Initial commit. Basic models mostly done.

venv/lib/python3.8/site-packages/asgiref/__init__.py

@@ -0,0 +1 @@
+__version__ = "3.2.7"

venv/lib/python3.8/site-packages/asgiref/compatibility.py

@@ -0,0 +1,47 @@
+import asyncio
+import inspect
+
+
+def is_double_callable(application):
+    """
+    Tests to see if an application is a legacy-style (double-callable) application.
+    """
+    # Look for a hint on the object first
+    if getattr(application, "_asgi_single_callable", False):
+        return False
+    if getattr(application, "_asgi_double_callable", False):
+        return True
+    # Uninstanted classes are double-callable
+    if inspect.isclass(application):
+        return True
+    # Instanted classes depend on their __call__
+    if hasattr(application, "__call__"):
+        # We only check to see if its __call__ is a coroutine function -
+        # if it's not, it still might be a coroutine function itself.
+        if asyncio.iscoroutinefunction(application.__call__):
+            return False
+    # Non-classes we just check directly
+    return not asyncio.iscoroutinefunction(application)
+
+
+def double_to_single_callable(application):
+    """
+    Transforms a double-callable ASGI application into a single-callable one.
+    """
+
+    async def new_application(scope, receive, send):
+        instance = application(scope)
+        return await instance(receive, send)
+
+    return new_application
+
+
+def guarantee_single_callable(application):
+    """
+    Takes either a single- or double-callable application and always returns it
+    in single-callable style. Use this to add backwards compatibility for ASGI
+    2.0 applications to your server/test harness/etc.
+    """
+    if is_double_callable(application):
+        application = double_to_single_callable(application)
+    return application

venv/lib/python3.8/site-packages/asgiref/current_thread_executor.py

@@ -0,0 +1,86 @@
+import queue
+import threading
+import time
+from concurrent.futures import Executor, Future
+
+
+class _WorkItem(object):
+    """
+    Represents an item needing to be run in the executor.
+    Copied from ThreadPoolExecutor (but it's private, so we're not going to rely on importing it)
+    """
+
+    def __init__(self, future, fn, args, kwargs):
+        self.future = future
+        self.fn = fn
+        self.args = args
+        self.kwargs = kwargs
+
+    def run(self):
+        if not self.future.set_running_or_notify_cancel():
+            return
+        try:
+            result = self.fn(*self.args, **self.kwargs)
+        except BaseException as exc:
+            self.future.set_exception(exc)
+            # Break a reference cycle with the exception 'exc'
+            self = None
+        else:
+            self.future.set_result(result)
+
+
+class CurrentThreadExecutor(Executor):
+    """
+    An Executor that actually runs code in the thread it is instantiated in.
+    Passed to other threads running async code, so they can run sync code in
+    the thread they came from.
+    """
+
+    def __init__(self):
+        self._work_thread = threading.current_thread()
+        self._work_queue = queue.Queue()
+        self._broken = False
+
+    def run_until_future(self, future):
+        """
+        Runs the code in the work queue until a result is available from the future.
+        Should be run from the thread the executor is initialised in.
+        """
+        # Check we're in the right thread
+        if threading.current_thread() != self._work_thread:
+            raise RuntimeError(
+                "You cannot run CurrentThreadExecutor from a different thread"
+            )
+        # Keep getting work items and checking the future
+        try:
+            while True:
+                # Get a work item and run it
+                try:
+                    work_item = self._work_queue.get(block=False)
+                except queue.Empty:
+                    # See if the future is done (we only exit if the work queue is empty)
+                    if future.done():
+                        return
+                    # Prevent hot-looping on nothing
+                    time.sleep(0.001)
+                else:
+                    work_item.run()
+                    del work_item
+        finally:
+            self._broken = True
+
+    def submit(self, fn, *args, **kwargs):
+        # Check they're not submitting from the same thread
+        if threading.current_thread() == self._work_thread:
+            raise RuntimeError(
+                "You cannot submit onto CurrentThreadExecutor from its own thread"
+            )
+        # Check they're not too late or the executor errored
+        if self._broken:
+            raise RuntimeError("CurrentThreadExecutor already quit or is broken")
+        # Add to work queue
+        f = Future()
+        work_item = _WorkItem(f, fn, args, kwargs)
+        self._work_queue.put(work_item)
+        # Return the future
+        return f

