First Steps =========== .. currentmodule:: weasyprint Installation ------------ WeasyPrint |version| depends on: * Python_ ≥ 3.8.0 * Pango_ ≥ 1.44.0 * pydyf_ ≥ 0.8.0 * CFFI_ ≥ 0.6 * html5lib_ ≥ 1.1 * tinycss2_ ≥ 1.0.0 * cssselect2_ ≥ 0.1 * Pyphen_ ≥ 0.9.1 * Pillow_ ≥ 9.1.0 * fontTools_ ≥ 4.0.0 .. _Python: https://www.python.org/ .. _Pango: https://pango.gnome.org/ .. _CFFI: https://cffi.readthedocs.io/ .. _html5lib: https://html5lib.readthedocs.io/ .. _pydyf: https://doc.courtbouillon.org/pydyf/ .. _tinycss2: https://doc.courtbouillon.org/tinycss2/ .. _cssselect2: https://doc.courtbouillon.org/cssselect2/ .. _Pyphen: https://pyphen.org/ .. _Pillow: https://python-pillow.org/ .. _fontTools: https://github.com/fonttools/fonttools There are many ways to install WeasyPrint, depending on the system you use. Linux ~~~~~ The easiest way to install WeasyPrint on Linux is to use the package manager of your distribution. WeasyPrint is packaged for recent versions of Debian_, Ubuntu_, Fedora_, Archlinux_, Gentoo_… .. _Debian: https://packages.debian.org/search?keywords=weasyprint&searchon=names&suite=all§ion=all .. _Ubuntu: https://packages.ubuntu.com/search?keywords=weasyprint&searchon=names&suite=all§ion=all .. _Fedora: https://src.fedoraproject.org/rpms/weasyprint .. _Archlinux: https://aur.archlinux.org/packages/python-weasyprint .. _Gentoo: https://packages.gentoo.org/packages/dev-python/weasyprint If WeasyPrint is not available on your distribution, or if you want to use a more recent version of WeasyPrint, you have to be sure that Python_ (at least version 3.7.0) and Pango_ (at least version 1.44.0) are installed on your system. You can verify this by launching:: python3 --version pango-view --version If the version of Pango provided by your distribution is too old, you can use version 52.5 of WeasyPrint which does not need recent Pango features. When everything is OK, you can install WeasyPrint directly on your system or in a `virtual environment`_ using `pip`_:: python3 -m venv venv source venv/bin/activate pip install weasyprint weasyprint --info .. _virtual environment: https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/ .. _pip: https://pip.pypa.io/ Alpine ≥ 3.14 +++++++++++++ To install WeasyPrint using your distribution’s package:: apk add weasyprint To install WeasyPrint inside a virtualenv using wheels (if possible), you need the following packages:: apk add py3-pip gcc musl-dev python3-dev pango zlib-dev jpeg-dev openjpeg-dev g++ libffi-dev To install WeasyPrint inside a virtualenv without using wheels, you need the following packages:: apk add py3-pip gcc musl-dev python3-dev pango zlib-dev jpeg-dev openjpeg-dev g++ libffi-dev Archlinux +++++++++ To install WeasyPrint using your distribution’s package:: pacman -S python-weasyprint To install WeasyPrint inside a virtualenv using wheels (if possible), you need the following packages:: pacman -S python-pip pango To install WeasyPrint inside a virtualenv without using wheels, you need the following packages:: pacman -S python-pip pango gcc libjpeg-turbo openjpeg2 Debian ≥ 11 +++++++++++ To install WeasyPrint using your distribution’s package:: apt install weasyprint To install WeasyPrint inside a virtualenv using wheels (if possible), you need the following packages:: apt install python3-pip libpango-1.0-0 libpangoft2-1.0-0 To install WeasyPrint inside a virtualenv without using wheels, you need the following packages:: apt install python3-pip libpango-1.0-0 libpangoft2-1.0-0 libjpeg-dev libopenjp2-7-dev libffi-dev Fedora ≥ 34 +++++++++++ To install WeasyPrint using your distribution’s package:: dnf install weasyprint To install WeasyPrint inside a virtualenv using wheels (if possible), you need the following packages:: dnf install python-pip pango To install WeasyPrint inside a virtualenv without using wheels, you need the following packages:: dnf install python3-pip pango gcc python3-devel gcc-c++ zlib-devel libjpeg-devel openjpeg2-devel libffi-devel Ubuntu ≥ 20.04 ++++++++++++++ To install WeasyPrint using your distribution’s package:: apt install weasyprint To install WeasyPrint inside a virtualenv using wheels (if possible), you need the following packages:: apt install python3-pip libpango-1.0-0 libharfbuzz0b libpangoft2-1.0-0 To install WeasyPrint inside a virtualenv without using wheels, you need the following packages:: apt install python3-pip libpango-1.0-0 libharfbuzz0b libpangoft2-1.0-0 libffi-dev libjpeg-dev libopenjp2-7-dev macOS ~~~~~ The easiest way to install WeasyPrint on macOS is to use Homebrew_:: brew install