PowerShellっぽく陸上自衛隊のイラク派遣日報をまとめてダウンロードしてみるのPowerShell非同期版

DownloadAsync.ps1

$cs = @"
using System;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;

public class Test
{
    private static HttpClient client = new HttpClient() { Timeout = TimeSpan.FromMinutes(5) };
    public static async Task DownloadASync(string[] uriStrings, string directory)
    {
        await Task.WhenAll(uriStrings.Select(x => new Uri(x))
        .Select(async x =>
        {
            var file = Path.Combine(directory, x.Segments.Last());
            using (var res = await client.GetAsync(x, HttpCompletionOption.ResponseHeadersRead))
            using (var fileStream = new FileStream(file, FileMode.OpenOrCreate))
            {
                var s = await res.Content.ReadAsStreamAsync();
                await s.CopyToAsync(fileStream);
            }
        }));
    }
}
"@
Add-Type -TypeDefinition $cs

$uris = (Invoke-WebRequest -Uri https://www.asahi.com/articles/ASL4J669JL4JUEHF016.html).Links.href |
Where {$_.EndsWith(".pdf")} |
Sort-Object -Unique
[System.Threading.Tasks.Task]::WaitsAll([Test]::DownloadASync($uris, $pwd))