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1 """
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2 LXML middleware
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3 """
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4
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5 from lxml import etree
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6
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7 class LXMLMiddleware(object):
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8 """
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9 abstract base class; inherit from and implement the manipulate method
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10 """
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11
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12 def __init__(self, app):
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13 self.app = app
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14
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15 ### methods dealing with HTTP
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16 def __call__(self, environ, start_response):
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17
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18 # set up to recompose on the way out
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19 if not 'lxml.recomposer' in environ:
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20 environ['lxml.recomposer'] = self
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21
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22 # get the response
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23 response = self.app(environ, start_response)
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24
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25 # get the DOM, if not already made
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26 if not isinstance(response, etree._Element):
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27 response = etree.fromstring(''.join(response))
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28
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29 # manipulate the DOM
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30 response = self.manipulate(environ, response)
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31
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32 # recompose the DOM if the last in the chain
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33 if environ['lxml.recomposer'] is self:
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34 response = [ etree.tostring(response) ]
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35
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36 # return the response
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37 return response
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38
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39 def manipulate(self, environ, tree):
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40 """manipulate the DOM; should return an etree._Element"""
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41 return tree
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42
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