47 lines
1.8 KiB
ReStructuredText
47 lines
1.8 KiB
ReStructuredText
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.. module:: sleekxmpp.xmlstream.tostring
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.. _tostring:
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XML Serialization
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=================
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Since the XML layer of SleekXMPP is based on :mod:`~xml.etree.ElementTree`,
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why not just use the built-in :func:`~xml.etree.ElementTree.tostring`
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method? The answer is that using that method produces ugly results when
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using namespaces. The :func:`tostring()` method used here intelligently
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hides namespaces when able and does not introduce excessive namespace
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prefixes::
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>>> from sleekxmpp.xmlstream.tostring import tostring
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>>> from xml.etree import cElementTree as ET
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>>> xml = ET.fromstring('<foo xmlns="bar"><baz /></foo>')
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>>> ET.tostring(xml)
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'<ns0:foo xmlns:ns0="bar"><ns0:baz /></foo>'
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>>> tostring(xml)
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'<foo xmlns="bar"><baz /></foo>'
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As a side effect of this namespace hiding, using :func:`tostring()` may
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produce unexpected results depending on how the :func:`tostring()` method
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is invoked. For example, when sending XML on the wire, the main XMPP
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stanzas with their namespace of ``jabber:client`` will not include the
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namespace because that is already declared by the stream header. But, if
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you create a :class:`~sleekxmpp.stanza.message.Message` instance and dump
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it to the terminal, the ``jabber:client`` namespace will appear.
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.. autofunction:: tostring
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Escaping Special Characters
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---------------------------
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In order to prevent errors when sending arbitrary text as the textual
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content of an XML element, certain characters must be escaped. These
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are: ``&``, ``<``, ``>``, ``"``, and ``'``. The default escaping
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mechanism is to replace those characters with their equivalent escape
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entities: ``&``, ``<``, ``>``, ``'``, and ``"``.
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In the future, the use of CDATA sections may be allowed to reduce the
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size of escaped text or for when other XMPP processing agents do not
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undertand these entities.
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.. autofunction:: xml_escape
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