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760'''
Source https://www.simple-is-better.org/template/pyratemp.html
License: MIT-like
'''
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
__version__ = "0.3.2"
__author__ = ""
__license__ = ""
#=========================================
import os, re, sys, types
if sys.version_info[0] >= 3:
import builtins
unicode = str
long = int
else:
import __builtin__ as builtins
from codecs import open
#=========================================
# some useful functions
#----------------------
# string-position: i <-> row,col
def srow(string, i):
return string.count("\n", 0, max(0, i)) + 1
def scol(string, i):
return i - string.rfind("\n", 0, max(0, i))
def sindex(string, row, col):
n = 0
for _ in range(row-1):
n = string.find("\n", n) + 1
return n+col-1
#----------------------
def dictkeyclean(d):
new_d = {}
for k, v in d.items():
new_d[str(k)] = v
return new_d
#----------------------
def dummy(*_, **__):
pass
def dummy_raise(exception, value):
def mydummy(*_, **__):
raise exception(value)
return mydummy
#=========================================
# escaping
(NONE, HTML, LATEX, MAIL_HEADER) = range(0, 4)
ESCAPE_SUPPORTED = {"NONE":None, "HTML":HTML, "LATEX":LATEX, "MAIL_HEADER":MAIL_HEADER}
def escape(s, format=HTML):
#Note: If you have to make sure that every character gets replaced
# only once (and if you cannot achieve this with the following code),
# use something like "".join([replacedict.get(c,c) for c in s])
# which is about 2-3 times slower (but maybe needs less memory).
#Note: This is one of the most time-consuming parts of the template.
if format is None or format == NONE:
pass
elif format == HTML:
s = s.replace("&", "&") # must be done first!
s = s.replace("<", "<")
s = s.replace(">", ">")
s = s.replace("\"", """)
s = s.replace("\"", "'")
elif format == LATEX:
s = s.replace("\\", "\\x") #must be done first!
s = s.replace("#", "\\#")
s = s.replace("$", "\\$")
s = s.replace("%", "\\%")
s = s.replace("&", "\\&")
s = s.replace("_", "\\_")
s = s.replace("{", "\\{")
s = s.replace("}", "\\}")
s = s.replace("\\x","\\textbackslash{}")
s = s.replace("~", "\\textasciitilde{}")
s = s.replace("^", "\\textasciicircum{}")
elif format == MAIL_HEADER:
import email.header
try:
s.encode("ascii")
return s
except UnicodeEncodeError:
return email.header.make_header([(s, "utf-8")]).encode()
else:
raise ValueError("Invalid format (only None, HTML, LATEX and MAIL_HEADER are supported).")
return s
#=========================================
#-----------------------------------------
# Exceptions
class TemplateException(Exception):
pass
class TemplateParseError(TemplateException):
def __init__(self, err, errpos):
self.err = err
self.filename, self.row, self.col = errpos
TemplateException.__init__(self)
def __str__(self):
if not self.filename:
return "line %d, col %d: %s" % (self.row, self.col, str(self.err))
else:
return "file %s, line %d, col %d: %s" % (self.filename, self.row, self.col, str(self.err))
class TemplateSyntaxError(TemplateParseError, SyntaxError):
pass
class TemplateIncludeError(TemplateParseError):
pass
class TemplateRenderError(TemplateException):
pass
#-----------------------------------------
# Loader
class LoaderString:
def __init__(self, encoding="utf-8"):
self.encoding = encoding
def load(self, s):
if isinstance(s, unicode):
u = s
else:
u = s.decode(self.encoding)
return u
class LoaderFile:
def __init__(self, allowed_path=None, encoding="utf-8"):
if allowed_path and not os.path.isdir(allowed_path):
raise ValueError("allowed_path has to be a directory.")
self.path = allowed_path
self.encoding = encoding
def load(self, filename):
if filename != os.path.basename(filename):
raise ValueError("No path allowed in filename. (%s)" %(filename))
filename = os.path.join(self.path, filename)
f = open(filename, "r", encoding=self.encoding)
u = f.read()
f.close()
return u
#-----------------------------------------
# Parser
class Parser(object):
# template-syntax
_comment_start = "#!"
