import jinja2
from django.conf import settings
from django.template import TemplateDoesNotExist, TemplateSyntaxError
from django.utils.functional import cached_property
from django.utils.module_loading import import_string
from .base import BaseEngine
[docs]class Jinja2(BaseEngine):
app_dirname = 'jinja2'
def __init__(self, params):
params = params.copy()
options = params.pop('OPTIONS').copy()
super().__init__(params)
self.context_processors = options.pop('context_processors', [])
environment = options.pop('environment', 'jinja2.Environment')
environment_cls = import_string(environment)
if 'loader' not in options:
options['loader'] = jinja2.FileSystemLoader(self.template_dirs)
options.setdefault('autoescape', True)
options.setdefault('auto_reload', settings.DEBUG)
options.setdefault('undefined',
jinja2.DebugUndefined if settings.DEBUG else jinja2.Undefined)
self.env = environment_cls(**options)
def from_string(self, template_code):
return Template(self.env.from_string(template_code), self)
def get_template(self, template_name):
try:
return Template(self.env.get_template(template_name), self)
except jinja2.TemplateNotFound as exc:
raise TemplateDoesNotExist(exc.name, backend=self) from exc
except jinja2.TemplateSyntaxError as exc:
new = TemplateSyntaxError(exc.args)
new.template_debug = get_exception_info(exc)
raise new from exc
@cached_property
def template_context_processors(self):
return [import_string(path) for path in self.context_processors]
class Template:
def __init__(self, template, backend):
self.template = template
self.backend = backend
self.origin = Origin(
name=template.filename, template_name=template.name,
)
def render(self, context=None, request=None):
from .utils import csrf_input_lazy, csrf_token_lazy
if context is None:
context = {}
if request is not None:
context['request'] = request
context['csrf_input'] = csrf_input_lazy(request)
context['csrf_token'] = csrf_token_lazy(request)
for context_processor in self.backend.template_context_processors:
context.update(context_processor(request))
return self.template.render(context)
class Origin:
"""
A container to hold debug information as described in the template API
documentation.
"""
def __init__(self, name, template_name):
self.name = name
self.template_name = template_name
def get_exception_info(exception):
"""
Format exception information for display on the debug page using the
structure described in the template API documentation.
"""
context_lines = 10
lineno = exception.lineno
lines = list(enumerate(exception.source.strip().split("\n"), start=1))
during = lines[lineno - 1][1]
total = len(lines)
top = max(0, lineno - context_lines - 1)
bottom = min(total, lineno + context_lines)
return {
'name': exception.filename,
'message': exception.message,
'source_lines': lines[top:bottom],
'line': lineno,
'before': '',
'during': during,
'after': '',
'total': total,
'top': top,
'bottom': bottom,
}
Oct 31, 2018