venv/lib/python3.8/site-packages/asgiref/local.py

@@ -0,0 +1,119 @@
+import random
+import string
+import sys
+import threading
+import weakref
+
+
+class Local:
+    """
+    A drop-in replacement for threading.locals that also works with asyncio
+    Tasks (via the current_task asyncio method), and passes locals through
+    sync_to_async and async_to_sync.
+
+    Specifically:
+     - Locals work per-coroutine on any thread not spawned using asgiref
+     - Locals work per-thread on any thread not spawned using asgiref
+     - Locals are shared with the parent coroutine when using sync_to_async
+     - Locals are shared with the parent thread when using async_to_sync
+       (and if that thread was launched using sync_to_async, with its parent
+       coroutine as well, with this working for indefinite levels of nesting)
+
+    Set thread_critical to True to not allow locals to pass from an async Task
+    to a thread it spawns. This is needed for code that truly needs
+    thread-safety, as opposed to things used for helpful context (e.g. sqlite
+    does not like being called from a different thread to the one it is from).
+    Thread-critical code will still be differentiated per-Task within a thread
+    as it is expected it does not like concurrent access.
+
+    This doesn't use contextvars as it needs to support 3.6. Once it can support
+    3.7 only, we can then reimplement the storage more nicely.
+    """
+
+    CLEANUP_INTERVAL = 60  # seconds
+
+    def __init__(self, thread_critical=False):
+        self._thread_critical = thread_critical
+        self._thread_lock = threading.RLock()
+        self._context_refs = []
+        # Random suffixes stop accidental reuse between different Locals,
+        # though we try to force deletion as well.
+        self._attr_name = "_asgiref_local_impl_%s_%s" % (
+            id(self),
+            "".join(random.choice(string.ascii_letters) for i in range(8)),
+        )
+
+    def _get_context_id(self):
+        """
+        Get the ID we should use for looking up variables
+        """
+        # Prevent a circular reference
+        from .sync import AsyncToSync, SyncToAsync
+
+        # First, pull the current task if we can
+        context_id = SyncToAsync.get_current_task()
+        context_is_async = True
+        # OK, let's try for a thread ID
+        if context_id is None:
+            context_id = threading.current_thread()
+            context_is_async = False
+        # If we're thread-critical, we stop here, as we can't share contexts.
+        if self._thread_critical:
+            return context_id
+        # Now, take those and see if we can resolve them through the launch maps
+        for i in range(sys.getrecursionlimit()):
+            try:
+                if context_is_async:
+                    # Tasks have a source thread in AsyncToSync
+                    context_id = AsyncToSync.launch_map[context_id]
+                    context_is_async = False
+                else:
+                    # Threads have a source task in SyncToAsync
+                    context_id = SyncToAsync.launch_map[context_id]
+                    context_is_async = True
+            except KeyError:
+                break
+        else:
+            # Catch infinite loops (they happen if you are screwing around
+            # with AsyncToSync implementations)
+            raise RuntimeError("Infinite launch_map loops")
+        return context_id
+
+    def _get_storage(self):
+        context_obj = self._get_context_id()
+        if not hasattr(context_obj, self._attr_name):
+            setattr(context_obj, self._attr_name, {})
+            self._context_refs.append(weakref.ref(context_obj))
+        return getattr(context_obj, self._attr_name)
+
+    def __del__(self):
+        for ref in self._context_refs:
+            context_obj = ref()
+            if context_obj:
+                try:
+                    delattr(context_obj, self._attr_name)
+                except AttributeError:
+                    pass
+
+    def __getattr__(self, key):
+        with self._thread_lock:
+            storage = self._get_storage()
+            if key in storage:
+                return storage[key]
+            else:
+                raise AttributeError("%r object has no attribute %r" % (self, key))
+
+    def __setattr__(self, key, value):
+        if key in ("_context_refs", "_thread_critical", "_thread_lock", "_attr_name"):
+            return super().__setattr__(key, value)
+        with self._thread_lock:
+            storage = self._get_storage()
+            storage[key] = value
+
+    def __delattr__(self, key):
+        with self._thread_lock:
+            storage = self._get_storage()
+            if key in storage:
+                del storage[key]
+            else:
+                raise AttributeError("%r object has no attribute %r" % (self, key))

