JezK
Edit File: ext.py
"""Extension API for adding custom tags and behavior.""" import pprint import re import typing as t from markupsafe import Markup from . import defaults from . import nodes from .environment import Environment from .exceptions import TemplateAssertionError from .exceptions import TemplateSyntaxError from .runtime import concat # type: ignore from .runtime import Context from .runtime import Undefined from .utils import import_string from .utils import pass_context if t.TYPE_CHECKING: import typing_extensions as te from .lexer import Token from .lexer import TokenStream from .parser import Parser class _TranslationsBasic(te.Protocol): def gettext(self, message: str) -> str: ... def ngettext(self, singular: str, plural: str, n: int) -> str: pass class _TranslationsContext(_TranslationsBasic): def pgettext(self, context: str, message: str) -> str: ... def npgettext(self, context: str, singular: str, plural: str, n: int) -> str: ... _SupportedTranslations = t.Union[_TranslationsBasic, _TranslationsContext] # I18N functions available in Jinja templates. If the I18N library # provides ugettext, it will be assigned to gettext. GETTEXT_FUNCTIONS: t.Tuple[str, ...] = ( "_", "gettext", "ngettext", "pgettext", "npgettext", ) _ws_re = re.compile(r"\s*\n\s*") class Extension: """Extensions can be used to add extra functionality to the Jinja template system at the parser level. Custom extensions are bound to an environment but may not store environment specific data on `self`. The reason for this is that an extension can be bound to another environment (for overlays) by creating a copy and reassigning the `environment` attribute. As extensions are created by the environment they cannot accept any arguments for configuration. One may want to work around that by using a factory function, but that is not possible as extensions are identified by their import name. The correct way to configure the extension is storing the configuration values on the environment. Because this way the environment ends up acting as central configuration storage the attributes may clash which is why extensions have to ensure that the names they choose for configuration are not too generic. ``prefix`` for example is a terrible name, ``fragment_cache_prefix`` on the other hand is a good name as includes the name of the extension (fragment cache). """ identifier: t.ClassVar[str] def __init_subclass__(cls) -> None: cls.identifier = f"{cls.__module__}.{cls.__name__}" #: if this extension parses this is the list of tags it's listening to. tags: t.Set[str] = set() #: the priority of that extension. This is especially useful for #: extensions that preprocess values. A lower value means higher #: priority. #: #: .. versionadded:: 2.4 priority = 100 def __init__(self, environment: Environment) -> None: self.environment = environment def bind(self, environment: Environment) -> "Extension": """Create a copy of this extension bound to another environment.""" rv = object.__new__(self.__class__) rv.__dict__.update(self.__dict__) rv.environment = environment return rv def preprocess( self, source: str, name: t.Optional[str], filename: t.Optional[str] = None ) -> str: """This method is called before the actual lexing and can be used to preprocess the source. The `filename` is optional. The return value must be the preprocessed source. """ return source def filter_stream( self, stream: "TokenStream" ) -> t.Union["TokenStream", t.Iterable["Token"]]: """It's passed a :class:`~jinja2.lexer.TokenStream` that can be used to filter tokens returned. This method has to return an iterable of :class:`~jinja2.lexer.Token`\\s, but it doesn't have to return a :class:`~jinja2.lexer.TokenStream`. """ return stream def parse(self, parser: "Parser") -> t.Union[nodes.Node, t.List[nodes.Node]]: """If any of the :attr:`tags` matched this method is called with the parser as first argument. The token the parser stream is pointing at is the name token that matched. This method has to return one or a list of multiple nodes. """ raise NotImplementedError() def attr( self, name: str, lineno: t.Optional[int] = None ) -> nodes.ExtensionAttribute: """Return an attribute node for the current