101 lines
4.4 KiB
Python
101 lines
4.4 KiB
Python
'''PX stands for *P*ython *X*ML. It is a templating engine that reuses the pod
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engine to produce XML (including XHTML) from templates written as a mix of
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Python and XML.'''
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# ------------------------------------------------------------------------------
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import xml.sax
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from px_parser import PxParser, PxEnvironment
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from appy.pod.buffers import MemoryBuffer
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# Exception class --------------------------------------------------------------
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class PxError(Exception): pass
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# ------------------------------------------------------------------------------
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class Px:
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'''Represents a (chunk of) PX code.'''
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xhtmlPrologue = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" '\
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'"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">\n'
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def __init__(self, content, isFileName=False, partial=True,
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template=None, hook=None, prologue=None):
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'''p_content is the PX code, as a string, or a file name if p_isFileName
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is True. If this code represents a complete XML file, p_partial is
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False. Else, we must surround p_content with a root tag to be able
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to parse it with a SAX parser.
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If this PX is based on another PX template, specify the PX template
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in p_template and the name of the p_hook where to insert this PX into
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the template PX.
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If a p_prologue is specified, it will be rendered at the start of the
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PX result.
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'''
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# Get the PX content
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if isFileName:
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f = file(content)
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self.content = f.read()
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f.close()
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else:
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self.content = content
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# It this content a complete XML file, or just some part of it?
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if partial:
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# Surround the partial chunk with a root tag: it must be valid XML.
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self.content = '<x>%s</x>' % self.content
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self.partial = partial
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# Create a PX parser
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self.parser = PxParser(PxEnvironment(), self)
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# Parses self.content (a PX code in a string) with self.parser, to
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# produce a tree of memory buffers.
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try:
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self.parser.parse(self.content)
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except xml.sax.SAXParseException, spe:
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self.completeErrorMessage(spe)
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raise spe
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# Is this PX based on a template PX?
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self.template = template
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self.hook = hook
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# Is there some (XML, XHTML...) prologue to dump?
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self.prologue = prologue
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def completeErrorMessage(self, parsingError):
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'''A p_parsingError occurred. Complete the error message with the
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erroneous line from self.content.'''
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# Split lines from self.content
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splitted = self.content.split('\n')
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i = parsingError.getLineNumber() - 1
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# Get the erroneous line, and add a subsequent line for indicating
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# the erroneous column.
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column = ' ' * (parsingError.getColumnNumber()-1) + '^'
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lines = [splitted[i], column]
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# Get the previous and next lines when present.
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if i > 0: lines.insert(0, splitted[i-1])
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if i < len(splitted)-1: lines.append(splitted[i+1])
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parsingError._msg += '\n%s' % '\n'.join(lines)
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def __call__(self, context, applyTemplate=True):
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'''Renders the PX.
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If the PX is based on a template PX, we have 2 possibilities.
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1. p_applyTemplate is True. This case corresponds to the initial
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call to the current PX. In this case we call the template with a
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context containing, in the hook variable, the current PX.
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2. p_applyTemplate is False. In this case, we are currently executing
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the PX template, and, at the hook, we must include the current PX,
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as is, without re-applying the template (else, an infinite
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recursion would occur).
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'''
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if self.hook and applyTemplate:
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# Call the template PX, filling the hook with the current PX.
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context[self.hook] = self
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return self.template(context)
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else:
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# Create a Memory buffer for storing the result.
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env = self.parser.env
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result = MemoryBuffer(env, None)
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env.ast.evaluate(result, context)
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res = result.content
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if self.prologue:
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res = self.prologue + res
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return res
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# ------------------------------------------------------------------------------
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