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1046 lines
37 KiB
Python
1046 lines
37 KiB
Python
#
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# Copyright 2009 Facebook
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""A simple template system that compiles templates to Python code.
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Basic usage looks like::
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t = template.Template("<html>{{ myvalue }}</html>")
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print(t.generate(myvalue="XXX"))
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`Loader` is a class that loads templates from a root directory and caches
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the compiled templates::
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loader = template.Loader("/home/btaylor")
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print(loader.load("test.html").generate(myvalue="XXX"))
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We compile all templates to raw Python. Error-reporting is currently... uh,
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interesting. Syntax for the templates::
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### base.html
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<html>
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<head>
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<title>{% block title %}Default title{% end %}</title>
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</head>
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<body>
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<ul>
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{% for student in students %}
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{% block student %}
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<li>{{ escape(student.name) }}</li>
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{% end %}
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{% end %}
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</ul>
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</body>
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</html>
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### bold.html
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{% extends "base.html" %}
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{% block title %}A bolder title{% end %}
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{% block student %}
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<li><span style="bold">{{ escape(student.name) }}</span></li>
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{% end %}
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Unlike most other template systems, we do not put any restrictions on the
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expressions you can include in your statements. ``if`` and ``for`` blocks get
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translated exactly into Python, so you can do complex expressions like::
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{% for student in [p for p in people if p.student and p.age > 23] %}
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<li>{{ escape(student.name) }}</li>
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{% end %}
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Translating directly to Python means you can apply functions to expressions
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easily, like the ``escape()`` function in the examples above. You can pass
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functions in to your template just like any other variable
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(In a `.RequestHandler`, override `.RequestHandler.get_template_namespace`)::
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### Python code
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def add(x, y):
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return x + y
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template.execute(add=add)
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### The template
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{{ add(1, 2) }}
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We provide the functions `escape() <.xhtml_escape>`, `.url_escape()`,
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`.json_encode()`, and `.squeeze()` to all templates by default.
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Typical applications do not create `Template` or `Loader` instances by
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hand, but instead use the `~.RequestHandler.render` and
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`~.RequestHandler.render_string` methods of
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`tornado.web.RequestHandler`, which load templates automatically based
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on the ``template_path`` `.Application` setting.
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Variable names beginning with ``_tt_`` are reserved by the template
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system and should not be used by application code.
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Syntax Reference
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----------------
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Template expressions are surrounded by double curly braces: ``{{ ... }}``.
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The contents may be any python expression, which will be escaped according
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to the current autoescape setting and inserted into the output. Other
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template directives use ``{% %}``.
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To comment out a section so that it is omitted from the output, surround it
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with ``{# ... #}``.
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To include a literal ``{{``, ``{%``, or ``{#`` in the output, escape them as
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``{{!``, ``{%!``, and ``{#!``, respectively.
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``{% apply *function* %}...{% end %}``
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Applies a function to the output of all template code between ``apply``
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and ``end``::
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{% apply linkify %}{{name}} said: {{message}}{% end %}
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Note that as an implementation detail apply blocks are implemented
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as nested functions and thus may interact strangely with variables
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set via ``{% set %}``, or the use of ``{% break %}`` or ``{% continue %}``
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within loops.
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``{% autoescape *function* %}``
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Sets the autoescape mode for the current file. This does not affect
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other files, even those referenced by ``{% include %}``. Note that
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autoescaping can also be configured globally, at the `.Application`
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or `Loader`.::
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{% autoescape xhtml_escape %}
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{% autoescape None %}
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``{% block *name* %}...{% end %}``
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Indicates a named, replaceable block for use with ``{% extends %}``.
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Blocks in the parent template will be replaced with the contents of
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the same-named block in a child template.::
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<!-- base.html -->
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<title>{% block title %}Default title{% end %}</title>
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<!-- mypage.html -->
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{% extends "base.html" %}
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{% block title %}My page title{% end %}
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``{% comment ... %}``
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A comment which will be removed from the template output. Note that
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there is no ``{% end %}`` tag; the comment goes from the word ``comment``
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to the closing ``%}`` tag.
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``{% extends *filename* %}``
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Inherit from another template. Templates that use ``extends`` should
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contain one or more ``block`` tags to replace content from the parent
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template. Anything in the child template not contained in a ``block``
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tag will be ignored. For an example, see the ``{% block %}`` tag.
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``{% for *var* in *expr* %}...{% end %}``
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Same as the python ``for`` statement. ``{% break %}`` and
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``{% continue %}`` may be used inside the loop.
