Intro

Wither is a library designed to make XML generation under python as simple and as nicely formatted as python code.

Wither is implemented as a thin statless wrapper around etree.Element objects and works by making use of the ‘with’ keyword in python to build a nested tree of etree objects that can be processed with standard tools/techniques

by using python as a DSL you can automatically ensure that all tags are properly closed and also execute arbitrary python code to build things such as lists or to embed widgets

Example

>>> import lxml.usedoctest
>>> from wither import Node
>>> n = Node('html')
>>> with n.head as head:
...     head.title == 'Wither README Example'
...     head.link(href='http://code.pocketnix.org/wither', rel='homepage')
<...>
>>> with n.body as body:
...     body.h1 == 'Welcome to the Wither README'
...     with body.div as div:
...         div.p == 'This is the example from the README file'
...         div.p(style='color: red;') == 'Big Red Warning'
<...>
>>> print(n)
<html><head><title>Wither README Example</title><link
href="http://code.pocketnix.org/wither"
rel="homepage"/></head><body><h1>Welcome to the Wither README</h1><div><p>This
is the example from the README file</p><p style="color: red;">Big Red
Warning</p></div></body></html>

Features

• Uses python as a DSL for XML Generation

• Uses/Abuses python syntax to make node generation shorter and more visually appealing

• Uses lxml for document generation

• Possibility to fall back to built in etree implementations (XXX TODO: Write me)

• Easy widget creation

• Implicit verification of document correctness (python’s indentation means you cant forget to close a tag)

Dependencies

• lxml - may be possible ot replace this with python’s inbuilt etree support

Installation

$ virtualenv env $ . env/bin/activate # pip install wither

Compatibility

Wither supports Python 2.7 and Python 3.2 and up as its supported python versions but may also work on earlier versions of python 3 and python 2.6. while these platforms are automatically tested to check for breakages these earlier versions are not officially supported and failing tests are for informational purposes only.

Motivations

Wither is very much a project that was written ‘because i can’. I have multiple python modules that abuse python syntax in interesting ways to do things like pattern matching of automatic retry of transactions for Databases that are all concise and visually appealing.

after seeing the ‘with’ statement and its use in python 2.6 with nesting for using multiple context generators (instead of python 2.7’s flattened version) i decided to see if i could use this to upgrade an existing XML generation program that used a similar concept with object.

the aim of this project is not to create a fast generator but create something that looks ‘right’ when included inline with python code and support dynamic features like a string template library would.

Futher Ideas

By using ‘yeild’ in strategic spots it may be possible to paritally render a template allowing one to send a prerendered ‘frame’ (or the head part of it at least) and then generate the body followed by the tail (of the frame) to the client thereby speeding up transmission of the first byte to the client and avoiding a dogpile of transmission at the end of the request. this should allow clients to render thier pages quicker as well as they have partial data with which they can start planning out the layout of the page