_comment_end = "!#"
_sub_start = "$!"
_sub_end = "!$"
_subesc_start = "@!"
_subesc_end = "!@"
_block_start = "<!--("
_block_end = ")-->"
# build regexps
# comment
# single-line, until end-tag or end-of-line.
_strComment = r"""%s(?P<content>.*?)(?P<end>%s|\n|$)""" \
% (re.escape(_comment_start), re.escape(_comment_end))
_reComment = re.compile(_strComment, re.M)
# escaped or unescaped substitution
# single-line ("|$" is needed to be able to generate good error-messges)
_strSubstitution = r"""
(
%s\s*(?P<sub>.*?)\s*(?P<end>%s|$) #substitution
|
%s\s*(?P<escsub>.*?)\s*(?P<escend>%s|$) #escaped substitution
)
""" % (re.escape(_sub_start), re.escape(_sub_end),
re.escape(_subesc_start), re.escape(_subesc_end))
_reSubstitution = re.compile(_strSubstitution, re.X|re.M)
# block
# - single-line, no nesting.
# or
# - multi-line, nested by whitespace indentation:
# * start- and end-tag of a block must have exactly the same indentation.
# * start- and end-tags of *nested* blocks should have a greater indentation.
# NOTE: A single-line block must not start at beginning of the line with
# the same indentation as the enclosing multi-line blocks!
# Note that " " and "\t" are different, although they may
# look the same in an editor!
_s = re.escape(_block_start)
_e = re.escape(_block_end)
_strBlock = r"""
^(?P<mEnd>[ \t]*)%send%s(?P<meIgnored>.*)\r?\n? # multi-line end (^ <!--(end)-->IGNORED_TEXT\n)
|
(?P<sEnd>)%send%s # single-line end (<!--(end)-->)
|
(?P<sSpace>[ \t]*) # single-line tag (no nesting)
%s(?P<sKeyw>\w+)[ \t]*(?P<sParam>.*?)%s
(?P<sContent>.*?)
(?=(?:%s.*?%s.*?)??%send%s) # (match until end or i.e. <!--(elif/else...)-->)
|
# multi-line tag, nested by whitespace indentation
^(?P<indent>[ \t]*) # save indentation of start tag
%s(?P<mKeyw>\w+)\s*(?P<mParam>.*?)%s(?P<mIgnored>.*)\r?\n
(?P<mContent>(?:.*\n)*?)
(?=(?P=indent)%s(?:.|\s)*?%s) # match indentation
""" % (_s, _e,
_s, _e,
_s, _e, _s, _e, _s, _e,
_s, _e, _s, _e)
_reBlock = re.compile(_strBlock, re.X|re.M)
# "for"-block parameters: "var(,var)* in ..."
_strForParam = r"""^(?P<names>\w+(?:\s*,\s*\w+)*)\s+in\s+(?P<iter>.+)$"""
_reForParam = re.compile(_strForParam)
# allowed macro-names
_reMacroParam = re.compile(r"""^\w+$""")
def __init__(self, loadfunc=None, testexpr=None, escape=HTML):
if loadfunc is None:
self._load = dummy_raise(NotImplementedError, "include not supported, since no loadfunc was given.")
else:
self._load = loadfunc
if testexpr is None:
self._testexprfunc = dummy
else:
try: # test if testexpr() works
testexpr("i==1")
except Exception as err:
raise ValueError("Invalid testexpr. (%s)" %(err))
self._testexprfunc = testexpr
if escape not in ESCAPE_SUPPORTED.values():
raise ValueError("Unsupported escape. (%s)" %(escape))
self.escape = escape
self._includestack = []
def parse(self, template):
self._includestack = [(None, template)] # for error-messages (_errpos)
return self._parse(template)
def _errpos(self, fpos):
filename, string = self._includestack[-1]
return filename, srow(string, fpos), scol(string, fpos)
def _testexpr(self, expr, fpos=0):
try:
self._testexprfunc(expr)
except SyntaxError as err:
raise TemplateSyntaxError(err, self._errpos(fpos))
def _parse_sub(self, parsetree, text, fpos=0):
curr = 0
for match in self._reSubstitution.finditer(text):
start = match.start()
if start > curr:
parsetree.append(("str", self._reComment.sub("", text[curr:start])))
if match.group("sub") is not None:
if not match.group("end"):
raise TemplateSyntaxError("Missing closing tag %s for %s."
