spiff-arena/SpiffWorkflow/bpmn/FeelLikeScriptEngine.py
burnettk 02855719b8 Squashed 'SpiffWorkflow/' changes from 98c6294f..0e61be85
0e61be85 Merge pull request #289 from sartography/improvement/execution-and-serialization-cleanup
527684da fix some typos in the class & method docs
0dff44a4 Merge branch 'main' into improvement/execution-and-serialization-cleanup
64737498 Allow for other PythonScriptEngine environments besides task data (#288)
dd63e916 remove some unused tests & diagrams
24aae519 clean up various small stuff
3b2dc35d use context when opening files for parsing
69eec3eb update class/method docs
24528dfb move all spec conversion classes to top level
5af33b11 remove some unused methods related to old serializer
931b90fb reorganize serializer
4e81ed29 consolidate pointless serializer classes
d62acf02 change task_spec._update_hook to return a boolean indicating whether the task is ready

git-subtree-dir: SpiffWorkflow
git-subtree-split: 0e61be85c47474a33037e6f398e64c96e02f13ad
2023-02-02 20:59:28 -05:00

314 lines
12 KiB
Python

# -*- coding: utf-8 -*-
import re
import datetime
import operator
from datetime import timedelta
from decimal import Decimal
from .PythonScriptEngine import PythonScriptEngine
# Copyright (C) 2020 Kelly McDonald
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
def feelConvertTime(datestr,parsestr):
return datetime.datetime.strptime(datestr,parsestr)
class FeelInterval():
def __init__(self, begin, end, leftOpen=False, rightOpen=False):
# pesky thing with python floats and Decimal comparison
if isinstance(begin,float):
begin = Decimal("%0.5f"%begin)
if isinstance(end, float):
end = Decimal("%0.5f" % end)
self.startInterval = begin
self.endInterval = end
self.leftOpen = leftOpen
self.rightOpen = rightOpen
def __eq__(self, other):
if self.leftOpen:
lhs = other > self.startInterval
else:
lhs = other >= self.startInterval
if self.rightOpen:
rhs = other < self.endInterval
else:
rhs = other <= self.endInterval
return lhs and rhs
class FeelContains():
def __init__(self, testItem,invert=False ):
self.test = testItem
self.invert = invert
def __eq__(self, other):
has = False
if isinstance(other,dict):
has = self.test in list(other.keys())
else:
has = self.test in list(other)
if self.invert:
return not has
else:
return has
class FeelNot():
def __init__(self, testItem):
self.test = testItem
def __eq__(self, other):
if other == self.test:
return False
else:
return True
def feelConcatenate(*lst):
ilist = []
for l in lst:
ilist = ilist + l
return ilist
def feelAppend(lst,item):
newlist = lst[:] # get a copy
newlist.append(item)
return newlist
def feelNow():
return datetime.datetime.now()
def feelGregorianDOW(date):
# we assume date is either date in Y-m-d format
# or it is of datetime class
if isinstance(date,str):
date = datetime.datetime.strptime(date,'%Y-%m-%d')
return date.isoweekday()%7
def transformDuration(duration,td):
if duration:
return td * float(duration)
else:
return timedelta(seconds=0)
def lookupPart(code,base):
x= re.search("([0-9.]+)"+code,base)
if x:
return x.group(1)
else:
return None
def feelFilter(var,a,b,op,column=None):
"""
here we are trying to cover some of the basic test cases,
dict, list of dicts and list.
"""
opmap = {'=':operator.eq,
'<':operator.lt,
'>':operator.gt,
'<=':operator.le,
'>=':operator.ge,
'!=':operator.ne}
b = eval(b)
# if it is a list and we are referring to 'item' then we
# expect the variable to be a simple list
if (isinstance(var,list)) and a == 'item':
return [x for x in var if opmap[op](x,b)]
# if it is a dictionary, and the keys refer to dictionaries,
# then we convert it to a list of dictionaries with the elements
# all having {'key':key,<rest of dict>}
# if it is a dictionary and the key refers to a non-dict, then
# we convert to a dict having {'key':key,'value':value}
if (isinstance(var,dict)):
newvar = []
for key in var.keys():
if isinstance(var[key],dict):
newterm = var[key]
newterm.update({'key':key})
newvar.append(newterm)
else:
newvar.append({'key':key,'value':var[key]})
var = newvar
if column!=None:
return [x.get(column) for x in var if opmap[op](x.get(a), b)]
else:
return [x for x in var if opmap[op](x.get(a), b)]
def feelParseISODuration(input):
"""
Given an ISO duration designation
such as :
P0Y1M2DT3H2S
and convert it into a python timedelta
Abbreviations may be made as in :
PT30S
NB:
Months are defined as 30 days currently - as I am dreading getting into
Date arithmetic edge cases.
