@ -25,26 +25,8 @@ export default async function NeuesSetPage({ searchParams }: { searchParams: Sea
 
   const importEnabled = isRebrickableEnabled();
 
-  if (manufacturers.length === 0) {
+  // One layout for both cases: the link import may create the first
-    return (
+  // manufacturer, and its draft must survive the refresh that follows.
-      <div className="space-y-6">
-        <h1 className="text-2xl font-semibold tracking-tight">Neues Set</h1>
-
-        {/* The Lego import creates its manufacturer itself, so it works even
-            on a completely empty instance. */}
-        <RebrickableImport enabled={importEnabled} />
-
-        <p className="rounded-lg border border-dashed border-border p-6 text-sm text-muted-foreground">
-          Für ein Set von Hand brauchst du zuerst einen Hersteller – Lego, Playmobil, Cobi oder
-          was auch immer im Kinderzimmer steht.
-        </p>
-        <Button asChild size="lg">
-          <Link href="/verwaltung/hersteller">Hersteller anlegen</Link>
-        </Button>
-      </div>
-    );
-  }
-
   return (
     <div className="space-y-6">
       <div>
@@ -54,15 +36,19 @@ export default async function NeuesSetPage({ searchParams }: { searchParams: Sea
           Sammlung hinzufügen“ fest.
         </p>
       </div>
+      {/* The Lego import creates its manufacturer itself, so it works even
+          on a completely empty instance. */}
       <RebrickableImport enabled={importEnabled} />
 
-      <div className="flex items-center gap-3 text-xs text-muted-foreground">
+      <NewSetEntry manufacturers={manufacturers} themes={themes} defaultEan={ean}>
-        <span className="h-px flex-1 bg-border" />
+        <p className="rounded-lg border border-dashed border-border p-6 text-sm text-muted-foreground">
-        oder von Hand
+          Für ein Set von Hand brauchst du zuerst einen Hersteller – Lego, Playmobil, Cobi oder
-        <span className="h-px flex-1 bg-border" />
+          was auch immer im Kinderzimmer steht.
-      </div>
+        </p>
-
+        <Button asChild size="lg">
-      <SetForm manufacturers={manufacturers} themes={themes} defaultEan={ean} />
+          <Link href="/verwaltung/hersteller">Hersteller anlegen</Link>
+        </Button>
+      </NewSetEntry>
     </div>
   );
 }

src/components/katalog/link-import.tsx

@@ -0,0 +1,155 @@
+'use client';
+
+import Link from 'next/link';
+import { useRouter } from 'next/navigation';
+import { useState, useTransition } from 'react';
+import { Link2, Loader2 } from 'lucide-react';
+import { toast } from 'sonner';
+import { previewSetFromLink, type LinkPreview } from '@/app/(app)/katalog/link-actions';
+import { SetForm, type SetPrefill } from '@/components/katalog/set-form';
+import { Button } from '@/components/ui/button';
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
+import { Field } from '@/components/ui/field';
+import { Input } from '@/components/ui/input';
+
+function toPrefill(preview: LinkPreview): SetPrefill {
+  return {
+    manufacturerId: preview.manufacturerId ?? undefined,
+    setNumber: preview.setNumber || undefined,
+    name: preview.name || undefined,
+    year: preview.year,
+    pieceCount: preview.pieceCount,
+    minifigCount: preview.minifigCount,
+    ean: preview.ean || null,
+    imageUrl: preview.imageUrl || null,
+    cacheImage: Boolean(preview.imageUrl),
+    notes: `Übernommen aus: ${preview.sourceUrl}`,
+  };
+}
+
+/**
+ * "Neues Set" with the link import on top: paste a link from a shop, a price
+ * comparison or a set database, check the prefilled form, save.
+ */
+export function NewSetEntry({
+  manufacturers,
+  themes,
+  defaultEan,
+  children,
+}: {
+  manufacturers: Array<{ id: string; name: string }>;
+  themes: Array<{ id: string; name: string; manufacturerId: string }>;
+  defaultEan?: string;
+  /** Shown instead of the form while there is no manufacturer yet. */
+  children?: React.ReactNode;
+}) {
+  const router = useRouter();
+  const [url, setUrl] = useState('');
+  const [prefill, setPrefill] = useState<SetPrefill | undefined>(undefined);
+  const [version, setVersion] = useState(0);
+  const [existing, setExisting] = useState<{ id: string; label: string } | null>(null);
+  const [pending, startTransition] = useTransition();
+
+  function submit(event: React.FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    setExisting(null);
+
+    startTransition(async () => {
+      const result = await previewSetFromLink({ url });
+      if (!result.ok) {
+        toast.error(result.error);
+        return;
+      }
+
+      const preview = result.data;
+      if (preview.existingSetId) {
+        setExisting({
+          id: preview.existingSetId,
+          label: [preview.setNumber, preview.name].filter(Boolean).join(' · '),
+        });
+        return;
+      }
+
+      setPrefill(toPrefill(preview));
+      setVersion((value) => value + 1);
+      // A manufacturer may just have been created for the draft.
+      router.refresh();
+
+      const missing = [
+        preview.manufacturerId ? null : 'Hersteller',
+        preview.setNumber ? null : 'Setnummer',
+        preview.name ? null : 'Name',
+      ].filter(Boolean);
+
+      toast.success(
+        missing.length === 0
+          ? `Übernommen aus ${preview.sources.join(', ')}. Bitte kurz prüfen und speichern.`
+          : `Übernommen aus ${preview.sources.join(', ')} – ${missing.join(', ')} bitte ergänzen.`,
+      );
+      if (preview.pageBlocked) {
+        toast.info('Die Seite selbst ließ sich nicht lesen – die Angaben stammen aus dem Link.');
+      }
+    });
+  }
+
+  return (
+    <>
+      <Card>
+        <CardHeader>
+          <CardTitle>Aus einem Link übernehmen</CardTitle>
+          <CardDescription>
+            Link zu Amazon, idealo, geizhals, zum Shop des Herstellers oder zu einer Set-Datenbank
+            einfügen. Die Angaben landen im Formular unten – gespeichert wird erst, wenn du es
+            sagst.
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="space-y-3">
+          <form onSubmit={submit} className="flex items-end gap-2">
+            <Field label="Link" htmlFor="import-link" className="flex-1">
+              <Input
+                id="import-link"
+                type="url"
+                inputMode="url"
+                value={url}
+                onChange={(event) => setUrl(event.target.value)}
+                placeholder="https://…"
+                maxLength={2000}
+              />
+            </Field>
+            <Button type="submit" size="lg" disabled={pending || url.trim().length === 0}>
+              {pending ? <Loader2 className="animate-spin" /> : <Link2 />}
+              Übernehmen
+            </Button>
+          </form>
+
+          {existing ? (
+            <p className="rounded-lg bg-muted p-3 text-sm">
+              Das Set ist schon im Katalog:{' '}
+              <Link href={`/katalog/${existing.id}`} className="font-semibold underline">
+                {existing.label}
+              </Link>
+            </p>
+          ) : null}
+        </CardContent>
+      </Card>
+
+      <div className="flex items-center gap-3 text-xs text-muted-foreground">
+        <span className="h-px flex-1 bg-border" />
+        {prefill ? 'Bitte prüfen und speichern' : 'oder von Hand'}
+        <span className="h-px flex-1 bg-border" />
+      </div>
+
+      {manufacturers.length === 0 ? (
+        children
+      ) : (
+        <SetForm
+          key={`${version}-${manufacturers.length}`}
+          manufacturers={manufacturers}
+          themes={themes}
+          defaultEan={defaultEan}
+          prefill={prefill}
+        />
+      )}
+    </>
+  );
+}