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``{% from *x* import *y* %}``
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Same as the python ``import`` statement.
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``{% if *condition* %}...{% elif *condition* %}...{% else %}...{% end %}``
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Conditional statement - outputs the first section whose condition is
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true. (The ``elif`` and ``else`` sections are optional)
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``{% import *module* %}``
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Same as the python ``import`` statement.
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``{% include *filename* %}``
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Includes another template file. The included file can see all the local
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variables as if it were copied directly to the point of the ``include``
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directive (the ``{% autoescape %}`` directive is an exception).
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Alternately, ``{% module Template(filename, **kwargs) %}`` may be used
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to include another template with an isolated namespace.
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``{% module *expr* %}``
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Renders a `~tornado.web.UIModule`. The output of the ``UIModule`` is
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not escaped::
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{% module Template("foo.html", arg=42) %}
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``UIModules`` are a feature of the `tornado.web.RequestHandler`
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class (and specifically its ``render`` method) and will not work
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when the template system is used on its own in other contexts.
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``{% raw *expr* %}``
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Outputs the result of the given expression without autoescaping.
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``{% set *x* = *y* %}``
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Sets a local variable.
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``{% try %}...{% except %}...{% else %}...{% finally %}...{% end %}``
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Same as the python ``try`` statement.
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``{% while *condition* %}... {% end %}``
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Same as the python ``while`` statement. ``{% break %}`` and
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``{% continue %}`` may be used inside the loop.
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``{% whitespace *mode* %}``
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Sets the whitespace mode for the remainder of the current file
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(or until the next ``{% whitespace %}`` directive). See
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`filter_whitespace` for available options. New in Tornado 4.3.
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"""
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import datetime
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from io import StringIO
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import linecache
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import os.path
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import posixpath
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import re
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import threading
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from tornado import escape
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from tornado.log import app_log
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from tornado.util import ObjectDict, exec_in, unicode_type
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from typing import Any, Union, Callable, List, Dict, Iterable, Optional, TextIO
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import typing
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if typing.TYPE_CHECKING:
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from typing import Tuple, ContextManager # noqa: F401
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_DEFAULT_AUTOESCAPE = "xhtml_escape"
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class _UnsetMarker:
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pass
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_UNSET = _UnsetMarker()
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def filter_whitespace(mode: str, text: str) -> str:
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"""Transform whitespace in ``text`` according to ``mode``.
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Available modes are:
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* ``all``: Return all whitespace unmodified.
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* ``single``: Collapse consecutive whitespace with a single whitespace
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character, preserving newlines.
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* ``oneline``: Collapse all runs of whitespace into a single space
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character, removing all newlines in the process.
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.. versionadded:: 4.3
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"""
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if mode == "all":
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return text
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elif mode == "single":
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text = re.sub(r"([\t ]+)", " ", text)
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text = re.sub(r"(\s*\n\s*)", "\n", text)
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return text
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elif mode == "oneline":
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return re.sub(r"(\s+)", " ", text)
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else:
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raise Exception("invalid whitespace mode %s" % mode)
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class Template:
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"""A compiled template.
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We compile into Python from the given template_string. You can generate
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the template from variables with generate().
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"""
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# note that the constructor's signature is not extracted with
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# autodoc because _UNSET looks like garbage. When changing
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# this signature update website/sphinx/template.rst too.
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def __init__(
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self,
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template_string: Union[str, bytes],
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name: str = "<string>",
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loader: Optional["BaseLoader"] = None,
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compress_whitespace: Union[bool, _UnsetMarker] = _UNSET,
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autoescape: Optional[Union[str, _UnsetMarker]] = _UNSET,
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whitespace: Optional[str] = None,
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) -> None:
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"""Construct a Template.
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:arg str template_string: the contents of the template file.
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:arg str name: the filename from which the template was loaded
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(used for error message).
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:arg tornado.template.BaseLoader loader: the `~tornado.template.BaseLoader` responsible
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for this template, used to resolve ``{% include %}`` and ``{% extend %}`` directives.
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:arg bool compress_whitespace: Deprecated since Tornado 4.3.
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Equivalent to ``whitespace="single"`` if true and
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``whitespace="all"`` if false.
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:arg str autoescape: The name of a function in the template
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namespace, or ``None`` to disable escaping by default.
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:arg str whitespace: A string specifying treatment of whitespace;
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see `filter_whitespace` for options.
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.. versionchanged:: 4.3
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Added ``whitespace`` parameter; deprecated ``compress_whitespace``.
