Getting started

Installation

Download Utils is published on OpenUPM. Add a scoped registry for tools.doji to Packages/manifest.json, then add the package:

{
  "scopedRegistries": [
    {
      "name": "OpenUPM",
      "url": "https://package.openupm.com",
      "scopes": [ "tools.doji" ]
    }
  ],
  "dependencies": {
    "tools.doji.downloads": "1.0.0"
  }
}

Download Utils requires Unity 6000.3 LTS or later. Its only dependency, Newtonsoft JSON (com.unity.nuget.newtonsoft-json), is installed by Package Manager.

If you build a package on top of Download Utils, add tools.doji.downloads to the dependencies of your own package.json instead.

Your first download

ResumableDownloader downloads one URL to one file. Call it from the Unity main thread, for example from an Editor menu item:

using System;
using System.Threading;
using Doji.Downloads;
using UnityEditor;
using UnityEngine;

static class DownloadExample
{
    [MenuItem("Tools/Download Example")]
    static async void Download()
    {
        var progress = new Progress<DownloadProgress>(value =>
            Debug.Log($"{value.DownloadedBytes} of {value.TotalBytes} bytes"));

        try
        {
            await new ResumableDownloader().DownloadFileAsync(
                "https://example.com/model.onnx",
                "Library/DownloadExample/model.onnx",
                expectedSizeInBytes: null,
                progress,
                CancellationToken.None);
            Debug.Log("Done");
        }
        catch (Exception exception)
        {
            Debug.LogError(exception.Message);
        }
    }
}

While the file downloads, two extra files sit next to the target:

  • model.onnx.downloading: the bytes received so far
  • model.onnx.downloading.json: what the server said about the file, used to resume safely

Stop the download, or disconnect the network, and run the menu item again: the download continues where it stopped. When it is complete, both files are replaced by model.onnx.

Tip

Download into Library/ or a folder outside Assets/. Inside Assets/, Unity imports the partial files while they grow.

Next steps