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- import typing as t
- from jinja2 import BaseLoader
- from jinja2 import Environment as BaseEnvironment
- from jinja2 import Template
- from jinja2 import TemplateNotFound
- from .globals import _app_ctx_stack
- from .globals import _request_ctx_stack
- from .signals import before_render_template
- from .signals import template_rendered
- if t.TYPE_CHECKING:
- from .app import Flask
- from .scaffold import Scaffold
- def _default_template_ctx_processor() -> t.Dict[str, t.Any]:
- """Default template context processor. Injects `request`,
- `session` and `g`.
- """
- reqctx = _request_ctx_stack.top
- appctx = _app_ctx_stack.top
- rv = {}
- if appctx is not None:
- rv["g"] = appctx.g
- if reqctx is not None:
- rv["request"] = reqctx.request
- rv["session"] = reqctx.session
- return rv
- class Environment(BaseEnvironment):
- """Works like a regular Jinja2 environment but has some additional
- knowledge of how Flask's blueprint works so that it can prepend the
- name of the blueprint to referenced templates if necessary.
- """
- def __init__(self, app: "Flask", **options: t.Any) -> None:
- if "loader" not in options:
- options["loader"] = app.create_global_jinja_loader()
- BaseEnvironment.__init__(self, **options)
- self.app = app
- class DispatchingJinjaLoader(BaseLoader):
- """A loader that looks for templates in the application and all
- the blueprint folders.
- """
- def __init__(self, app: "Flask") -> None:
- self.app = app
- def get_source( # type: ignore
- self, environment: Environment, template: str
- ) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable]]:
- if self.app.config["EXPLAIN_TEMPLATE_LOADING"]:
- return self._get_source_explained(environment, template)
- return self._get_source_fast(environment, template)
- def _get_source_explained(
- self, environment: Environment, template: str
- ) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable]]:
- attempts = []
- rv: t.Optional[t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]]
- trv: t.Optional[
- t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]
- ] = None
- for srcobj, loader in self._iter_loaders(template):
- try:
- rv = loader.get_source(environment, template)
- if trv is None:
- trv = rv
- except TemplateNotFound:
- rv = None
- attempts.append((loader, srcobj, rv))
- from .debughelpers import explain_template_loading_attempts
- explain_template_loading_attempts(self.app, template, attempts)
- if trv is not None:
- return trv
- raise TemplateNotFound(template)
- def _get_source_fast(
- self, environment: Environment, template: str
- ) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable]]:
- for _srcobj, loader in self._iter_loaders(template):
- try:
- return loader.get_source(environment, template)
- except TemplateNotFound:
- continue
- raise TemplateNotFound(template)
- def _iter_loaders(
- self, template: str
- ) -> t.Generator[t.Tuple["Scaffold", BaseLoader], None, None]:
- loader = self.app.jinja_loader
- if loader is not None:
- yield self.app, loader
- for blueprint in self.app.iter_blueprints():
- loader = blueprint.jinja_loader
- if loader is not None:
- yield blueprint, loader
- def list_templates(self) -> t.List[str]:
- result = set()
- loader = self.app.jinja_loader
- if loader is not None:
- result.update(loader.list_templates())
- for blueprint in self.app.iter_blueprints():
- loader = blueprint.jinja_loader
- if loader is not None:
- for template in loader.list_templates():
- result.add(template)
- return list(result)
- def _render(template: Template, context: dict, app: "Flask") -> str:
- """Renders the template and fires the signal"""
- before_render_template.send(app, template=template, context=context)
- rv = template.render(context)
- template_rendered.send(app, template=template, context=context)
- return rv
- def render_template(
- template_name_or_list: t.Union[str, t.List[str]], **context: t.Any
- ) -> str:
- """Renders a template from the template folder with the given
- context.
- :param template_name_or_list: the name of the template to be
- rendered, or an iterable with template names
- the first one existing will be rendered
- :param context: the variables that should be available in the
- context of the template.
- """
- ctx = _app_ctx_stack.top
- ctx.app.update_template_context(context)
- return _render(
- ctx.app.jinja_env.get_or_select_template(template_name_or_list),
- context,
- ctx.app,
- )
- def render_template_string(source: str, **context: t.Any) -> str:
- """Renders a template from the given template source string
- with the given context. Template variables will be autoescaped.
- :param source: the source code of the template to be
- rendered
- :param context: the variables that should be available in the
- context of the template.
- """
- ctx = _app_ctx_stack.top
- ctx.app.update_template_context(context)
- return _render(ctx.app.jinja_env.from_string(source), context, ctx.app)
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