src/components/katalog/set-form.tsx

@@ -47,19 +47,26 @@ export type SetFormValues = {
   notes: string | null;
 };
 
+/** A draft for a new set, e.g. from the link import. */
+export type SetPrefill = Partial<Omit<SetFormValues, 'id' | 'imagePath'>> & {
+  /** Download imageUrl on save and keep it locally. */
+  cacheImage?: boolean;
+};
+
 type Props = {
   manufacturers: Array<{ id: string; name: string }>;
   themes: Array<{ id: string; name: string; manufacturerId: string }>;
   set?: SetFormValues;
   /** Prefilled EAN coming from the barcode scanner (phase 2). */
   defaultEan?: string;
+  prefill?: SetPrefill;
 };
 
-export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
+export function SetForm({ manufacturers, themes, set, defaultEan, prefill }: Props) {
   const router = useRouter();
   const [pending, startTransition] = useTransition();
   const [manufacturerId, setManufacturerId] = useState(
-    set?.manufacturerId ?? manufacturers[0]?.id ?? '',
+    set?.manufacturerId ?? prefill?.manufacturerId ?? manufacturers[0]?.id ?? '',
   );
   const [duplicates, setDuplicates] = useState<DuplicateCandidate[] | null>(null);
   const pendingForm = useRef<FormData | null>(null);
@@ -167,7 +174,7 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
           <Input
             id="setNumber"
             name="setNumber"
-            defaultValue={set?.setNumber ?? ''}
+            defaultValue={set?.setNumber ?? prefill?.setNumber ?? ''}
             required
             maxLength={40}
             placeholder="60398"
@@ -179,7 +186,7 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
           <Input
             id="name"
             name="name"
-            defaultValue={set?.name ?? ''}
+            defaultValue={set?.name ?? prefill?.name ?? ''}
             required
             maxLength={160}
             placeholder="Familienhaus und Elektroauto"
@@ -192,7 +199,7 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
             name="year"
             type="number"
             inputMode="numeric"
-            defaultValue={set?.year ?? ''}
+            defaultValue={set?.year ?? prefill?.year ?? ''}
             min={1930}
             max={new Date().getFullYear() + 5}
           />
@@ -204,7 +211,7 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
             name="pieceCount"
             type="number"
             inputMode="numeric"
-            defaultValue={set?.pieceCount ?? ''}
+            defaultValue={set?.pieceCount ?? prefill?.pieceCount ?? ''}
             min={0}
           />
         </Field>
@@ -215,7 +222,7 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
             name="minifigCount"
             type="number"
             inputMode="numeric"
-            defaultValue={set?.minifigCount ?? ''}
+            defaultValue={set?.minifigCount ?? prefill?.minifigCount ?? ''}
             min={0}
           />
         </Field>
@@ -235,7 +242,7 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
             id="ean"
             name="ean"
             inputMode="numeric"
-            defaultValue={set?.ean ?? defaultEan ?? ''}
+            defaultValue={set?.ean ?? prefill?.ean ?? defaultEan ?? ''}
             maxLength={20}
             className="font-mono"
           />
@@ -256,10 +263,18 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
           name="imageUrl"
           type="url"
           inputMode="url"
-          defaultValue={set?.imageUrl ?? ''}
+          defaultValue={set?.imageUrl ?? prefill?.imageUrl ?? ''}
           placeholder="https://…"
         />
       </Field>
+      {prefill?.cacheImage && prefill.imageUrl ? (
+        <>
+          <input type="hidden" name="cacheImage" value="on" />
+          <p className="-mt-4 text-xs text-muted-foreground">
+            Das Bild aus dem Link wird beim Speichern heruntergeladen und lokal abgelegt.
+          </p>
+        </>
+      ) : null}
 
       <div className="space-y-2">
         <Label htmlFor="image">Bild hochladen</Label>
@@ -286,7 +301,12 @@ export function SetForm({ manufacturers, themes, set, defaultEan }: Props) {
       </div>
 
       <Field label="Notizen" htmlFor="notes">
-        <Textarea id="notes" name="notes" defaultValue={set?.notes ?? ''} rows={4} />
+        <Textarea
+          id="notes"
+          name="notes"
+          defaultValue={set?.notes ?? prefill?.notes ?? ''}
+          rows={4}
+        />
       </Field>
 