weasyprint .. _Homebrew: https://brew.sh/ Windows ~~~~~~~ To use WeasyPrint on Windows, the easiest way is to use the `executable`_ of the latest release. If you want to use WeasyPrint as a Python library, you’ll have to follow a few extra steps. Please read this chapter carefully. The first step is to install the latest version of Python from the `Microsoft Store`_. When Python is installed, you have to install GTK. Download the latest `GTK3 installer`_ and launch it. If you don’t know what some options mean, you can safely keep the default options selected. You can then launch a command prompt by clicking on the Start menu, typing "cmd" and clicking the "Command Prompt" icon. Install WeasyPrint in a `virtual environment`_ using `pip`_:: python3 -m venv venv venv\Scripts\activate.bat python3 -m pip install weasyprint python3 -m weasyprint --info .. _executable: https://github.com/Kozea/WeasyPrint/releases .. _Microsoft Store: https://apps.microsoft.com/store/search/python .. _GTK3 installer: https://github.com/tschoonj/GTK-for-Windows-Runtime-Environment-Installer/releases Other Solutions ~~~~~~~~~~~~~~~ Other solutions are available to install WeasyPrint. These solutions are not tested but they are known to work for some use cases on specific platforms. Macports ++++++++ On macOS, you can install WeasyPrint’s dependencies with Macports_:: sudo port install py-pip pango libffi You can then install WeasyPrint in a `virtual environment`_ using `pip`_:: python3 -m venv venv source venv/bin/activate pip install weasyprint weasyprint --info .. _Macports: https://www.macports.org/ Conda +++++ On Linux and macOS, WeasyPrint is available on Conda_, with `a WeasyPrint package on Conda Forge`_. .. _Conda: https://docs.conda.io/projects/conda/en/latest/ .. _a WeasyPrint package on Conda Forge: https://anaconda.org/conda-forge/weasyprint WSL +++ On Windows, you can also use WSL_ and install WeasyPrint the same way it has to be installed on Linux. .. _WSL: https://docs.microsoft.com/en-us/windows/wsl/ .NET Wrapper ++++++++++++ On Windows, Bader Albarrak maintains `a .NET wrapper`_. .. _a .NET wrapper: https://github.com/balbarak/WeasyPrint-netcore AWS +++ Kotify maintains `an AWS Lambda layer`_, see issue `#1003`_ for more information. .. _an AWS Lambda layer: https://github.com/kotify/cloud-print-utils .. _#1003: https://github.com/Kozea/WeasyPrint/issues/1003 Troubleshooting ~~~~~~~~~~~~~~~ Most of the installation problems have already been met, and some `issues on GitHub`_ could help you to solve them. Missing Library +++++++++++++++ On Windows, most of the problems come from unreachable libraries. If you get an error like ``cannot load library 'xxx': error xxx``, it means that WeasyPrint can’t find this library. You can set the ``WEASYPRINT_DLL_DIRECTORIES`` environment variable to list the folders where the libraries can be found. For example, in ``cmd.exe``: .. code-block:: doscon > set WEASYPRINT_DLL_DIRECTORIES=C:\GTK3\bin;D:\GTK3\bin You can find more about this issue in `#589`_, `#721`_ or `#1240`_. .. _issues on GitHub: https://github.com/Kozea/WeasyPrint/issues .. _#589: https://github.com/Kozea/WeasyPrint/issues/589 .. _#721: https://github.com/Kozea/WeasyPrint/issues/721 .. _#1240: https://github.com/Kozea/WeasyPrint/issues/1240 Missing Fonts +++++++++++++ If no character is drawn in the generated PDF, or if you get squares instead of letters, you have to install fonts and make them available to WeasyPrint. Following the standard way to install fonts on your system should be enough. You can also use ``@font-face`` rules to explicitly reference fonts using URLs. Command-Line ------------ Using the WeasyPrint command line interface can be as simple as this: .. code-block:: sh weasyprint https://weasyprint.org /tmp/weasyprint-website.pdf You may see warnings on the standard error output about unsupported CSS properties. See :ref:`Command-Line API` for the details of all available options. In particular, the ``-s`` option can add a filename for a :ref:`user stylesheet `. For quick experimentation however, you may not want to create a file. In bash or zsh, you can use the shell’s redirection instead: .. code-block:: sh weasyprint https://weasyprint.org /tmp/weasyprint-website.pdf \ -s <(echo 'body { font-family: serif !important }') If you have many documents to convert you may prefer using the Python API in long-lived processes to avoid paying the start-up costs every time. Python Library -------------- .. attention:: Using WeasyPrint with untrusted HTML or untrusted CSS may lead to various :ref:`security problems `. Quickstart ~~~~~~~~~~ The Python version of the above example goes like this: .. code-block:: python from weasyprint import HTML HTML('https://weasyprint.org/').write_pdf('/tmp/weasyprint-website.pdf') … or with the inline stylesheet: .. code-block:: python from weasyprint import HTML, CSS HTML('https://weasyprint.org/').write_pdf('/tmp/weasyprint-website.pdf', stylesheets=[CSS(string='body { font-family: serif !important }')]) Instantiating HTML and CSS Objects ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If you have a file name, an absolute URL or a readable :term:`file object`, you can just pass it to :class:`HTML` or :class:`CSS` to create an instance. Alternatively, use a named argument so that no guessing is involved: .. code-block:: python from weasyprint import HTML HTML('../foo.html') # Same as … HTML(filename='../foo.html') HTML('https://weasyprint.org') # Same as … HTML(url='https://weasyprint.org') HTML(sys.stdin) # Same as … HTML(file_obj=sys.stdin) If you have a byte string or Unicode string already in memory you can also pass that, although the argument must be named: .. code-block:: python from weasyprint import HTML, CSS # HTML('

foo') would be filename HTML(string='''

The title

Content goes here ''') CSS(string='@page { size: A3; margin: 1cm }') If you have ``@font-face`` rules in your CSS, you have to create a ``FontConfiguration`` object: .. code-block:: python from weasyprint import HTML, CSS from weasyprint.text.fonts import FontConfiguration font_config = FontConfiguration() html = HTML(string='

The title

') css = CSS(string=''' @font-face { font-family: Gentium; src: url(https://example.com/fonts/Gentium.otf); } h1 { font-family: Gentium }''', font_config=font_config) html.write_pdf( '/tmp/example.pdf', stylesheets=[css], font_config=font_config) Rendering to a Single File ~~~~~~~~~~~~~~~~~~~~~~~~~~ Once you have a :class:`HTML` object, call its :meth:`HTML.write_pdf` method to get the rendered document in a single PDF file. Without arguments, this method returns a byte string in memory. If you pass a file name or a writable :term:`file object`, they will write there directly instead. (**Warning**: with a filename, these methods will overwrite existing files silently.) Individual Pages & Meta-Data ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If you want more than a single PDF, the :meth:`HTML.render` method gives you a :class:`document.Document` object with access to individual :class:`document.Page` objects. Thus you can get the number of pages, their size\ [#]_, the details of hyperlinks and bookmarks, etc. Documents also have a :meth:`document.Document.write_pdf` method, and you can get a subset of the pages with :meth:`document.Document.copy()`. Finally, for ultimate control, :meth:`document.Page.paint` individual pages anywhere on any :class:`pydyf.Stream`. .. [#] Pages in the same document do not always have the same size. See the :ref:`Python API` for details. A few random examples: .. code-block:: python # Write odd and even pages separately: # Lists count from 0 but page numbers usually from 1 # [::2] is a slice of even list indexes but odd-numbered pages. document.copy(document.pages[::2]).write_pdf('odd_pages.pdf') document.copy(document.pages[1::2]).write_pdf('even_pages.pdf') .. code-block:: python # Print the outline of the document. # Output on https://www.w3.org/TR/CSS21/intro.html # 1. Introduction to CSS 2.1 (page 2) # 1. A brief CSS 2.1 tutorial for HTML (page 2) # 2. A brief CSS 2.1 tutorial for XML (page 5) # 3. The CSS 2.1 processing model (page 6) # 1. The canvas (page 7) # 2. CSS 2.1 addressing model (page 7) # 4. CSS design principles (page 8) def print_outline(bookmarks, indent=0): for i, bookmark in enumerate(bookmarks, 1): page = bookmark.destination[0] print('%s%d. %s (page %d)' % ( ' ' * indent, i, bookmark.label.lstrip('0123456789. '), page)) print_outline(bookmark.children, indent + 2) print_outline(document.make_bookmark_tree()) URL Fetchers ~~~~~~~~~~~~ WeasyPrint goes through a *URL fetcher* to fetch external resources such as images or CSS stylesheets. The default fetcher can natively open file and HTTP URLs, but the HTTP client does not support advanced features like cookies or authentication. This can be worked-around by passing a custom ``url_fetcher`` callable to the :class:`HTML` or :class:`CSS` classes. It must have the same signature as :func:`default_url_fetcher`. Custom fetchers can choose to handle some URLs and defer others to the default fetcher: .. code-block:: python from