I’m not privy to the JavaScript language design discussions, but I assume it’s for the same reasons that the C# language requires async (also see my blog). Namely: Backwards compatibility. If await was suddenly a new keyword everywhere, then any existing code using await as a variable name would break. Since await is a contextual … Read more
Should I use AsyncController at ASP.NET MVC 4? No. Should I replace uses of AsyncController to Controller? Yes, asynchronous actions are implemented in new way in asp.net-mvc 4, using Task Class The ASP.NET MVC 4 Controller class in combination .NET 4.5 enables you to write asynchronous action methods that return an object of type Task. … 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
How interesting! It appears that Thread.CurrentPrincipal is based on the logical call context, not the per-thread call context. IMO this is quite unintuitive and I’d be curious to hear why it was implemented this way. In .NET 4.5., async methods interact with the logical call context so that it will more properly flow with async … 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
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
var t = new Task<int>(() => GetIntAsync(“3”).Result); Or var t = new Task<int>((ob) => GetIntAsync((string) ob).Result, “3”); To avoid using lambda, you need to write a static method like this: private static int GetInt(object state) { return GetIntAsync(((string) state)).Result; } And then: var t = new Task<int>(GetInt, “3”);
I think this is most likely an aiohttp bug. Specifically, I found this issue on their github: https://github.com/aio-libs/aiohttp/issues/4324 I realise this doesn’t necessarily help you, but maybe you can switch back and stop banging your head against a wall. Your code is fine!