       <div className="flex gap-3">

src/lib/link-import.ts

@@ -0,0 +1,380 @@
+import { isValidEan, normalizeEan } from './ean';
+
+/**
+ * Reads set data out of a pasted link and, where the page can be fetched, out
+ * of its structured data (schema.org JSON-LD, Open Graph).
+ *
+ * Pure: no network, no database. The server action in katalog/link-actions.ts
+ * does the fetching and decides what to trust.
+ */
+
+export type LinkHints = {
+  manufacturer?: string;
+  setNumber?: string;
+  name?: string;
+  ean?: string;
+  imageUrl?: string;
+  pieceCount?: number;
+  year?: number;
+};
+
+/** Brands we recognise in links and page data, with how we spell them. */
+const BRANDS: Array<{ name: string; aliases: string[] }> = [
+  { name: 'Lego', aliases: ['lego'] },
+  { name: 'Playmobil', aliases: ['playmobil'] },
+  { name: 'Cobi', aliases: ['cobi'] },
+  { name: 'BlueBrixx', aliases: ['bluebrixx', 'bluebrixxpro', 'bb'] },
+  { name: 'Mega Bloks', aliases: ['megabloks', 'megaconstrux', 'mega'] },
+  { name: 'Mould King', aliases: ['mouldking'] },
+  { name: 'Cada', aliases: ['cada'] },
+  { name: 'Sluban', aliases: ['sluban'] },
+  { name: 'Qman', aliases: ['qman', 'keeppley'] },
+  { name: 'Xingbao', aliases: ['xingbao'] },
+];
+
+function key(value: string): string {
+  return value.toLowerCase().replace(/[^a-z0-9]/g, '');
+}
+
+/** "LEGO®", "lego", "BlueBrixx Pro" -> "Lego", "BlueBrixx". */
+export function canonicalBrand(value: string | undefined | null): string | undefined {
+  if (!value) return undefined;
+  const wanted = key(value);
+  if (!wanted) return undefined;
+  for (const brand of BRANDS) {
+    if (brand.aliases.some((alias) => wanted === alias || (alias.length > 3 && wanted.startsWith(alias)))) {
+      return brand.name;
+    }
+  }
+  return undefined;
+}
+
+/** Where a link points, in words for the UI. */
+export function sourceLabel(url: URL): string {
+  const host = url.hostname.replace(/^www\./, '');
+  if (/(^|\.)amazon\./.test(host) || /^amzn\./.test(host)) return 'Amazon';
+  if (/(^|\.)idealo\./.test(host)) return 'idealo';
+  if (/(^|\.)geizhals\./.test(host)) return 'geizhals';
+  if (/(^|\.)brickmerge\./.test(host)) return 'brickmerge';
+  if (/(^|\.)brickfact\./.test(host)) return 'Brickfact';
+  if (/(^|\.)merlinsbricks\./.test(host)) return 'Merlins Bricks';
+  if (/(^|\.)ebay\./.test(host)) return 'eBay';
+  return host;
+}
+
+// Words that sit in shop slugs but never in a set name.
+const STOPWORDS = new Set([
+  'set', 'sets', 'bausatz', 'bausteine', 'klemmbausteine', 'baustein', 'spielzeug', 'spielset',
+  'kinder', 'jungen', 'maedchen', 'mädchen', 'ab', 'jahre', 'jahren', 'jahr', 'teile', 'teilig',
+  'geschenk', 'geschenkidee', 'the', 'and', 'for', 'kids', 'boys',
+  'girls', 'toy', 'toys', 'building', 'kit', 'bricks', 'brick', 'preisvergleich', 'dp', 'html',
+  'neu', 'ovp', 'new', 'sealed',
+]);
+
+const KEEP_LOWER = new Set(['und', 'mit', 'der', 'die', 'das', 'von', 'im', 'am', 'zum', 'zur']);
+
+function looksLikeYear(value: string): boolean {
+  const year = Number(value);
+  return year >= 1950 && year <= 2040;
+}
+
+/**
+ * A set number in a list of slug tokens: 4 to 7 digits, longer ones first,
+ * and four-digit years only as a last resort. Cobi's "2-30500" style is kept.
+ */
+function findSetNumber(tokens: string[]): string | undefined {
+  const joined = tokens.join('-');
+  const cobi = /(?:^|-)(\d-\d{5})(?:-|$)/.exec(joined);
+  if (cobi) return cobi[1];
+
+  const numbers = tokens.filter((token) => /^\d{4,7}$/.test(token));
+  const best =
+    numbers.find((token) => token.length >= 5) ?? numbers.find((token) => !looksLikeYear(token));
+  return best;
+}
+
+function titleCase(word: string): string {
+  if (KEEP_LOWER.has(word)) return word;
+  return word.charAt(0).toUpperCase() + word.slice(1);
+}
+
+/** The descriptive part of a shop URL, split into words. */
+function slugTokens(url: URL): string[] {
+  const segments = decodeURIComponent(url.pathname)
+    .split('/')
+    .filter(Boolean)
+    .map((segment) => segment.replace(/\.html?$/i, ''));
+
+  let slug = '';
+  const host = url.hostname;
+
+  if (/amazon\./.test(host)) {
+    // amazon.de/LEGO-60398-Familienhaus-Elektroauto/dp/B0...: the part before /dp/.
+    const dp = segments.findIndex((segment) => segment === 'dp' || segment === 'gp');
+    slug = dp > 0 ? segments[dp - 1]! : '';
+  } else if (/idealo\./.test(host)) {
+    // .../OffersOfProduct/202595377_-familienhaus-mit-elektroauto-60398-lego
+    slug = (segments.at(-1) ?? '').replace(/^\d+_-?/, '');
+  } else if (/geizhals\./.test(host)) {
+    // geizhals.de/lego-city-familienhaus-...-60398-a2875000
+    slug = (segments.at(-1) ?? '').replace(/-a\d+$/, '');
+  } else {
+    // Generic: the longest segment with dashes is usually the product slug.
+    slug = [...segments].sort((a, b) => b.split(/[-_]/).length - a.split(/[-_]/).length)[0] ?? '';
+  }
+
+  return slug
+    .toLowerCase()
+    .split(/[-_+\s]+/)
+    .map((token) => token.replace(/[^\p{L}\p{N}]/gu, ''))
+    .filter(Boolean);
+}
+
+/** Everything the address alone tells us - useful when the page blocks us. */
+export function hintsFromUrl(url: URL): LinkHints {
+  const host = url.hostname.replace(/^www\./, '');
+
+  // merlinsbricks.com/sets/bb-108782, /sets/cobi-2400: brand and number in one.
+  const merlin = /merlinsbricks\./.test(host)
+    ? /\/sets\/([a-z]+)-([\w-]+?)\/?$/i.exec(url.pathname)
+    : null;
+  if (merlin) {
+    return { manufacturer: canonicalBrand(merlin[1]), setNumber: merlin[2] };
+  }
+
+  const tokens = slugTokens(url);
+  const setNumber = findSetNumber(tokens);
+
+  let manufacturer: string | undefined;
+  for (const token of tokens) {
+    manufacturer = canonicalBrand(token);
+    if (manufacturer) break;
+  }
+  manufacturer ??= canonicalBrand(host.split('.').at(-2));
+
+  const words = tokens.filter(
+    (token) =>
+      token !== setNumber &&
+      !/^\d+$/.test(token) &&
+      !STOPWORDS.has(token) &&
+      !canonicalBrand(token) &&
+      token.length > 1,
+  );
+  const name = words.length > 0 ? words.slice(0, 8).map(titleCase).join(' ') : undefined;
+
+  return { manufacturer, setNumber, name };
+}
+
+// --- page data ------------------------------------------------------------
+
+const ENTITIES: Record<string, string> = {
+  amp: '&', lt: '<', gt: '>', quot: '"', apos: "'", nbsp: ' ', '#39': "'",
+  auml: 'ä', ouml: 'ö', uuml: 'ü', Auml: 'Ä', Ouml: 'Ö', Uuml: 'Ü', szlig: 'ß',
+};
+
+function decodeEntities(value: string): string {
+  return value
+    .replace(/&#(\d+);/g, (_, code: string) => String.fromCodePoint(Number(code)))
+    .replace(/&#x([\da-f]+);/gi, (_, code: string) => String.fromCodePoint(parseInt(code, 16)))
+    .replace(/&([a-z]+|#39);/gi, (match, name: string) => ENTITIES[name] ?? match);
+}
+
+function metaContent(html: string, property: string): string | undefined {
+  const escaped = property.replace(/[.:]/g, '\\$&');
+  const pattern = new RegExp(
+    `<meta[^>]+(?:property|name)=["']${escaped}["'][^>]*content=["']([^"']*)["']|<meta[^>]+content=["']([^"']*)["'][^>]*(?:property|name)=["']${escaped}["']`,
+    'i',
+  );
+  const match = pattern.exec(html);
+  const value = match?.[1] ?? match?.[2];
+  return value ? decodeEntities(value).trim() : undefined;
+}
+
+type JsonObject = Record<string, unknown>;
+
+function isObject(value: unknown): value is JsonObject {
+  return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
+
+/** All schema.org Product objects on the page, however they are nested. */
+function jsonLdProducts(html: string): JsonObject[] {
+  const products: JsonObject[] = [];
+  const pattern = /<script[^>]+application\/ld\+json[^>]*>([\s\S]*?)<\/script>/gi;
+
+  const visit = (node: unknown) => {
+    if (Array.isArray(node)) return node.forEach(visit);
+    if (!isObject(node)) return;
+    const type = node['@type'];
+    const types = Array.isArray(type) ? type : [type];
+    if (types.includes('Product') || types.includes('ProductGroup')) products.push(node);
+    if (node['@graph']) visit(node['@graph']);
+  };
+
+  for (const match of html.matchAll(pattern)) {
+    try {
+      visit(JSON.parse(match[1]!.trim()));
+    } catch {
+      // A broken block on someone else's page is not our problem.
+    }
+  }
+  return products;
+}
+
+function text(value: unknown): string | undefined {
+  if (typeof value === 'string') return decodeEntities(value).trim() || undefined;
+  if (typeof value === 'number') return String(value);
+  if (isObject(value)) return text(value.name) ?? text(value.url);
+  if (Array.isArray(value)) return text(value[0]);
+  return undefined;
+}
+
+function cleanEan(value: unknown): string | undefined {
+  const raw = text(value);
+  if (!raw) return undefined;
+  const ean = normalizeEan(raw);
+  return isValidEan(ean) ? ean : undefined;
+}
+
+function absoluteUrl(value: string | undefined, base: URL): string | undefined {
+  if (!value) return undefined;
+  try {
+    const url = new URL(value, base);
+    return url.protocol === 'https:' || url.protocol === 'http:' ? url.toString() : undefined;
+  } catch {
+    return undefined;
+  }
+}
+
+/** "462 Teile", "450 pieces" in a description. */
+function piecesFrom(value: string | undefined): number | undefined {
+  const match = value && /(\d{1,3}(?:[.,]\d{3})*|\d+)\s*(?:teilen?|pieces|pcs|steinen?|bausteinen?|parts)\b/i.exec(value);
+  if (!match) return undefined;
+  const pieces = Number(match[1]!.replace(/[.,]/g, ''));
+  return pieces > 0 && pieces < 100_000 ? pieces : undefined;
+}
+
+/** "from 2025", "aus 2023", "Jahr: 2021" in a description. */
+function yearFrom(value: string | undefined): number | undefined {
+  const match = value && /\b(?:from|aus|jahr:?|released|erschienen)\s+((?:19|20)\d{2})\b/i.exec(value);
+  return match ? Number(match[1]) : undefined;
+}
+
+function stripTags(value: string): string {
+  return decodeEntities(value.replace(/<[^>]+>/g, ' '))
