Class Template

python/python3/tornado/template.py:252–389

A compiled template. We compile into Python from the given template_string. You can generate the template from variables with generate().

class Template(object):
    """A compiled template.

    We compile into Python from the given template_string. You can generate
    the template from variables with generate().
    """

    # note that the constructor's signature is not extracted with
    # autodoc because _UNSET looks like garbage.  When changing
    # this signature update website/sphinx/template.rst too.
    def __init__(
        self,
        template_string: Union[str, bytes],
        name: str = "<string>",
        loader: Optional["BaseLoader"] = None,
        compress_whitespace: Union[bool, _UnsetMarker] = _UNSET,
        autoescape: Optional[Union[str, _UnsetMarker]] = _UNSET,
        whitespace: Optional[str] = None,
    ) -> None:
        """Construct a Template.

        :arg str template_string: the contents of the template file.
        :arg str name: the filename from which the template was loaded
            (used for error message).
        :arg tornado.template.BaseLoader loader: the `~tornado.template.BaseLoader` responsible
            for this template, used to resolve ``{% include %}`` and ``{% extend %}`` directives.
        :arg bool compress_whitespace: Deprecated since Tornado 4.3.
            Equivalent to ``whitespace="single"`` if true and
            ``whitespace="all"`` if false.
        :arg str autoescape: The name of a function in the template
            namespace, or ``None`` to disable escaping by default.
        :arg str whitespace: A string specifying treatment of whitespace;
            see `filter_whitespace` for options.

        .. versionchanged:: 4.3
           Added ``whitespace`` parameter; deprecated ``compress_whitespace``.
        """
        self.name = escape.native_str(name)

        if compress_whitespace is not _UNSET:
            # Convert deprecated compress_whitespace (bool) to whitespace (str).
            if whitespace is not None:
                raise Exception("cannot set both whitespace and compress_whitespace")
            whitespace = "single" if compress_whitespace else "all"
        if whitespace is None:
            if loader and loader.whitespace:
                whitespace = loader.whitespace
            else:
                # Whitespace defaults by filename.
                if name.endswith(".html") or name.endswith(".js"):
                    whitespace = "single"
                else:
                    whitespace = "all"
        # Validate the whitespace setting.
        assert whitespace is not None
        filter_whitespace(whitespace, "")

        if not isinstance(autoescape, _UnsetMarker):