Questions tagged [async]

The tag has no usage guidance.

6
votes
1answer
236 views

Is the C# async/Task construct equivalent to Java's Executor/Future?

I'm a long time Java developer, but with so little traffic on SE, I don't limit my viewing to any single tags. I've noticed that C# questions with async/await come up a lot, and as far as I've read it'...
0
votes
1answer
125 views

Async - why have an async for a login?

C# web scaffolding has an async call for every member. Why? For example: Async for a login call makes no sense. User has to wait for validation. What else would the app do until the application ...
0
votes
2answers
81 views

How possible it is to keep web scraped data in sync at scale [closed]

I have taken a look at Google Shopping for Hakko FX888D-23BY Soldering Station, and it gives this: Notice that Walmart is $115.19 here. Meanwhile, at Walmart.com it looks like this: So it's $97.79 ...
2
votes
1answer
169 views

Must we define methods and async when we don't know whether the implementation is synchronous or asynchronous?

I think I know the answer to this, but it's particular enough that I don't want to go telling other people stuff until I'm 100% certain. Suppose I have a class with some dependency: public interface ...
0
votes
0answers
49 views

Using signalR for streaming alongside a microservice architecture

I have a cluster of micro services with an exposed search API serving a client app. I want to "stream" in real time the aggregated results of a complex search. The search will be kicked of by the ...
0
votes
0answers
29 views

Asp.Net Core: creating files in background

I have a web app with SPA client. When user requests a report, that request should create an excel or pdf file in background and notify user via SignalR. I guess I need to save that file somewhere ...
-1
votes
1answer
125 views

Does avoiding Promises and Async leads to clean code?

While applying for a job interview I found this line in requirements. Experience with clean code writing practices like avoiding callback hell like promises, async Does this line make any sense ? ...
-4
votes
2answers
66 views

Should I use async for networking application/library [closed]

I decided to make an application, networking application, don't know what it has to do yet but mainly it should be a cross-client kind of like framework networking application/library. Since ...
0
votes
3answers
154 views

If callback function, promises and async/await patterns all can be used to achieve asynchronous behaviour then why don't we stick to one?

As far as I have seen then async/await, callbacks and promises are and can only be used to achieve asynchronous programming. Correct? So my questions are: 1) Is it correct that the former three is ...
0
votes
0answers
25 views

How to provide an extension point for library that should authenticate asynchronously using WebClient?

I'm trying to design a library (nuget package) that would read data from a REST API and deserialize it to DTO objects. The API requires authentication which is usually done with Microsoft's ADAL ...
1
vote
1answer
133 views

Will (await method).ToList() block the thread? [closed]

I'm using a lot of async Task<IEnumerable<T>> methods and I want to stop doing this everytime to get the items as a list: var items = await AsyncMethodThatReturnsEnumerable(); var ...
0
votes
1answer
95 views

What does await do in JavaScript?

Sorry for this naive question. Reading some existing JavaScript I see a function with code like ... async function _load() { await ensureDir(path); return await readFile(filename); } ... why ...
1
vote
1answer
51 views

How to control multiply consoles from Java code?

I have Java application. I try to realize multiplayer chat with TCP protocol, but I have an issue. I cannot output all messages I get on client tier (server tier works perfectly), because I give ...
104
votes
5answers
11k views

Aren't the guidelines of async/await usage in C# contradicting the concepts of good architecture and abstraction layering?

This question concerns the C# language, but I expect it to cover other languages such as Java or TypeScript. Microsoft recommends best practices on using asynchronous calls in .NET. Among these ...
1
vote
2answers
100 views

Is it okay for async function to update a common object

I have a couple of functions, each function verifies a set of rules and updates a common object. The common object is just a container that holds a list of rules that passed or failed. I would like to ...
1
vote
0answers
63 views

Wrapper method for ConfigureAwait(false)?

Does it make sense to declare a async method as private and then create a public method to act as a wrapper that calls the private method with ConfigureAwait(false)? The intended purpose is design an ...
2
votes
2answers
138 views

Is it conventional to use both await and .then()?

