jinja2.runtime.Context

class documentation

class Context: (source)

The template context holds the variables of a template. It stores the values passed to the template and also the names the template exports. Creating instances is neither supported nor useful as it's created automatically at various stages of the template evaluation and should not be created by hand. The context is immutable. Modifications on :attr:`parent` **must not** happen and modifications on :attr:`vars` are allowed from generated template code only. Template filters and global functions marked as :func:`pass_context` get the active context passed as first argument and are allowed to access the context read-only. The template context supports read only dict operations (`get`, `keys`, `values`, `items`, `iterkeys`, `itervalues`, `iteritems`, `__getitem__`, `__contains__`). Additionally there is a :meth:`resolve` method that doesn't fail with a `KeyError` but returns an :class:`Undefined` object for missing variables.

Method	`__contains__`	Undocumented
Method	`__getitem__`	Look up a variable by name with ``[]`` syntax, or raise a ``KeyError`` if the key is not found.
Method	`__init__`	Undocumented
Method	`__repr__`	Undocumented
Method	`call`	Call the callable with the arguments and keyword arguments provided but inject the active context or environment as first argument if the callable has :func:`pass_context` or :func:`pass_environment`.
Method	`derived`	Internal helper function to create a derived context. This is used in situations where the system needs a new context in the same template that is independent.
Method	`get`	Look up a variable by name, or return a default if the key is not found.
Method	`get_all`	Return the complete context as dict including the exported variables. For optimizations reasons this might not return an actual copy so be careful with using it.
Method	`get_exported`	Get a new dict with the exported variables.
Method	`resolve`	Look up a variable by name, or return an :class:`Undefined` object if the key is not found.
Method	`resolve_or_missing`	Look up a variable by name, or return a ``missing`` sentinel if the key is not found.
Method	`super`	Render a parent block.
Class Variable	`items`	Undocumented
Class Variable	`keys`	Undocumented
Class Variable	`values`	Undocumented
Instance Variable	`blocks`	Undocumented
Instance Variable	`environment`	Undocumented
Instance Variable	`eval_ctx`	Undocumented
Instance Variable	`exported_vars`	Undocumented
Instance Variable	`globals_keys`	Undocumented
Instance Variable	`name`	Undocumented
Instance Variable	`parent`	Undocumented
Instance Variable	`vars`	Undocumented

def __contains__(self, name): (source)

Undocumented

Parameters
name:`str`	Undocumented
Returns
`bool`	Undocumented

def __getitem__(self, key): (source)

Look up a variable by name with ``[]`` syntax, or raise a ``KeyError`` if the key is not found.

Parameters
key:`str`	Undocumented
Returns
`t.Any`	Undocumented

def __init__(self, environment, parent, name, blocks, globals=None): (source)

Undocumented

Parameters
environment:`Environment`	Undocumented
parent:`t.Dict[str, t.Any]`	Undocumented
name:`t.Optional[str]`	Undocumented
blocks:`t.Dict[str, t.Callable[[Context], t.Iterator[str]]]`	Undocumented
globals:`t.Optional[t.MutableMapping[str, t.Any]]`	Undocumented

def __repr__(self): (source)

Undocumented

Returns
`str`	Undocumented

@internalcode
def call(__self, __obj, *args, **kwargs): (source)

Call the callable with the arguments and keyword arguments provided but inject the active context or environment as first argument if the callable has :func:`pass_context` or :func:`pass_environment`.

Parameters
__self	Undocumented
__obj:`t.Callable`	Undocumented
*args:`t.Any`	Undocumented
**kwargs:`t.Any`	Undocumented
Returns
`t.Union[t.Any, Undefined]`	Undocumented

def derived(self, locals=None): (source)

Internal helper function to create a derived context. This is used in situations where the system needs a new context in the same template that is independent.

Parameters
locals:`t.Optional[t.Dict[str, t.Any]]`	Undocumented
Returns
`Context`	Undocumented

def get(self, key, default=None): (source)

Look up a variable by name, or return a default if the key is not found. :param key: The variable name to look up. :param default: The value to return if the key is not found.

Parameters
key:`str`	Undocumented
default:`t.Any`	Undocumented
Returns
`t.Any`	Undocumented

def get_all(self): (source)

Return the complete context as dict including the exported variables. For optimizations reasons this might not return an actual copy so be careful with using it.

Returns
`t.Dict[str, t.Any]`	Undocumented

def get_exported(self): (source)

Get a new dict with the exported variables.

Returns
`t.Dict[str, t.Any]`	Undocumented

def resolve(self, key): (source)

Look up a variable by name, or return an :class:`Undefined` object if the key is not found. If you need to add custom behavior, override :meth:`resolve_or_missing`, not this method. The various lookup functions use that method, not this one. :param key: The variable name to look up.

Parameters
key:`str`	Undocumented
Returns
`t.Union[t.Any, Undefined]`	Undocumented

def resolve_or_missing(self, key): (source)

Look up a variable by name, or return a ``missing`` sentinel if the key is not found. Override this method to add custom lookup behavior. :meth:`resolve`, :meth:`get`, and :meth:`__getitem__` use this method. Don't call this method directly. :param key: The variable name to look up.