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Diffstat (limited to 'python/jinja2/asyncsupport.py')
| -rw-r--r-- | python/jinja2/asyncsupport.py | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/python/jinja2/asyncsupport.py b/python/jinja2/asyncsupport.py new file mode 100644 index 0000000..b1e7b5c --- /dev/null +++ b/python/jinja2/asyncsupport.py @@ -0,0 +1,256 @@ +# -*- 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) |