I've written a bit of code that looks like this: async function fetchData() { const json = await fetch(ENDPOINT + key.key).then(data => data.json()); //Do something with the data } It's ...
4
votes
2answers
1k views

Who did async/await first?

Python added the async/await constructs in 3.5 in 2015. The Javascript community made steps towards it for a bazzillion years and finally added a very similar implementation to the draft in ES8 ...
2
votes
2answers
3k views

Better to block on async with HttpClient than use synchronous API like WebRequest?

I have been a staunch advocate of never blocking on async code. I felt it was always better to use a synchronous API than to run the less efficient state machine generated by the compiler even if ...
0
votes
1answer
140 views

Best approach for web service that calls other web services

The scenario is: client makes request to server A Server A makes potentially multiple requests to server B. Edit to clarify, server A makes the requests concurrently using Futures. Server A blocks ...
1
vote
4answers
703 views

Problem with async/await pattern — in C# and JavaScript — how to return sync value

In old-style await'less NodeJS, when you call a function that had an asynchronous aspect, you'd pass in the well-known callback which gets called when the asynchronous portion is done. This didn't ...
1
vote
1answer
109 views

sequential command processing with an async io cloud upsert

We are new to c# and still trying to grok the async idioms. We have a windows service that requires us to iterate a list of results queried from a PC database to feed the parse cloud server (which ...
1
vote
1answer
86 views

Design: HTTP and Websockets working together

I'm at a bit of crossroads here and I wanted to ask the opinion of the community. I am creating a chat application for our company. Now, like every chat application out there, the messages are saved ...
0
votes
1answer
97 views

How to statically check you didn't forget to await for an async function

A common bug in JavaScript is to forget the await keyword when calling an async function. Of course you don't always want to await, sometimes you really want to get a promise. And of course you can't ...
-2
votes
1answer
1k views

Check is finish async and await behavior

I am trying to understand the async and await.Now i want to apply async and await keyword in my current project.My process structure are: //DataAccess Private List<Users> GetAllUsers() { ......
1
vote
1answer
551 views

Multiple API calls potentially spawning multiple Websockets - Threading vs Async

I am designing a program with the flow as outlined below. Note, these are all network calls, there is no system I/O (hard drive). Initially, multiple independent API calls need to happen - they don'...
6
votes
1answer
187 views

Immediately awaiting an asynchronous call [duplicate]

While working on an inherited project, I noticed the original dev(s) created many asynchronous functions that never seem to take advantage of being, well, asynchronous. For example: // The async ...
3
votes
1answer
419 views

How can I reduce bloat in my callback based serial communication?

I'm communicating with a device that's connected to the computer via com port. The device accepts certain predefined commands in order to interact with it. I'm essentially creating a more abstract API ...
1
vote
0answers
161 views

Proper code structure for a Servlet using caching and async

I'm using an Java Servlet (with embedded Jetty, no Spring, no frameworks) and I'm adding asynchronous processing and caching to it. The exact implementation is irrelevant to this question and it's not ...
4
votes
2answers
1k views

Correct way to implement non blocking async methods in .net?

I've made the code below work and it is mostly non-blocking except where the process.start code is. However, my question is, in my winforms application is this the best way to implement the use of ...
1
vote
2answers
1k views

JS: convention to distinguish immediate vs async methods

I normally have a laissez faire attitude on method naming conventions but now I am working on a module in JavaScript that will have some methods that can return the value directly (immediate / plain ...
1
vote
1answer
2k views

Creating a (System.Threading.Tasks.)Task scheduler

I'm working on rearchitecting a game engine in which multiple concurrent scripts run in parallel threads, which unfortunately occasionally gives rise to race conditions. I'm trying to set it up so ...
3
votes
1answer
21k views

Correct usage of async/await and Task.Run()

I am developing an application that will read excel files from disk and then process tests based on the data in the files. In order to keep the user interface from locking up when loading files and ...
1
vote
0answers
222 views

Why are most ReactiveX implementations push-based?