% (self._sub_end, match.group()), self._errpos(fpos+start))
if len(match.group("sub")) > 0:
self._testexpr(match.group("sub"), fpos+start)
parsetree.append(("sub", match.group("sub")))
else:
assert(match.group("escsub") is not None)
if not match.group("escend"):
raise TemplateSyntaxError("Missing closing tag %s for %s."
% (self._subesc_end, match.group()), self._errpos(fpos+start))
if len(match.group("escsub")) > 0:
self._testexpr(match.group("escsub"), fpos+start)
parsetree.append(("esc", self.escape, match.group("escsub")))
curr = match.end()
if len(text) > curr:
parsetree.append(("str", self._reComment.sub("", text[curr:])))
def _parse(self, template, fpos=0):
# blank out comments
# (So that its content does not collide with other syntax, and
# because removing them completely would falsify the character-
# position ("match.start()") of error-messages)
template = self._reComment.sub(lambda match: self._comment_start+" "*len(match.group(1))+match.group(2), template)
# init parser
parsetree = []
curr = 0 # current position (= end of previous block)
block_type = None # block type: if,for,macro,raw,...
block_indent = None # None: single-line, >=0: multi-line
# find blocks
for match in self._reBlock.finditer(template):
start = match.start()
# process template-part before this block
if start > curr:
self._parse_sub(parsetree, template[curr:start], fpos)
# analyze block syntax (incl. error-checking and -messages)
keyword = None
block = match.groupdict()
pos__ = fpos + start # shortcut
if block["sKeyw"] is not None: # single-line block tag
block_indent = None
keyword = block["sKeyw"]
param = block["sParam"]
content = block["sContent"]
if block["sSpace"]: # restore spaces before start-tag
if len(parsetree) > 0 and parsetree[-1][0] == "str":
parsetree[-1] = ("str", parsetree[-1][1] + block["sSpace"])
else:
parsetree.append(("str", block["sSpace"]))
pos_p = fpos + match.start("sParam") # shortcuts
pos_c = fpos + match.start("sContent")
elif block["mKeyw"] is not None: # multi-line block tag
block_indent = len(block["indent"])
keyword = block["mKeyw"]
param = block["mParam"]
content = block["mContent"]
pos_p = fpos + match.start("mParam")
pos_c = fpos + match.start("mContent")
ignored = block["mIgnored"].strip()
if ignored and ignored != self._comment_start:
raise TemplateSyntaxError("No code allowed after block-tag.", self._errpos(fpos+match.start("mIgnored")))
elif block["mEnd"] is not None: # multi-line block end
if block_type is None:
raise TemplateSyntaxError("No block to end here/invalid indent.", self._errpos(pos__) )
if block_indent != len(block["mEnd"]):
raise TemplateSyntaxError("Invalid indent for end-tag.", self._errpos(pos__) )
ignored = block["meIgnored"].strip()
if ignored and ignored != self._comment_start:
raise TemplateSyntaxError("No code allowed after end-tag.", self._errpos(fpos+match.start("meIgnored")))
block_type = None
elif block["sEnd"] is not None: # single-line block end
if block_type is None:
raise TemplateSyntaxError("No block to end here/invalid indent.", self._errpos(pos__))
if block_indent is not None:
raise TemplateSyntaxError("Invalid indent for end-tag.", self._errpos(pos__))
block_type = None
else:
raise TemplateException("FATAL: Block regexp error. Please contact the author. (%s)" % match.group())
# analyze block content (mainly error-checking and -messages)
if keyword:
keyword = keyword.lower()
if "for" == keyword:
if block_type is not None:
raise TemplateSyntaxError("Missing block-end-tag before new block at %s." %(match.group()), self._errpos(pos__))
block_type = "for"
cond = self._reForParam.match(param)
if cond is None:
raise TemplateSyntaxError("Invalid for ... at %s." %(param), self._errpos(pos_p))
names = tuple(n.strip() for n in cond.group("names").split(","))
self._testexpr(cond.group("iter"), pos_p+cond.start("iter"))