venv/lib/python3.8/site-packages/asgiref/server.py

@@ -0,0 +1,154 @@
+import asyncio
+import logging
+import time
+import traceback
+
+logger = logging.getLogger(__name__)
+
+
+class StatelessServer:
+    """
+    Base server class that handles basic concepts like application instance
+    creation/pooling, exception handling, and similar, for stateless protocols
+    (i.e. ones without actual incoming connections to the process)
+
+    Your code should override the handle() method, doing whatever it needs to,
+    and calling get_or_create_application_instance with a unique `scope_id`
+    and `scope` for the scope it wants to get.
+
+    If an application instance is found with the same `scope_id`, you are
+    given its input queue, otherwise one is made for you with the scope provided
+    and you are given that fresh new input queue. Either way, you should do
+    something like:
+
+    input_queue = self.get_or_create_application_instance(
+        "user-123456",
+        {"type": "testprotocol", "user_id": "123456", "username": "andrew"},
+    )
+    input_queue.put_nowait(message)
+
+    If you try and create an application instance and there are already
+    `max_application` instances, the oldest/least recently used one will be
+    reclaimed and shut down to make space.
+
+    Application coroutines that error will be found periodically (every 100ms
+    by default) and have their exceptions printed to the console. Override
+    application_exception() if you want to do more when this happens.
+
+    If you override run(), make sure you handle things like launching the
+    application checker.
+    """
+
+    application_checker_interval = 0.1
+
+    def __init__(self, application, max_applications=1000):
+        # Parameters
+        self.application = application
+        self.max_applications = max_applications
+        # Initialisation
+        self.application_instances = {}
+
+    ### Mainloop and handling
+
+    def run(self):
+        """
+        Runs the asyncio event loop with our handler loop.
+        """
+        event_loop = asyncio.get_event_loop()
+        asyncio.ensure_future(self.application_checker())
+        try:
+            event_loop.run_until_complete(self.handle())
+        except KeyboardInterrupt:
+            logger.info("Exiting due to Ctrl-C/interrupt")
+
+    async def handle(self):
+        raise NotImplementedError("You must implement handle()")
+
+    async def application_send(self, scope, message):
+        """
+        Receives outbound sends from applications and handles them.
+        """
+        raise NotImplementedError("You must implement application_send()")
+
+    ### Application instance management
+
+    def get_or_create_application_instance(self, scope_id, scope):
+        """
+        Creates an application instance and returns its queue.
+        """
+        if scope_id in self.application_instances:
+            self.application_instances[scope_id]["last_used"] = time.time()
+            return self.application_instances[scope_id]["input_queue"]
+        # See if we need to delete an old one
+        while len(self.application_instances) > self.max_applications:
+            self.delete_oldest_application_instance()
+        # Make an instance of the application
+        input_queue = asyncio.Queue()
+        application_instance = self.application(scope=scope)
+        # Run it, and stash the future for later checking
+        future = asyncio.ensure_future(
+            application_instance(
+                receive=input_queue.get,
+                send=lambda message: self.application_send(scope, message),
+            )
+        )
+        self.application_instances[scope_id] = {
+            "input_queue": input_queue,
+            "future": future,
+            "scope": scope,
+            "last_used": time.time(),
+        }
+        return input_queue
+
+    def delete_oldest_application_instance(self):
+        """
+        Finds and deletes the oldest application instance
+        """
+        oldest_time = min(
+            details["last_used"] for details in self.application_instances.values()
+        )
+        for scope_id, details in self.application_instances.items():
+            if details["last_used"] == oldest_time:
+                self.delete_application_instance(scope_id)
+                # Return to make sure we only delete one in case two have
+                # the same oldest time
+                return
+
+    def delete_application_instance(self, scope_id):
+        """
+        Removes an application instance (makes sure its task is stopped,
+        then removes it from the current set)
+        """
+        details = self.application_instances[scope_id]
+        del self.application_instances[scope_id]
+        if not details["future"].done():
+            details["future"].cancel()
+
+    async def application_checker(self):
+        """
+        Goes through the set of current application instance Futures and cleans up
+        any that are done/prints exceptions for any that errored.
+        """
+        while True:
+            await asyncio.sleep(self.application_checker_interval)
+            for scope_id, details in list(self.application_instances.items()):
+                if details["future"].done():
+                    exception = details["future"].exception()
+                    if exception:
+                        await self.application_exception(exception, details)
+                    try:
+                        del self.application_instances[scope_id]
+                    except KeyError:
+                        # Exception handling might have already got here before us. That's fine.
+                        pass
+
+    async def application_exception(self, exception, application_details):
+        """
+        Called whenever an application coroutine has an exception.
+        """
+        logging.error(
+            "Exception inside application: %s\n%s%s",
+            exception,
+            "".join(traceback.format_tb(exception.__traceback__)),
+            "  {}".format(exception),
+        )

