JezK

Edit File: builder.py

# cython: language_level=2

#
# 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.
"""

from __future__ import absolute_import

import lxml.etree as ET
_QName = ET.QName

from functools import partial

try:
    basestring
except NameError:
    basestring = str

try:
    unicode
except NameError:
    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"))
 '<tag/>'
 >>> ET.tostring(E("tag", "text"))
 '<tag>text</tag>'
 >>> ET.tostring(E("tag", "text", key="value"))
 '<tag key="value">text</tag>'
 >>> ET.tostring(E("tag", E("subtag", "text"), "tail"))
 '<tag><subtag>text</subtag>tail</tag>'

For simple tags, the factory also allows you to write ``E.tag(...)`` instead
    of ``E('tag', ...)``::

>>> ET.tostring(E.tag())
 '<tag/>'
 >>> ET.tostring(E.tag("text"))
 '<tag>text</tag>'
 >>> ET.tostring(E.tag(E.subtag("text"), "tail"))
 '<tag><subtag>text</subtag>tail</tag>'

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 reserved characters: <spam&egg>."),
 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::

<html>
 <head>
 <title>This is a sample document</title>
 </head>
 <body>
 <h1 class="title">Hello!</h1>
 This is a paragraph with bold text in it!
 This is another paragraph, with <a href="http://www.python.org">link</a>.
 Here are some reserved characters: &lt;spam&amp;egg&gt;.
 And finally, here is an embedded XHTML fragment.
 </body>
 </html>

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 ))
 <test xmlns="http://my.ns/"/>

>>> E = ElementMaker(namespace="http://my.ns/", nsmap={'p':'http://my.ns/'})
 >>> print(ET.tostring( E.test ))
 <p:test xmlns:p="http://my.ns/"/>
 """

def __init__(self, typemap=None,
                 namespace=None, nsmap=None, makeelement=None):
        self._namespace = '{' + namespace + '}' if namespace is not None else None
        self._nsmap = dict(nsmap) if nsmap else None

assert makeelement is None or callable(makeelement)
        self._makeelement = makeelement if makeelement is not None else ET.Element

# initialize the default type map functions for this element factory
        typemap = dict(typemap) if typemap else {}

def add_text(elem, item):
            try:
                last_child = elem[-1]
            except IndexError:
                elem.text = (elem.text or "") + item
            else:
                last_child.tail = (last_child.tail or "") + item

def add_cdata(elem, cdata):
            if elem.text:
                raise ValueError("Can't add a CDATA section. Element already has some text: %r" % elem.text)
            elem.text = cdata

if str not in typemap:
            typemap[str] = add_text
        if unicode not in typemap:
            typemap[unicode] = add_text
        if ET.CDATA not in typemap:
            typemap[ET.CDATA] = add_cdata

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):
        typemap = self._typemap

# We'll usually get a 'str', and the compiled type check is very fast.
        if not isinstance(tag, str) and isinstance(tag, _QName):
            # A QName is explicitly qualified, do not look at self._namespace.
            tag = tag.text
        elif self._namespace is not None and tag[0] != '{':
            tag = self._namespace + tag
        elem = self._makeelement(tag, nsmap=self._nsmap)
        if attrib:
            typemap[dict](elem, attrib)

for item in children:
            if callable(item):
                item = item()
            t = typemap.get(type(item))
            if t is None:
                if ET.iselement(item):
                    elem.append(item)
                    continue
                for basetype in type(item).__mro__:
                    # See if the typemap knows of any of this type's bases.
                    t = typemap.get(basetype)
                    if t is not None:
                        break
                else:
                    raise TypeError("bad argument type: %s(%r)" %
                                    (type(item).__name__, item))
            v = t(elem, item)
            if v:
                typemap.get(type(v))(elem, v)

return elem

def __getattr__(self, tag):
        return partial(self, tag)

# create factory object
E = ElementMaker()