public async Task <IActionResult> DownloadAsync([Required] string fileToken, [Required] string handler, string modifier)
{
if (!DecodeAndCheckFileToken(fileToken, out FileToken fToken, out DataResult <object> errResult))
{
return(StatusCode(401, errResult.ErrorMsg));
}
var rawPath = _storageSvce.GetRawFilePath(fToken.PseudoId, fToken.FileCreateTime, fToken.FileId);
if (System.IO.File.Exists(rawPath))
{
//如果原文件存在，并且包含缓存头则认为是未修改
//因为文件只会删除，不会修改
var reqHeaders = Request.GetTypedHeaders();
if (reqHeaders.IfNoneMatch?.Any() == true)
{
return(StatusCode(304));
}
}
else
{
return(NotFound("您访问的文件不存在或已被删除啦"));
}
try
{
var fileHandler = _fileHandlerMgr.GetFileHandlerByName(handler);
if (fileHandler == null)
{
return(StatusCode(400, handler + " 不存在"));
}
//返回文件
var rawMime = _mimeProvider.GetMimeById(fToken.MimeId);
var hCtx = new FileHandleContext()
{
SourcePath = rawPath,
SourceMime = rawMime,
Modifier = modifier,
FileToken = fToken
};
var result = await fileHandler.HandleAsync(hCtx);
//添加缓存头
var rspHeaders = Response.GetTypedHeaders();
rspHeaders.ETag = new EntityTagHeaderValue($"\"{fToken.PseudoId}\"", true);
rspHeaders.CacheControl = new CacheControlHeaderValue()
{
MaxAge = TimeSpan.FromDays(365)
};
rspHeaders.Expires = DateTime.UtcNow.AddYears(1);
return(result);
}
catch (Exception ex)
{
Logger.LogError(nameof(DownloadAsync), ex.ToString());
return(StatusCode(500, ex.Message));
}
}
public async Task <IActionResult> HandleAsync(FileHandleContext context)
{
if (string.IsNullOrEmpty(context.Modifier))
{
throw new ArgumentNullException(nameof(context.Modifier));
}
var imgMod = ParseModifier(context.Modifier, context.SourceMime);
if (ShouldRsponseRaw(imgMod, context))
{
return(new PhysicalFileResult(context.SourcePath, context.SourceMime.ContentType));
}
//判断是否有缓存
var rawDirPath = Path.GetDirectoryName(context.SourcePath);
var dstFilePath = Path.Combine(rawDirPath, $"image_{imgMod.Size.Name}_{imgMod.Mime.ExtensionNames.First()}");
if (!File.Exists(dstFilePath))
{
await _imgCvter.ConvertAsync(context.SourcePath, context.SourceMime, dstFilePath, imgMod);
}
return(new PhysicalFileResult(dstFilePath, imgMod.Mime.ContentType));
}
/// <summary>
/// 是否应该返回源文件
/// </summary>
private bool ShouldRsponseRaw(ImageModifier imgMod, FileHandleContext context)
{
if (imgMod.Mime == context.SourceMime)
{
if (imgMod.Size == ImageSize.Raw)
{
return(true);
}
}
return(false);
}
public async Task <IActionResult> HandleAsync(FileHandleContext context)
{
if (!System.IO.File.Exists(context.SourcePath))
{
return(new NotFoundResult());
}
string fileName = null;
if (_options.CurrentValue.QueryFileName)
{
fileName = await FileRepository.GetFileNameByIdAsync(context.FileToken.PseudoId, context.FileToken.FileOwnerId);
}
return(new PhysicalFileResult(context.SourcePath, context.SourceMime.ContentType)
{
FileDownloadName = fileName
});
}
