# -*- coding: iso-8859-1 -*-
# Copyright (c) 2016, Jan Brohl <janbrohl@t-online.de>
# All rights reserved.
# See LICENSE.txt
# Copyright (c) 2005 Colin Stewart (http://www.owlfish.com/)
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# If you make any bug fixes or feature enhancements please let me know!
""" simpleTALES Implementation
The classes in this module implement the TALES specification, used
by the simpleTAL module.
"""
from __future__ import absolute_import
import sys
import logging
from simpletal.simpleTALConstants import DEFAULTVALUE
if sys.version_info >= (3, 0):
unicode = str
[docs]class PathNotFoundException (Exception):
pass
[docs]class ContextContentException (Exception):
""" This is raised when invalid content has been placed into the Context object.
For example using non-ascii characters instead of Unicode strings.
"""
pass
PATHNOTFOUNDEXCEPTION = PathNotFoundException()
[docs]class ContextVariable(Exception):
def __init__(self, value=None):
self.ourValue = value
[docs] def value(self, currentPath=None):
if (callable(self.ourValue)):
return self.ourValue()
return self.ourValue
[docs] def rawValue(self):
return self.ourValue
def __str__(self):
return repr(self.ourValue)
[docs]class RepeatVariable (ContextVariable):
""" To be written"""
def __init__(self, sequence):
ContextVariable.__init__(self, 1)
self.sequence = sequence
self.position = 0
self.map = None
[docs] def value(self, currentPath=None):
if (self.map is None):
self.createMap()
return self.map
[docs] def rawValue(self):
return self.value()
[docs] def getCurrentValue(self):
return self.sequence[self.position]
[docs] def increment(self):
self.position += 1
if (self.position == len(self.sequence)):
raise IndexError("Repeat Finished")
[docs] def createMap(self):
self.map = {}
self.map['index'] = self.getIndex
self.map['number'] = self.getNumber
self.map['even'] = self.getEven
self.map['odd'] = self.getOdd
self.map['start'] = self.getStart
self.map['end'] = self.getEnd
# TODO: first and last need to be implemented.
self.map['length'] = len(self.sequence)
self.map['letter'] = self.getLowerLetter
self.map['Letter'] = self.getUpperLetter
self.map['roman'] = self.getLowerRoman
self.map['Roman'] = self.getUpperRoman
# Repeat implementation goes here
[docs] def getIndex(self):
return self.position
[docs] def getNumber(self):
return self.position + 1
[docs] def getEven(self):
if ((self.position % 2) != 0):
return 0
return 1
[docs] def getOdd(self):
if ((self.position % 2) == 0):
return 0
return 1
[docs] def getStart(self):
if (self.position == 0):
return 1
return 0
[docs] def getEnd(self):
if (self.position == len(self.sequence) - 1):
return 1
return 0
[docs] def getLowerLetter(self):
result = ""
nextCol = self.position
if (nextCol == 0):
return 'a'
while (nextCol > 0):
nextCol, thisCol = divmod(nextCol, 26)
result = chr(ord('a') + thisCol) + result
return result
[docs] def getUpperLetter(self):
return self.getLowerLetter().upper()
[docs] def getLowerRoman(self):
romanNumeralList = (('m', 1000), ('cm', 900), ('d', 500), ('cd', 400), ('c', 100), ('xc', 90), ('l', 50), ('xl', 40), ('x', 10), ('ix', 9), ('v', 5), ('iv', 4), ('i', 1)
)
if (self.position > 3999):
# Roman numbers only supported up to 4000
return ' '
num = self.position + 1
result = ""
for roman, integer in romanNumeralList:
while (num >= integer):
result += roman
num -= integer
return result
[docs] def getUpperRoman(self):
return self.getLowerRoman().upper()
[docs]class IteratorRepeatVariable (RepeatVariable):
def __init__(self, sequence):
RepeatVariable.__init__(self, sequence)
self.curValue = None
self.iterStatus = 0
[docs] def getCurrentValue(self):
if (self.iterStatus == 0):
self.iterStatus = 1
try:
self.curValue = next(self.sequence)
except StopIteration as e:
self.iterStatus = 2
raise IndexError("Repeat Finished")
return self.curValue
[docs] def increment(self):