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"""
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self.name = escape.native_str(name)
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if compress_whitespace is not _UNSET:
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# Convert deprecated compress_whitespace (bool) to whitespace (str).
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if whitespace is not None:
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raise Exception("cannot set both whitespace and compress_whitespace")
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whitespace = "single" if compress_whitespace else "all"
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if whitespace is None:
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if loader and loader.whitespace:
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whitespace = loader.whitespace
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else:
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# Whitespace defaults by filename.
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if name.endswith(".html") or name.endswith(".js"):
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whitespace = "single"
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else:
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whitespace = "all"
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# Validate the whitespace setting.
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assert whitespace is not None
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filter_whitespace(whitespace, "")
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if not isinstance(autoescape, _UnsetMarker):
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self.autoescape = autoescape # type: Optional[str]
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elif loader:
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self.autoescape = loader.autoescape
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else:
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self.autoescape = _DEFAULT_AUTOESCAPE
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self.namespace = loader.namespace if loader else {}
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reader = _TemplateReader(name, escape.native_str(template_string), whitespace)
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self.file = _File(self, _parse(reader, self))
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self.code = self._generate_python(loader)
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self.loader = loader
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try:
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# Under python2.5, the fake filename used here must match
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# the module name used in __name__ below.
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# The dont_inherit flag prevents template.py's future imports
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# from being applied to the generated code.
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self.compiled = compile(
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escape.to_unicode(self.code),
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"%s.generated.py" % self.name.replace(".", "_"),
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"exec",
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dont_inherit=True,
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)
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except Exception:
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formatted_code = _format_code(self.code).rstrip()
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app_log.error("%s code:\n%s", self.name, formatted_code)
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raise
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def generate(self, **kwargs: Any) -> bytes:
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"""Generate this template with the given arguments."""
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namespace = {
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"escape": escape.xhtml_escape,
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"xhtml_escape": escape.xhtml_escape,
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"url_escape": escape.url_escape,
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"json_encode": escape.json_encode,
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"squeeze": escape.squeeze,
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"linkify": escape.linkify,
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"datetime": datetime,
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"_tt_utf8": escape.utf8, # for internal use
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"_tt_string_types": (unicode_type, bytes),
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# __name__ and __loader__ allow the traceback mechanism to find
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# the generated source code.
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"__name__": self.name.replace(".", "_"),
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"__loader__": ObjectDict(get_source=lambda name: self.code),
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}
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namespace.update(self.namespace)
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namespace.update(kwargs)
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exec_in(self.compiled, namespace)
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execute = typing.cast(Callable[[], bytes], namespace["_tt_execute"])
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# Clear the traceback module's cache of source data now that
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# we've generated a new template (mainly for this module's
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# unittests, where different tests reuse the same name).
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linecache.clearcache()
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return execute()
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def _generate_python(self, loader: Optional["BaseLoader"]) -> str:
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buffer = StringIO()
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try:
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# named_blocks maps from names to _NamedBlock objects
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named_blocks = {} # type: Dict[str, _NamedBlock]
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ancestors = self._get_ancestors(loader)
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ancestors.reverse()
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for ancestor in ancestors:
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ancestor.find_named_blocks(loader, named_blocks)
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writer = _CodeWriter(buffer, named_blocks, loader, ancestors[0].template)
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ancestors[0].generate(writer)
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return buffer.getvalue()
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finally:
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buffer.close()
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def _get_ancestors(self, loader: Optional["BaseLoader"]) -> List["_File"]:
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ancestors = [self.file]
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for chunk in self.file.body.chunks:
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if isinstance(chunk, _ExtendsBlock):
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if not loader:
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raise ParseError(
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"{% extends %} block found, but no " "template loader"
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)
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template = loader.load(chunk.name, self.name)
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ancestors.extend(template._get_ancestors(loader))
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return ancestors
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class BaseLoader:
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"""Base class for template loaders.
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You must use a template loader to use template constructs like
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``{% extends %}`` and ``{% include %}``. The loader caches all
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templates after they are loaded the first time.
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"""
|
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def __init__(
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self,
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autoescape: Optional[str] = _DEFAULT_AUTOESCAPE,
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namespace: Optional[Dict[str, Any]] = None,
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whitespace: Optional[str] = None,
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) -> None:
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"""Construct a template loader.
|
|
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:arg str autoescape: The name of a function in the template
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namespace, such as "xhtml_escape", or ``None`` to disable
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autoescaping by default.
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:arg dict namespace: A dictionary to be added to the default template
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namespace, or ``None``.
