annotate roundup/cgi/PageTemplates/PythonExpr.py @ 1065:0f9aa62917bd

much nicer error messages when there's a templating error
author Richard Jones <richard@users.sourceforge.net>
date Fri, 06 Sep 2002 07:21:31 +0000
parents b9988e118055
children c08b3820edd1
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 ##############################################################################
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2 #
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3 # Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
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4 #
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5 # This software is subject to the provisions of the Zope Public License,
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6 # Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.
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7 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
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8 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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9 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
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10 # FOR A PARTICULAR PURPOSE
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11 #
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12 ##############################################################################
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13
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14 """Generic Python Expression Handler
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15 """
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16
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17 __version__='$Revision: 1.2 $'[11:-2]
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18
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19 from TALES import CompilerError
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20 from string import strip, split, join, replace, lstrip
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21 from sys import exc_info
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22
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23 class getSecurityManager:
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24 '''Null security manager'''
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25 def validate(self, *args, **kwargs):
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26 return 1
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27 addContext = removeContext = validateValue = validate
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28
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29 class PythonExpr:
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30 def __init__(self, name, expr, engine):
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31 self.expr = expr = replace(strip(expr), '\n', ' ')
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32 try:
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33 d = {}
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34 exec 'def f():\n return %s\n' % strip(expr) in d
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35 self._f = d['f']
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36 except:
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37 raise CompilerError, ('Python expression error:\n'
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38 '%s: %s') % exc_info()[:2]
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39 self._get_used_names()
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40
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41 def _get_used_names(self):
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42 self._f_varnames = vnames = []
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43 for vname in self._f.func_code.co_names:
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44 if vname[0] not in '$_':
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45 vnames.append(vname)
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46
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47 def _bind_used_names(self, econtext):
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48 # Bind template variables
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49 names = {}
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50 vars = econtext.vars
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51 getType = econtext._engine.getTypes().get
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52 for vname in self._f_varnames:
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53 has, val = vars.has_get(vname)
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54 if not has:
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55 has = val = getType(vname)
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56 if has:
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57 val = ExprTypeProxy(vname, val, econtext)
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58 if has:
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59 names[vname] = val
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60 return names
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61
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62 def __call__(self, econtext):
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63 __traceback_info__ = 'python expression "%s"'%self.expr
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64 f = self._f
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65 f.func_globals.update(self._bind_used_names(econtext))
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66 return f()
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67
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68 def __str__(self):
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69 return 'Python expression "%s"' % self.expr
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70 def __repr__(self):
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71 return '<PythonExpr %s>' % self.expr
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72
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73 class ExprTypeProxy:
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74 '''Class that proxies access to an expression type handler'''
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75 def __init__(self, name, handler, econtext):
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76 self._name = name
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77 self._handler = handler
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78 self._econtext = econtext
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79 def __call__(self, text):
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80 return self._handler(self._name, text,
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81 self._econtext._engine)(self._econtext)
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82

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