使用方法：
csharp
var request = UnityWebRequest.Get("文件地址");
DownloadHandlerFileRange mCurrentDownloadHandler = new DownloadHandlerFileRange("文件保存的路径", request);
request.downloadHandler = mCurrentDownloadHandler;
//进度监听回调
mCurrentDownloadHandler.DownloadedSizeUpdateEvent += DownLoadProgress;
yield return request.SendWebRequest();
if (request.responseCode != 416 && !string.IsNullOrEmpty(request.error))
{
if ((request.result == UnityWebRequest.Result.ConnectionError || request.error != null))
{
}
else if (request.result == UnityWebRequest.Result.ProtocolError)
{
}
}
csharp
using UnityEngine.Networking;
using System.IO;
using System;
using UnityEngine;
/// <summary>
/// 使用方式:
/// UnityWebRequest unityWebRequest = new UnityWebRequest("url");
/// unityWebRequest.downloadHandler = new DownloadHandlerFileRange("文件保存的路径", unityWebRequest);
/// unityWebRequest.SendWebRequest();
/// </summary>
public class DownloadHandlerFileRange : DownloadHandlerScript
{
/// <summary>
/// 文件正式开始下载事件,此事件触发以后即可获取到文件的总大小
/// </summary>
public event System.Action StartDownloadEvent;
/// <summary>
/// ReceiveData()之后调用的回调，参数是本地文件已经下载的总大小
/// </summary>
public event System.Action<ulong> DownloadedSizeUpdateEvent;
public event System.Action DownloadedEndEvent;
/// <summary>
/// 下载状态0：下载中，1：下载完成，2：解压中
/// </summary>
public int mDownLoadState = 0;
#region 属性
/// <summary>
/// 下载速度,单位:KB/S 保留两位小数
/// </summary>
public float Speed
{
get
{
//kb/s
return ((int)(DownloadSpeed / 1024 * 100)) / 100.0f;
//return (((int)DownloadSpeed / 1024.0f) / 1024.0f) /*/ 100.0f*/;
}
}
/// <summary>
/// 文件的总大小
/// </summary>
public long FileSize
{
get
{
return TotalFileSize;
}
}
/// <summary>
/// 下载进度[0,1]
/// </summary>
public float DownloadProgress
{
get
{
return GetProgress();
}
}
#endregion
#region 公共方法
/// <summary>
/// 使用1MB的缓存,在补丁2017.2.1p1中对DownloadHandlerScript的优化中,目前最大传入数据量也仅仅是1024*1024,再多也没用
/// </summary>
/// <param name="path">文件保存的路径</param>
/// <param name="request">UnityWebRequest对象,用来获文件大小,设置断点续传的请求头信息</param>
public DownloadHandlerFileRange(string path, UnityWebRequest request) : base(new byte[1024 * 1024])
{
Debug.Log($"[Download] DownloadHandlerFileRange start");
FilePath = path /*+ postfix*/;
SavePath = Path.GetDirectoryName(path);
//Debug.Log(FilePath);
//Debug.Log(SavePath);
mDownLoadState = 0;
FileName = Path.GetFileNameWithoutExtension(path);
FileStream = new FileStream(FilePath, FileMode.Append, FileAccess.Write);
unityWebRequest = request;
if (File.Exists(path))
{
LocalFileSize = new System.IO.FileInfo(path).Length;
}
CurFileSize = LocalFileSize;
unityWebRequest.SetRequestHeader("Range", "bytes=" + LocalFileSize + "-");
Debug.Log($"[Download] DownloadHandlerFileRange end LocalFileSize {LocalFileSize}");
}
/// <summary>
/// 清理资源,该方法没办法重写,只能隐藏,如果想要强制中止下载,并清理资源(UnityWebRequest.Dispose()),该方法并不会被调用,这让人很苦恼
/// </summary>
public new void Dispose()
{
Debug.Log("[Download] Dispose()");
Clean();
}
public void ManualDispose()
{
Debug.Log("[Download] ManualDispose()");
Clean();
}
public void RemoveFolder()
{
unityWebRequest.Dispose();
if (FileStream != null)
{
FileStream.Flush();
FileStream.Dispose();
FileStream = null;
}
if (Directory.Exists(SavePath))
{
Directory.Delete(SavePath,true);
}
if (File.Exists(FilePath))
File.Delete(FilePath);
}
public void CloceUnityWebRequest()
{
unityWebRequest.Dispose();
}
/// <summary>
/// 改名
/// </summary>
private void ChangeName()
{
string filepathName = SavePath + "/" + FileName;
if (File.Exists(filepathName))
File.Delete(filepathName);
File.Move(FilePath, filepathName);
}
#endregion
#region 私有方法
/// <summary>
/// 关闭文件流
/// </summary>
private void Clean()
{
Debug.Log("[Download] Clean()");
DownloadSpeed = 0.0f;
if (FileStream != null)