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:arg str whitespace: A string specifying default behavior for
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whitespace in templates; see `filter_whitespace` for options.
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Default is "single" for files ending in ".html" and ".js" and
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"all" for other files.
|
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.. versionchanged:: 4.3
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Added ``whitespace`` parameter.
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"""
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self.autoescape = autoescape
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self.namespace = namespace or {}
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self.whitespace = whitespace
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self.templates = {} # type: Dict[str, Template]
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# self.lock protects self.templates. It's a reentrant lock
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# because templates may load other templates via `include` or
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# `extends`. Note that thanks to the GIL this code would be safe
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# even without the lock, but could lead to wasted work as multiple
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# threads tried to compile the same template simultaneously.
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self.lock = threading.RLock()
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|
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def reset(self) -> None:
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"""Resets the cache of compiled templates."""
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with self.lock:
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self.templates = {}
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|
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def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:
|
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"""Converts a possibly-relative path to absolute (used internally)."""
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raise NotImplementedError()
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|
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def load(self, name: str, parent_path: Optional[str] = None) -> Template:
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"""Loads a template."""
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name = self.resolve_path(name, parent_path=parent_path)
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with self.lock:
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if name not in self.templates:
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self.templates[name] = self._create_template(name)
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return self.templates[name]
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|
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def _create_template(self, name: str) -> Template:
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raise NotImplementedError()
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|
|
|
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class Loader(BaseLoader):
|
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"""A template loader that loads from a single root directory."""
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|
|
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def __init__(self, root_directory: str, **kwargs: Any) -> None:
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super().__init__(**kwargs)
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self.root = os.path.abspath(root_directory)
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|
|
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def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:
|
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if (
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parent_path
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and not parent_path.startswith("<")
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and not parent_path.startswith("/")
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and not name.startswith("/")
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):
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current_path = os.path.join(self.root, parent_path)
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file_dir = os.path.dirname(os.path.abspath(current_path))
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relative_path = os.path.abspath(os.path.join(file_dir, name))
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if relative_path.startswith(self.root):
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name = relative_path[len(self.root) + 1 :]
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return name
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|
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def _create_template(self, name: str) -> Template:
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path = os.path.join(self.root, name)
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with open(path, "rb") as f:
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template = Template(f.read(), name=name, loader=self)
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return template
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|
|
|
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class DictLoader(BaseLoader):
|
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"""A template loader that loads from a dictionary."""
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|
|
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def __init__(self, dict: Dict[str, str], **kwargs: Any) -> None:
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super().__init__(**kwargs)
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self.dict = dict
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|
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def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:
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if (
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parent_path
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and not parent_path.startswith("<")
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and not parent_path.startswith("/")
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and not name.startswith("/")
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):
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file_dir = posixpath.dirname(parent_path)
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name = posixpath.normpath(posixpath.join(file_dir, name))
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return name
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|
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def _create_template(self, name: str) -> Template:
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return Template(self.dict[name], name=name, loader=self)
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|
|
|
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class _Node:
|
|
def each_child(self) -> Iterable["_Node"]:
|
|
return ()
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
raise NotImplementedError()
|
|
|
|
def find_named_blocks(
|
|
self, loader: Optional[BaseLoader], named_blocks: Dict[str, "_NamedBlock"]
|
|
) -> None:
|
|
for child in self.each_child():
|
|
child.find_named_blocks(loader, named_blocks)
|
|
|
|
|
|
class _File(_Node):
|
|
def __init__(self, template: Template, body: "_ChunkList") -> None:
|
|
self.template = template
|
|
self.body = body
|
|
self.line = 0
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
writer.write_line("def _tt_execute():", self.line)
|
|
with writer.indent():
|
|
writer.write_line("_tt_buffer = []", self.line)
|
|
writer.write_line("_tt_append = _tt_buffer.append", self.line)
|
|
self.body.generate(writer)
|
|
writer.write_line("return _tt_utf8('').join(_tt_buffer)", self.line)
|
|
|
|
def each_child(self) -> Iterable["_Node"]:
|
|
return (self.body,)
|
|
|
|
|
|
class _ChunkList(_Node):
|
|
def __init__(self, chunks: List[_Node]) -> None:
|
|
self.chunks = chunks
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
for chunk in self.chunks:
|
|
chunk.generate(writer)
|
|
|
|
def each_child(self) -> Iterable["_Node"]:
|
|
return self.chunks
|
|
|
|
|
|
class _NamedBlock(_Node):
|
|
def __init__(self, name: str, body: _Node, template: Template, line: int) -> None:
|
|
self.name = name
|
|
self.body = body
|
|
self.template = template
|
|
self.line = line
|
|
|
|
def each_child(self) -> Iterable["_Node"]:
|
|
return (self.body,)
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
block = writer.named_blocks[self.name]
|
|
with writer.include(block.template, self.line):
|
|
block.body.generate(writer)
|
|
|
|
def find_named_blocks(
|
|
self, loader: Optional[BaseLoader], named_blocks: Dict[str, "_NamedBlock"]
|
|
) -> None:
|
|
named_blocks[self.name] = self
|
|
_Node.find_named_blocks(self, loader, named_blocks)
|
|
|
|
|
|
class _ExtendsBlock(_Node):
|
|
def __init__(self, name: str) -> None:
|
|
self.name = name
|
|
|
|
|
|
class _IncludeBlock(_Node):
|
|
def __init__(self, name: str, reader: "_TemplateReader", line: int) -> None:
|
|
self.name = name
|
|
self.template_name = reader.name
|
|
self.line = line
|
|
|
|
def find_named_blocks(
|
|
self, loader: Optional[BaseLoader], named_blocks: Dict[str, _NamedBlock]
|
|
) -> None:
|
|
assert loader is not None
|
|
included = loader.load(self.name, self.template_name)
|
|
included.file.find_named_blocks(loader, named_blocks)
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
assert writer.loader is not None
|
|
included = writer.loader.load(self.name, self.template_name)
|
|
with writer.include(included, self.line):
|
|
included.file.body.generate(writer)
|
|
|
|
|
|
class _ApplyBlock(_Node):
|
|
def __init__(self, method: str, line: int, body: _Node) -> None:
|
|
self.method = method
|
|
self.line = line
|
|
self.body = body
|
|
|
|
def each_child(self) -> Iterable["_Node"]:
|
|
return (self.body,)
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
method_name = "_tt_apply%d" % writer.apply_counter
|
|
writer.apply_counter += 1
|
|
writer.write_line("def %s():" % method_name, self.line)
|
|
with writer.indent():
|
|
writer.write_line("_tt_buffer = []", self.line)
|
|
writer.write_line("_tt_append = _tt_buffer.append", self.line)
|
|
self.body.generate(writer)
|
|
writer.write_line("return _tt_utf8('').join(_tt_buffer)", self.line)
|
|
writer.write_line(
|
|
f"_tt_append(_tt_utf8({self.method}({method_name}())))", self.line
|
|
)
|
|
|
|
|
|
class _ControlBlock(_Node):
|
|
def __init__(self, statement: str, line: int, body: _Node) -> None:
|
|
self.statement = statement
|
|
self.line = line
|
|
self.body = body
|
|
|
|
def each_child(self) -> Iterable[_Node]:
|
|
return (self.body,)
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
writer.write_line("%s:" % self.statement, self.line)
|
|
with writer.indent():
|
|
self.body.generate(writer)
|
|
# Just in case the body was empty
|
|
writer.write_line("pass", self.line)
|
|
|
|
|
|
class _IntermediateControlBlock(_Node):
|
|
def __init__(self, statement: str, line: int) -> None:
|
|
self.statement = statement
|
|
self.line = line
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
# In case the previous block was empty
|
|
writer.write_line("pass", self.line)
|
|
writer.write_line("%s:" % self.statement, self.line, writer.indent_size() - 1)
|
|
|
|
|
|
class _Statement(_Node):
|
|
def __init__(self, statement: str, line: int) -> None:
|
|
self.statement = statement
|
|
self.line = line
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
writer.write_line(self.statement, self.line)
|
|
|
|
|
|
class _Expression(_Node):
|
|
def __init__(self, expression: str, line: int, raw: bool = False) -> None:
|
|
self.expression = expression
|
|
self.line = line
|
|
self.raw = raw
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
writer.write_line("_tt_tmp = %s" % self.expression, self.line)
|
|
writer.write_line(
|
|
"if isinstance(_tt_tmp, _tt_string_types):" " _tt_tmp = _tt_utf8(_tt_tmp)",
|
|
self.line,
|
|
)
|
|
writer.write_line("else: _tt_tmp = _tt_utf8(str(_tt_tmp))", self.line)
|
|
if not self.raw and writer.current_template.autoescape is not None:
|
|
# In python3 functions like xhtml_escape return unicode,
|
|
# so we have to convert to utf8 again.
|
|
writer.write_line(
|
|
"_tt_tmp = _tt_utf8(%s(_tt_tmp))" % writer.current_template.autoescape,
|
|
self.line,
|
|
)
|
|
writer.write_line("_tt_append(_tt_tmp)", self.line)
|
|
|
|
|
|
class _Module(_Expression):
|
|
def __init__(self, expression: str, line: int) -> None:
|
|
super().__init__("_tt_modules." + expression, line, raw=True)
|
|
|
|
|
|
class _Text(_Node):
|
|
def __init__(self, value: str, line: int, whitespace: str) -> None:
|
|
self.value = value
|
|
self.line = line
|
|
self.whitespace = whitespace
|
|
|
|
def generate(self, writer: "_CodeWriter") -> None:
|
|
value = self.value
|
|
|
|
# Compress whitespace if requested, with a crude heuristic to avoid
|
|
# altering preformatted whitespace.
|
|
if "<pre>" not in value:
|
|
value = filter_whitespace(self.whitespace, value)
|
|
|
|
if value:
|
|
writer.write_line("_tt_append(%r)" % escape.utf8(value), self.line)
|
|
|
|
|
|
class ParseError(Exception):
|
|
"""Raised for template syntax errors.
|
|
|
|
``ParseError`` instances have ``filename`` and ``lineno`` attributes
|
|
indicating the position of the error.
|
|
|
|
.. versionchanged:: 4.3
|
|
Added ``filename`` and ``lineno`` attributes.
|
|
"""
|
|
|
|
def __init__(
|
|
self, message: str, filename: Optional[str] = None, lineno: int = 0
|
|
) -> None:
|
|
self.message = message
|
|
# The names "filename" and "lineno" are chosen for consistency
|
|
# with python SyntaxError.
|
|
self.filename = filename
|
|
self.lineno = lineno
|
|
|
|
def __str__(self) -> str:
|
|
return "%s at %s:%d" % (self.message, self.filename, self.lineno)
|
|
|
|
|
|
class _CodeWriter:
|
|
def __init__(
|
|
self,
|
|
file: TextIO,
|
|
named_blocks: Dict[str, _NamedBlock],
|
|
loader: Optional[BaseLoader],
|
|
current_template: Template,
|
|
) -> None:
|
|
self.file = file
|
|
self.named_blocks = named_blocks
|
|
self.loader = loader
|
|
self.current_template = current_template
|
|
self.apply_counter = 0
|
|
self.include_stack = [] # type: List[Tuple[Template, int]]
|
|
self._indent = 0
|
|
|
|
def indent_size(self) -> int:
|
|
return self._indent
|
|
|
|
def indent(self) -> "ContextManager":
|
|
class Indenter:
|
|
def __enter__(_) -> "_CodeWriter":
|
|
self._indent += 1
|
|
return self
|
|
|
|
def __exit__(_, *args: Any) -> None:
|
|
assert self._indent > 0
|
|
self._indent -= 1
|
|
|
|
return Indenter()
|
|
|
|
def include(self, template: Template, line: int) -> "ContextManager":
|
|
self.include_stack.append((self.current_template, line))
|
|
self.current_template = template
|
|
|
|
class IncludeTemplate:
|
|
def __enter__(_) -> "_CodeWriter":
|
|
return self
|
|
|
|
def __exit__(_, *args: Any) -> None:
|
|
self.current_template = self.include_stack.pop()[0]
|
|
|
|
return IncludeTemplate()
|
|
|
|
def write_line(
|
|
self, line: str, line_number: int, indent: Optional[int] = None
|
|
) -> None:
|
|
if indent is None:
|
|
indent = self._indent
|
|
line_comment = " # %s:%d" % (self.current_template.name, line_number)
|
|
if self.include_stack:
|
|
ancestors = [
|
|
"%s:%d" % (tmpl.name, lineno) for (tmpl, lineno) in self.include_stack
|
|
]
|
|