+    .replace(/[‎‏]/g, '')
+    .replace(/\s+/g, ' ')
+    .trim();
+}
+
+/**
+ * Amazon has no schema.org data, but a stable page skeleton: the title in
+ * #productTitle, the brand in the byline, pictures as "hiRes" in a script and
+ * the facts in the "Produktinformation" table or bullet list.
+ */
+function hintsFromAmazon(html: string): LinkHints {
+  const facts = new Map<string, string>();
+  for (const match of html.matchAll(/<th[^>]*>([\s\S]*?)<\/th>\s*<td[^>]*>([\s\S]*?)<\/td>/gi)) {
+    facts.set(stripTags(match[1]!).toLowerCase(), stripTags(match[2]!));
+  }
+  for (const match of html.matchAll(
+    /<span class="a-text-bold">([\s\S]*?)<\/span>\s*<span[^>]*>([\s\S]*?)<\/span>/gi,
+  )) {
+    facts.set(stripTags(match[1]!).replace(/[:\s]+$/, '').toLowerCase(), stripTags(match[2]!));
+  }
+  const fact = (...labels: string[]) => {
+    for (const [label, value] of facts) {
+      if (labels.some((wanted) => label.includes(wanted))) return value;
+    }
+    return undefined;
+  };
+
+  const title = /id="productTitle"[^>]*>([\s\S]*?)<\/span>/i.exec(html);
+  const byline = /id="bylineInfo"[^>]*>([\s\S]*?)<\/a>/i.exec(html);
+  const brandText = byline
+    ? stripTags(byline[1]!).replace(/^(marke|brand):\s*/i, '').replace(/^besuche den\s+|-store$|\s+store$/gi, '')
+    : fact('marke', 'hersteller');
+  const image = /"hiRes":"(https:[^"]+)"/.exec(html) ?? /data-old-hires="(https:[^"]+)"/.exec(html);
+  const pieces = Number((fact('anzahl der teile', 'teileanzahl', 'anzahl teile') ?? '').replace(/\D/g, ''));
+
+  return {
+    manufacturer: canonicalBrand(brandText),
+    setNumber: fact('modellnummer', 'herstellerreferenz')?.replace(/\s/g, ''),
+    name: title ? stripTags(title[1]!) : undefined,
+    ean: cleanEan(fact('ean', 'gtin')),
+    imageUrl: image?.[1],
+    pieceCount: pieces > 0 && pieces < 100_000 ? pieces : undefined,
+  };
+}
+
+export function hintsFromHtml(html: string, pageUrl: URL): LinkHints {
+  const hints = /(^|\.)amazon\./.test(pageUrl.hostname) ? hintsFromAmazon(html) : hintsFromStructuredData(html, pageUrl);
+
+  // A shop's own article number (an ASIN, a long SKU) is not a set number.
+  if (hints.setNumber && !/^[\d-]{3,12}$/.test(hints.setNumber)) delete hints.setNumber;
+
+  // Titles usually carry the number: "LEGO City 60398 Familienhaus".
+  if (!hints.setNumber && hints.name) {
+    const fromName = findSetNumber(hints.name.toLowerCase().split(/[\s()[\]:,/|]+/).filter(Boolean));
+    if (fromName) hints.setNumber = fromName;
+  }
+  return hints;
+}
+
+function hintsFromStructuredData(html: string, pageUrl: URL): LinkHints {
+  const product = jsonLdProducts(html)[0];
+  const description = text(product?.description) ?? metaContent(html, 'og:description');
+
+  const hints: LinkHints = {
+    manufacturer: canonicalBrand(text(product?.brand)) ?? canonicalBrand(metaContent(html, 'product:brand')),
+    setNumber: text(product?.mpn) ?? text(product?.sku),
+    name: text(product?.name) ?? metaContent(html, 'og:title'),
+    ean: cleanEan(product?.gtin13) ?? cleanEan(product?.gtin) ?? cleanEan(product?.gtin12) ?? cleanEan(product?.gtin8),
+    imageUrl: absoluteUrl(text(product?.image) ?? metaContent(html, 'og:image'), pageUrl),
+    pieceCount: piecesFrom(description),
+    year: yearFrom(description),
+  };
+  return hints;
+}
+
+/** First value wins per field: pass the most trusted source first. */
+export function mergeHints(...sources: Array<LinkHints | null | undefined>): LinkHints {
+  const merged: LinkHints = {};
+  for (const source of sources) {
+    if (!source) continue;
+    for (const [field, value] of Object.entries(source) as Array<[keyof LinkHints, never]>) {
+      if (merged[field] === undefined && value !== undefined && value !== '') merged[field] = value;
+    }
+  }
+  return merged;
+}
+
+/**
+ * Shop titles carry everything: "LEGO® City Familienhaus mit Elektroauto
+ * 60398", "BlueBrixx - Technisches Hilfswerk™ Vehicle | Set 108782". Keeps
+ * the part that is the set's own name.
+ */
+export function cleanSetName(name: string, manufacturer?: string, setNumber?: string): string {
+  let result = name.replace(/[®™©]/g, '');
+
+  // Site names and set references after a separator.
+  result = result.split(/\s+[|•·]\s+/)[0]!;
+
+  // Price-comparison titles: "... ab € 4,20 (2026)", "... ab 52,99 €".
+  result = result.replace(/\s+ab\s+(?:€\s*)?\d[\d.,]*\s*(?:€|EUR)?.*$/i, '');
+
+  if (setNumber) {
+    const escaped = setNumber.replace(/[-]/g, '\\-');
+    result = result.replace(new RegExp(`\\(?\\b${escaped}\\b\\)?`, 'g'), '');
+  }
+
+  if (manufacturer) {
+    for (const brand of BRANDS.filter((entry) => entry.name === manufacturer)) {
+      for (const alias of [brand.name, ...brand.aliases]) {
+        if (alias.length < 3) continue;
+        result = result.replace(new RegExp(`^\\s*${alias}\\b\\s*[-–:]?\\s*`, 'i'), '');
+      }
+    }
+  }
+
+  return result.replace(/\s{2,}/g, ' ').replace(/^[\s\-–:]+|[\s\-–:,]+$/g, '').trim();
+}

