Unicode
-------
-Jinja2 is using unicode internally which means that you have to pass unicode
+Jinja2 is using Unicode internally which means that you have to pass Unicode
objects to the render function or bytestrings that only consist of ASCII
characters. Additionally newlines are normalized to one end of line
sequence which is per default UNIX style (``\n``).
used. With Python 2.6 it is possible to make `unicode` the default on a per
module level and with Python 3 it will be the default.
-To explicitly use a unicode string you have to prefix the string literal
+To explicitly use a Unicode string you have to prefix the string literal
with a `u`: ``u'Hänsel und Gretel sagen Hallo'``. That way Python will
-store the string as unicode by decoding the string with the character
+store the string as Unicode by decoding the string with the character
encoding from the current Python module. If no encoding is specified this
defaults to 'ASCII' which means that you can't use any non ASCII identifier.
To set a better module encoding add the following comment to the first or
-second line of the Python module using the unicode literal::
+second line of the Python module using the Unicode literal::
# -*- coding: utf-8 -*-
backwards compatible to ASCII. For Jinja2 the default encoding of templates
is assumed to be utf-8.
-It is not possible to use Jinja2 to process non unicode data. The reason
+It is not possible to use Jinja2 to process non-Unicode data. The reason
for this is that Jinja2 uses Unicode already on the language level. For
example Jinja2 treats the non-breaking space as valid whitespace inside
expressions which requires knowledge of the encoding or operating on an
-unicode string.
+Unicode string.
-For more details about unicode in Python have a look at the excellent
+For more details about Unicode in Python have a look at the excellent
`Unicode documentation`_.
Another important thing is how Jinja2 is handling string literals in
-templates. A naive implementation would be using unicode strings for
+templates. A naive implementation would be using Unicode strings for
all string literals but it turned out in the past that this is problematic
as some libraries are typechecking against `str` explicitly. For example
-`datetime.strftime` does not accept unicode arguments. To not break it
+`datetime.strftime` does not accept Unicode arguments. To not break it
completely Jinja2 is returning `str` for strings that fit into ASCII and
for everything else `unicode`:
<jinja-extensions>`.
.. autoclass:: Environment([options])
- :members: from_string, get_template, join_path, extend, compile_expression
+ :members: from_string, get_template, select_template,
+ get_or_select_template, join_path, extend, compile_expression
.. attribute:: shared
:members: disable_buffering, enable_buffering, dump
+Autoescaping
+------------
+
+.. versionadded:: 2.4
+
+As of Jinja 2.4 the preferred way to do autoescaping is to enable the
+:ref:`autoescape-extension` and to configure a sensible default for
+autoescaping. This makes it possible to enable and disable autoescaping
+on a per-template basis (HTML versus text for instance).
+
+Here a recommended setup that enables autoescaping for templates ending
+in ``'.html'``, ``'.htm'`` and ``'.xml'`` and disabling it by default
+for all other extensions::
+
+ def guess_autoescape(template_name):
+ if template_name is None or '.' not in template_name:
+ return False
+ ext = template_name.rsplit('.', 1)[1]
+ return ext in ('html', 'htm', 'xml')
+
+ env = Environment(autoescape=guess_autoescape,
+ loader=PackageLoader('mypackage'),
+ extensions=['jinja2.ext.autoescape'])
+
+When implementing a guessing autoescape function, make sure you also
+accept `None` as valid template name. This will be passed when generating
+templates from strings.
+
+Inside the templates the behaviour can be temporarily changed by using
+the `autoescape` block (see :ref:`autoescape-overrides`).
+
+
.. _identifier-naming:
Notes on Identifiers
blocks registered. The last item in each list is the current active
block (latest in the inheritance chain).
+ .. attribute:: eval_ctx
+
+ The current :ref:`eval-context`.
