C#•2y ago

❔ Are TryAsync methods acceptable?

I've just been refactoring some implementations of a method I have to go from T Load() to bool TryLoad(out T? result), which as far as I'm concerned is not an anti pattern. I was about to do the same for my Task<T> LoadAsync methods but am wondering if this is bad practice and having bool TryLoadAsync(out Task<T?> result) may have some unforeseen consequences?

8 Replies

Angius•2y ago

I mean, if it has to be async, it has to be async

Anarchist•2y ago

It doesn't have to be, I've got an ILoad and an IAsyncLoad that some classes implement both of so down the line I have the option. It also doesn't have to be a try method, but if there's no issues I think it's a good idea

Angius•2y ago

If a method doesn't do any awaiting inside... why do you want an async version of it?

Anarchist•2y ago

For context, this is the class. It's a FIleLoader where the user has the option to load a file async or synchronously.

internal class FileLoader : ILoader<string?>, IAsyncLoader<string>
{
    private readonly string _path;

    public FileLoader(string path)
    {
        _path = path;
    }

    public bool TryLoad(out string? data)
    {
        return TryDoLoad(path => File.ReadAllText(path), out data);
    }

    public bool TryLoadAsync(out Task<string>? data)
    {
        return TryDoLoad(path => File.ReadAllTextAsync(path), out data);
    }

    // Used so reading can optionally be async whilst reusing the rest DoLoad
    private delegate T ReadFileFunc<out T>(string path);

    private bool TryDoLoad<T>(ReadFileFunc<T?> read, out T? data)
    {
        data = default;
        try
        {
            data = read.Invoke(_path);
            return true;
        }
        catch (FileNotFoundException ex)
        {
            Console.WriteLine($"Could not find file at {_path}");
            Console.WriteLine(ex);
        }
        catch (IOException ex)
        {
            Console.WriteLine($"Failed to read file at {_path}");
            Console.WriteLine(ex);
        }

        return false;
    }
}

internal class FileLoader : ILoader<string?>, IAsyncLoader<string>
{
    private readonly string _path;

    public FileLoader(string path)
    {
        _path = path;
    }

    public bool TryLoad(out string? data)
    {
        return TryDoLoad(path => File.ReadAllText(path), out data);
    }

    public bool TryLoadAsync(out Task<string>? data)
    {
        return TryDoLoad(path => File.ReadAllTextAsync(path), out data);
    }

    // Used so reading can optionally be async whilst reusing the rest DoLoad
    private delegate T ReadFileFunc<out T>(string path);

    private bool TryDoLoad<T>(ReadFileFunc<T?> read, out T? data)
    {
        data = default;
        try
        {
            data = read.Invoke(_path);
            return true;
        }
        catch (FileNotFoundException ex)
        {
            Console.WriteLine($"Could not find file at {_path}");
            Console.WriteLine(ex);
        }
        catch (IOException ex)
        {
            Console.WriteLine($"Failed to read file at {_path}");
            Console.WriteLine(ex);
        }

        return false;
    }
}

Sossenbinder•2y ago

Try...Async usually breaks once you realize that ref, in and out parameters are not allowed for async methods

Angius•2y ago

Also, not sure how it would work with this delegate That sometimes is async, sometimes isn't

Anarchist•2y ago

Hmm yeah perhaps this is too problematic, I might just drop the async approach since atm it's a single threaded console app

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Are TryAsync methods acceptable?