src/lib/net-guard.ts

@@ -0,0 +1,66 @@
+import { BlockList, isIP } from 'node:net';
+
+/**
+ * Which addresses the server may fetch on a user's behalf.
+ *
+ * The link import downloads pages and pictures from URLs people paste. Without
+ * a guard, a link to http://192.168.1.1/ would make the server talk to the
+ * router - or to any other device in the home network. Only public unicast
+ * addresses pass. Pure, so it is unit tested.
+ */
+
+const blocked = new BlockList();
+
+for (const [network, prefix] of [
+  ['0.0.0.0', 8], // "this" network
+  ['10.0.0.0', 8], // private
+  ['100.64.0.0', 10], // carrier-grade NAT
+  ['127.0.0.0', 8], // loopback
+  ['169.254.0.0', 16], // link-local, cloud metadata
+  ['172.16.0.0', 12], // private
+  ['192.0.0.0', 24], // IETF protocol assignments
+  ['192.0.2.0', 24], // documentation
+  ['192.168.0.0', 16], // private
+  ['198.18.0.0', 15], // benchmarking
+  ['198.51.100.0', 24], // documentation
+  ['203.0.113.0', 24], // documentation
+  ['224.0.0.0', 4], // multicast
+  ['240.0.0.0', 4], // reserved, broadcast
+] as const) {
+  blocked.addSubnet(network, prefix, 'ipv4');
+}
+
+for (const [network, prefix] of [
+  ['::', 128], // unspecified
+  ['::1', 128], // loopback
+  ['64:ff9b::', 96], // NAT64 - would reach IPv4 space behind it
+  ['100::', 64], // discard
+  ['2001:db8::', 32], // documentation
+  ['fc00::', 7], // unique local
+  ['fe80::', 10], // link-local
+  ['ff00::', 8], // multicast
+] as const) {
+  blocked.addSubnet(network, prefix, 'ipv6');
+}
+
+export function isPublicAddress(address: string): boolean {
+  const version = isIP(address);
+  if (version === 0) return false;
+
+  if (version === 6) {
+    // An IPv4 address in IPv6 clothing is judged as what it really is.
+    const mapped = /^::ffff:(\d+\.\d+\.\d+\.\d+)$/i.exec(address);
+    if (mapped) return isPublicAddress(mapped[1]!);
+    return !blocked.check(address, 'ipv6');
+  }
+
+  return !blocked.check(address, 'ipv4');
+}
+
+/** Only plain web URLs on the standard ports; no credentials in the URL. */
+export function isAllowedWebUrl(url: URL): boolean {
+  if (url.protocol !== 'https:' && url.protocol !== 'http:') return false;
+  if (url.username || url.password) return false;
+  if (url.port && url.port !== '80' && url.port !== '443') return false;
+  return true;
+}

src/lib/safe-fetch.ts

@@ -0,0 +1,167 @@
+import 'server-only';
+import { lookup as dnsLookup, type LookupAddress } from 'node:dns';
+import http from 'node:http';
+import https from 'node:https';
+import { isIP, type LookupFunction } from 'node:net';
+import { Readable } from 'node:stream';
+import zlib from 'node:zlib';
+import { isAllowedWebUrl, isPublicAddress } from './net-guard';
+
+/**
+ * Fetches a URL a user pasted - and nothing else.
+ *
+ * - Every hostname is resolved first and refused if any of its addresses is
+ *   not public (see net-guard.ts). The check happens inside the socket's DNS
+ *   lookup, so a second resolution cannot swap in a private address.
+ * - Redirects are followed by hand, and every hop passes the same checks.
+ * - Size and time are capped, compressed bodies included.
+ */
+
+export class SafeFetchError extends Error {}
+
+export type SafeResponse = {
+  status: number;
+  url: string;
+  contentType: string;
+  body: Buffer;
+};
+
+type Options = {
+  maxBytes?: number;
+  timeoutMs?: number;
+  accept?: string;
+};
+
+const MAX_REDIRECTS = 4;
+
+// A regular browser identity: some shops answer anything else with an error
+// page. It is one request per paste, the same a browser preview would make.
+const USER_AGENT =
+  'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0 Safari/537.36';
+
+const guardedLookup = ((
+  hostname: string,
+  options: { all?: boolean; family?: number },
+  callback: (error: Error | null, address: string | LookupAddress[], family?: number) => void,
+) => {
+  dnsLookup(hostname, { family: options.family ?? 0, all: true }, (error, addresses) => {
+    if (error) return callback(error, '', 4);
+    if (addresses.length === 0 || addresses.some((entry) => !isPublicAddress(entry.address))) {
+      return callback(new SafeFetchError(`${hostname} zeigt auf eine interne Adresse.`), '', 4);
+    }
+    if (options.all) return callback(null, addresses);
+    callback(null, addresses[0]!.address, addresses[0]!.family);
+  });
+}) as unknown as LookupFunction;
+
+function checkUrl(url: URL) {
+  if (!isAllowedWebUrl(url)) throw new SafeFetchError('Nur normale http- und https-Links.');
+
+  // Literal IPs never reach the DNS lookup, so they are checked here.
+  const host = url.hostname.replace(/^\[|\]$/g, '');
+  if (isIP(host) && !isPublicAddress(host)) {
+    throw new SafeFetchError('Interne Adressen werden nicht abgerufen.');
+  }
+}
+
+function decode(response: http.IncomingMessage): Readable {
+  switch ((response.headers['content-encoding'] ?? '').toLowerCase()) {
+    case 'gzip':
+    case 'x-gzip':
+      return response.pipe(zlib.createGunzip());
+    case 'deflate':
+      return response.pipe(zlib.createInflate());
+    case 'br':
+      return response.pipe(zlib.createBrotliDecompress());
+    default:
+      return response;
+  }
+}
+
+function requestOnce(url: URL, options: Required<Options>, signal: AbortSignal) {
+  return new Promise<{ status: number; location: string | null; contentType: string; body: Buffer }>(
+    (resolve, reject) => {
+      const client = url.protocol === 'https:' ? https : http;
+      const request = client.get(
+        url,
+        {
+          lookup: guardedLookup,
+          signal,
+          headers: {
+            'user-agent': USER_AGENT,
+            accept: options.accept,
+            'accept-language': 'de-DE,de;q=0.9,en;q=0.6',
+            'accept-encoding': 'gzip, deflate, br',
+          },
+        },
+        (response) => {
+          const status = response.statusCode ?? 0;
+          const location = response.headers.location ?? null;
+          const contentType = response.headers['content-type'] ?? '';
+
+          if (status >= 300 && status < 400 && location) {
+            response.resume();
+            resolve({ status, location, contentType, body: Buffer.alloc(0) });
+            return;
+          }
+
+          const chunks: Buffer[] = [];
+          let size = 0;
+          const stream = decode(response);
+          stream.on('data', (chunk: Buffer) => {
+            size += chunk.byteLength;
+            if (size > options.maxBytes) {
+              request.destroy();
+              stream.destroy();
+              reject(new SafeFetchError('Die Seite ist zu groß.'));
+              return;
+            }
+            chunks.push(chunk);
+          });
+          stream.on('end', () =>
+            resolve({ status, location: null, contentType, body: Buffer.concat(chunks) }),
+          );
+          stream.on('error', reject);
+        },
+      );
+      request.on('error', reject);
+    },
+  );
+}
+
+export async function safeFetch(rawUrl: string | URL, options: Options = {}): Promise<SafeResponse> {
+  const settings: Required<Options> = {
+    maxBytes: options.maxBytes ?? 3 * 1024 * 1024,
+    timeoutMs: options.timeoutMs ?? 10_000,
+    accept: options.accept ?? 'text/html,application/xhtml+xml;q=0.9,*/*;q=0.5',
+  };
+  const signal = AbortSignal.timeout(settings.timeoutMs);
+
+  let url = new URL(rawUrl);
+  for (let hop = 0; hop <= MAX_REDIRECTS; hop += 1) {
+    checkUrl(url);
+
+    let result;
+    try {
+      result = await requestOnce(url, settings, signal);
+    } catch (error) {
+      if (error instanceof SafeFetchError) throw error;
+      if (signal.aborted) throw new SafeFetchError('Die Seite hat zu lange gebraucht.');
+      throw new SafeFetchError('Die Seite war nicht erreichbar.');
+    }
+
+    if (result.location) {
+      url = new URL(result.location, url);
+      continue;
+    }
+
+    return {
+      status: result.status,
+      url: url.toString(),
+      contentType: result.contentType,
+      body: result.body,
+    };
+  }
+
+  throw new SafeFetchError('Zu viele Weiterleitungen.');
+}

