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Libxml2 is the XML C parser and toolkit developed for the Gnome project (but usable outside of the Gnome platform), it is free software available under the MIT License. XML itself is a metalanguage to design markup languages, i.e. text language where semantic and structure are added to the content using extra "markup" information enclosed between angle brackets. HTML is the most well-known markup language. Though the library is written in C a variety of language bindings make it available in other environments.

Libxml2 is known to be very portable, the library should build and work without serious troubles on a variety of systems (Linux, Unix, Windows, CygWin, MacOS, RISC Os, OS/2, VMS, QNX, MVS, ...)

Libxml2 implements a number of existing standards related to markup languages:

In most cases libxml2 tries to implement the specifications in a relatively strictly compliant way. As of release 2.4.16, libxml2 passed all 1800+ tests from the OASIS XML Tests Suite.

To some extent libxml2 provides support for the following additional specifications but doesn't claim to implement them completely:

  • Document Object Model (DOM) https://www.w3.org/TR/DOM-Level-2-Core/ the document model, but it doesn't implement the API itself, gdome2 does this on top of libxml2
  • RFC 959 : libxml2 implements a basic FTP client code
  • RFC 1945 : HTTP/1.0, again a basic HTTP client code
  • SAX: a SAX2 like interface and a minimal SAX1 implementation compatible with early expat versions

Here are some key points about libxml:

  • Libxml2 exports Push (progressive) and Pull (blocking) type parser interfaces for both XML and HTML.
  • Libxml2 can do DTD validation at parse time, using a parsed document instance, or with an arbitrary DTD.
  • Libxml2 includes complete XPath 1.0, XPointer and XInclude 1.0 implementations.
  • It is written in plain C, making as few assumptions as possible, and sticking closely to ANSI C/POSIX for easy embedding. Works on Linux/Unix/Windows, ported to a number of other platforms.
  • Basic support for HTTP and FTP client allowing applications to fetch remote resources.
  • The design is modular, most of the extensions can be compiled out.
  • The internal document representation is as close as possible to the DOM interfaces.
  • Libxml2 also has a SAX like interface; the interface is designed to be compatible with Expat.
  • This library is released under the MIT License. See the Copyright file in the distribution for the precise wording.

HTML Documentation

Generated HTML documentation is available via GitLab Pages:

Mailing list

There is a mailing-list xml@gnome.org for libxml, with an on-line archive. To subscribe to this list, please visit the associated web page and follow the instructions.

Language bindings

There are a number of language bindings and wrappers available for libxml2, the list below is not exhaustive.

  • Libxml++ seems the most up-to-date C++ bindings for libxml2, check the documentation and the examples.
  • xmlwrapp, a C++ library built atop libxml2.
  • XML::LibXML Perl bindings are available on CPAN, as well as XML::LibXSLT Perl libxslt bindings.
  • If you're interested into scripting XML processing, have a look at XSH an XML editing shell based on Libxml2 Perl bindings.
  • Petr Kozelka provides Pascal units to glue libxml2 with Kylix, Delphi and other Pascal compilers.
  • Uwe Fechner also provides idom2, a DOM2 implementation for Kylix2/D5/D6 from Borland.
  • There are bindings for Ruby and libxml2 bindings are also available in Ruby through Nokogiri.
  • Steve Ball and contributors maintains libxml2 and libxslt bindings for Tcl.
  • libxml2 and libxslt are the default XML libraries for PHP5.
  • LibxmlJ is an effort to create a 100% JAXP-compatible Java wrapper for libxml2 and libxslt as part of GNU ClasspathX project.
  • Patrick McPhee provides Rexx bindings for libxml2 and libxslt, look for RexxXML.
  • Satimage provides XMLLib osax. This is an osax for Mac OS X with a set of commands to implement in AppleScript the XML DOM, XPATH and XSLT. Also includes commands for Property-lists (Apple's fast lookup table XML format.)
  • Francesco Montorsi developed wxXml2 wrappers that interface libxml2, allowing wxWidgets applications to load/save/edit XML instances.

Contributions

  • Bjorn Reese, William Brack and Thomas Broyer have provided a number of patches, Gary Pennington worked on the validation API, threading support and Solaris port.
  • John Fleck helps maintaining the documentation and man pages.
  • Igor Zlatkovic is now the maintainer of the Windows port, he provides binaries
  • Felix Natter and Geert Kloosterman provide an emacs module to lookup libxml(2) functions documentation
  • Ziying Sherwin provided man pages
  • Dave Kuhlman provided the first version of libxml/libxslt wrappers for Python
  • Aleksey Sanin implemented the XML Canonicalization and XML Digital Signature implementations for libxml2