extension. This is useful to pass constants on extensions to generated template code. :: self.attr('_my_attribute', lineno=lineno) """ return nodes.ExtensionAttribute(self.identifier, name, lineno=lineno) def call_method( self, name: str, args: t.Optional[t.List[nodes.Expr]] = None, kwargs: t.Optional[t.List[nodes.Keyword]] = None, dyn_args: t.Optional[nodes.Expr] = None, dyn_kwargs: t.Optional[nodes.Expr] = None, lineno: t.Optional[int] = None, ) -> nodes.Call: """Call a method of the extension. This is a shortcut for :meth:`attr` + :class:`jinja2.nodes.Call`. """ if args is None: args = [] if kwargs is None: kwargs = [] return nodes.Call( self.attr(name, lineno=lineno), args, kwargs, dyn_args, dyn_kwargs, lineno=lineno, ) @pass_context def _gettext_alias( __context: Context, *args: t.Any, **kwargs: t.Any ) -> t.Union[t.Any, Undefined]: return __context.call(__context.resolve("gettext"), *args, **kwargs) def _make_new_gettext(func: t.Callable[[str], str]) -> t.Callable[..., str]: @pass_context def gettext(__context: Context, __string: str, **variables: t.Any) -> str: rv = __context.call(func, __string) if __context.eval_ctx.autoescape: rv = Markup(rv) # Always treat as a format string, even if there are no # variables. This makes translation strings more consistent # and predictable. This requires escaping return rv % variables # type: ignore return gettext def _make_new_ngettext(func: t.Callable[[str, str, int], str]) -> t.Callable[..., str]: @pass_context def ngettext( __context: Context, __singular: str, __plural: str, __num: int, **variables: t.Any, ) -> str: variables.setdefault("num", __num) rv = __context.call(func, __singular, __plural, __num) if __context.eval_ctx.autoescape: rv = Markup(rv) # Always treat as a format string, see gettext comment above. return rv % variables # type: ignore return ngettext def _make_new_pgettext(func: t.Callable[[str, str], str]) -> t.Callable[..., str]: @pass_context def pgettext( __context: Context, __string_ctx: str, __string: str, **variables: t.Any ) -> str: variables.setdefault("context", __string_ctx) rv = __context.call(func, __string_ctx, __string) if __context.eval_ctx.autoescape: rv = Markup(rv) # Always treat as a format string, see gettext comment above. return rv % variables # type: ignore return pgettext def _make_new_npgettext( func: t.Callable[[str, str, str, int], str] ) -> t.Callable[..., str]: @pass_context def npgettext( __context: Context, __string_ctx: str, __singular: str, __plural: str, __num: int, **variables: t.Any, ) -> str: variables.setdefault("context", __string_ctx) variables.setdefault("num", __num) rv = __context.call(func, __string_ctx, __singular, __plural, __num) if __context.eval_ctx.autoescape: rv = Markup(rv) # Always treat as a format string, see gettext comment above. return rv % variables # type: ignore return npgettext class InternationalizationExtension(Extension): """This extension adds gettext support to Jinja.""" tags = {"trans"} # TODO: the i18n extension is currently reevaluating values in a few # situations. Take this example: # {% trans count=something() %}{{ count }} foo{% pluralize # %}{{ count }} fooss{% endtrans %} # something is called twice here. One time for the gettext value and # the other time for the n-parameter of the ngettext function. def __init__(self, environment: Environment) -> None: super().__init__(environment) environment.globals["_"] = _gettext_alias environment.extend( install_gettext_translations=self._install, install_null_translations=self._install_null, install_gettext_callables=self._install_callables, uninstall_gettext_translations=self._uninstall, extract_translations=self._extract, newstyle_gettext=False, ) def _install( self, translations: "_SupportedTranslations", newstyle: t.Optional[bool] = None ) -> None: # ugettext and ungettext are preferred in case the I18N library # is providing compatibility with older Python versions. gettext = getattr(translations, "ugettext", None) if gettext is None: gettext = translations.gettext ngettext = getattr(translations, "ungettext", None) if ngettext is None: ngettext = translations.ngettext pgettext = getattr(translations, "pgettext", None) npgettext = getattr(translations, "npgettext", None) self._install_callables( gettext, ngettext, newstyle=newstyle, pgettext=pgettext, npgettext=npgettext ) def _install_null(self, newstyle: t.Optional[bool] = None) -> None: import gettext translations = gettext.NullTranslations() if hasattr(translations, "pgettext"): # Python < 3.8 pgettext = translations.pgettext # type: ignore else: def pgettext(c: str, s: str) -> str: return s if hasattr(translations, "npgettext"): npgettext = translations.npgettext # type: ignore else: def npgettext(c: str, s: str, p: str, n: int) -> str: return s if n == 1 else p self._install_callables( gettext=translations.gettext, ngettext=translations.ngettext, newstyle=newstyle, pgettext=pgettext, npgettext=npgettext, ) def _install_callables( self, gettext: t.Callable[[str], str], ngettext: t.Callable[[str, str, int], str], newstyle: t.Optional[bool] = None, pgettext: t.Optional[t.Callable[[str, str], str]] = None, npgettext: t.Optional[t.Callable[[str, str, str, int], str]] = None, ) -> None: if newstyle is not None: self.environment.newstyle_gettext = newstyle # type: ignore if self.environment.newstyle_gettext: # type: ignore gettext = _make_new_gettext(gettext) ngettext = _make_new_ngettext(ngettext) if pgettext is not None: pgettext = _make_new_pgettext(pgettext) if npgettext is not None: npgettext = _make_new_npgettext(npgettext) self.environment.globals.update( gettext=gettext, ngettext=ngettext, pgettext=pgettext, npgettext=npgettext ) def _uninstall(self, translations: "_SupportedTranslations") -> None: for key in ("gettext", "ngettext", "pgettext", "npgettext"): self.environment.globals.pop(key, None) def _extract( self, source: t.Union[str, nodes.Template], gettext_functions: t.Sequence[str] = GETTEXT_FUNCTIONS, ) -> t.Iterator[ t.Tuple[int, str, t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]]] ]: if isinstance(source, str): source = self.environment.parse(source) return extract_from_ast(source, gettext_functions) def parse(self, parser: "Parser") -> t.Union[nodes.Node, t.List[nodes.Node]]: """Parse a translatable tag.""" lineno = next(parser.stream).lineno context = None context_token = parser.stream.next_if("string") if context_token is not None: context = context_token.value # find all the variables referenced. Additionally a variable can be # defined in the body of the trans block too, but this is checked at # a later state. plural_expr: t.Optional[nodes.Expr] = None plural_expr_assignment: t.Optional[nodes.Assign] = None num_called_num = False variables: t.Dict[str, nodes.Expr] = {} trimmed = None while parser.stream.current.type != "block_end": if variables: parser.stream.expect("comma") # skip colon for python compatibility if parser.stream.skip_if("colon"): break token = parser.stream.expect("name") if token.value in variables: parser.fail( f"translatable variable {token.value!r} defined twice.", token.lineno, exc=TemplateAssertionError, ) # expressions if parser.stream.current.type == "assign": next(parser.stream) variables[token.value] = var = parser.parse_expression() elif trimmed is None and token.value in ("trimmed", "notrimmed"): trimmed = token.value == "trimmed" continue else: variables[token.value] = var = nodes.Name(token.value, "load") if plural_expr is None: if isinstance(var, nodes.Call): plural_expr = nodes.Name("_trans", "load") variables[token.value] = plural_expr plural_expr_assignment = nodes.Assign( nodes.Name("_trans", "store"), var ) else: plural_expr = var num_called_num = token.value == "num" parser.stream.expect("block_end") plural = None have_plural = False referenced = set() # now parse until endtrans or pluralize singular_names, singular = self._parse_block(parser, True) if singular_names: referenced.update(singular_names) if plural_expr is None: plural_expr = nodes.Name(singular_names[0], "load") num_called_num = singular_names[0] == "num" # if we have a pluralize block, we parse that too if parser.stream.current.test("name:pluralize"): have_plural = True next(parser.stream) if parser.stream.current.type != "block_end": token = parser.stream.expect("name") if token.value not in variables: parser.fail( f"unknown variable {token.value!r} for pluralization", token.lineno, exc=TemplateAssertionError, ) plural_expr = variables[token.value] num_called_num = token.value == "num" parser.stream.expect("block_end") plural_names, plural = self._parse_block(parser, False) next(parser.stream) referenced.update(plural_names) else: next(parser.stream) # register free names as simple name expressions for name in referenced: if name not in variables: variables[name] = nodes.Name(name, "load") if not have_plural: plural_expr = None elif plural_expr is None: parser.fail("pluralize without variables", lineno) if trimmed is None: trimmed = self.environment.policies["ext.i18n.trimmed"] if trimmed: singular = self._trim_whitespace(singular) if plural: plural = self._trim_whitespace(plural) node = self._make_node( singular, plural, context, variables, plural_expr, bool(referenced), num_called_num and have_plural, ) node.set_lineno(lineno) if plural_expr_assignment is not None: return [plural_expr_assignment, node] else: return node def _trim_whitespace(self, string: str, _ws_re: t.Pattern[str] = _ws_re) -> str: return _ws_re.sub(" ", string.strip()) def _parse_block( self, parser: "Parser", allow_pluralize: bool ) -> t.Tuple[t.List[str], str]: """Parse until the next block tag with a given name.""" referenced = [] buf = [] while True: if parser.stream.current.type == "data": buf.append(parser.stream.current.value.replace("%", "%%")) next(parser.stream) elif parser.stream.current.type == "variable_begin": next(parser.stream) name = parser.stream.expect("name").value referenced.append(name) buf.append(f"%({name})s") parser.stream.expect("variable_end") elif parser.stream.current.type == "block_begin": next(parser.stream) if parser.stream.current.test("name:endtrans"): break elif parser.stream.current.test("name:pluralize"): if allow_pluralize: break parser.fail( "a translatable section can have only one pluralize section" ) parser.fail( "control structures in translatable sections are not allowed" ) elif parser.stream.eos: parser.fail("unclosed translation block") else: raise RuntimeError("internal parser error") return referenced, concat(buf) def _make_node( self, singular: str, plural: t.Optional[str], context: t.Optional[str], variables: t.Dict[str, nodes.Expr], plural_expr: t.Optional[nodes.Expr], vars_referenced: bool, num_called_num: bool, ) -> nodes.Output: """Generates a useful node from the data provided.""" newstyle = self.environment.newstyle_gettext # type: ignore node: nodes.Expr # no variables referenced? no need to escape for old style # gettext invocations only if there are vars. if not vars_referenced and not newstyle: singular = singular.replace("%%", "%") if plural: plural = plural.replace("%%", "%") func_name = "gettext" func_args: t.List[nodes.Expr] = [nodes.Const(singular)] if context is not None: func_args.insert(0, nodes.Const(context)) func_name = f"p{func_name}" if plural_expr is not None: func_name = f"n{func_name}" func_args.extend((nodes.Const(plural), plural_expr)) node = nodes.Call(nodes.Name(func_name, "load"), func_args, [], None, None) # in case newstyle gettext is used, the method is powerful # enough to handle the variable expansion and autoescape # handling itself if newstyle: for key, value in variables.items(): # the function adds that later anyways in case num was # called num, so just skip it. if num_called_num and key == "num": continue node.kwargs.append(nodes.Keyword(key, value)) # otherwise do that here else: # mark the return value as safe if we are in an # environment with autoescaping turned on node = nodes.MarkSafeIfAutoescape(node) if variables: node = nodes.Mod( node, nodes.Dict( [ nodes.Pair(nodes.Const(key), value) for key, value in variables.items() ] ), ) return nodes.Output([node]) class ExprStmtExtension(Extension): """Adds a `do` tag to Jinja that works like the print statement just that it doesn't print the return value. """ tags = {"do"} def parse(self, parser: "Parser") -> nodes.ExprStmt: node = nodes.ExprStmt(lineno=next(parser.stream).lineno) node.node = parser.parse_tuple() return node class LoopControlExtension(Extension): """Adds break and continue to the template engine.""" tags = {"break", "continue"} def parse(self, parser: "Parser") -> t.Union[nodes.Break, nodes.Continue]: token = next(parser.stream) if token.value == "break": return nodes.Break(lineno=token.lineno) return nodes.Continue(lineno=token.lineno) class DebugExtension(Extension): """A ``{% debug %}`` tag that dumps the available variables, filters, and tests. .. code-block:: html+jinja <pre>{% debug %}</pre> .. code-block:: text {'context': {'cycler': <class 'jinja2.utils.Cycler'>, ..., 'namespace': <class 'jinja2.utils.Namespace'>}, 'filters': ['abs', 'attr', 'batch', 'capitalize', 'center', 'count', 'd', ..., 'urlencode', 'urlize', 'wordcount', 'wordwrap', 'xmlattr'], 'tests': ['!