tests/unit/link-import.test.ts

@@ -0,0 +1,209 @@
+import { describe, expect, it } from 'vitest';
+import {
+  canonicalBrand,
+  cleanSetName,
+  hintsFromHtml,
+  hintsFromUrl,
+  mergeHints,
+  sourceLabel,
+} from '@/lib/link-import';
+import { isAllowedWebUrl, isPublicAddress } from '@/lib/net-guard';
+
+describe('Hersteller erkennen', () => {
+  it('kennt die gaengigen Schreibweisen', () => {
+    expect(canonicalBrand('LEGO®')).toBe('Lego');
+    expect(canonicalBrand('Blue Brixx')).toBe('BlueBrixx');
+    expect(canonicalBrand('BlueBrixx Pro')).toBe('BlueBrixx');
+    expect(canonicalBrand('Mega Construx')).toBe('Mega Bloks');
+    expect(canonicalBrand('COBI')).toBe('Cobi');
+  });
+
+  it('raet nicht bei Unbekanntem', () => {
+    expect(canonicalBrand('Ravensburger')).toBeUndefined();
+    expect(canonicalBrand('')).toBeUndefined();
+    expect(canonicalBrand('legoland')).toBe('Lego');
+  });
+});
+
+describe('Daten aus dem Link', () => {
+  it('liest Amazon-Links mit Produktnamen', () => {
+    const url = new URL(
+      'https://www.amazon.de/LEGO-60398-Familienhaus-Elektroauto-Spielzeug/dp/B0BYZJXGZQ/ref=sr_1_1?keywords=lego',
+    );
+    expect(sourceLabel(url)).toBe('Amazon');
+    expect(hintsFromUrl(url)).toEqual({
+      manufacturer: 'Lego',
+      setNumber: '60398',
+      name: 'Familienhaus Elektroauto',
+    });
+  });
+
+  it('nimmt aus einem Amazon-Link ohne Namen nicht die ASIN', () => {
+    const hints = hintsFromUrl(new URL('https://www.amazon.de/dp/B0BYZJXGZQ'));
+    expect(hints.setNumber).toBeUndefined();
+  });
+
+  it('liest idealo und geizhals', () => {
+    expect(
+      hintsFromUrl(
+        new URL(
+          'https://www.idealo.de/preisvergleich/OffersOfProduct/202595377_-familienhaus-mit-elektroauto-60398-lego.html',
+        ),
+      ),
+    ).toEqual({ manufacturer: 'Lego', setNumber: '60398', name: 'Familienhaus mit Elektroauto' });
+
+    expect(
+      hintsFromUrl(new URL('https://geizhals.de/bluebrixx-burg-blaustein-101400-a2101234.html')),
+    ).toEqual({ manufacturer: 'BlueBrixx', setNumber: '101400', name: 'Burg Blaustein' });
+  });
+
+  it('erkennt Cobi-Nummern mit Bindestrich und Jahreszahlen nicht als Setnummer', () => {
+    expect(hintsFromUrl(new URL('https://example.com/shop/cobi-2-30500-ford-mustang-gt')).setNumber).toBe(
+      '2-30500',
+    );
+    expect(
+      hintsFromUrl(new URL('https://example.com/p/playmobil-adventskalender-2024-71472')).setNumber,
+    ).toBe('71472');
+  });
+
+  it('liest Marke und Nummer aus Merlins-Bricks-Adressen', () => {
+    expect(hintsFromUrl(new URL('https://www.merlinsbricks.com/sets/bb-108782/'))).toEqual({
+      manufacturer: 'BlueBrixx',
+      setNumber: '108782',
+    });
+    expect(hintsFromUrl(new URL('https://www.merlinsbricks.com/sets/cobi-2400'))).toEqual({
+      manufacturer: 'Cobi',
+      setNumber: '2400',
+    });
+  });
+
+  it('erkennt den Hersteller am Shop', () => {
+    expect(hintsFromUrl(new URL('https://www.bluebrixx.com/de/star-trek/108123/raumstation')).manufacturer).toBe(
+      'BlueBrixx',
+    );
+  });
+});
+
+describe('Daten aus der Seite', () => {
+  const page = new URL('https://brickfact.com/de-de/sets/lego-city-familienhaus-60398');
+
+  it('nimmt schema.org-Produktdaten', () => {
+    const html = `<html><head>
+      <script type="application/ld+json">{"@context":"https://schema.org","@graph":[
+        {"@type":"WebSite","name":"Brickfact"},
+        {"@type":"Product","name":"LEGO&#174; City Familienhaus mit Elektroauto 60398",
+         "sku":"60398","mpn":"60398","gtin13":"5702017462363",
+         "brand":{"@type":"Brand","name":"LEGO"},
+         "image":["/img/60398.webp"],
+         "description":"Ein Set mit 462 Teilen aus 2023."}]}
+      </script></head></html>`;
+
+    expect(hintsFromHtml(html, page)).toEqual({
+      manufacturer: 'Lego',
+      setNumber: '60398',
+      name: 'LEGO® City Familienhaus mit Elektroauto 60398',
+      ean: '5702017462363',
+      imageUrl: 'https://brickfact.com/img/60398.webp',
+      pieceCount: 462,
+      year: 2023,
+    });
+  });
+
+  it('faellt auf Open Graph zurueck und verwirft ungueltige EAN', () => {
