The libxml2dom package provides a traditional DOM wrapper around the -Python bindings for libxml2. In contrast -to the libxml2 bindings, libxml2dom provides an API reminiscent of minidom, -pxdom and other Python-based and Python-related XML toolkits. Performance is -disappointing, given the typical high speed of libxml2 processing, but this -is to be expected since large numbers of Python objects are instantiated at -two levels of document tree representation. However, serialisation of -documents is much faster than many other toolkits because it can make direct -use of libxml2.
- -The main libxml2dom package is relatively slow, even when compared to -Python-only XML toolkits, but previous experiments into source code analysis -suggested that with a slightly altered coding style, programs could be -transformed into a style which utilises the underlying libxml2mod API -directly; this API employs opaque handles which are exposed to Python but -which can only be investigated through the functions in the API. One -significant advantage of accessing the libxml2mod API directly is that the -libxml2 wrapper objects do not need to be instantiated, let alone the -additional libxml2dom wrapper objects, and the consequences are obvious: -reduced memory consumption and improved performance.
- -The libxml2macro approach is as follows:
-libxml2macro.py on the source
- file.A description of the process is given in the README.txt file
-within the source code distribution. However, what libxml2macro does is to
-take code like this...
for my_node in my_element.childNodes: - if my_node.nodeType == TEXT_NODE: - print my_node.nodeValue- -
...and to transform it into something more or less like this (although in -practice the actual libxml2mod calls are provided in a library, although more -aggressive transformations could result in something actually like this):
-for my_node in libxml2mod.children(my_element): - if libxml2mod.type(my_node) == "text": - print libxml2mod.xmlNodeGetContent(my_node)- -
The result is that developers can still write DOM-style code but not be -penalised for the object-related overhead that such an approach typically -incurs.
- +Python bindings for libxml2. In +contrast +to the standard libxml2 +bindings, libxml2dom provides an API reminiscent of minidom, +pxdom and +other Python-based and +Python-related XML toolkits. Performance is +fairly respectable since libxml2dom makes direct use of libxml2mod - +the low-level wrapping of libxml2 for Python. Moreover, serialisation +of +documents is much faster than many other toolkits because libxml2dom +can make direct +use of libxml2 rather than employing Python-level mechanisms to visit +and serialise nodes.For reasons of consistency, libxml2dom uses the same MIT-style licence as +
For reasons of consistency, libxml2dom uses the same MIT-style
+licence as
libxml2. See the file COPYING.txt in the docs
directory within the source code distribution.
Given the availability of libxml2, libxml2dom only needs to reside on the +
Given the availability of libxml2, libxml2dom only needs to reside
+on the
PYTHONPATH and can be installed using the setup.py script
provided:
python setup.py install-
The following descriptions identify dependencies and describe appropriate +
The following descriptions identify dependencies and describe +appropriate installation issues with each dependency:
-Building libxml2 from source and configuring the Python bindings can be +
Building libxml2 from source and configuring the Python bindings can +be done as follows:
-cd libxml2-2.6.16 -./configure --with-python=/usr/local/bin/python -make- +
cd libxml2-2.6.16
./configure --with-python=/usr/local/bin/python
make
If you are to use an installation of Python installed outside
/usr/local then specify the "prefix" accordingly. Install
(possibly as root) in the usual way:
make install- -
Previous releases of libxml2 in the 2.6 series may work, but some bugs -were observed with the previously recommended 2.6.0 and these may not have +
Previous releases of libxml2 in the 2.6 series may work, but some +bugs +were observed with the previously recommended 2.6.0 and these may not +have been fixed until 2.6.16 or slightly earlier.
-The patches directory in the source code distribution
-contains a patch against libxml2 2.5.7 which resolves an issue exposed by
-libxml2dom. Although it is recommended that later releases of libxml2 are
-used instead, the source code distribution of libxml2 2.5.7 can be patched as
+contains a patch against libxml2 2.5.7 which resolves an issue exposed
+by
+libxml2dom. Although it is recommended that later releases of libxml2
+are
+used instead, the source code distribution of libxml2 2.5.7 can be
+patched as
follows:
patch -p0 < libxml2dom/patches/libxml2/libxml.c.diff-
The command should be run outside/above the libxml2-2.5.7
directory, and the stated path should be adjusted accordingly.
Python releases from 2.2 onwards should be compatible with libxml2dom. The -principal requirement from such releases is the new-style class support which +
Python releases from 2.2 onwards should be compatible with +libxml2dom. The +principal requirement from such releases is the new-style class support +which permits the use of properties in the libxml2dom implementation, thus simplifying the code somewhat.
-The libxml2macro tool and accompanying libraries (libxml2dom.macrolib)
+provide and experimental mechanism for writing normal DOM-style code
+(with node objects) and being able to transform such code into direct
+calls and accesses to the low-level libxml2mod API. Since libxml2dom
+now makes use of these libraries, and since the objects created at the
+libxml2dom level do not necessarily introduce a huge time or memory
+overhead, this mechanism is now more an experimental curiosity than
+anything of practical use. Moreover, the generated code does not
+attempt to clean up after libxml2, potentially introducing memory leaks
+into programs.
The libxml2macro approach is as follows:
+libxml2macro.py on the source
+file.A description of the process is given in the README.txt
+file
+within the source code distribution. However, what libxml2macro does is
+to
+take code like this...
for my_node in my_element.childNodes:+
if my_node.nodeType == TEXT_NODE:
print my_node.nodeValue
...and to transform it into something more or less like this +(although in +practice the actual libxml2mod calls are provided in a library, +although more +aggressive transformations could result in something actually like +this):
+for my_node in libxml2mod.children(my_element):+
if libxml2mod.type(my_node) == "text":
print libxml2mod.xmlNodeGetContent(my_node)
The result is that developers can still write DOM-style code but not +be +penalised for the object-related overhead that such an approach +typically +incurs.
+ +