asynchronous

问题 I'm wrapping my dynamoDB function into another function and I'm having issues with returning it to the "item" const. What I'm missing here? Works: const params = { TableName: table, Key: { id: id }, }; dynamoDb.get(params, (error, result) => { if (error) { console.error(error); callback(null, { statusCode: error.statusCode || 501, body: 'Couldn\'t fetch the item.', }); return; } const item = result.Item }) Doesn't work (returns undefinied): const getFromDb = () => { const params = { TableName

问题 I'm writing an API in Flask with 1000+ requests to get data and I'd like to limit the number of requests per second. I tried with: conn = aiohttp.TCPConnector(limit_per_host=20) and conn = aiohttp.TCPConnector(limit=20) But is seems doesn't work My code looks like this: import logging import asyncio import aiohttp logging.basicConfig(filename="logfilename.log", level=logging.INFO, format='%(asctime)s %(levelname)s:%(message)s') async def fetch(session, url): async with session.get(url,

问题 If I have the following code new Promise(res => res(1)) .then(val => console.log(val)) is this equivalent to let val = await new Promise(res => res(1)) console.log(val) I know one difference is that I have to wrap the second one in an async function, but otherwise are they equivalent? 回答1: Because your promise always resolves (never rejects), they are equivalent. You could also do: Promise.resolve(1).then(val => console.log(val)); Keep in mind that a major difference with await (besides it

问题 If I have the following code new Promise(res => res(1)) .then(val => console.log(val)) is this equivalent to let val = await new Promise(res => res(1)) console.log(val) I know one difference is that I have to wrap the second one in an async function, but otherwise are they equivalent? 回答1: Because your promise always resolves (never rejects), they are equivalent. You could also do: Promise.resolve(1).then(val => console.log(val)); Keep in mind that a major difference with await (besides it

问题 I have a background service in Xamarin Android but the problem is I cannot use it as Async method, it gives an error. return type must be 'StartCommandResult' to match overridden member 'Service.OnStartCommand(Intent, StartCommandFlags, int) The actual overridden method is void but to use await I have to change it to async Task<T> and then it produces the error. I searched everywhere but couldn't find a proper solution on this. The code snippet for entire class is here: { [Service

问题 I'm using some Promise() functions to fetch some data and I got stuck with this problem on a project. example1 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo1'); }, 3000); }); example2 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo2'); }, 3000); }); doStuff = () => { const listExample = ['a','b','c']; let s = ""; listExample.forEach((item,index) => { console.log(item); example1().then(() => { console.log("Fisrt"); s =

问题 I'm using some Promise() functions to fetch some data and I got stuck with this problem on a project. example1 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo1'); }, 3000); }); example2 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo2'); }, 3000); }); doStuff = () => { const listExample = ['a','b','c']; let s = ""; listExample.forEach((item,index) => { console.log(item); example1().then(() => { console.log("Fisrt"); s =

问题 This question already has an answer here : How do I create a scheduler which never executes more than one Task at a time using async-await? (1 answer) Closed 14 days ago . I had to ask since I cannot found the same way as UI BeginInvoke asynchronous done. My sample program running on Winforms and all the delegate method is calling in the main UI thread. I have log the status and found it run on same thread on different BeginInvoke . Log from Winforms UI: 13/01/2021 11:57:23

问题 So I'm working on a project that involves a LCD screen that can update 60 times per second. It uses a BitmapFrame and I need to copy those pixels to a library that updates the screen. Currently I'm getting about 30-35 FPS which is too low. So I'm trying to use multi-threading but this creates a lot of problems. The DisplayController already creates a thead to do all the work on like so: public void Start() { _looper = new Thread(Loop); _looper.IsBackground = true; _looper.Start(); } private

问题 Source code: https://think-async.com/Asio/asio-1.18.0/doc/asio/tutorial/tutdaytime7/src.html tcp_server shows an intention to use socket on the heap, wrapped by a type called tcp_connection. class tcp_server { private: void start_accept() { tcp_connection::pointer new_connection = tcp_connection::create(io_context_); acceptor_.async_accept(new_connection->socket(), boost::bind(&tcp_server::handle_accept, this, new_connection, asio::placeholders::error)); } void handle_accept(tcp_connection: