# # Element generator factory by Fredrik Lundh. # # Source: # http://online.effbot.org/2006_11_01_archive.htm#et-builder # http://effbot.python-hosting.com/file/stuff/sandbox/elementlib/builder.py # # -------------------------------------------------------------------- # The ElementTree toolkit is # # Copyright (c) 1999-2004 by Fredrik Lundh # # By obtaining, using, and/or copying this software and/or its # associated documentation, you agree that you have read, understood, # and will comply with the following terms and conditions: # # Permission to use, copy, modify, and distribute this software and # its associated documentation for any purpose and without fee is # hereby granted, provided that the above copyright notice appears in # all copies, and that both that copyright notice and this permission # notice appear in supporting documentation, and that the name of # Secret Labs AB or the author not be used in advertising or publicity # pertaining to distribution of the software without specific, written # prior permission. # # SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD # TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT- # ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR # BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE # OF THIS SOFTWARE. # -------------------------------------------------------------------- """ The ``E`` Element factory for generating XML documents. """ import lxml.etree as ET try: from functools import partial except ImportError: # fake it for pre-2.5 releases def partial(func, tag): return lambda *args, **kwargs: func(tag, *args, **kwargs) try: callable except NameError: # Python 3 def callable(f): return hasattr(f, '__call__') try: basestring = __builtins__["basestring"] except (NameError, KeyError): basestring = str try: unicode = __builtins__["unicode"] except (NameError, KeyError): unicode = str class ElementMaker(object): """Element generator factory. Unlike the ordinary Element factory, the E factory allows you to pass in more than just a tag and some optional attributes; you can also pass in text and other elements. The text is added as either text or tail attributes, and elements are inserted at the right spot. Some small examples:: >>> from lxml import etree as ET >>> from lxml.builder import E >>> ET.tostring(E("tag")) '' >>> ET.tostring(E("tag", "text")) 'text' >>> ET.tostring(E("tag", "text", key="value")) 'text' >>> ET.tostring(E("tag", E("subtag", "text"), "tail")) 'texttail' For simple tags, the factory also allows you to write ``E.tag(...)`` instead of ``E('tag', ...)``:: >>> ET.tostring(E.tag()) '' >>> ET.tostring(E.tag("text")) 'text' >>> ET.tostring(E.tag(E.subtag("text"), "tail")) 'texttail' Here's a somewhat larger example; this shows how to generate HTML documents, using a mix of prepared factory functions for inline elements, nested ``E.tag`` calls, and embedded XHTML fragments:: # some common inline elements A = E.a I = E.i B = E.b def CLASS(v): # helper function, 'class' is a reserved word return {'class': v} page = ( E.html( E.head( E.title("This is a sample document") ), E.body( E.h1("Hello!", CLASS("title")), E.p("This is a paragraph with ", B("bold"), " text in it!"), E.p("This is another paragraph, with a ", A("link", href="http://www.python.org"), "."), E.p("Here are some reservered characters: ."), ET.XML("

And finally, here is an embedded XHTML fragment.

"), ) ) ) print ET.tostring(page) Here's a prettyprinted version of the output from the above script:: This is a sample document

Hello!

This is a paragraph with bold text in it!

This is another paragraph, with link.

Here are some reservered characters: <spam&egg>.

And finally, here is an embedded XHTML fragment.

For namespace support, you can pass a namespace map (``nsmap``) and/or a specific target ``namespace`` to the ElementMaker class:: >>> E = ElementMaker(namespace="http://my.ns/") >>> print(ET.tostring( E.test )) >>> E = ElementMaker(namespace="http://my.ns/", nsmap={'p':'http://my.ns/'}) >>> print(ET.tostring( E.test )) """ def __init__(self, typemap=None, namespace=None, nsmap=None, makeelement=None): if namespace is not None: self._namespace = '{' + namespace + '}' else: self._namespace = None if nsmap: self._nsmap = dict(nsmap) else: self._nsmap = None if makeelement is not None: assert callable(makeelement) self._makeelement = makeelement else: self._makeelement = ET.Element # initialize type map for this element factory if typemap: typemap = typemap.copy() else: typemap = {} def add_text(elem, item): if len(elem): elem[-1].tail = (elem[-1].tail or "") + item else: elem.text = (elem.text or "") + item if str not in typemap: typemap[str] = add_text if unicode not in typemap: typemap[unicode] = add_text def add_dict(elem, item): attrib = elem.attrib for k, v in item.items(): if isinstance(v, basestring): attrib[k] = v else: attrib[k] = typemap[type(v)](None, v) if dict not in typemap: typemap[dict] = add_dict self._typemap = typemap def __call__(self, tag, *children, **attrib): get = self._typemap.get if self._namespace is not None and tag[0] != '{': tag = self._namespace + tag elem = self._makeelement(tag, nsmap=self._nsmap) if attrib: get(dict)(elem, attrib) for item in children: if callable(item): item = item() t = get(type(item)) if t is None: if ET.iselement(item): elem.append(item) continue raise TypeError("bad argument type: %r" % item) else: v = t(elem, item) if v: get(type(v))(elem, v) return elem def __getattr__(self, tag): return partial(self, tag) # create factory object E = ElementMaker()