[Zope-Checkins] CVS: Zope3/lib/python/Zope/PageTemplate - ZRPythonExpr.py:1.1.2.1

[Fred L. Drake, Jr.]

Update of /cvs-repository/Zope3/lib/python/Zope/PageTemplate
In directory cvs.zope.org:/tmp/cvs-serv22167

Added Files:
      Tag: Zope-3x-branch
	ZRPythonExpr.py 
Log Message:
Support for Zope-style restricted Python expressions.

=== Added File Zope3/lib/python/Zope/PageTemplate/ZRPythonExpr.py ===
##############################################################################
#
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
# 
# This software is subject to the provisions of the Zope Public License,
# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE
# 
##############################################################################

"""Zope-specific Python Expression Handler

Handler for Python expressions that uses the RestrictedPython package.
"""

__version__='$Revision: 1.1.2.1 $'[11:-2]

from string import join

from Zope.RestrictedPython import compile_restricted_eval
from Zope.RestrictedPython.ZopeGuards import \
     safe_builtins, guarded_getattr, guarded_getitem

from PythonExpr import PythonExpr
from TALES import CompilerError


newline_join = "\n".join


class PythonExpr(PythonExpr):
    _globals = {'__debug__': __debug__,
                '__builtins__': safe_builtins,
                '_getattr_': guarded_getattr,
                '_getitem_': guarded_getitem,}

    def __init__(self, name, expr, engine):
        self.expr = expr = expr.strip().replace('\n', ' ')
        code, err, warn, use = compile_restricted_eval(expr, str(self))
        if err:
            raise CompilerError, ('Python expression error:\n%s' %
                                  newline_join(err))
        self._f_varnames = use.keys()
        self._code = code
        
    def __call__(self, econtext):
        __traceback_info__ = self.expr
        code = self._code
        g = self._bind_used_names(econtext)
        g.update(self._globals)        
        return eval(code, g, {})

class _SecureModuleImporter:
    __allow_access_to_unprotected_subobjects__ = 1
    def __getitem__(self, module):
        mod = safe_builtins['__import__'](module)
        path = module.split('.')
        for name in path[1:]:
            mod = getattr(mod, name)
        return mod

## from DocumentTemplate.DT_Util import TemplateDict, InstanceDict
## from AccessControl.DTML import RestrictedDTML
## class Rtd(RestrictedDTML, TemplateDict):
##     this = None

## def call_with_ns(f, ns, arg=1):
##     td = Rtd()
##     td.this = ns['here']
##     td._push(ns['request'])
##     td._push(InstanceDict(td.this, td))
##     td._push(ns)
##     try:
##         if arg==2:
##             return f(None, td)
##         else:
##             return f(td)
##     finally:
##         td._pop(3)