"""
if input[0] != 'P':
raise Exception("ISO Duration format must begin with the letter P")
input = input[1:]
days, time = input.split("T")
lookups = [("Y",days,timedelta(days=365)),
("M", days, timedelta(days=30)),
("W", days, timedelta(days=7)),
("D", days, timedelta(days=1)),
("H", time, timedelta(seconds=60*60)),
("M", time, timedelta(seconds=60)),
("S", time, timedelta(seconds=1)),
]
totaltime = [transformDuration(lookupPart(x[0],x[1]),x[2]) for x in lookups]
return sum(totaltime,timedelta(seconds=0))
# Order Matters!!
fixes = [(r'string\s+length\((.+?)\)','len(\\1)'),
(r'count\((.+?)\)','len(\1)'),
(r'concatenate\((.+?)\)','feelConcatenate(\\1)'),
(r'append\((.+?),(.+?)\)','feelAppend(\\1,\\2)'), # again will not work with literal list
(r'list\s+contains\((.+?),(.+?)\)','\\2 in \\1'), # list contains(['a','b','stupid,','c'],'stupid,') will break
(r'contains\((.+?),(.+?)\)','\\2 in \\1'), # contains('my stupid, stupid comment','stupid') will break
(r'not\s+?contains\((.+?)\)','FeelContains(\\1,invert=True)'), # not contains('something')
(r'not\((.+?)\)','FeelNot(\\1)'), # not('x')
(r'now\(\)','feelNow()'),
(r'contains\((.+?)\)', 'FeelContains(\\1)'), # contains('x')
# date and time (<datestr>)
(r'date\s+?and\s+?time\s*\((.+?)\)', 'feelConvertTime(\\1,"%Y-%m-%dT%H:%M:%S")'),
(r'date\s*\((.+?)\)', 'feelConvertTime(\\1,"%Y-%m-%d)'), # date (<datestring>)
(r'day\s+of\s+\week\((.+?)\)','feelGregorianDOW(\\1)'),
(r'\[([^\[\]]+?)[.]{2}([^\[\]]+?)\]','FeelInterval(\\1,\\2)'), # closed interval on both sides
(r'[\]\(]([^\[\]\(\)]+?)[.]{2}([^\[\]\)\(]+?)\]','FeelInterval(\\1,\\2,leftOpen=True)'), # open lhs
(r'\[([^\[\]\(\)]+?)[.]{2}([^\[\]\(\)]+?)[\[\)]','FeelInterval(\\1,\\2,rightOpen=True)'), # open rhs