=', '<', '<=', '==', '>', '>=', 'callable', 'defined', ..., 'odd', 'sameas', 'sequence', 'string', 'undefined', 'upper']} .. versionadded:: 2.11.0 """ tags = {"debug"} def parse(self, parser: "Parser") -> nodes.Output: lineno = parser.stream.expect("name:debug").lineno context = nodes.ContextReference() result = self.call_method("_render", [context], lineno=lineno) return nodes.Output([result], lineno=lineno) def _render(self, context: Context) -> str: result = { "context": context.get_all(), "filters": sorted(self.environment.filters.keys()), "tests": sorted(self.environment.tests.keys()), } # Set the depth since the intent is to show the top few names. return pprint.pformat(result, depth=3, compact=True) def extract_from_ast( ast: nodes.Template, gettext_functions: t.Sequence[str] = GETTEXT_FUNCTIONS, babel_style: bool = True, ) -> t.Iterator[ t.Tuple[int, str, t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]]] ]: """Extract localizable strings from the given template node. Per default this function returns matches in babel style that means non string parameters as well as keyword arguments are returned as `None`. This allows Babel to figure out what you really meant if you are using gettext functions that allow keyword arguments for placeholder expansion. If you don't want that behavior set the `babel_style` parameter to `False` which causes only strings to be returned and parameters are always stored in tuples. As a consequence invalid gettext calls (calls without a single string parameter or string parameters after non-string parameters) are skipped. This example explains the behavior: >>> from jinja2 import Environment >>> env = Environment() >>> node = env.parse('{{ (_("foo"), _(), ngettext("foo", "bar", 42)) }}') >>> list(extract_from_ast(node)) [(1, '_', 'foo'), (1, '_', ()), (1, 'ngettext', ('foo', 'bar', None))] >>> list(extract_from_ast(node, babel_style=False)) [(1, '_', ('foo',)), (1, 'ngettext', ('foo', 'bar'))] For every string found this function yields a ``(lineno, function, message)`` tuple, where: * ``lineno`` is the number of the line on which the string was found, * ``function`` is the name of the ``gettext`` function used (if the string was extracted from embedded Python code), and * ``message`` is the string, or a tuple of strings for functions with multiple string arguments. This extraction function operates on the AST and is because of that unable to extract any comments. For comment support you have to use the babel extraction interface or extract comments yourself. """ out: t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]] for node in ast.find_all(nodes.Call): if ( not isinstance(node.node, nodes.Name) or node.node.name not in gettext_functions ): continue strings: t.List[t.Optional[str]] = [] for arg in node.args: if isinstance(arg, nodes.Const) and isinstance(arg.value, str): strings.append(arg.value) else: strings.append(None) for _ in node.kwargs: strings.append(None) if node.dyn_args is not None: strings.append(None) if node.dyn_kwargs is not None: strings.append(None) if not babel_style: out = tuple(x for x in strings if x is not None) if not out: continue else: if len(strings) == 1: out = strings[0] else: out = tuple(strings) yield node.lineno, node.node.name, out class _CommentFinder: """Helper class to find comments in a token stream. Can only find comments for gettext calls forwards. Once the comment from line 4 is found, a comment for line 1 will not return a usable value. """ def __init__( self, tokens: t.Sequence[t.Tuple[int, str, str]], comment_tags: t.Sequence[str] ) -> None: self.tokens = tokens