feat: add modular dynamic PDF generation for Payload pages

app/api/pages/[slug]/pdf/route.tsx

@@ -0,0 +1,64 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getPayload } from 'payload';
+import configPromise from '@payload-config';
+import { renderToStream } from '@react-pdf/renderer';
+import React from 'react';
+import { PDFPage } from '@/lib/pdf-page';
+
+export async function GET(req: NextRequest, { params }: { params: Promise<{ slug: string }> }) {
+  try {
+    const { slug } = await params;
+
+    // Get Payload App
+    const payload = await getPayload({ config: configPromise });
+
+    // Fetch the page
+    const pages = await payload.find({
+      collection: 'pages',
+      where: {
+        slug: { equals: slug },
+        _status: { equals: 'published' },
+      },
+      limit: 1,
+    });
+
+    if (pages.totalDocs === 0) {
+      return new NextResponse('Page not found', { status: 404 });
+    }
+
+    const page = pages.docs[0];
+
+    // Determine locale from searchParams or default to 'de'
+    const searchParams = req.nextUrl.searchParams;
+    const locale = (searchParams.get('locale') as 'en' | 'de') || 'de';
+
+    // Render the React-PDF document into a stream
+    const stream = await renderToStream(<PDFPage page={page} locale={locale} />);
+
+    // Pipe the Node.js Readable stream into a valid fetch/Web Response stream
+    const body = new ReadableStream({
+      start(controller) {
+        stream.on('data', (chunk) => controller.enqueue(chunk));
+        stream.on('end', () => controller.close());
+        stream.on('error', (err) => controller.error(err));
+      },
+      cancel() {
+        (stream as any).destroy?.();
+      },
+    });
+
+    const filename = `${slug}.pdf`;
+
+    return new NextResponse(body, {
+      status: 200,
+      headers: {
+        'Content-Type': 'application/pdf',
+        'Content-Disposition': `attachment; filename="${filename}"`,
+        // Cache control if needed, skip for now.
+      },
+    });
+  } catch (error) {
+    console.error('Error generating PDF:', error);
+    return new NextResponse('Internal Server Error', { status: 500 });
+  }
+}