venv/lib/python3.8/site-packages/asgiref/sync.py

@@ -0,0 +1,341 @@
+import asyncio
+import asyncio.coroutines
+import functools
+import os
+import sys
+import threading
+from concurrent.futures import Future, ThreadPoolExecutor
+
+from .current_thread_executor import CurrentThreadExecutor
+from .local import Local
+
+try:
+    import contextvars  # Python 3.7+ only.
+except ImportError:
+    contextvars = None
+
+
+class AsyncToSync:
+    """
+    Utility class which turns an awaitable that only works on the thread with
+    the event loop into a synchronous callable that works in a subthread.
+
+    If the call stack contains an async loop, the code runs there.
+    Otherwise, the code runs in a new loop in a new thread.
+
+    Either way, this thread then pauses and waits to run any thread_sensitive
+    code called from further down the call stack using SyncToAsync, before
+    finally exiting once the async task returns.
+    """
+
+    # Maps launched Tasks to the threads that launched them (for locals impl)
+    launch_map = {}
+
+    # Keeps track of which CurrentThreadExecutor to use. This uses an asgiref
+    # Local, not a threadlocal, so that tasks can work out what their parent used.
+    executors = Local()
+
+    def __init__(self, awaitable, force_new_loop=False):
+        self.awaitable = awaitable
+        try:
+            self.__self__ = self.awaitable.__self__
+        except AttributeError:
+            pass
+        if force_new_loop:
+            # They have asked that we always run in a new sub-loop.
+            self.main_event_loop = None
+        else:
+            try:
+                self.main_event_loop = asyncio.get_event_loop()
+            except RuntimeError:
+                # There's no event loop in this thread. Look for the threadlocal if
+                # we're inside SyncToAsync
+                self.main_event_loop = getattr(
+                    SyncToAsync.threadlocal, "main_event_loop", None
+                )
+
+    def __call__(self, *args, **kwargs):
+        # You can't call AsyncToSync from a thread with a running event loop
+        try:
+            event_loop = asyncio.get_event_loop()
+        except RuntimeError:
+            pass
+        else:
+            if event_loop.is_running():
+                raise RuntimeError(
+                    "You cannot use AsyncToSync in the same thread as an async event loop - "
+                    "just await the async function directly."
+                )
+        # Make a future for the return information
+        call_result = Future()
+        # Get the source thread
+        source_thread = threading.current_thread()
+        # Make a CurrentThreadExecutor we'll use to idle in this thread - we
+        # need one for every sync frame, even if there's one above us in the
+        # same thread.
+        if hasattr(self.executors, "current"):
+            old_current_executor = self.executors.current
+        else:
+            old_current_executor = None
+        current_executor = CurrentThreadExecutor()
+        self.executors.current = current_executor
+        # Use call_soon_threadsafe to schedule a synchronous callback on the
+        # main event loop's thread if it's there, otherwise make a new loop
+        # in this thread.
+        try:
+            if not (self.main_event_loop and self.main_event_loop.is_running()):
+                # Make our own event loop - in a new thread - and run inside that.
+                loop = asyncio.new_event_loop()
+                loop_executor = ThreadPoolExecutor(max_workers=1)
+                loop_future = loop_executor.submit(
+                    self._run_event_loop,
+                    loop,
+                    self.main_wrap(
+                        args, kwargs, call_result, source_thread, sys.exc_info()
+                    ),
+                )
+                if current_executor:
+                    # Run the CurrentThreadExecutor until the future is done
+                    current_executor.run_until_future(loop_future)
+                # Wait for future and/or allow for exception propagation
+                loop_future.result()
+            else:
+                # Call it inside the existing loop
+                self.main_event_loop.call_soon_threadsafe(
+                    self.main_event_loop.create_task,
+                    self.main_wrap(
+                        args, kwargs, call_result, source_thread, sys.exc_info()
+                    ),
+                )
+                if current_executor:
+                    # Run the CurrentThreadExecutor until the future is done
+                    current_executor.run_until_future(call_result)
+        finally:
+            # Clean up any executor we were running
+            if hasattr(self.executors, "current"):
+                del self.executors.current
+            if old_current_executor:
+                self.executors.current = old_current_executor
+        # Wait for results from the future.
+        return call_result.result()
+
+    def _run_event_loop(self, loop, coro):
+        """
+        Runs the given event loop (designed to be called in a thread).
+        """
+        asyncio.set_event_loop(loop)
+        try:
+            loop.run_until_complete(coro)
+        finally:
+            try:
+                # mimic asyncio.run() behavior
+                # cancel unexhausted async generators
+                if sys.version_info >= (3, 7, 0):
+                    tasks = asyncio.all_tasks(loop)
+                else:
+                    tasks = asyncio.Task.all_tasks(loop)
+                for task in tasks:
+                    task.cancel()
+                loop.run_until_complete(asyncio.gather(*tasks, return_exceptions=True))
+                for task in tasks:
+                    if task.cancelled():
+                        continue
+                    if task.exception() is not None:
+                        loop.call_exception_handler(
+                            {
+                                "message": "unhandled exception during loop shutdown",
+                                "exception": task.exception(),
+                                "task": task,
+                            }
+                        )
+                if hasattr(loop, "shutdown_asyncgens"):
+                    loop.run_until_complete(loop.shutdown_asyncgens())
+            finally:
+                loop.close()
+                asyncio.set_event_loop(self.main_event_loop)
+
+    def __get__(self, parent, objtype):
+        """
+        Include self for methods
+        """
+        func = functools.partial(self.__call__, parent)
