[Bug]: html-to-pdf endpoint error on zip input

[onief]

Installation Method

Local Installation

The Problem

When using Stirlings HTML-to-PDF abilities you get an error when trying to provide a zip-file which contains the html and its resources (e.g. css or images).

This should not be the case since the swagger-docu states "[/api/v1/convert/html/pdf] Convert an HTML or ZIP (containing HTML and CSS) to PDF".
It happens for both cases: Docker and Local Installation.

I investigated the case since I needed it for local testing. What happens is that Stirling calls WeasyPrint CLI with the whole zipped folder as arguments, whereas WeasyPrint only excepts the plain html.
I already realized a working solution for me, so I can directly raise a PR once I am assigned.

If I'm missing any crucial steps please let me now!

Version of Stirling-PDF

2.3.1 (newest commit at that time)

Last Working Version of Stirling-PDF

No response

Page Where the Problem Occurred

localhost:8080/api/v1/convert/html/pdf

Docker Configuration

-e SYSTEM_DISABLESANITIZE=true
(since I want my external css to be applied)

Relevant Log Output

11:53:08.923 [virtual-137] INFO  s.s.common.util.ProcessExecutor - Running command: weasyprint -e utf-8 -v --pdf-forms /var/folders/x1/g31nxx854k38jyfndl02w69r0000gp/T/stirling-pdf/stirling-pdf-10709287287484235973.zip /var/folders/x1/g31nxx854k38jyfndl02w69r0000gp/T/stirling-pdf/stirling-pdf-8799506396568818203.pdf
11:53:09.205 [Thread-38] INFO  s.s.common.util.ProcessExecutor - INFO: Step 1 - Fetching and parsing HTML - /var/folders/x1/g31nxx854k38jyfndl02w69r0000gp/T/stirling-pdf/stirling-pdf-10709287287484235973.zip
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor - Traceback (most recent call last):
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/bin/weasyprint", line 7, in <module>
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     sys.exit(main())
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -              ~~~~^^
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/__main__.py", line 205, in main
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     html.write_pdf(output, **options)
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
11:53:09.232 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/__init__.py", line 270, in write_pdf
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     self.render(font_config, counter_style, color_profiles, **options)
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/__init__.py", line 226, in render
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     return Document._render(
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -            ~~~~~~~~~~~~~~~~^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -         self, font_config, counter_style, color_profiles, options)
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/document.py", line 249, in _render
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     context = cls._build_layout_context(
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -         html, font_config, counter_style, color_profiles, options)
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/document.py", line 225, in _build_layout_context
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     style_for = get_all_computed_styles(
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -         html, user_stylesheets, options['presentational_hints'], font_config,
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -         counter_style, color_profiles, page_rules, layers, target_collector,
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -         options['pdf_forms'])
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/css/__init__.py", line 1803, in get_all_computed_styles
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     for sheet in find_stylesheets(
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -                  ~~~~~~~~~~~~~~~~^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -             html.wrapper_element, html.media_type, html.url_fetcher,
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -             html.base_url, font_config, counter_style, color_profiles, page_rules,
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -             layers):
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -             ^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/weasyprint/css/__init__.py", line 268, in find_stylesheets
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     for wrapper in wrapper_element.query_all('style', 'link'):
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -                    ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/cssselect2/tree.py", line 272, in <genexpr>
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     if any(test(element) for test in tests))
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -        ^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/cssselect2/tree.py", line 272, in <genexpr>
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     if any(test(element) for test in tests))
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -            ~~~~^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "<string>", line 1, in <lambda>
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/python@3.14/3.14.2/Frameworks/Python.framework/Versions/3.14/lib/python3.14/functools.py", line 1126, in __get__
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     val = self.func(instance)
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/cssselect2/tree.py", line 307, in local_name
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     namespace_url, local_name = _split_etree_tag(self.etree_element.tag)
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -                                 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -   File "/opt/homebrew/Cellar/weasyprint/67.0/libexec/lib/python3.14/site-packages/cssselect2/tree.py", line 377, in _split_etree_tag
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -     assert tag[0] == '{'
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor -            ^^^^^^^^^^^^^
11:53:09.233 [Thread-38] INFO  s.s.common.util.ProcessExecutor - AssertionError

Additional Information

No response

Browsers Affected

No response

No Duplicate of the Issue

• I have verified that there are no existing issues raised related to my problem.

[dosubot]

Hi @onief! I'm Dosu and I’m helping the Stirling-PDF team.

Your understanding is correct: the documentation states that the HTML-to-PDF endpoint should accept both HTML and ZIP files containing HTML, CSS, and images for conversion using WeasyPrint — so ZIP input is an expected feature see docs. The technical cause of your issue is that WeasyPrint CLI does not accept ZIP files directly; it expects a plain HTML file, so the ZIP should be extracted and the main HTML file passed to WeasyPrint.

There are no existing issues, discussions, or merged pull requests addressing this bug, and the documentation does not mention any special requirements or known problems with ZIP input. Based on available evidence, it appears the code does not currently extract ZIPs before invoking WeasyPrint.

For contributions, the project welcomes small bug fixes as direct pull requests without prior discussion — just follow the guidelines in the CONTRIBUTING.md and the contribution docs. You’re good to go with your PR!

To reply, just mention @dosu.

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