# -*- coding: utf-8 -*-
"""
flask.templating
~~~~~~~~~~~~~~~~
Implements the bridge to Jinja2.
:copyright: (c) 2015 by Armin Ronacher.
:license: BSD, see LICENSE for more details.
"""
from jinja2 import BaseLoader, Environment as BaseEnvironment, \
TemplateNotFound
from .globals import _request_ctx_stack, _app_ctx_stack
from .signals import template_rendered, before_render_template
def _default_template_ctx_processor():
"""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, **options):
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):
self.app = app
def get_source(self, environment, template):
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, template):
attempts = []
trv = 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, template):
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):
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):
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, context, app):
"""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
[docs]def render_template(template_name_or_list, **context):
"""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)
[docs]def render_template_string(source, **context):
"""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)