+        return functools.update_wrapper(func, self.awaitable)
+
+    async def main_wrap(self, args, kwargs, call_result, source_thread, exc_info):
+        """
+        Wraps the awaitable with something that puts the result into the
+        result/exception future.
+        """
+        current_task = SyncToAsync.get_current_task()
+        self.launch_map[current_task] = source_thread
+        try:
+            # If we have an exception, run the function inside the except block
+            # after raising it so exc_info is correctly populated.
+            if exc_info[1]:
+                try:
+                    raise exc_info[1]
+                except:
+                    result = await self.awaitable(*args, **kwargs)
+            else:
+                result = await self.awaitable(*args, **kwargs)
+        except Exception as e:
+            call_result.set_exception(e)
+        else:
+            call_result.set_result(result)
+        finally:
+            del self.launch_map[current_task]
+
+
+class SyncToAsync:
+    """
+    Utility class which turns a synchronous callable into an awaitable that
+    runs in a threadpool. It also sets a threadlocal inside the thread so
+    calls to AsyncToSync can escape it.
+
+    If thread_sensitive is passed, the code will run in the same thread as any
+    outer code. This is needed for underlying Python code that is not
+    threadsafe (for example, code which handles SQLite database connections).
+
+    If the outermost program is async (i.e. SyncToAsync is outermost), then
+    this will be a dedicated single sub-thread that all sync code runs in,
+    one after the other. If the outermost program is sync (i.e. AsyncToSync is
+    outermost), this will just be the main thread. This is achieved by idling
+    with a CurrentThreadExecutor while AsyncToSync is blocking its sync parent,
+    rather than just blocking.
+    """
+
+    # If they've set ASGI_THREADS, update the default asyncio executor for now
+    if "ASGI_THREADS" in os.environ:
+        loop = asyncio.get_event_loop()
+        loop.set_default_executor(
+            ThreadPoolExecutor(max_workers=int(os.environ["ASGI_THREADS"]))
+        )
+
+    # Maps launched threads to the coroutines that spawned them
+    launch_map = {}
+
+    # Storage for main event loop references
+    threadlocal = threading.local()
+
+    # Single-thread executor for thread-sensitive code
+    single_thread_executor = ThreadPoolExecutor(max_workers=1)
+
+    def __init__(self, func, thread_sensitive=False):
+        self.func = func
+        functools.update_wrapper(self, func)
+        self._thread_sensitive = thread_sensitive
+        self._is_coroutine = asyncio.coroutines._is_coroutine
+        try:
+            self.__self__ = func.__self__
+        except AttributeError:
+            pass
+
+    async def __call__(self, *args, **kwargs):
+        loop = asyncio.get_event_loop()
+
+        # Work out what thread to run the code in
+        if self._thread_sensitive:
+            if hasattr(AsyncToSync.executors, "current"):
+                # If we have a parent sync thread above somewhere, use that
+                executor = AsyncToSync.executors.current
+            else:
+                # Otherwise, we run it in a fixed single thread
+                executor = self.single_thread_executor
+        else:
+            executor = None  # Use default
+
+        if contextvars is not None:
+            context = contextvars.copy_context()
+            child = functools.partial(self.func, *args, **kwargs)
+            func = context.run
+            args = (child,)
+            kwargs = {}
+        else:
+            func = self.func
+
+        # Run the code in the right thread
+        future = loop.run_in_executor(
+            executor,
+            functools.partial(
+                self.thread_handler,
+                loop,
+                self.get_current_task(),
+                sys.exc_info(),
+                func,
+                *args,
+                **kwargs
+            ),
+        )
+        ret = await asyncio.wait_for(future, timeout=None)
+
+        if contextvars is not None:
+            # Check for changes in contextvars, and set them to the current
+            # context for downstream consumers
+            for cvar in context:
+                try:
+                    if cvar.get() != context.get(cvar):
+                        cvar.set(context.get(cvar))
+                except LookupError:
+                    cvar.set(context.get(cvar))
+
+        return ret
+
+    def __get__(self, parent, objtype):
+        """
+        Include self for methods
+        """
+        return functools.partial(self.__call__, parent)
+
+    def thread_handler(self, loop, source_task, exc_info, func, *args, **kwargs):
+        """
+        Wraps the sync application with exception handling.
+        """
+        # Set the threadlocal for AsyncToSync
+        self.threadlocal.main_event_loop = loop
+        # Set the task mapping (used for the locals module)
+        current_thread = threading.current_thread()
+        if AsyncToSync.launch_map.get(source_task) == current_thread:
+            # Our parent task was launched from this same thread, so don't make
+            # a launch map entry - let it shortcut over us! (and stop infinite loops)
+            parent_set = False
+        else:
+            self.launch_map[current_thread] = source_task
+            parent_set = True
+        # Run the function
+        try:
+            # If we have an exception, run the function inside the except block
+            # after raising it so exc_info is correctly populated.
+            if exc_info[1]:
+                try:
+                    raise exc_info[1]
+                except:
+                    return func(*args, **kwargs)
+            else:
+                return func(*args, **kwargs)
+        finally:
+            # Only delete the launch_map parent if we set it, otherwise it is
+            # from someone else.
+            if parent_set:
+                del self.launch_map[current_thread]
+
+    @staticmethod
+    def get_current_task():
+        """
+        Cross-version implementation of asyncio.current_task()
+
+        Returns None if there is no task.
+        """
+        try:
+            if hasattr(asyncio, "current_task"):
+                # Python 3.7 and up
+                return asyncio.current_task()
+            else:
+                # Python 3.6
+                return asyncio.Task.current_task()
+        except RuntimeError:
+            return None
+
+
+# Lowercase is more sensible for most things
+sync_to_async = SyncToAsync
+async_to_sync = AsyncToSync

