On Wednesday, 6 July 2022 at 09:26:35 UTC, Bagomot wrote:
Hello! I have a few questions about multithreading, asynchrony
and how it works with the GUI.
1) How to make asynchronous HTTP requests with curl in order to
receive progress and status? And how do you know that the
request is completed? This question is related to the next one,
so it should be answered in the context of working with the GUI.
2) How to get and update information in the GUI (I use dlangui)
about the execution of an asynchronous http request (for
example, downloading a file)? Something like a progress bar.
3) My application must perform some work in a separate thread
(I do this through inheritance of the worker from
core.thread.Thread, is that correct?). I need to be able to
manage data in the GUI from this thread without blocking GUI. I
found that you can use RunnableEvent for dlangui, but I can’t
figure out how to do it (and I didn’t find any examples). Could
you suggest how to do it?
Sorry if the questions here are a bit from different topics,
but they are all related to dlangui.
I can't say anything about making asynchronous requests, but in
dlangui simply updating any of the properties should cause a
redraw. This means, if you set a new value to a progress bar,
there isn't much else to do. Ideally, your library will provide a
callback in which you can update anything you need.
If you don't receive a callback from your requests lib, you can
poll it using timers in dlangui. For that you'd need to subclass
any widget and override the `onTimer` method:
```d
class CustomCanvas : CanvasWidget
{
this(string ID = null)
{
super(ID);
}
override bool onTimer(ulong id)
{
window.showMessageBox("OnTimer"d, "OnTimer"d);
return true;
}
}
```
And then set a timer in your code somewhere
```d
auto window = ...
auto canvas = new CustomCanvas("canvas");
window.setTimer(canvas, 1000); // will call onTimer every 1000ms
```