self.comment_tags = comment_tags self.offset = 0 self.last_lineno = 0 def find_backwards(self, offset: int) -> t.List[str]: try: for _, token_type, token_value in reversed( self.tokens[self.offset : offset] ): if token_type in ("comment", "linecomment"): try: prefix, comment = token_value.split(None, 1) except ValueError: continue if prefix in self.comment_tags: return [comment.rstrip()] return [] finally: self.offset = offset def find_comments(self, lineno: int) -> t.List[str]: if not self.comment_tags or self.last_lineno > lineno: return [] for idx, (token_lineno, _, _) in enumerate(self.tokens[self.offset :]): if token_lineno > lineno: return self.find_backwards(self.offset + idx) return self.find_backwards(len(self.tokens)) def babel_extract( fileobj: t.BinaryIO, keywords: t.Sequence[str], comment_tags: t.Sequence[str], options: t.Dict[str, t.Any], ) -> t.Iterator[ t.Tuple[ int, str, t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]], t.List[str] ] ]: """Babel extraction method for Jinja templates. .. versionchanged:: 2.3 Basic support for translation comments was added. If `comment_tags` is now set to a list of keywords for extraction, the extractor will try to find the best preceding comment that begins with one of the keywords. For best results, make sure to not have more than one gettext call in one line of code and the matching comment in the same line or the line before. .. versionchanged:: 2.5.1 The `newstyle_gettext` flag can be set to `True` to enable newstyle gettext calls. .. versionchanged:: 2.7 A `silent` option can now be provided. If set to `False` template syntax errors are propagated instead of being ignored. :param fileobj: the file-like object the messages should be extracted from :param keywords: a list of keywords (i.e. function names) that should be recognized as translation functions :param comment_tags: a list of translator tags to search for and include in the results. :param options: a dictionary of additional options (optional) :return: an iterator over ``(lineno, funcname, message, comments)`` tuples. (comments will be empty currently) """ extensions: t.Dict[t.Type[Extension], None] = {} for extension_name in options.get("extensions", "").split(","): extension_name = extension_name.strip() if not extension_name: continue extensions[import_string(extension_name)] = None if InternationalizationExtension not in extensions: extensions[InternationalizationExtension] = None def getbool(options: t.Mapping[str, str], key: str, default: bool = False) -> bool: return options.get(key, str(default)).lower() in {"1", "on", "yes", "true"} silent = getbool(options, "silent", True) environment = Environment( options.get("block_start_string", defaults.BLOCK_START_STRING), options.get("block_end_string", defaults.BLOCK_END_STRING), options.get("variable_start_string", defaults.VARIABLE_START_STRING), options.get("variable_end_string", defaults.VARIABLE_END_STRING), options.get("comment_start_string", defaults.COMMENT_START_STRING), options.get("comment_end_string", defaults.COMMENT_END_STRING), options.get("line_statement_prefix") or defaults.LINE_STATEMENT_PREFIX, options.get("line_comment_prefix") or defaults.LINE_COMMENT_PREFIX, getbool(options, "trim_blocks", defaults.TRIM_BLOCKS), getbool(options, "lstrip_blocks", defaults.LSTRIP_BLOCKS), defaults.NEWLINE_SEQUENCE, getbool(options, "keep_trailing_newline", defaults.KEEP_TRAILING_NEWLINE), tuple(extensions), cache_size=0, auto_reload=False, ) if getbool(options, "trimmed"): environment.policies["ext.i18n.trimmed"] = True if getbool(options, "newstyle_gettext"): environment.newstyle_gettext = True # type: ignore source = fileobj.read().decode(options.get("encoding", "utf-8")) try: node = environment.parse(source) tokens = list(environment.lex(environment.preprocess(source))) except TemplateSyntaxError: if not silent: raise # skip templates with syntax errors return finder = _CommentFinder(tokens, comment_tags) for lineno, func, message in extract_from_ast(node, keywords): yield lineno, func, message, finder.find_comments(lineno) #: nicer import names i18n = InternationalizationExtension do = ExprStmtExtension loopcontrols = LoopControlExtension debug = DebugExtension