venv/lib/python3.8/site-packages/asgiref/testing.py

@@ -0,0 +1,97 @@
+import asyncio
+import time
+
+from .compatibility import guarantee_single_callable
+from .timeout import timeout as async_timeout
+
+
+class ApplicationCommunicator:
+    """
+    Runs an ASGI application in a test mode, allowing sending of
+    messages to it and retrieval of messages it sends.
+    """
+
+    def __init__(self, application, scope):
+        self.application = guarantee_single_callable(application)
+        self.scope = scope
+        self.input_queue = asyncio.Queue()
+        self.output_queue = asyncio.Queue()
+        self.future = asyncio.ensure_future(
+            self.application(scope, self.input_queue.get, self.output_queue.put)
+        )
+
+    async def wait(self, timeout=1):
+        """
+        Waits for the application to stop itself and returns any exceptions.
+        """
+        try:
+            async with async_timeout(timeout):
+                try:
+                    await self.future
+                    self.future.result()
+                except asyncio.CancelledError:
+                    pass
+        finally:
+            if not self.future.done():
+                self.future.cancel()
+                try:
+                    await self.future
+                except asyncio.CancelledError:
+                    pass
+
+    def stop(self, exceptions=True):
+        if not self.future.done():
+            self.future.cancel()
+        elif exceptions:
+            # Give a chance to raise any exceptions
+            self.future.result()
+
+    def __del__(self):
+        # Clean up on deletion
+        try:
+            self.stop(exceptions=False)
+        except RuntimeError:
+            # Event loop already stopped
+            pass
+
+    async def send_input(self, message):
+        """
+        Sends a single message to the application
+        """
+        # Give it the message
+        await self.input_queue.put(message)
+
+    async def receive_output(self, timeout=1):
+        """
+        Receives a single message from the application, with optional timeout.
+        """
+        # Make sure there's not an exception to raise from the task
+        if self.future.done():
+            self.future.result()
+        # Wait and receive the message
+        try:
+            async with async_timeout(timeout):
+                return await self.output_queue.get()
+        except asyncio.TimeoutError as e:
+            # See if we have another error to raise inside
+            if self.future.done():
+                self.future.result()
+            else:
+                self.future.cancel()
+                try:
+                    await self.future
+                except asyncio.CancelledError:
+                    pass
+            raise e
+
+    async def receive_nothing(self, timeout=0.1, interval=0.01):
+        """
+        Checks that there is no message to receive in the given time.
+        """
+        # `interval` has precedence over `timeout`
+        start = time.monotonic()
+        while time.monotonic() - start < timeout:
+            if not self.output_queue.empty():
+                return False
+            await asyncio.sleep(interval)
+        return self.output_queue.empty()