+
.. automethod:: jinja2.runtime.Context.call(callable, \*args, \**kwargs)
.. autofunction:: jinja2.contextfilter
+.. autofunction:: jinja2.evalcontextfilter
+
.. autofunction:: jinja2.environmentfunction
.. autofunction:: jinja2.contextfunction
+.. autofunction:: jinja2.evalcontextfunction
+
.. function:: escape(s)
Convert the characters ``&``, ``<``, ``>``, ``'``, and ``"`` in string `s`
.. autoexception:: jinja2.TemplateNotFound
+.. autoexception:: jinja2.TemplatesNotFound
+
.. autoexception:: jinja2.TemplateSyntaxError
.. attribute:: message
Filters can also be passed the current template context or environment. This
is useful if a filter wants to return an undefined value or check the current
:attr:`~Environment.autoescape` setting. For this purpose two decorators
-exist: :func:`environmentfilter` and :func:`contextfilter`.
+exist: :func:`environmentfilter`, :func:`contextfilter` and
+:func:`evalcontextfilter`.
Here a small example filter that breaks a text into HTML line breaks and
paragraphs and marks the return value as safe HTML string if autoescaping is
_paragraph_re = re.compile(r'(?:\r\n|\r|\n){2,}')
- @environmentfilter
- def nl2br(environment, value):
+ @evalcontextfilter
+ def nl2br(eval_ctx, value):
result = u'\n\n'.join(u'<p>%s</p>' % p.replace('\n', '<br>\n')
for p in _paragraph_re.split(escape(value)))
- if environment.autoescape:
+ if eval_ctx.autoescape:
result = Markup(result)
return result
active :class:`Context` rather then the environment.
+.. _eval-context:
+
+Evaluation Context
+------------------
+
+The evaluation context (short eval context or eval ctx) is a new object
+introducted in Jinja 2.4 that makes it possible to activate and deactivate
+compiled features at runtime.
+
+Currently it is only used to enable and disable the automatic escaping but
+can be used for extensions as well.
+
+In previous Jinja versions filters and functions were marked as
+environment callables in order to check for the autoescape status from the
+environment. In new versions it's encouraged to check the setting from the
+evaluation context instead.
+
+Previous versions::
+
+ @environmentfilter
+ def filter(env, value):
+ result = do_something(value)
+ if env.autoescape:
+ result = Markup(result)
+ return result
+
+In new versions you can either use a :func:`contextfilter` and access the
+evaluation context from the actual context, or use a
+:func:`evalcontextfilter` which directly passes the evaluation context to
+the function::
+
+ @contextfilter
+ def filter(context, value):
+ result = do_something(value)
+ if context.eval_ctx.autoescape:
+ result = Markup(result)
+ return result
+
+ @evalcontextfilter
+ def filter(eval_ctx, value):
+ result = do_something(value)
+ if eval_ctx.autoescape:
+ result = Markup(result)
+ return result
+
+The evaluation context must not be modified at runtime. Modifications
+must only happen with a :class:`nodes.EvalContextModifier` and
+:class:`nodes.ScopedEvalContextModifier` from an extension, not on the
+eval context object itself.
+
+.. autoclass:: jinja2.nodes.EvalContext
+
+ .. attribute:: autoescape
+
+ `True` or `False` depending on if autoescaping is active or not.
+
+ .. attribute:: volatile
+
+ `True` if the compiler cannot evaluate some expressions at compile
+ time. At runtime this should always be `False`.
+
+
.. _writing-tests:
Custom Tests
change it in a backwards incompatible way but modifications in the Jinja2
core may shine through. For example if Jinja2 introduces a new AST node
in later versions that may be returned by :meth:`~Environment.parse`.
+
+The Meta API
+------------
+
+.. versionadded:: 2.2
+
+The meta API returns some information about abstract syntax trees that
+could help applications to implement more advanced template concepts. All
+the functions of the meta API operate on an abstract syntax tree as
+returned by the :meth:`Environment.parse` method.
+
+.. autofunction:: jinja2.meta.find_undeclared_variables
+
+.. autofunction:: jinja2.meta.find_referenced_templates
projects / jinja2.git / blobdiff