I do not understand why it is necessary to have the async keyword before the function keyword. For the same reason that we have the * symbol before generator functions: They mark the function as extraordinary. They are quite similar in that regard – they add a visual marker that the body of this function … Read more
I’ve discovered that TaskCompletionSource.SetResult(); invokes the code awaiting the task before returning. In my case that result in a deadlock. Yes, I have a blog post documenting this (AFAIK it’s not documented on MSDN). The deadlock happens because of two things: There’s a mixture of async and blocking code (i.e., an async method is calling … Read more
Dealing with unhandled rejected native promises (and async/await uses native promises) is a feature supported now in V8. It’s used in the latest Chrome to output debugging information when a rejected promise is unhandled; try the following at the Babel REPL: async function executor() { console.log(“execute”); } async function doStuff() { console.log(“do stuff”); throw new … Read more
As long as your web.config settings are correct, async/await works perfectly well with HttpContext.Current. I recommend setting httpRuntime targetFramework to 4.5 to remove all “quirks mode” behavior. Once that is done, plain async/await will work perfectly well. You’ll only run into problems if you’re doing work on another thread or if your await code is … Read more
This code Future<List<String>> readHeaderData() async { List<String> l = new List(); List<String> files = await readHeaders(); // Gets filenames files.forEach((filename) async { final file = await File(filename); String contents = await file.readAsString(); User user = User.fromJson(json.decode(contents)); String name = user.NameLast + “, ” + user.NameFirst; print(name); l.add(name); } return l; } returns the list l … Read more
private async void RequestData(string uri, Action<string> action) { var client = new WebClient(); string data = await client.DownloadStringTaskAsync(uri); action(data); } See: http://msdn.microsoft.com/en-us/library/hh194294.aspx
Use direct __await__() call: async def new_sleep(): await asyncio.sleep(2) class Waiting: def __await__(self): return new_sleep().__await__() The solution was recommended by Yury Selivanov (the author of PEP 492) for aioodbc library
RegisterWaitForSingleObject will combine waits onto dedicated waiter threads, each of which can wait on multiple handles (specifically, 63 of them, which is MAXIMUM_WAIT_OBJECTS minus one for a “control” handle). So you should be able to use something like this (warning: untested): public static class WaitHandleExtensions { public static Task AsTask(this WaitHandle handle) { return AsTask(handle, … Read more
Here is what you may want to do: public async Task<PewPew> SomeMethod(Foo foo) { // get the stuff on another thread var cTask = Task.Run(() => GetAllTheCats(foo)); var fTask = Task.Run(() => GetAllTheFood(foo)); var cats = await cTask; var food = await fTask; return new PewPew { Cats = cats, Food = food }; } … Read more
Since all answers are missing some bits (catch blocks, checking that client is not null) I came with my own solution. Tested with Mongo server v4.0.7 and Node JS driver 3.2.2. Note that the example is a console program, where we close the connection to the server in the finally block. In a web application, … Read more