Feel free to correct my history, but as far as I understand it, Rx and the Reactive Manifesto trace their roots back to C# and its Reactive Extensions, which is uses push (callback-based) messaging, ...
2
votes
1answer
634 views

Pattern for subclass overload with different arguments

I'm in the process of writing an bidirectional, asynchronous socket server and server handler. The base handler class I'm working off of is as follows: class BaseAsyncSocketHandler: async def ...
2
votes
1answer
737 views

Task Parallel Library Console Application Design - How do I lock a thread to a specific context?

I'm currently developing an application which relies on multiple sockets listening for chat messages. When the messages come in, they're passed off to a bot that's associated with their channels. ...
9
votes
2answers
10k views

What exactly happens when a thread awaits a task inside a while loop?

After dealing with C#'s async/await pattern for a while now, I suddenly came to realization that I don't really know how to explain what happens in the following code: async void MyThread() { ...
16
votes
3answers
30k views

Calling multiple async services in parallel

I have few async REST services which are not dependent on each other. That is while "awaiting" a response from Service1, I can call Service2, Service3 and so on. For example, refer below code: var ...
0
votes
1answer
2k views

Executing a periodic Task with std::async

I am writing a class which periodically has to check, if the data it manages is too old, if so it should delete it. I am new to the C++11 multithreading library and I have the following questions: ...
3
votes
1answer
2k views

Does omitting await keyword once in the call stack break the asynchronous behavior of the whole stack?

Call stack may contain several methods returning Task. If all of them are decorated with async, the flow of execution is quite simple. However, what if one of them is not awaited - are other method ...
2
votes
3answers
2k views

How to avoid pollution of logic with lazy-loaded async properties

To be able to scale I would like to use async programming. It works really well if I have to read something from db and push to frontend, however I do not know how to use it correctly in blobs of ...
20
votes
5answers
20k views

Why would you ever 'await' a method, and then immediately interrogate its return value?

In this MSDN article, the following example code is provided (slightly edited for brevity): public async Task<ActionResult> Details(int? id) { if (id == null) { return new ...
1
vote
2answers
668 views

Why are Promises not “awaited” by default?

In the latest version of languages like TypeScript or ECMAScript you can use async/await constructs to write code that combines the clean structure of synchronous programming with the performance ...
3
votes
1answer
208 views

async methods: are there any concurrency issues the programmer must address

Let's say this getPhotoAsync method can be invoked a few times a second, and that the responses from the remote server can take anywhere from half a second to thirty seconds, depending on the size of ...
0
votes
1answer
217 views

Async web server and associated 'workers' implementation

In a regular WSGI service provider implementation there is a blocking HTTP server that services clients. When a client, for example, creates an invoice, the server simply makes a CRUD operation that ...
1
vote
1answer
326 views

Need Async/Await equivalent for BackgroundWorker

Given the following code in the DoWork() event of a BackgroundWorker object, how can the concept be converted to the Async/Await model? I wish to execute multiple downloads simultaneously in order to ...
1
vote
1answer
4k views

What are the benefits of Asynchronous HTTP

Q.1 I know that when we are talking about synchronous HTTP, for each request a Thread may be spawn and get blocked, so when number of simultaneous connections increase, we will encounter massive ...
3
votes
1answer
143 views

How do async action methods maintain their network connnection?

In ASP.Net MVC, the classic (synchronous) way to write an action method is to return ActionResult. More recently, the ability to perform action methods asynchronously was added, by allowing action ...
1
vote
0answers
67 views

Downloading information, but just when needed

I'm struggling with thinking of how to implement the following (in java): I try to create a program, that displays information about lots of tv series. For this i use the website "Burning Series" (...
16
votes
2answers
5k views

Why does C# allow you to make an override async?

In C#, when you override a method, it is permitted to make the override async when the original method was not. This seems like poor form. The example that brought me to this was this — I was ...