# Need this for the repeat variable functions.
self.position += 1
try:
self.curValue = next(self.sequence)
except StopIteration as e:
self.iterStatus = 2
raise IndexError("Repeat Finished")
[docs] def createMap(self):
self.map = {}
self.map['index'] = self.getIndex
self.map['number'] = self.getNumber
self.map['even'] = self.getEven
self.map['odd'] = self.getOdd
self.map['start'] = self.getStart
self.map['end'] = self.getEnd
# TODO: first and last need to be implemented.
self.map['length'] = sys.maxsize
self.map['letter'] = self.getLowerLetter
self.map['Letter'] = self.getUpperLetter
self.map['roman'] = self.getLowerRoman
self.map['Roman'] = self.getUpperRoman
[docs] def getEnd(self):
if (self.iterStatus == 2):
return 1
return 0
[docs]class PathFunctionVariable (ContextVariable):
def __init__(self, func):
ContextVariable.__init__(self, value=func)
self.func = func
[docs] def value(self, currentPath=None):
if (currentPath is not None):
index, paths = currentPath
result = ContextVariable(self.func('/'.join(paths[index:])))
# Fast track the result
raise result
[docs]class CachedFuncResult (ContextVariable):
[docs] def value(self, currentPath=None):
try:
return self.cachedValue
except:
self.cachedValue = ContextVariable.value(self)
return self.cachedValue
[docs] def clearCache(self):
try:
del self.cachedValue
except:
pass
[docs]class PythonPathFunctions(object):
def __init__(self, context):
self.context = context
[docs] def path(self, expr):
return self.context.evaluatePath(expr)
[docs] def string(self, expr):
return self.context.evaluateString(expr)
[docs] def exists(self, expr):
return self.context.evaluateExists(expr)
[docs] def nocall(self, expr):
return self.context.evaluateNoCall(expr)
[docs] def test(self, *arguments):
if (len(arguments) % 2):
# We have an odd number of arguments - which means the last one is
# a default
pairs = arguments[:-1]
defaultValue = arguments[-1]
else:
# No default - so use None
pairs = arguments
defaultValue = None
index = 0
while (index < len(pairs)):
test = pairs[index]
index += 1
value = pairs[index]
index += 1
if (test):
return value
return defaultValue
[docs]class Context(object):
def __init__(self, options=None, allowPythonPath=0):
self.allowPythonPath = allowPythonPath
self.globals = {}
self.locals = {}
self.localStack = []
self.repeatStack = []
self.populateDefaultVariables(options)
self.log = logging.getLogger("simpleTALES.Context")
self.true = 1
self.false = 0
self.pythonPathFuncs = PythonPathFunctions(self)
[docs] def addRepeat(self, name, var, initialValue):
# Pop the current repeat map onto the stack
self.repeatStack.append(self.repeatMap)
self.repeatMap = self.repeatMap.copy()
self.repeatMap[name] = var
# Map this repeatMap into the global space
self.addGlobal('repeat', self.repeatMap)
# Add in the locals
self.pushLocals()
self.setLocal(name, initialValue)
[docs] def removeRepeat(self, name):
# Bring the old repeat map back
self.repeatMap = self.repeatStack.pop()
# Map this repeatMap into the global space
self.addGlobal('repeat', self.repeatMap)
[docs] def addGlobal(self, name, value):
self.globals[name] = value
[docs] def pushLocals(self):