parsetree.append(("for", names, cond.group("iter"), self._parse(content, pos_c)))
elif "if" == keyword:
if block_type is not None:
raise TemplateSyntaxError("Missing block-end-tag before new block at %s." %(match.group()), self._errpos(pos__))
if not param:
raise TemplateSyntaxError("Missing condition for if at %s." %(match.group()), self._errpos(pos__))
block_type = "if"
self._testexpr(param, pos_p)
parsetree.append(("if", param, self._parse(content, pos_c)))
elif "elif" == keyword:
if block_type != "if":
raise TemplateSyntaxError("elif may only appear after if at %s." %(match.group()), self._errpos(pos__))
if not param:
raise TemplateSyntaxError("Missing condition for elif at %s." %(match.group()), self._errpos(pos__))
self._testexpr(param, pos_p)
parsetree.append(("elif", param, self._parse(content, pos_c)))
elif "else" == keyword:
if block_type not in ("if", "for"):
raise TemplateSyntaxError("else may only appear after if or for at %s." %(match.group()), self._errpos(pos__))
if param:
raise TemplateSyntaxError("else may not have parameters at %s." %(match.group()), self._errpos(pos__))
parsetree.append(("else", self._parse(content, pos_c)))
elif "macro" == keyword:
if block_type is not None:
raise TemplateSyntaxError("Missing block-end-tag before new block %s." %(match.group()), self._errpos(pos__))
block_type = "macro"
# make sure param is "\w+" (instead of ".+")
if not param:
raise TemplateSyntaxError("Missing name for macro at %s." %(match.group()), self._errpos(pos__))
if not self._reMacroParam.match(param):
raise TemplateSyntaxError("Invalid name for macro at %s." %(match.group()), self._errpos(pos__))
#remove last newline
if len(content) > 0 and content[-1] == "\n":
content = content[:-1]
if len(content) > 0 and content[-1] == "\r":
content = content[:-1]
parsetree.append(("macro", param, self._parse(content, pos_c)))
# parser-commands
elif "raw" == keyword:
if block_type is not None:
raise TemplateSyntaxError("Missing block-end-tag before new block %s." %(match.group()), self._errpos(pos__))
if param:
raise TemplateSyntaxError("raw may not have parameters at %s." %(match.group()), self._errpos(pos__))
block_type = "raw"
parsetree.append(("str", content))
elif "include" == keyword:
if block_type is not None:
raise TemplateSyntaxError("Missing block-end-tag before new block %s." %(match.group()), self._errpos(pos__))
if param:
raise TemplateSyntaxError("include may not have parameters at %s." %(match.group()), self._errpos(pos__))
block_type = "include"
try:
u = self._load(content.strip())
except Exception as err:
raise TemplateIncludeError(err, self._errpos(pos__))
self._includestack.append((content.strip(), u)) # current filename/template for error-msg.
p = self._parse(u)
self._includestack.pop()
parsetree.extend(p)
elif "set_escape" == keyword:
if block_type is not None:
raise TemplateSyntaxError("Missing block-end-tag before new block %s." %(match.group()), self._errpos(pos__))
if param:
raise TemplateSyntaxError("set_escape may not have parameters at %s." %(match.group()), self._errpos(pos__))
block_type = "set_escape"
esc = content.strip().upper()
if esc not in ESCAPE_SUPPORTED:
raise TemplateSyntaxError("Unsupported escape %s." %(esc), self._errpos(pos__))
self.escape = ESCAPE_SUPPORTED[esc]
else:
raise TemplateSyntaxError("Invalid keyword %s." %(keyword), self._errpos(pos__))
curr = match.end()
if block_type is not None:
raise TemplateSyntaxError("Missing end-tag.", self._errpos(pos__))
if len(template) > curr: # process template-part after last block
self._parse_sub(parsetree, template[curr:], fpos+curr)
return parsetree
#-----------------------------------------
# Evaluation
# some checks
assert len(eval("dir()", {"__builtins__":{"dir":dir}})) == 1, \
"FATAL: eval does not work as expected (%s)."
