Update app.py

app.py

@@ -227,6 +227,7 @@ def html_to_pdf_playwright(html_path: str, pdf_path: str) -> bool:
     """Convert HTML to PDF using Playwright with Windows compatibility"""
     import asyncio
     import sys
+    import traceback
     
     async def create_pdf():
         from playwright.async_api import async_playwright
@@ -255,17 +256,49 @@ def html_to_pdf_playwright(html_path: str, pdf_path: str) -> bool:
             
             await browser.close()
     
+    def _try_generate() -> bool:
+        try:
+            # Set event loop policy for Windows compatibility
+            if sys.platform == "win32":
+                asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
+            asyncio.run(create_pdf())
+            return True
+        except Exception as ex:
+            raise ex
+
+    def _install_playwright_browser_once() -> bool:
+        flag = os.path.join(tempfile.gettempdir(), 'playwright_browser_installed')
+        if os.path.exists(flag):
+            return True
+        try:
+            subprocess.run([sys.executable, "-m", "playwright", "install", "chromium"], check=True)
+            with open(flag, 'w') as f:
+                f.write('installed')
+            print("✅ Playwright Chromium downloaded at runtime.")
+            return True
+        except Exception as ex:
+            print(f"❌ Runtime Playwright browser install failed: {ex}")
+            return False
+
     try:
         # Set event loop policy for Windows compatibility
         if sys.platform == "win32":
             asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
-        
-        # Run the async function
-        asyncio.run(create_pdf())
-        return True
+        # First attempt
+        if _try_generate():
+            return True
         
     except Exception as e:
         print(f"Playwright conversion failed: {e}")
+        err_text = f"{e}\n{traceback.format_exc()}"
+        # If browsers are not downloaded, try to fetch them once and retry
+        if "Executable doesn't exist" in err_text or "playwright install" in err_text:
+            if _install_playwright_browser_once():
+                try:
+                    if _try_generate():
+                        return True
+                except Exception as e2:
+                    print(f"Retry after browser install failed: {e2}")
         # Additional debugging for Windows issues
         if "NotImplementedError" in str(e):
             print("Windows asyncio compatibility issue detected. Trying alternative approach...")