line_comment += " (via %s)" % ", ".join(reversed(ancestors))
|
|
print(" " * indent + line + line_comment, file=self.file)
|
|
|
|
|
|
class _TemplateReader:
|
|
def __init__(self, name: str, text: str, whitespace: str) -> None:
|
|
self.name = name
|
|
self.text = text
|
|
self.whitespace = whitespace
|
|
self.line = 1
|
|
self.pos = 0
|
|
|
|
def find(self, needle: str, start: int = 0, end: Optional[int] = None) -> int:
|
|
assert start >= 0, start
|
|
pos = self.pos
|
|
start += pos
|
|
if end is None:
|
|
index = self.text.find(needle, start)
|
|
else:
|
|
end += pos
|
|
assert end >= start
|
|
index = self.text.find(needle, start, end)
|
|
if index != -1:
|
|
index -= pos
|
|
return index
|
|
|
|
def consume(self, count: Optional[int] = None) -> str:
|
|
if count is None:
|
|
count = len(self.text) - self.pos
|
|
newpos = self.pos + count
|
|
self.line += self.text.count("\n", self.pos, newpos)
|
|
s = self.text[self.pos : newpos]
|
|
self.pos = newpos
|
|
return s
|
|
|
|
def remaining(self) -> int:
|
|
return len(self.text) - self.pos
|
|
|
|
def __len__(self) -> int:
|
|
return self.remaining()
|
|
|
|
def __getitem__(self, key: Union[int, slice]) -> str:
|
|
if isinstance(key, slice):
|
|
size = len(self)
|
|
start, stop, step = key.indices(size)
|
|
if start is None:
|
|
start = self.pos
|
|
else:
|
|
start += self.pos
|
|
if stop is not None:
|
|
stop += self.pos
|
|
return self.text[slice(start, stop, step)]
|
|
elif key < 0:
|
|
return self.text[key]
|
|
else:
|
|
return self.text[self.pos + key]
|
|
|
|
def __str__(self) -> str:
|
|
return self.text[self.pos :]
|
|
|
|
def raise_parse_error(self, msg: str) -> None:
|
|
raise ParseError(msg, self.name, self.line)
|
|
|
|
|
|
def _format_code(code: str) -> str:
|
|
lines = code.splitlines()
|
|
format = "%%%dd %%s\n" % len(repr(len(lines) + 1))
|
|
return "".join([format % (i + 1, line) for (i, line) in enumerate(lines)])
|
|
|
|
|
|
def _parse(
|
|
reader: _TemplateReader,
|
|
template: Template,
|
|
in_block: Optional[str] = None,
|
|
in_loop: Optional[str] = None,
|
|
) -> _ChunkList:
|
|
body = _ChunkList([])
|
|
while True:
|
|
# Find next template directive
|
|
curly = 0
|
|
while True:
|
|
curly = reader.find("{", curly)
|
|
if curly == -1 or curly + 1 == reader.remaining():
|
|
# EOF
|
|
if in_block:
|
|
reader.raise_parse_error(
|
|
"Missing {%% end %%} block for %s" % in_block
|
|
)
|
|
body.chunks.append(
|
|
_Text(reader.consume(), reader.line, reader.whitespace)
|
|
)
|
|
return body
|
|
# If the first curly brace is not the start of a special token,
|
|
# start searching from the character after it
|
|
if reader[curly + 1] not in ("{", "%", "#"):
|
|
curly += 1
|
|
continue
|
|
# When there are more than 2 curlies in a row, use the
|
|
# innermost ones. This is useful when generating languages
|
|
# like latex where curlies are also meaningful
|
|
if (
|
|
curly + 2 < reader.remaining()
|
|
and reader[curly + 1] == "{"
|
|
and reader[curly + 2] == "{"
|
|
):
|
|
curly += 1
|
|
continue
|
|
break
|
|
|
|
# Append any text before the special token
|
|
if curly > 0:
|
|
cons = reader.consume(curly)
|
|
body.chunks.append(_Text(cons, reader.line, reader.whitespace))
|
|
|
|
start_brace = reader.consume(2)