weasyprint import default_url_fetcher, HTML def my_fetcher(url): if url.startswith('graph:'): graph_data = map(float, url[6:].split(',')) string = generate_graph(graph_data) return {'string': string, 'mime_type': 'image/png'} return default_url_fetcher(url) source = '' HTML(string=source, url_fetcher=my_fetcher).write_pdf('out.pdf') Flask-WeasyPrint_ for Flask_ and Django-Weasyprint_ for Django_ both make use of a custom URL fetcher to integrate WeasyPrint and use the filesystem instead of a network call for static and media files. A custom fetcher should be returning a :obj:`dict` with * One of ``string`` (a :obj:`bytestring `) or ``file_obj`` (a :term:`file object`). * Optionally: ``mime_type``, a MIME type extracted e.g. from a *Content-Type* header. If not provided, the type is guessed from the file extension in the URL. * Optionally: ``encoding``, a character encoding extracted e.g. from a *charset* parameter in a *Content-Type* header * Optionally: ``redirected_url``, the actual URL of the resource if there were e.g. HTTP redirects. * Optionally: ``filename``, the filename of the resource. Usually derived from the *filename* parameter in a *Content-Disposition* header If a ``file_obj`` is given, the resource will be closed automatically by the function internally used by WeasyPrint to retrieve data. .. _Flask-Weasyprint: https://github.com/Kozea/Flask-WeasyPrint .. _Flask: https://flask.pocoo.org/ .. _Django-WeasyPrint: https://github.com/fdemmer/django-weasyprint .. _Django: https://www.djangoproject.com/ Image Cache and Optimization ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ WeasyPrint provides many options to deal with images: ``optimize_images``, ``jpeg_quality``, ``dpi`` and ``image_cache``. ``optimize_images`` can enable size optimization for images. When enabled, the generated PDF will include smaller images with no quality penalty, but the rendering time may be slightly increased. The ``jpeg_quality`` option can be set to decrease the quality of JPEG images included in the PDF. You can set a value between 95 (best quality) to 0 (smaller image size), depending on your needs. The ``dpi`` option offers the possibility to reduce the size (in pixels, and thus in bytes) of all included raster images. The resolution, set in dots per inch, indicates the maximum number of pixels included in one inch on the generated PDF. .. code-block:: python # Original high-quality images, faster, but generated PDF is larger HTML('https://weasyprint.org/').write_pdf('weasyprint.pdf') # Optimized lower-quality images, a bit slower, but generated PDF is smaller HTML('https://weasyprint.org/').write_pdf( 'weasyprint.pdf', optimize_images=True, jpeg_quality=60, dpi=150) ``image_cache`` gives the possibility to use a cache for images, avoiding to download, parse and optimize them each time they are used. By default, the cache is used document by document, but you can share it between documents if needed. This feature can save a lot of network and CPU time when you render a lot of documents that use the same images. .. code-block:: python cache = {} for i in range(10): HTML(f'https://weasyprint.org/').write_pdf( f'example-{i}.pdf', image_cache=cache) It’s also possible to cache images on disk instead of keeping them in memory. The ``--cache-folder`` CLI option can be used to define the folder used to store temporary images. You can also provide this folder path as a string for ``image_cache``. Logging ~~~~~~~ Most errors (unsupported CSS property, missing image, ...) are not fatal and will not prevent a document from being rendered. WeasyPrint uses the :mod:`logging` module from the Python standard library to log these errors and let you know about them. When WeasyPrint is launched in a terminal, logged messaged will go to *stderr* by default. You can change that by configuring the ``weasyprint`` logger object: .. code-block:: python import logging logger = logging.getLogger('weasyprint') logger.addHandler(logging.FileHandler('/path/to/weasyprint.log')) The ``weasyprint.progress`` logger is used to report the rendering progress. It is useful to get feedback when WeasyPrint is launched in a terminal (using the ``--verbose`` or ``--debug`` option), or to give this feedback to end users when used as a library. See the documentation of the :mod:`logging` module for details. Security -------- When used with untrusted HTML or untrusted CSS, WeasyPrint can meet security problems. You will need extra configuration in your Python application to avoid high memory use, endless renderings or local files leaks. *This section has been added thanks to the very useful reports and advice from Raz Becker.