# I was having problems with this matching a "P" somewhere in another expression
# so I added a bunch of different cases that should isolate this.
(r'^(P(([0-9.]+Y)?([0-9.]+M)?([0-9.]+W)?([0-9.]+D)?)?(T([0-9.]+H)?([0-9.]+M)?([0-9.]+S)?)?)$',
'feelParseISODuration("\\1")'), ## Parse ISO Duration convert to timedelta - standalone
(r'^(P(([0-9.]+Y)?([0-9.]+M)?([0-9.]+W)?([0-9.]+D)?)?(T([0-9.]+H)?([0-9.]+M)?([0-9.]+S)?)?)\s',
'feelParseISODuration("\\1") '), ## Parse ISO Duration convert to timedelta beginning
(r'\s(P(([0-9.]+Y)?([0-9.]+M)?([0-9.]+W)?([0-9.]+D)?)?(T([0-9.]+H)?([0-9.]+M)?([0-9.]+S)?)?)\s',
' feelParseISODuration("\\1") '), ## Parse ISO Duration convert to timedelta in context
(r'\s(P(([0-9.]+Y)?([0-9.]+M)?([0-9.]+W)?([0-9.]+D)?)?(T([0-9.]+H)?([0-9.]+M)?([0-9.]+S)?)?)$',
' feelParseISODuration("\\1")'), ## Parse ISO Duration convert to timedelta end
(r'(.+)\[(\S+)?(<=)(.+)]\.(\S+)', 'feelFilter(\\1,"\\2","\\4","\\3","\\5")'), # implement a simple filter
(r'(.+)\[(\S+)?(>=)(.+)]\.(\S+)', 'feelFilter(\\1,"\\2","\\4","\\3","\\5")'), # implement a simple filter
(r'(.+)\[(\S+)?(!=)(.+)]\.(\S+)', 'feelFilter(\\1,"\\2","\\4","\\3","\\5")'), # implement a simple filter
(r'(.+)\[(\S+)?([=<>])(.+)]\.(\S+)', 'feelFilter(\\1,"\\2",\\4,"\\3","\\5")'), # implement a simple filter
(r'(.+)\[(\S+)?(<=)(.+)]', 'feelFilter(\\1,"\\2","\\4","\\3")'), # implement a simple filter
(r'(.+)\[(\S+)?(>=)(.+)]', 'feelFilter(\\1,"\\2","\\4","\\3")'), # implement a simple filter
(r'(.+)\[(\S+)?(!=)(.+)]', 'feelFilter(\\1,"\\2","\\4","\\3")'), # implement a simple filter
(r'(.+)\[(\S+)?([=<>])(.+)]','feelFilter(\\1,"\\2","\\4","\\3")'), # implement a simple filter
(r'[\]\(]([^\[\]\(\)]+?)[.]{2}([^\[\]\(\)]+?)[\[\)]',
'FeelInterval(\\1,\\2,rightOpen=True,leftOpen=True)'), # open both
# parse dot.dict for several different edge cases
# make sure that it begins with a letter character - otherwise we
# may get float numbers.
# will not work for cases where we do something like:
# x contains(this.dotdict.item)
# and it may be difficult, because we do not want to replace for the case of
# somedict.keys() - because that is actually in the tests.
# however, it would be fixed by doing:
# x contains( this.dotdict.item )
('true','True'),
('false','False')
]
externalFuncs = {
'feelConvertTime':feelConvertTime,
'FeelInterval':FeelInterval,
'FeelNot':FeelNot,
'Decimal':Decimal,
'feelConcatenate': feelConcatenate,
'feelAppend': feelAppend,
'feelFilter': feelFilter,
'feelNow': feelNow,
'FeelContains': FeelContains,
'datetime':datetime,
'feelParseISODuration': feelParseISODuration,
'feelGregorianDOW':feelGregorianDOW,
}
class FeelLikeScriptEngine(PythonScriptEngine):
"""
This should serve as a base for all scripting & expression evaluation
operations that are done within both BPMN and BMN. Eventually it will also
serve as a base for FEEL expressions as well
If you are uncomfortable with the use of eval() and exec, then you should
provide a specialised subclass that parses and executes the scripts /
expressions in a mini-language of your own.
"""
def __init__(self, environment=None):
super().__init__(environment=environment)
def validate(self, expression):
super().validate(self.patch_expression(expression))
def patch_expression(self, invalid_python, lhs=''):
if invalid_python is None:
return None
proposed_python = invalid_python
for transformation in fixes:
if isinstance(transformation[1], str):
proposed_python = re.sub(transformation[0], transformation[1], proposed_python)
else:
for x in re.findall(transformation[0], proposed_python):
if '.' in(x):
proposed_python = proposed_python.replace(x, transformation[1](x))
if lhs is not None:
proposed_python = lhs + proposed_python
return proposed_python
def _evaluate(self, expression, context, task=None, external_methods=None):
"""
Evaluate the given expression, within the context of the given task and
return the result.
"""
if external_methods is None:
external_methods = {}
revised = self.patch_expression(expression)
external_methods.update(externalFuncs)
return super()._evaluate(revised, context, external_methods=external_methods)
def execute(self, task, script, data, external_methods=None):
"""
Execute the script, within the context of the specified task
"""
if external_methods is None:
external_methods = {}
external_methods.update(externalFuncs)
super(PythonScriptEngine).execute(task, script, external_methods)