assert compile("0 .__class__", "<string>", "eval").co_names == ("__class__",), \
"FATAL: compile does not work as expected."
class EvalPseudoSandbox:
safe_builtins = {
"True" : True,
"False" : False,
"None" : None,
"abs" : builtins.abs,
"chr" : builtins.chr,
"divmod" : builtins.divmod,
"hash" : builtins.hash,
"hex" : builtins.hex,
"isinstance": builtins.isinstance,
"len" : builtins.len,
"max" : builtins.max,
"min" : builtins.min,
"oct" : builtins.oct,
"ord" : builtins.ord,
"pow" : builtins.pow,
"range" : builtins.range,
"round" : builtins.round,
"sorted" : builtins.sorted,
"sum" : builtins.sum,
"unichr" : builtins.chr,
"zip" : builtins.zip,
"bool" : builtins.bool,
"bytes" : builtins.bytes,
"complex" : builtins.complex,
"dict" : builtins.dict,
"enumerate" : builtins.enumerate,
"float" : builtins.float,
"int" : builtins.int,
"list" : builtins.list,
"long" : long,
"reversed" : builtins.reversed,
"set" : builtins.set,
"str" : builtins.str,
"tuple" : builtins.tuple,
"unicode" : unicode,
"dir" : builtins.dir,
}
if sys.version_info[0] < 3:
safe_builtins["unichr"] = builtins.unichr
def __init__(self):
self._compile_cache = {}
self.vars_ptr = None
self.eval_allowed_builtins = self.safe_builtins.copy()
self.register("__import__", self.f_import)
self.register("exists", self.f_exists)
self.register("default", self.f_default)
self.register("setvar", self.f_setvar)
self.register("escape", self.f_escape)
def register(self, name, obj):
self.eval_allowed_builtins[name] = obj
def _check_code_names(self, code, expr):
for name in code.co_names:
if name[0] == "_" and name != "_[1]": # _[1] is necessary for [x for x in y]
raise NameError("Name %s is not allowed in %s." % (name, expr))
# recursively check sub-codes (e.g. lambdas)
for const in code.co_consts:
if isinstance(const, types.CodeType):
self._check_code_names(const, expr)
def compile(self, expr):
if expr not in self._compile_cache:
c = compile(expr, "", "eval")
self._check_code_names(c, expr)
self._compile_cache[expr] = c
return self._compile_cache[expr]
def eval(self, expr, variables):
sav = self.vars_ptr
self.vars_ptr = variables
try:
x = eval(self.compile(expr), {"__builtins__": self.eval_allowed_builtins}, variables)
except NameError:
# workaround for lambdas like ``sorted(..., key=lambda x: my_f(x))``
vars2 = {"__builtins__": self.eval_allowed_builtins}
vars2.update(variables)
x = eval(self.compile(expr), vars2)
self.vars_ptr = sav
return x
def f_import(self, name, *_, **__):
if self.vars_ptr is not None and name in self.vars_ptr and isinstance(self.vars_ptr[name], types.ModuleType):
return self.vars_ptr[name]
else:
raise ImportError("import not allowed in pseudo-sandbox; try to import %s yourself (and maybe pass it to the sandbox/template)" % name)
def f_exists(self, varname):
return (varname in self.vars_ptr)
def f_default(self, expr, default=None):
try:
r = self.eval(expr, self.vars_ptr)
if r is None:
return default
return r
#TODO: which exceptions should be catched here?
except (NameError, LookupError, TypeError, AttributeError):
return default
def f_setvar(self, name, expr):
self.vars_ptr[name] = self.eval(expr, self.vars_ptr)
return ""
def f_escape(self, s, format="HTML"):
if isinstance(format, (str, unicode)):
format = ESCAPE_SUPPORTED[format.upper()]
return escape(unicode(s), format)
#-----------------------------------------
# basic template / subtemplate
class TemplateBase:
def __init__(self, parsetree, renderfunc, data=None):
#TODO: parameter-checking?
