from __future__ import annotations
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 .sansio.app import App
from .sansio.scaffold import Scaffold
def _default_template_ctx_processor() -> dict[str, t.Any]:
"""Default template context processor. Injects `request`,
`session` and `g`.
"""
appctx = _cv_app.get(None)
reqctx = _cv_request.get(None)
rv: 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 Jinja 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: App, **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: App) -> None:
self.app = app
def get_source(
self, environment: BaseEnvironment, template: str
) -> tuple[str, str | None, t.Callable[[], bool] | None]:
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: BaseEnvironment, template: str
) -> tuple[str, str | None, t.Callable[[], bool] | None]:
attempts = []
rv: tuple[str, str | None, t.Callable[[], bool] | None] | None
trv: None | (tuple[str, str | None, t.Callable[[], bool] | None]) = 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: BaseEnvironment, template: str
) -> tuple[str, str | None, t.Callable[[], bool] | None]:
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.Iterator[tuple[Scaffold, BaseLoader]]:
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) -> 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: dict[str, t.Any]) -> str:
app.update_template_context(context)
before_render_template.send(
app, _async_wrapper=app.ensure_sync, template=template, context=context
)
rv = template.render(context)
template_rendered.send(
app, _async_wrapper=app.ensure_sync, template=template, context=context
)
return rv
[docs]
def render_template(
template_name_or_list: str | Template | list[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: dict[str, t.Any]
) -> t.Iterator[str]:
app.update_template_context(context)
before_render_template.send(
app, _async_wrapper=app.ensure_sync, template=template, context=context
)
def generate() -> t.Iterator[str]:
yield from template.generate(context)
template_rendered.send(
app, _async_wrapper=app.ensure_sync, 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: str | Template | list[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)