|
|
line = reader.line
|
|
|
|
# Template directives may be escaped as "{{!" or "{%!".
|
|
# In this case output the braces and consume the "!".
|
|
# This is especially useful in conjunction with jquery templates,
|
|
# which also use double braces.
|
|
if reader.remaining() and reader[0] == "!":
|
|
reader.consume(1)
|
|
body.chunks.append(_Text(start_brace, line, reader.whitespace))
|
|
continue
|
|
|
|
# Comment
|
|
if start_brace == "{#":
|
|
end = reader.find("#}")
|
|
if end == -1:
|
|
reader.raise_parse_error("Missing end comment #}")
|
|
contents = reader.consume(end).strip()
|
|
reader.consume(2)
|
|
continue
|
|
|
|
# Expression
|
|
if start_brace == "{{":
|
|
end = reader.find("}}")
|
|
if end == -1:
|
|
reader.raise_parse_error("Missing end expression }}")
|
|
contents = reader.consume(end).strip()
|
|
reader.consume(2)
|
|
if not contents:
|
|
reader.raise_parse_error("Empty expression")
|
|
body.chunks.append(_Expression(contents, line))
|
|
continue
|
|
|
|
# Block
|
|
assert start_brace == "{%", start_brace
|
|
end = reader.find("%}")
|
|
if end == -1:
|
|
reader.raise_parse_error("Missing end block %}")
|
|
contents = reader.consume(end).strip()
|
|
reader.consume(2)
|
|
if not contents:
|
|
reader.raise_parse_error("Empty block tag ({% %})")
|
|
|
|
operator, space, suffix = contents.partition(" ")
|
|
suffix = suffix.strip()
|
|
|
|
# Intermediate ("else", "elif", etc) blocks
|
|
intermediate_blocks = {
|
|
"else": {"if", "for", "while", "try"},
|
|
"elif": {"if"},
|
|
"except": {"try"},
|
|
"finally": {"try"},
|
|
}
|
|
allowed_parents = intermediate_blocks.get(operator)
|
|
if allowed_parents is not None:
|
|
if not in_block:
|
|
reader.raise_parse_error(f"{operator} outside {allowed_parents} block")
|
|
if in_block not in allowed_parents:
|
|
reader.raise_parse_error(
|
|
f"{operator} block cannot be attached to {in_block} block"
|
|
)
|
|
body.chunks.append(_IntermediateControlBlock(contents, line))
|
|
continue
|
|
|
|
# End tag
|
|
elif operator == "end":
|
|
if not in_block:
|
|
reader.raise_parse_error("Extra {% end %} block")
|
|
return body
|
|
|
|
elif operator in (
|
|
"extends",
|
|
"include",
|
|
"set",
|
|
"import",
|
|
"from",
|
|
"comment",
|
|
"autoescape",
|
|
"whitespace",
|
|
"raw",
|
|
"module",
|
|
):
|
|
if operator == "comment":
|
|
continue
|
|
if operator == "extends":
|
|
suffix = suffix.strip('"').strip("'")
|
|
if not suffix:
|
|
reader.raise_parse_error("extends missing file path")
|
|
block = _ExtendsBlock(suffix) # type: _Node
|
|
elif operator in ("import", "from"):
|
|
if not suffix:
|
|
reader.raise_parse_error("import missing statement")
|
|
block = _Statement(contents, line)
|
|
elif operator == "include":
|
|
suffix = suffix.strip('"').strip("'")
|
|
if not suffix:
|
|
reader.raise_parse_error("include missing file path")
|
|
block = _IncludeBlock(suffix, reader, line)
|
|
elif operator == "set":
|
|
if not suffix:
|
|
reader.raise_parse_error("set missing statement")
|
|
block = _Statement(suffix, line)
|
|
elif operator == "autoescape":
|
|
fn = suffix.strip() # type: Optional[str]
|
|
if fn == "None":
|
|
fn = None
|
|
template.autoescape = fn
|
|
continue
|
|
elif operator == "whitespace":
|
|
mode = suffix.strip()
|
|
# Validate the selected mode
|
|
filter_whitespace(mode, "")
|
|
reader.whitespace = mode
|
|
continue
|
|
elif operator == "raw":
|
|
block = _Expression(suffix, line, raw=True)
|
|
elif operator == "module":
|
|
block = _Module(suffix, line)
|
|
body.chunks.append(block)
|
|
continue
|
|
|
|
elif operator in ("apply", "block", "try", "if", "for", "while"):
|
|
# parse inner body recursively
|
|
if operator in ("for", "while"):
|
|
block_body = _parse(reader, template, operator, operator)
|
|
elif operator == "apply":
|
|
# apply creates a nested function so syntactically it's not
|
|
# in the loop.
|
|
block_body = _parse(reader, template, operator, None)
|
|
else:
|
|
block_body = _parse(reader, template, operator, in_loop)
|
|
|
|
if operator == "apply":
|
|
if not suffix:
|
|
reader.raise_parse_error("apply missing method name")
|
|
block = _ApplyBlock(suffix, line, block_body)
|
|
elif operator == "block":
|
|
if not suffix:
|
|
reader.raise_parse_error("block missing name")
|
|
block = _NamedBlock(suffix, block_body, template, line)
|
|
else:
|
|
block = _ControlBlock(contents, line, block_body)
|
|
body.chunks.append(block)
|
|
continue
|
|
|
|
elif operator in ("break", "continue"):
|
|
if not in_loop:
|
|
reader.raise_parse_error(
|
|
"{} outside {} block".format(operator, {"for", "while"})
|
|
)
|
|
body.chunks.append(_Statement(contents, line))
|
|
continue
|
|
|
|
else:
|
|
reader.raise_parse_error("unknown operator: %r" % operator)
|