jinja2.environment.Environment

Undocumented

Internal hook that can be overridden to hook a different compile method in.

Undocumented

Internal hook that can be overridden to hook a different generate method in.

Undocumented

Adds an extension after the environment was created.

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.

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.

Compile a node or template source code. The name parameter is the load name of the template after it was joined using 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.

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

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 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.

Use select_template if an iterable of template names is given, or get_template if one name is given.

Load a template by name with loader and return a Template. If the template does not exist a TemplateNotFound exception is raised.

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 preprocess method.

Returns a list of templates for this environment. This requires that the loader supports the loader's ~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 TypeError is raised.

Make the globals map for a template. Any given template globals overlay the environment globals.

Returns a 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.

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.

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.

Like get_template, but tries loading multiple names. If none of the names can be loaded a TemplatesNotFound exception is raised.