venv/lib/python3.8/site-packages/asgiref/timeout.py

@@ -0,0 +1,128 @@
+# This code is originally sourced from the aio-libs project "async_timeout",
+# under the Apache 2.0 license. You may see the original project at
+# https://github.com/aio-libs/async-timeout
+
+# It is vendored here to reduce chain-dependencies on this library, and
+# modified slightly to remove some features we don't use.
+
+
+import asyncio
+import sys
+from types import TracebackType
+from typing import Any, Optional, Type  # noqa
+
+PY_37 = sys.version_info >= (3, 7)
+
+
+class timeout:
+    """timeout context manager.
+
+    Useful in cases when you want to apply timeout logic around block
+    of code or in cases when asyncio.wait_for is not suitable. For example:
+
+    >>> with timeout(0.001):
+    ...     async with aiohttp.get('https://github.com') as r:
+    ...         await r.text()
+
+
+    timeout - value in seconds or None to disable timeout logic
+    loop - asyncio compatible event loop
+    """
+
+    def __init__(
+        self,
+        timeout: Optional[float],
+        *,
+        loop: Optional[asyncio.AbstractEventLoop] = None
+    ) -> None:
+        self._timeout = timeout
+        if loop is None:
+            loop = asyncio.get_event_loop()
+        self._loop = loop
+        self._task = None  # type: Optional[asyncio.Task[Any]]
+        self._cancelled = False
+        self._cancel_handler = None  # type: Optional[asyncio.Handle]
+        self._cancel_at = None  # type: Optional[float]
+
+    def __enter__(self) -> "timeout":
+        return self._do_enter()
+
+    def __exit__(
+        self,
+        exc_type: Type[BaseException],
+        exc_val: BaseException,
+        exc_tb: TracebackType,
+    ) -> Optional[bool]:
+        self._do_exit(exc_type)
+        return None
+
+    async def __aenter__(self) -> "timeout":
+        return self._do_enter()
+
+    async def __aexit__(
+        self,
+        exc_type: Type[BaseException],
+        exc_val: BaseException,
+        exc_tb: TracebackType,
+    ) -> None:
+        self._do_exit(exc_type)
+
+    @property
+    def expired(self) -> bool:
+        return self._cancelled
+
+    @property
+    def remaining(self) -> Optional[float]:
+        if self._cancel_at is not None:
+            return max(self._cancel_at - self._loop.time(), 0.0)
+        else:
+            return None
+
+    def _do_enter(self) -> "timeout":
+        # Support Tornado 5- without timeout
+        # Details: https://github.com/python/asyncio/issues/392
+        if self._timeout is None:
+            return self
+
+        self._task = current_task(self._loop)
+        if self._task is None:
+            raise RuntimeError(
+                "Timeout context manager should be used " "inside a task"
+            )
+
+        if self._timeout <= 0:
+            self._loop.call_soon(self._cancel_task)
+            return self
+
+        self._cancel_at = self._loop.time() + self._timeout
+        self._cancel_handler = self._loop.call_at(self._cancel_at, self._cancel_task)
+        return self
+
+    def _do_exit(self, exc_type: Type[BaseException]) -> None:
+        if exc_type is asyncio.CancelledError and self._cancelled:
+            self._cancel_handler = None
+            self._task = None
+            raise asyncio.TimeoutError
+        if self._timeout is not None and self._cancel_handler is not None:
+            self._cancel_handler.cancel()
+            self._cancel_handler = None
+        self._task = None
+        return None
+
+    def _cancel_task(self) -> None:
+        if self._task is not None:
+            self._task.cancel()
+            self._cancelled = True
+
+
+def current_task(loop: asyncio.AbstractEventLoop) -> "asyncio.Task[Any]":
+    if PY_37:
+        task = asyncio.current_task(loop=loop)  # type: ignore
+    else:
+        task = asyncio.Task.current_task(loop=loop)
+    if task is None:
+        # this should be removed, tokio must use register_task and family API
+        if hasattr(loop, "current_task"):
+            task = loop.current_task()  # type: ignore
+
+    return task

