在 Unity 中使用 WebClient 下载文件时遇到问题

Question

So I am having a big issue when coding for Unity. I am very new to C# and so have used examples I have found online to make this code. My only issue is there are no errors popping up but it won't download the file properly.

I am using this code so that it will be easy for my users to import unitypackages they would use often. I have a button that works as intended, it shows download and then changes to import if the file exists. However, if I click it when it says download it will instantly say "Download Complete" and the file won't show up for a few minutes. When it finally does the file is 0KB in size.

I really need help figured out why my file isn't downloading properly. I am super stumped.

This code is the script for the WebClient.

using UnityEngine;
using System.IO;
using System.Net;
using System;
using System.ComponentModel;
using UnityEditor;      

namespace SentinelsSDK
{
public class SentinelsSDK_ImportManager
{
    private static string localPath = "Assets/VRCSDK/Dependencies/VRChat/Imports/";
    private static string localDownloadPath = "Assets/VRCSDK/Dependencies/VRChat/Imports/";
    private static string urlStart = "https://www.sentinels.xyz/uploads/2/0/9/0/20909832/";

    public static void DownloadAndImportAssetFromServer(string assetName)
    {
        if (File.Exists(localDownloadPath + assetName))
        {
            sentLog(assetName + " exists. Importing it..");
            importDownloadedAsset(assetName);
        }
        else
        {
            sentLog(assetName + " does not exist. Starting download..");
            downloadFile(assetName);
        }
    }

    private static void downloadFile(string assetName)
    {
        WebClient w = new WebClient();
        w.Headers.Set(HttpRequestHeader.UserAgent, "Webkit Gecko wHTTPS (Keep Alive 55)");
        w.QueryString.Add("assetName", assetName);
        w.DownloadFileCompleted += fileDownloadCompleted;
        w.DownloadProgressChanged += fileDownloadProgress;
        string url = urlStart + assetName;
        w.DownloadFileAsync(new Uri(url), localDownloadPath + assetName);
    }

    private static void fileDownloadCompleted(object sender, AsyncCompletedEventArgs e)
    {
        string assetName = ((WebClient)(sender)).QueryString["assetName"];
        sentLog("Download of file " + assetName + " completed!");
    }

    private static void fileDownloadProgress(object sender, DownloadProgressChangedEventArgs e)
    {
        sentLog("Progress is at " + e.ProgressPercentage.ToString() + "%");
    }

    private static void sentLog(string message)
    {
        Debug.Log("[SentinelsSDK] AssetDownloader: " + message);
    }

    public static void importAsset(string assetName)
    {
        AssetDatabase.ImportPackage(localPath + assetName, true);
    }

    public static void importDownloadedAsset(string assetName)
    {
        AssetDatabase.ImportPackage(localDownloadPath + assetName, true);
    }
}

}

This code is the button calling the download from my other script.

using SentinelsSDK;
    ...
    private static string localDownloadPath = "Assets/VRCSDK/Dependencies/VRChat/Imports/";
    ...
    GUILayout.BeginHorizontal();
    if (GUILayout.Button((File.Exists(localDownloadPath + "poiyomitoon.unitypackage") ? "Import" : "Download") + " - Poiyomi Toon"))
      {
          SentinelsSDK_ImportManager.DownloadAndImportAssetFromServer("poiyomitoon.unitypackage");
      }
    GUILayout.EndHorizontal();

Answer 1

So I figured out my issue, but I am not sure why it was an issue. Apparently putting "https://" for the urlstart instead of "http://" broke it, despite you being able to download the file normally regardless of the protocol used. If someone can help me figure out why that is I would be grateful!