feat: enhance production readiness with environment configuration, dependency checks, and sitemap updates

backend/app/services/html_to_pdf_service.py

@@ -1,6 +1,7 @@
 """HTML to PDF conversion service."""
 import os
 import logging
+from importlib.metadata import PackageNotFoundError, version
 
 logger = logging.getLogger(__name__)
 
@@ -10,6 +11,54 @@ class HtmlToPdfError(Exception):
     pass
 
 
+def _parse_version_parts(raw_version: str | None) -> tuple[int, ...]:
+    """Parse a package version into comparable integer parts."""
+    if not raw_version:
+        return ()
+
+    parts: list[int] = []
+    for token in raw_version.replace("-", ".").split("."):
+        digits = "".join(ch for ch in token if ch.isdigit())
+        if not digits:
+            break
+        parts.append(int(digits))
+    return tuple(parts)
+
+
+def _get_installed_version(package_name: str) -> str | None:
+    """Return installed package version, if available."""
+    try:
+        return version(package_name)
+    except PackageNotFoundError:
+        return None
+
+
+def _get_dependency_mismatch_error() -> str | None:
+    """
+    Detect the known WeasyPrint/pydyf incompatibility before conversion starts.
+
+    WeasyPrint 61.x instantiates pydyf.PDF with constructor arguments, while
+    pydyf 0.11+ moved these parameters to PDF.write(). That mismatch raises:
+    "PDF.__init__() takes 1 positional argument but 3 were given".
+    """
+    weasyprint_version = _get_installed_version("weasyprint")
+    pydyf_version = _get_installed_version("pydyf")
+    if not weasyprint_version or not pydyf_version:
+        return None
+
+    if (
+        _parse_version_parts(weasyprint_version) < (62,)
+        and _parse_version_parts(pydyf_version) >= (0, 11)
+    ):
+        return (
+            "Installed HTML-to-PDF dependencies are incompatible: "
+            f"WeasyPrint {weasyprint_version} with pydyf {pydyf_version}. "
+            "Reinstall backend dependencies after pinning pydyf<0.11."
+        )
+
+    return None
+
+
 def html_to_pdf(
     input_path: str,
     output_path: str,
@@ -30,6 +79,10 @@ def html_to_pdf(
     os.makedirs(os.path.dirname(output_path), exist_ok=True)
 
     try:
+        dependency_error = _get_dependency_mismatch_error()
+        if dependency_error:
+            raise HtmlToPdfError(dependency_error)
+
         from weasyprint import HTML
 
         HTML(filename=input_path).write_pdf(output_path)
@@ -67,6 +120,10 @@ def html_string_to_pdf(
     os.makedirs(os.path.dirname(output_path), exist_ok=True)
 
     try:
+        dependency_error = _get_dependency_mismatch_error()
+        if dependency_error:
+            raise HtmlToPdfError(dependency_error)
+
         from weasyprint import HTML
 
         HTML(string=html_content).write_pdf(output_path)