{
FileStream.Flush();
FileStream.Dispose();
FileStream = null;
}
StartDownloadEvent = null;
DownloadedSizeUpdateEvent = null;
}
#endregion
#region 私有继承的方法
/// <summary>
/// 下载完成后清理资源
/// </summary>
protected override void CompleteContent()
{
Debug.Log("[Download] CompleteContent()");
DownloadedEndEvent?.Invoke();
mDownLoadState = 1;
base.CompleteContent();
Clean();
//ChangeName();
}
/// <summary>
/// 调用UnityWebRequest.downloadHandler.data属性时,将会调用该方法,用于以byte[]的方式返回下载的数据,目前总是返回null
/// </summary>
/// <returns></returns>
protected override byte[] GetData()
{
Debug.Log("[Download] GetData()");
return null;
}
/// <summary>
/// 调用UnityWebRequest.downloadProgress属性时,将会调用该方法,用于返回下载进度
/// </summary>
/// <returns></returns>
protected override float GetProgress()
{
return TotalFileSize == 0 ? 0 : ((float)CurFileSize) / TotalFileSize;
}
/// <summary>
/// 调用UnityWebRequest.downloadHandler.text属性时,将会调用该方法,用于以string的方式返回下载的数据,目前总是返回null
/// </summary>
/// <returns></returns>
protected override string GetText()
{
return null;
}
//Note:当下载的文件数据大于2G时,该int类型的参数将会数据溢出,所以先自己通过响应头来获取长度,获取不到再使用参数的方式
[System.Obsolete]
protected override void ReceiveContentLength(int contentLength)
{
Debug.Log($"[Download] ReceiveContentLength {contentLength}");
string contentLengthStr = unityWebRequest.GetResponseHeader("Content-Length");
if (!string.IsNullOrEmpty(contentLengthStr))
{
try
{
TotalFileSize = long.Parse(contentLengthStr);
}
catch (System.FormatException e)
{
UnityEngine.Debug.Log("获取文件长度失败,contentLengthStr:" + contentLengthStr + "," + e.Message);
TotalFileSize = contentLength;
}
catch (System.Exception e)
{
UnityEngine.Debug.Log("获取文件长度失败,contentLengthStr:" + contentLengthStr + "," + e.Message);
TotalFileSize = contentLength;
}
}
else
{
TotalFileSize = contentLength;
}
//这里拿到的下载大小是待下载的文件大小,需要加上本地已下载文件的大小才等于总大小
TotalFileSize += LocalFileSize;
LastTime = UnityEngine.Time.time;
LastDataSize = CurFileSize;
if (StartDownloadEvent != null)
{
StartDownloadEvent();
}
mDownLoadState = 0;
}
//在2017.3.0(包括该版本)以下的正式版本中存在一个性能上的问题
//该回调方法有性能上的问题,每次传入的数据量最大不会超过65536(2^16)个字节,不论缓存区有多大
//在下载速度中的体现,大约相当于每秒下载速度不会超过3.8MB/S
//这个问题在 "补丁2017.2.1p1" 版本中被优化(2017.12.21发布)(https://unity3d.com/cn/unity/qa/patch-releases/2017.2.1p1)
//(965165) - Web: UnityWebRequest: improve performance for DownloadHandlerScript.
//优化后,每次传入数据量最大不会超过1048576(2^20)个字节(1MB),基本满足下载使用
protected override bool ReceiveData(byte[] data, int dataLength)
{
if (data == null || dataLength == 0 || unityWebRequest.responseCode > 400)
{
Debug.Log($"[Download] ReceiveData return false: data: {data} length: {dataLength} responseCode: {unityWebRequest.responseCode}");
return false;
}
if (FileStream == null)
{
return false;
}
FileStream.Write(data, 0, dataLength);
CurFileSize += dataLength;
//统计下载速度
if (UnityEngine.Time.time - LastTime >= 1.0f)
{
DownloadSpeed = (CurFileSize - LastDataSize) / (UnityEngine.Time.time - LastTime);
LastTime = UnityEngine.Time.time;
LastDataSize = CurFileSize;
}
//Debug.Log("DownloadSpeed:" + DownloadSpeed);
DownloadedSizeUpdateEvent?.Invoke((ulong)CurFileSize);
return true;
}
~DownloadHandlerFileRange()
{
Debug.Log("[Download] ~DownloadHandlerFileRange()");
Clean();
}
#endregion
#region 私有字段
private string FilePath;//文件保存的路径 带文件名称
private string SavePath;//文件保存的路径 不带文件名称
private string FileName;//文件名称
private string postfix = ".temp"; //临时文件后缀名
private FileStream FileStream;
private UnityWebRequest unityWebRequest;
private long LocalFileSize = 0;//本地已经下载的文件的大小
private long TotalFileSize = 0;//文件的总大小
private long CurFileSize = 0;//当前的文件大小
private float LastTime = 0;//用作下载速度的时间统计
private float LastDataSize = 0;//用来作为下载速度的大小统计
private float DownloadSpeed = 0;//下载速度,单位:Byte/S
#endregion
}