+    const html = `<meta property="og:title" content="Burg Blaustein &amp; Zubeh&ouml;r">
+      <meta content="https://cdn.example.com/burg.jpg" property="og:image">
+      <script type="application/ld+json">{"@type":"Product","gtin13":"1234567890123"}</script>`;
+
+    const hints = hintsFromHtml(html, new URL('https://example.com/burg'));
+    expect(hints.name).toBe('Burg Blaustein & Zubehör');
+    expect(hints.imageUrl).toBe('https://cdn.example.com/burg.jpg');
+    expect(hints.ean).toBeUndefined();
+  });
+
+  it('haelt Shop-Artikelnummern nicht fuer Setnummern', () => {
+    const html = '<script type="application/ld+json">{"@type":"Product","sku":"B0BYZJXGZQ"}</script>';
+    expect(hintsFromHtml(html, page).setNumber).toBeUndefined();
+  });
+
+  it('liest Amazon-Seiten ohne schema.org', () => {
+    const html = `
+      <span id="productTitle" class="a-size-large"> LEGO City Familienhaus mit Elektroauto, 60398 </span>
+      <a id="bylineInfo" href="/stores/LEGO">Besuche den LEGO-Store</a>
+      <script>var data = {"hiRes":"https://m.media-amazon.com/images/I/81abc.jpg","thumb":"x"};</script>
+      <table><tr><th class="prodDetSectionEntry"> Modellnummer </th><td> &lrm;60398 </td></tr>
+      <tr><th class="prodDetSectionEntry"> Anzahl der Teile </th><td> 462 </td></tr></table>`;
+
+    expect(hintsFromHtml(html, new URL('https://www.amazon.de/dp/B0BYZJXGZQ'))).toEqual({
+      manufacturer: 'Lego',
+      setNumber: '60398',
+      name: 'LEGO City Familienhaus mit Elektroauto, 60398',
+      ean: undefined,
+      imageUrl: 'https://m.media-amazon.com/images/I/81abc.jpg',
+      pieceCount: 462,
+    });
+  });
+
+  it('findet die Setnummer im Produktnamen', () => {
+    const html = '<meta property="og:title" content="Cobi 2400 Ford GP ab € 12,90 (2026)">';
+    const hints = hintsFromHtml(html, new URL('https://geizhals.de/x-a1.html'));
+    expect(hints.setNumber).toBe('2400');
+    expect(cleanSetName(hints.name!, 'Cobi', hints.setNumber)).toBe('Ford GP');
+  });
+
+  it('uebersteht kaputtes JSON', () => {
+    const html = '<script type="application/ld+json">{ kaputt </script><meta property="og:title" content="X">';
+    expect(hintsFromHtml(html, page).name).toBe('X');
+  });
+});
+
+describe('Zusammenfuehren und Namen putzen', () => {
+  it('nimmt pro Feld die erste Quelle mit Wert', () => {
+    expect(
+      mergeHints({ name: 'Seite', pieceCount: undefined }, { name: 'Link', pieceCount: 450 }, null),
+    ).toEqual({ name: 'Seite', pieceCount: 450 });
+  });
+
+  it('entfernt Marke, Nummer und Seitennamen', () => {
+    expect(cleanSetName('LEGO® City Familienhaus mit Elektroauto 60398', 'Lego', '60398')).toBe(
+      'City Familienhaus mit Elektroauto',
+    );
+    expect(
+      cleanSetName('BlueBrixx - Technisches Hilfswerk™ Bi-Directional Vehicle | Set 108782', 'BlueBrixx', '108782'),
+    ).toBe('Technisches Hilfswerk Bi-Directional Vehicle');
+    expect(cleanSetName('Cobi Ford GP • Set 2400 • SetDB • Merlins Bricks', 'Cobi', '2400')).toBe('Ford GP');
+  });
+});
+
+describe('Nur oeffentliche Adressen', () => {
+  it('sperrt Heimnetz, Loopback und Metadaten-Adressen', () => {
+    for (const address of [
+      '127.0.0.1',
+      '10.0.0.5',
+      '172.16.3.4',
+      '192.168.178.1',
+      '169.254.169.254',
+      '100.64.0.1',
+      '0.0.0.0',
+      '::1',
+      'fd00::1',
+      'fe80::1',
+      '::ffff:192.168.1.1',
+    ]) {
+      expect(isPublicAddress(address), address).toBe(false);
+    }
+  });
+
+  it('laesst oeffentliche Adressen durch', () => {
+    expect(isPublicAddress('93.184.216.34')).toBe(true);
+    expect(isPublicAddress('2a00:1450:4001:80b::200e')).toBe(true);
+    expect(isPublicAddress('::ffff:93.184.216.34')).toBe(true);
+  });
+
+  it('erlaubt nur normale Web-Links', () => {
+    expect(isAllowedWebUrl(new URL('https://example.com/a'))).toBe(true);
+    expect(isAllowedWebUrl(new URL('http://example.com:80/a'))).toBe(true);
+    expect(isAllowedWebUrl(new URL('file:///etc/passwd'))).toBe(false);
+    expect(isAllowedWebUrl(new URL('https://example.com:8443/'))).toBe(false);
+    expect(isAllowedWebUrl(new URL('https://user:pw@example.com/'))).toBe(false);
+  });
+});