Initial version

DataTransfer.Client/Services/BotCheckSolver.cs

@@ -0,0 +1,21 @@
+using DataTransfer.Client.Shared;
+using Microsoft.AspNetCore.Components;
+using Microsoft.JSInterop;
+
+namespace DataTransfer.Client.Services;
+
+/// <summary>Solves the server's proof-of-work bot check in web workers (<c>wwwroot/js/bot-check.js</c> of the server).</summary>
+public sealed class BotCheckSolver(IJSRuntime js, NavigationManager navigation)
+{
+    /// <returns>The solution, or <c>-1</c> if none was found.</returns>
+    public async Task<int> SolveAsync(BotCheckChallenge challenge)
+    {
+        ArgumentNullException.ThrowIfNull(challenge);
+
+        // An absolute URL, so the module resolves relative to the app's base URI under any path base.
+        await using var module = await js.InvokeAsync<IJSObjectReference>(
+            "import",
+            navigation.ToAbsoluteUri("js/bot-check.js").ToString());
+        return await module.InvokeAsync<int>("solve", challenge.Salt, challenge.Hash, challenge.MaxNumber);
+    }
+}