jinja2.environment.Environment

Undocumented

Adds an extension after the environment was created. .. versionadded:: 2.5

Invoke a filter on a value the same way the compiler does. This might return a coroutine if the filter is running from an environment in async mode and the filter supports async execution. It's your responsibility to await this if needed. .. versionadded:: 2.7

Invoke a test on a value the same way the compiler does. This might return a coroutine if the test is running from an environment in async mode and the test supports async execution. It's your responsibility to await this if needed. .. versionchanged:: 3.0 Tests support ``@pass_context``, etc. decorators. Added the ``context`` and ``eval_ctx`` parameters. .. versionadded:: 2.7

Compile a node or template source code. The `name` parameter is the load name of the template after it was joined using :meth:`join_path` if necessary, not the filename on the file system. the `filename` parameter is the estimated filename of the template on the file system. If the template came from a database or memory this can be omitted. The return value of this method is a python code object. If the `raw` parameter is `True` the return value will be a string with python code equivalent to the bytecode returned otherwise. This method is mainly used internally. `defer_init` is use internally to aid the module code generator. This causes the generated code to be able to import without the global environment variable to be set. .. versionadded:: 2.4 `defer_init` parameter added.

A handy helper method that returns a callable that accepts keyword arguments that appear as variables in the expression. If called it returns the result of the expression. This is useful if applications want to use the same rules as Jinja in template "configuration files" or similar situations. Example usage: >>> env = Environment() >>> expr = env.compile_expression('foo == 42') >>> expr(foo=23) False >>> expr(foo=42) True Per default the return value is converted to `None` if the expression returns an undefined value. This can be changed by setting `undefined_to_none` to `False`. >>> env.compile_expression('var')() is None True >>> env.compile_expression('var', undefined_to_none=False)() Undefined .. versionadded:: 2.1

Finds all the templates the loader can find, compiles them and stores them in `target`. If `zip` is `None`, instead of in a zipfile, the templates will be stored in a directory. By default a deflate zip algorithm is used. To switch to the stored algorithm, `zip` can be set to ``'stored'``. `extensions` and `filter_func` are passed to :meth:`list_templates`. Each template returned will be compiled to the target folder or zipfile. By default template compilation errors are ignored. In case a log function is provided, errors are logged. If you want template syntax errors to abort the compilation you can set `ignore_errors` to `False` and you will get an exception on syntax errors. .. versionadded:: 2.4

Add the items to the instance of the environment if they do not exist yet. This is used by :ref:`extensions <writing-extensions>` to register callbacks and configuration values without breaking inheritance.

Load a template from a source string without using :attr:`loader`. :param source: Jinja source to compile into a template. :param globals: Extend the environment :attr:`globals` with these extra variables available for all renders of this template. If the template has already been loaded and cached, its globals are updated with any new items. :param template_class: Return an instance of this :class:`Template` class.

Use :meth:`select_template` if an iterable of template names is given, or :meth:`get_template` if one name is given. .. versionadded:: 2.3

Load a template by name with :attr:`loader` and return a :class:`Template`. If the template does not exist a :exc:`TemplateNotFound` exception is raised. :param name: Name of the template to load. When loading templates from the filesystem, "/" is used as the path separator, even on Windows. :param parent: The name of the parent template importing this template. :meth:`join_path` can be used to implement name transformations with this. :param globals: Extend the environment :attr:`globals` with these extra variables available for all renders of this template. If the template has already been loaded and cached, its globals are updated with any new items. .. versionchanged:: 3.0 If a template is loaded from cache, ``globals`` will update the template's globals instead of ignoring the new values. .. versionchanged:: 2.4 If ``name`` is a :class:`Template` object it is returned unchanged.

Get an item or attribute of an object but prefer the attribute. Unlike :meth:`getitem` the attribute *must* be a string.

Get an item or attribute of an object but prefer the item.

Exception handling helper. This is used internally to either raise rewritten exceptions or return a rendered traceback for the template.

Iterates over the extensions by priority.

Join a template with the parent. By default all the lookups are relative to the loader root so this method returns the `template` parameter unchanged, but if the paths should be relative to the parent template, this function can be used to calculate the real template name. Subclasses may override this method and implement template path joining here.

Lex the given sourcecode and return a generator that yields tokens as tuples in the form ``(lineno, token_type, value)``. This can be useful for :ref:`extension development <writing-extensions>` and debugging templates. This does not perform preprocessing. If you want the preprocessing of the extensions to be applied you have to filter source through the :meth:`preprocess` method.

Returns a list of templates for this environment. This requires that the loader supports the loader's :meth:`~BaseLoader.list_templates` method. If there are other files in the template folder besides the actual templates, the returned list can be filtered. There are two ways: either `extensions` is set to a list of file extensions for templates, or a `filter_func` can be provided which is a callable that is passed a template name and should return `True` if it should end up in the result list. If the loader does not support that, a :exc:`TypeError` is raised. .. versionadded:: 2.4

Make the globals map for a template. Any given template globals overlay the environment :attr:`globals`. Returns a :class:`collections.ChainMap`. This allows any changes to a template's globals to only affect that template, while changes to the environment's globals are still reflected. However, avoid modifying any globals after a template is loaded. :param d: Dict of template-specific globals. .. versionchanged:: 3.0 Use :class:`collections.ChainMap` to always prevent mutating environment globals.

Create a new overlay environment that shares all the data with the current environment except for cache and the overridden attributes. Extensions cannot be removed for an overlayed environment. An overlayed environment automatically gets all the extensions of the environment it is linked to plus optional extra extensions. Creating overlays should happen after the initial environment was set up completely. Not all attributes are truly linked, some are just copied over so modifications on the original environment may not shine through. .. versionchanged:: 3.1.2 Added the ``newline_sequence``,, ``keep_trailing_newline``, and ``enable_async`` parameters to match ``__init__``.

Parse the sourcecode and return the abstract syntax tree. This tree of nodes is used by the compiler to convert the template into executable source- or bytecode. This is useful for debugging or to extract information from templates. If you are :ref:`developing Jinja extensions <writing-extensions>` this gives you a good overview of the node tree generated.

Preprocesses the source with all extensions. This is automatically called for all parsing and compiling methods but *not* for :meth:`lex` because there you usually only want the actual source tokenized.

Like :meth:`get_template`, but tries loading multiple names. If none of the names can be loaded a :exc:`TemplatesNotFound` exception is raised. :param names: List of template names to try loading in order. :param parent: The name of the parent template importing this template. :meth:`join_path` can be used to implement name transformations with this. :param globals: Extend the environment :attr:`globals` with these extra variables available for all renders of this template. If the template has already been loaded and cached, its globals are updated with any new items. .. versionchanged:: 3.0 If a template is loaded from cache, ``globals`` will update the template's globals instead of ignoring the new values. .. versionchanged:: 2.11 If ``names`` is :class:`Undefined`, an :exc:`UndefinedError` is raised instead. If no templates were found and ``names`` contains :class:`Undefined`, the message is more helpful. .. versionchanged:: 2.4 If ``names`` contains a :class:`Template` object it is returned unchanged. .. versionadded:: 2.3