self.parsetree = parsetree
if isinstance(data, dict):
self.data = data
elif data is None:
self.data = {}
else:
raise TypeError("data must be a dict (or None).")
self.current_data = data
self._render = renderfunc
def __call__(self, **override):
self.current_data = self.data.copy()
self.current_data.update(override)
u = "".join(self._render(self.parsetree, self.current_data))
self.current_data = self.data # restore current_data
return _dontescape(u) # (see class _dontescape)
def __unicode__(self):
return self.__call__()
def __str__(self):
return self.__call__()
#-----------------------------------------
# Renderer
class _dontescape(unicode):
__slots__ = []
class Renderer(object):
def __init__(self, evalfunc, escapefunc):
#TODO: test evalfunc
self.evalfunc = evalfunc
self.escapefunc = escapefunc
def _eval(self, expr, data):
try:
return self.evalfunc(expr, data)
#TODO: any other errors to catch here?
except (TypeError, NameError, LookupError, AttributeError, SyntaxError) as err:
raise TemplateRenderError("Cannot eval expression %s. (%s: %s)" %(expr, err.__class__.__name__, err))
def render(self, parsetree, data):
_eval = self._eval # shortcut
output = []
do_else = False # use else/elif-branch?
if parsetree is None:
return ""
for elem in parsetree:
if "str" == elem[0]:
output.append(elem[1])
elif "sub" == elem[0]:
output.append(unicode(_eval(elem[1], data)))
elif "esc" == elem[0]:
obj = _eval(elem[2], data)
#prevent double-escape
if isinstance(obj, _dontescape) or isinstance(obj, TemplateBase):
output.append(unicode(obj))
else:
output.append(self.escapefunc(unicode(obj), elem[1]))
elif "for" == elem[0]:
do_else = True
(names, iterable) = elem[1:3]
try:
loop_iter = iter(_eval(iterable, data))
except TypeError:
raise TemplateRenderError("Cannot loop over %s." % iterable)
for i in loop_iter:
do_else = False
if len(names) == 1:
data[names[0]] = i
else:
data.update(zip(names, i)) #"for a,b,.. in list"
output.extend(self.render(elem[3], data))
elif "if" == elem[0]:
do_else = True
if _eval(elem[1], data):
do_else = False
output.extend(self.render(elem[2], data))
elif "elif" == elem[0]:
if do_else and _eval(elem[1], data):
do_else = False
output.extend(self.render(elem[2], data))
elif "else" == elem[0]:
if do_else:
do_else = False
output.extend(self.render(elem[1], data))
elif "macro" == elem[0]:
data[elem[1]] = TemplateBase(elem[2], self.render, data)
else:
raise TemplateRenderError("Invalid parse-tree (%s)." %(elem))
return output
#-----------------------------------------
# template user-interface (putting it all together)
class Template(TemplateBase):
def __init__(self, string=None,filename=None,parsetree=None, encoding="utf-8", data=None, escape=HTML,
loader_class=LoaderFile,
parser_class=Parser,
renderer_class=Renderer,
eval_class=EvalPseudoSandbox,
escape_func=escape):
if [string, filename, parsetree].count(None) != 2:
raise ValueError("Exactly 1 of string,filename,parsetree is necessary.")
tmpl = None
# load template
if filename is not None:
incl_load = loader_class(os.path.dirname(filename), encoding).load
tmpl = incl_load(os.path.basename(filename))
if string is not None:
incl_load = dummy_raise(NotImplementedError, "include not supported for template-strings.")
tmpl = LoaderString(encoding).load(string)
# eval (incl. compile-cache)
templateeval = eval_class()
# parse
if tmpl is not None:
p = parser_class(loadfunc=incl_load, testexpr=templateeval.compile, escape=escape)
parsetree = p.parse(tmpl)
del p
# renderer
renderfunc = renderer_class(templateeval.eval, escape_func).render
#create template
TemplateBase.__init__(self, parsetree, renderfunc, data)
#=========================================