# -*- coding: utf-8 -*-
"""
jinja2.asyncsupport
~~~~~~~~~~~~~~~~~~~
Has all the code for async support which is implemented as a patch
for supported Python versions.
:copyright: (c) 2017 by the Jinja Team.
:license: BSD, see LICENSE for more details.
"""
import sys
import asyncio
import inspect
from functools import update_wrapper
from jinja2.utils import concat, internalcode, Markup
from jinja2.environment import TemplateModule
from jinja2.runtime import LoopContextBase, _last_iteration
async def concat_async(async_gen):
rv = []
async def collect():
async for event in async_gen:
rv.append(event)
await collect()
return concat(rv)
async def generate_async(self, *args, **kwargs):
vars = dict(*args, **kwargs)
try:
async for event in self.root_render_func(self.new_context(vars)):
yield event
except Exception:
exc_info = sys.exc_info()
else:
return
yield self.environment.handle_exception(exc_info, True)
def wrap_generate_func(original_generate):
def _convert_generator(self, loop, args, kwargs):
async_gen = self.generate_async(*args, **kwargs)
try:
while 1:
yield loop.run_until_complete(async_gen.__anext__())
except StopAsyncIteration:
pass
def generate(self, *args, **kwargs):
if not self.environment.is_async:
return original_generate(self, *args, **kwargs)
return _convert_generator(self, asyncio.get_event_loop(), args, kwargs)
return update_wrapper(generate, original_generate)
async def render_async(self, *args, **kwargs):
if not self.environment.is_async:
raise RuntimeError('The environment was not created with async mode '
'enabled.')
vars = dict(*args, **kwargs)
ctx = self.new_context(vars)
try:
return await concat_async(self.root_render_func(ctx))
except Exception:
exc_info = sys.exc_info()
return self.environment.handle_exception(exc_info, True)
def wrap_render_func(original_render):
def render(self, *args, **kwargs):
if not self.environment.is_async:
return original_render(self, *args, **kwargs)
loop = asyncio.get_event_loop()
return loop.run_until_complete(self.render_async(*args, **kwargs))
return update_wrapper(render, original_render)
def wrap_block_reference_call(original_call):
@internalcode
async def async_call(self):
rv = await concat_async(self._stack[self._depth](self._context))
if self._context.eval_ctx.autoescape:
rv = Markup(rv)
return rv
@internalcode
def __call__(self):
if not self._context.environment.is_async:
return original_call(self)
return async_call(self)
return update_wrapper(__call__, original_call)
def wrap_macro_invoke(original_invoke):
@internalcode
async def async_invoke(self, arguments, autoescape):
rv = await self._func(*arguments)
if autoescape:
rv = Markup(rv)
return rv
@internalcode
def _invoke(self, arguments, autoescape):
if not self._environment.is_async:
return original_invoke(self, arguments, autoescape)
return async_invoke(self, arguments, autoescape)
return update_wrapper(_invoke, original_invoke)
@internalcode
async def get_default_module_async(self):
if self._module is not None:
return self._module
self._module = rv = await self.make_module_async()
return rv
def wrap_default_module(original_default_module):
@internalcode
def _get_default_module(self):
if self.environment.is_async:
raise RuntimeError('Template module attribute is unavailable '
'in async mode')
return original_default_module(self)
return _get_default_module
async def make_module_async(self, vars=None, shared=False, locals=None):
context = self.new_context(vars, shared, locals)
body_stream = []
async for item in self.root_render_func(context):
body_stream.append(item)
return TemplateModule(self, context, body_stream)
def patch_template():
from jinja2 import Template
Template.generate = wrap_generate_func(Template.generate)
Template.generate_async = update_wrapper(
generate_async, Template.generate_async)
Template.render_async = update_wrapper(
render_async, Template.render_async)
Template.render = wrap_render_func(Template.render)
Template._get_default_module = wrap_default_module(
Template._get_default_module)
Template._get_default_module_async = get_default_module_async
Template.make_module_async = update_wrapper(
make_module_async, Template.make_module_async)
def patch_runtime():
from jinja2.runtime import BlockReference, Macro
BlockReference.__call__ = wrap_block_reference_call(
BlockReference.__call__)
Macro._invoke = wrap_macro_invoke(Macro._invoke)
def patch_filters():
from jinja2.filters import FILTERS
from jinja2.asyncfilters import ASYNC_FILTERS
FILTERS.update(ASYNC_FILTERS)
def patch_all():
patch_template()
patch_runtime()
patch_filters()
async def auto_await(value):
if inspect.isawaitable(value):
return await value
return value
async def auto_aiter(iterable):
if hasattr(iterable, '__aiter__'):
async for item in iterable:
yield item
return
for item in iterable:
yield item
class AsyncLoopContext(LoopContextBase):
def __init__(self, async_iterator, undefined, after, length, recurse=None,
depth0=0):
LoopContextBase.__init__(self, undefined, recurse, depth0)
self._async_iterator = async_iterator
self._after = after
self._length = length
@property
def length(self):
if self._length is None:
raise TypeError('Loop length for some iterators cannot be '
'lazily calculated in async mode')
return self._length
def __aiter__(self):
return AsyncLoopContextIterator(self)
class AsyncLoopContextIterator(object):
__slots__ = ('context',)
def __init__(self, context):
self.context = context
def __aiter__(self):
return self
async def __anext__(self):
ctx = self.context
ctx.index0 += 1
if ctx._after is _last_iteration:
raise StopAsyncIteration()
ctx._before = ctx._current
ctx._current = ctx._after
try:
ctx._after = await ctx._async_iterator.__anext__()
except StopAsyncIteration:
ctx._after = _last_iteration
return ctx._current, ctx
async def make_async_loop_context(iterable, undefined, recurse=None, depth0=0):
# Length is more complicated and less efficient in async mode. The
# reason for this is that we cannot know if length will be used
# upfront but because length is a property we cannot lazily execute it
# later. This means that we need to buffer it up and measure :(
#
# We however only do this for actual iterators, not for async
# iterators as blocking here does not seem like the best idea in the
# world.
try:
length = len(iterable)
except (TypeError, AttributeError):
if not hasattr(iterable, '__aiter__'):
iterable = tuple(iterable)
length = len(iterable)
else:
length = None
async_iterator = auto_aiter(iterable)
try:
after = await async_iterator.__anext__()
except StopAsyncIteration:
after = _last_iteration
return AsyncLoopContext(async_iterator, undefined, after, length, recurse,
depth0)