venv/lib/python3.8/site-packages/asgiref/wsgi.py

@@ -0,0 +1,145 @@
+from io import BytesIO
+from tempfile import SpooledTemporaryFile
+
+from asgiref.sync import AsyncToSync, sync_to_async
+
+
+class WsgiToAsgi:
+    """
+    Wraps a WSGI application to make it into an ASGI application.
+    """
+
+    def __init__(self, wsgi_application):
+        self.wsgi_application = wsgi_application
+
+    async def __call__(self, scope, receive, send):
+        """
+        ASGI application instantiation point.
+        We return a new WsgiToAsgiInstance here with the WSGI app
+        and the scope, ready to respond when it is __call__ed.
+        """
+        await WsgiToAsgiInstance(self.wsgi_application)(scope, receive, send)
+
+
+class WsgiToAsgiInstance:
+    """
+    Per-socket instance of a wrapped WSGI application
+    """
+
+    def __init__(self, wsgi_application):
+        self.wsgi_application = wsgi_application
+        self.response_started = False
+
+    async def __call__(self, scope, receive, send):
+        if scope["type"] != "http":
+            raise ValueError("WSGI wrapper received a non-HTTP scope")
+        self.scope = scope
+        with SpooledTemporaryFile(max_size=65536) as body:
+            # Alright, wait for the http.request messages
+            while True:
+                message = await receive()
+                if message["type"] != "http.request":
+                    raise ValueError("WSGI wrapper received a non-HTTP-request message")
+                body.write(message.get("body", b""))
+                if not message.get("more_body"):
+                    break
+            body.seek(0)
+            # Wrap send so it can be called from the subthread
+            self.sync_send = AsyncToSync(send)
+            # Call the WSGI app
+            await self.run_wsgi_app(body)
+
+    def build_environ(self, scope, body):
+        """
+        Builds a scope and request body into a WSGI environ object.
+        """
+        environ = {
+            "REQUEST_METHOD": scope["method"],
+            "SCRIPT_NAME": scope.get("root_path", ""),
+            "PATH_INFO": scope["path"],
+            "QUERY_STRING": scope["query_string"].decode("ascii"),
+            "SERVER_PROTOCOL": "HTTP/%s" % scope["http_version"],
+            "wsgi.version": (1, 0),
+            "wsgi.url_scheme": scope.get("scheme", "http"),
+            "wsgi.input": body,
+            "wsgi.errors": BytesIO(),
+            "wsgi.multithread": True,
+            "wsgi.multiprocess": True,
+            "wsgi.run_once": False,
+        }
+        # Get server name and port - required in WSGI, not in ASGI
+        if "server" in scope:
+            environ["SERVER_NAME"] = scope["server"][0]
+            environ["SERVER_PORT"] = str(scope["server"][1])
+        else:
+            environ["SERVER_NAME"] = "localhost"
+            environ["SERVER_PORT"] = "80"
+
+        if "client" in scope:
+            environ["REMOTE_ADDR"] = scope["client"][0]
+
+        # Go through headers and make them into environ entries
+        for name, value in self.scope.get("headers", []):
+            name = name.decode("latin1")
+            if name == "content-length":
+                corrected_name = "CONTENT_LENGTH"
+            elif name == "content-type":
+                corrected_name = "CONTENT_TYPE"
+            else:
+                corrected_name = "HTTP_%s" % name.upper().replace("-", "_")
+            # HTTPbis say only ASCII chars are allowed in headers, but we latin1 just in case
+            value = value.decode("latin1")
+            if corrected_name in environ:
+                value = environ[corrected_name] + "," + value
+            environ[corrected_name] = value
+        return environ
+
+    def start_response(self, status, response_headers, exc_info=None):
+        """
+        WSGI start_response callable.
+        """
+        # Don't allow re-calling once response has begun
+        if self.response_started:
+            raise exc_info[1].with_traceback(exc_info[2])
+        # Don't allow re-calling without exc_info
+        if hasattr(self, "response_start") and exc_info is None:
+            raise ValueError(
+                "You cannot call start_response a second time without exc_info"
+            )
+        # Extract status code
+        status_code, _ = status.split(" ", 1)
+        status_code = int(status_code)
+        # Extract headers
+        headers = [
+            (name.lower().encode("ascii"), value.encode("ascii"))
+            for name, value in response_headers
+        ]
+        # Build and send response start message.
+        self.response_start = {
+            "type": "http.response.start",
+            "status": status_code,
+            "headers": headers,
+        }
+
+    @sync_to_async
+    def run_wsgi_app(self, body):
+        """
+        Called in a subthread to run the WSGI app. We encapsulate like
+        this so that the start_response callable is called in the same thread.
+        """
+        # Translate the scope and incoming request body into a WSGI environ
+        environ = self.build_environ(self.scope, body)
+        # Run the WSGI app
+        for output in self.wsgi_application(environ, self.start_response):
+            # If this is the first response, include the response headers
+            if not self.response_started:
+                self.response_started = True
+                self.sync_send(self.response_start)
+            self.sync_send(
+                {"type": "http.response.body", "body": output, "more_body": True}
+            )
+        # Close connection
+        if not self.response_started:
+            self.response_started = True
+            self.sync_send(self.response_start)
+        self.sync_send({"type": "http.response.body"})