* Long Renderings ~~~~~~~~~~~~~~~ WeasyPrint is pretty slow and can take a long time to render long documents or specially crafted HTML pages. When WeasyPrint used on a server with HTML or CSS files from untrusted sources, this problem can lead to very long time renderings, with processes with high CPU and memory use. Even small documents may lead to really long rendering times, restricting HTML document size is not enough. If you use WeasyPrint on a server with HTML or CSS samples coming from untrusted users, you should: - limit rendering time and memory use of your process, for example using ``evil-reload-on-as`` and ``harakiri`` options if you use uWSGI, - limit memory use at the OS level, for example with ``ulimit`` on Linux, - automatically kill the process when it uses too much memory or when the rendering time is too high, by regularly launching a script to do so if no better option is available, - truncate and sanitize HTML and CSS input to avoid very long documents and access to external URLs. Infinite Requests ~~~~~~~~~~~~~~~~~ WeasyPrint can reach files on the network, for example using ``https://`` URIs. For various reasons, HTTP requests may take a long time and lead to problems similar to :ref:`Long Renderings`. WeasyPrint has a default timeout of 10 seconds for HTTP, HTTPS and FTP resources. This timeout has no effect with other protocols, including access to ``file://`` URIs. If you use WeasyPrint on a server with HTML or CSS samples coming from untrusted users, or need to reach network resources, you should: - use a custom :ref:`URL fetcher `, - follow solutions listed in :ref:`Long Renderings`. Infinite Loops ~~~~~~~~~~~~~~ WeasyPrint has been hit by a large number of bugs, including infinite loops. Specially crafted HTML and CSS files can quite easily lead to infinite loops and infinite rendering times. If you use WeasyPrint on a server with HTML or CSS samples coming from untrusted users, you should: - follow solutions listed in :ref:`Long Renderings`. Huge Values ~~~~~~~~~~~ WeasyPrint doesn't restrict integer and float values used in CSS. Using huge values for some properties (page sizes, font sizes, block sizes) can lead to various problems, including infinite rendering times, huge PDF files, high memory use and crashes. This problem is really hard to avoid. Even parsing CSS stylesheets and searching for huge values is not enough, as it is quite easy to trick CSS pre-processors using relative units (``em`` and ``%`` for example). If you use WeasyPrint on a server with HTML or CSS samples coming from untrusted users, you should: - follow solutions listed in :ref:`Long Renderings`. Access to Local Files ~~~~~~~~~~~~~~~~~~~~~ As any web renderer, WeasyPrint can reach files on the local filesystem using ``file://`` URIs. These files can be shown in ``img`` or ``embed`` tags for example. When WeasyPrint used on a server with HTML or CSS files from untrusted sources, this feature may be used to know if files are present on the server filesystem, and to embed them in generated documents. Unix-like systems also have special local files with infinite size, like ``/dev/urandom``. Referencing these files in HTML or CSS files obviously lead to infinite time renderings. If you use WeasyPrint on a server with HTML or CSS samples coming from untrusted users, you should: - restrict your process access to trusted files using sandboxing solutions, - use a custom :ref:`URL fetcher ` that doesn't allow ``file://`` URLs or filters access depending on given paths. - follow solutions listed in :ref:`Long Renderings`. System Information Leaks ~~~~~~~~~~~~~~~~~~~~~~~~ WeasyPrint relies on many libraries that can leak hardware and software information. Even when this information looks useless, it can be used by attackers to exploit other security breaches. Leaks can include (but are not restricted to): - locally installed fonts (using ``font-family`` and ``@font-face``), - network configuration (IPv4 and IPv6 support, IP addressing, firewall configuration, using ``https://`` URIs and tracking time used to render documents), - Python, Pango and other libraries versions (implementation details lead to different renderings). SVG Images ~~~~~~~~~~ Rendering SVG images more or less suffers from the same problems as the ones listed here for WeasyPrint. Security advices apply for untrusted SVG files as they apply for untrusted HTML and CSS documents. Note that WeasyPrint’s URL fetcher is used to render SVG files.