# Push the current locals onto a stack so that we can safely over-ride
# them.
self.localStack.append(self.locals)
self.locals = self.locals.copy()
[docs] def setLocal(self, name, value):
# Override the current local if present with the new one
self.locals[name] = value
[docs] def popLocals(self):
self.locals = self.localStack.pop()
[docs] def evaluate(self, expr, originalAtts=None):
# Returns a ContextVariable
#self.log.debug ("Evaluating %s" % expr)
if (originalAtts is not None):
# Call from outside
self.globals['attrs'] = originalAtts
suppressException = 1
else:
suppressException = 0
# Supports path, exists, nocall, not, and string
expr = expr.strip()
try:
if expr.startswith('path:'):
return self.evaluatePath(expr[5:].lstrip())
elif expr.startswith('exists:'):
return self.evaluateExists(expr[7:].lstrip())
elif expr.startswith('nocall:'):
return self.evaluateNoCall(expr[7:].lstrip())
elif expr.startswith('not:'):
return self.evaluateNot(expr[4:].lstrip())
elif expr.startswith('string:'):
return self.evaluateString(expr[7:].lstrip())
elif expr.startswith('python:'):
return self.evaluatePython(expr[7:].lstrip())
else:
# Not specified - so it's a path
return self.evaluatePath(expr)
except PathNotFoundException as e:
if (suppressException):
return None
raise e
[docs] def evaluatePython(self, expr):
if (not self.allowPythonPath):
self.log.warning(
"Parameter allowPythonPath is false. NOT Evaluating python expression %s" % expr)
return self.false
#self.log.debug ("Evaluating python expression %s" % expr)
globals = {}
for name, value in self.globals.items():
if (isinstance(value, ContextVariable)):
value = value.rawValue()
globals[name] = value
globals['path'] = self.pythonPathFuncs.path
globals['string'] = self.pythonPathFuncs.string
globals['exists'] = self.pythonPathFuncs.exists
globals['nocall'] = self.pythonPathFuncs.nocall
globals['test'] = self.pythonPathFuncs.test
locals = {}
for name, value in self.locals.items():
if (isinstance(value, ContextVariable)):
value = value.rawValue()
locals[name] = value
try:
result = eval(expr, globals, locals)
if (isinstance(result, ContextVariable)):
return result.value()
return result
except Exception as e:
# An exception occured evaluating the template, return the
# exception as text
self.log.warning(
"Exception occurred evaluating python path, exception: " + str(e))
return "Exception: %s" % str(e)
[docs] def evaluatePath(self, expr):
#self.log.debug ("Evaluating path expression %s" % expr)
allPaths = expr.split('|')
if (len(allPaths) > 1):
for path in allPaths:
# Evaluate this path
try:
return self.evaluate(path.strip())
except PathNotFoundException as e:
# Path didn't exist, try the next one
pass
# No paths evaluated - raise exception.
raise PATHNOTFOUNDEXCEPTION
else:
# A single path - so let's evaluate it.
# This *can* raise PathNotFoundException
return self.traversePath(allPaths[0])
[docs] def evaluateExists(self, expr):
#self.log.debug ("Evaluating %s to see if it exists" % expr)
allPaths = expr.split('|')
# The first path is for us
# Return true if this first bit evaluates, otherwise test the rest
try:
result = self.traversePath(allPaths[0], canCall=0)
return self.true
except PathNotFoundException as e:
# Look at the rest of the paths.
pass
for path in allPaths[1:]:
# Evaluate this path
try:
pathResult = self.evaluate(path.strip())
# If this is part of a "exists: path1 | exists: path2" path
# then we need to look at the actual result.
if (pathResult):
return self.true
except PathNotFoundException as e:
pass
# If we get this far then there are *no* paths that exist.
return self.false
[docs] def evaluateNoCall(self, expr):
#self.log.debug ("Evaluating %s using nocall" % expr)
allPaths = expr.split('|')
# The first path is for us
try:
return self.traversePath(allPaths[0], canCall=0)
except PathNotFoundException as e:
# Try the rest of the paths.
pass
for path in allPaths[1:]:
# Evaluate this path
try:
return self.evaluate(path.strip())
except PathNotFoundException as e:
pass
# No path evaluated - raise error
raise PATHNOTFOUNDEXCEPTION
[docs] def evaluateNot(self, expr):
#self.log.debug ("Evaluating NOT value of %s" % expr)
# Evaluate what I was passed
try:
pathResult = self.evaluate(expr)
except PathNotFoundException as e:
# In SimpleTAL the result of "not: no/such/path" should be TRUE not
# FALSE.
return self.true
if (pathResult is None):
# Value was Nothing
return self.true
if (pathResult is DEFAULTVALUE):
return self.false
try:
resultLen = len(pathResult)
if (resultLen > 0):
return self.false
else:
return self.true
except:
# Not a sequence object.
pass
if (not pathResult):
return self.true
# Everything else is true, so we return false!
return self.false
[docs] def evaluateString(self, expr):
#self.log.debug ("Evaluating String %s" % expr)
result = ""
skipCount = 0
for position in range(0, len(expr)):
if (skipCount > 0):
skipCount -= 1
else:
if (expr[position] == '$'):
try:
if (expr[position + 1] == '$'):
# Escaped $ sign
result += '$'
skipCount = 1
elif (expr[position + 1] == '{'):
# Looking for a path!
endPos = expr.find('}', position + 1)
if (endPos > 0):
path = expr[position + 2:endPos]
# Evaluate the path - missing paths raise
# exceptions as normal.
try:
pathResult = self.evaluate(path)
except PathNotFoundException as e:
# This part of the path didn't evaluate to
# anything - leave blank
pathResult = ''
if (pathResult is not None):
if (isinstance(pathResult, unicode)):
result += pathResult
else:
# THIS IS NOT A BUG!
# Use Unicode in Context if you aren't
# using Ascii!
result += unicode(pathResult)
skipCount = endPos - position
else:
# It's a variable
endPos = expr.find(' ', position + 1)
if (endPos == -1):
endPos = len(expr)
path = expr[position + 1:endPos]
# Evaluate the variable - missing paths raise
# exceptions as normal.
try:
pathResult = self.traversePath(path)
except PathNotFoundException as e:
# This part of the path didn't evaluate to
# anything - leave blank
pathResult = ''
if (pathResult is not None):
if (isinstance(pathResult, unicode)):
result += pathResult
else:
# THIS IS NOT A BUG!
# Use Unicode in Context if you aren't
# using Ascii!
result += unicode(pathResult)
skipCount = endPos - position - 1
except IndexError as e:
# Trailing $ sign - just suppress it
self.log.warning("Trailing $ detected")
pass
else:
result += expr[position]
return result
[docs] def traversePath(self, expr, canCall=1):
# canCall only applies to the *final* path destination, not points down the path.
# Check for and correct for trailing/leading quotes
if (expr.startswith('"') or expr.startswith("'")):
if (expr.endswith('"') or expr.endswith("'")):
expr = expr[1:-1]
else:
expr = expr[1:]
elif (expr.endswith('"') or expr.endswith("'")):
expr = expr[0:-1]
pathList = expr.split('/')
path = pathList[0]
if path.startswith('?'):
path = path[1:]
if path in self.locals:
path = self.locals[path]
if (isinstance(path, ContextVariable)):
path = path.value()
elif (callable(path)):
path = path()
elif path in self.globals:
path = self.globals[path]
if (isinstance(path, ContextVariable)):
path = path.value()
elif (callable(path)):
path = path()
#self.log.debug ("Dereferenced to %s" % path)
if path in self.locals:
val = self.locals[path]
elif path in self.globals:
val = self.globals[path]
else:
# If we can't find it then raise an exception
raise PATHNOTFOUNDEXCEPTION
index = 1
for path in pathList[1:]:
#self.log.debug ("Looking for path element %s" % path)
if path.startswith('?'):
path = path[1:]
if path in self.locals:
path = self.locals[path]
if (isinstance(path, ContextVariable)):
path = path.value()
elif (callable(path)):
path = path()
elif path in self.globals:
path = self.globals[path]
if (isinstance(path, ContextVariable)):
path = path.value()
elif (callable(path)):
path = path()
#self.log.debug ("Dereferenced to %s" % path)
try:
if (isinstance(val, ContextVariable)):
temp = val.value((index, pathList))
elif (callable(val)):
temp = val()
else:
temp = val
except ContextVariable as e:
# Fast path for those functions that return values
return e.value()
if (hasattr(temp, path)):
val = getattr(temp, path)
else:
try:
try:
val = temp[path]
except TypeError:
val = temp[int(path)]
except:
#self.log.debug ("Not found.")
raise PATHNOTFOUNDEXCEPTION
index = index + 1
#self.log.debug ("Found value %s" % str (val))
if (canCall):
try:
if (isinstance(val, ContextVariable)):
result = val.value((index, pathList))
elif (callable(val)):
result = val()
else:
result = val
except ContextVariable as e:
# Fast path for those functions that return values
return e.value()
else:
if (isinstance(val, ContextVariable)):
result = val.realValue
else:
result = val
return result
def __str__(self):
return "Globals: " + str(self.globals) + "Locals: " + str(self.locals)
[docs] def populateDefaultVariables(self, options):
vars = {}
self.repeatMap = {}
vars['nothing'] = None
vars['default'] = DEFAULTVALUE
vars['options'] = options
# To start with there are no repeats
vars['repeat'] = self.repeatMap
vars['attrs'] = None
# Add all of these to the global context
for name in vars.keys():
self.addGlobal(name, vars[name])
# Add also under CONTEXTS
self.addGlobal('CONTEXTS', vars)