JezK
Edit File: templating.py
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 _cv_app from .globals import _cv_request from .globals import current_app from .globals import request from .helpers import stream_with_context from .signals import before_render_template from .signals import template_rendered if t.TYPE_CHECKING: # pragma: no cover 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`. """ appctx = _cv_app.get(None) reqctx = _cv_request.get(None) rv: t.Dict[str, t.Any] = {} 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(app: "Flask", template: Template, context: t.Dict[str, t.Any]) -> str: app.update_template_context(context) 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, Template, t.List[t.Union[str, Template]]], **context: t.Any ) -> str: """Render a template by name with the given context. :param template_name_or_list: The name of the template to render. If a list is given, the first name to exist will be rendered. :param context: The variables to make available in the template. """ app = current_app._get_current_object() # type: ignore[attr-defined] template = app.jinja_env.get_or_select_template(template_name_or_list) return _render(app, template, context) def render_template_string(source: str, **context: t.Any) -> str: """Render a template from the given source string with the given context. :param source: The source code of the template to render. :param context: The variables to make available in the template. """ app = current_app._get_current_object() # type: ignore[attr-defined] template = app.jinja_env.from_string(source) return _render(app, template, context) def _stream( app: "Flask", template: Template, context: t.Dict[str, t.Any] ) -> t.Iterator[str]: app.update_template_context(context) before_render_template.send(app, template=template, context=context) def generate() -> t.Iterator[str]: yield from template.generate(context) template_rendered.send(app, template=template, context=context) rv = generate() # If a request context is active, keep it while generating. if request: rv = stream_with_context(rv) return rv def stream_template( template_name_or_list: t.Union[str, Template, t.List[t.Union[str, Template]]], **context: t.Any ) -> t.Iterator[str]: """Render a template by name with the given context as a stream. This returns an iterator of strings, which can be used as a streaming response from a view. :param template_name_or_list: The name of the template to render. If a list is given, the first name to exist will be rendered. :param context: The variables to make available in the template. .. versionadded:: 2.2 """ app = current_app._get_current_object() # type: ignore[attr-defined] template = app.jinja_env.get_or_select_template(template_name_or_list) return _stream(app, template, context) def stream_template_string(source: str, **context: t.Any) -> t.Iterator[str]: """Render a template from the given source string with the given context as a stream. This returns an iterator of strings, which can be used as a streaming response from a view. :param source: The source code of the template to render. :param context: The variables to make available in the template. .. versionadded:: 2.2 """ app = current_app._get_current_object() # type: ignore[attr-defined] template = app.jinja_env.from_string(source) return _stream(app, template, context)