async Task FlushAsync(HttpContext context, CancellationToken cancellationToken)
{
// prepare
var requestUri = context.GetRequestUri();
var pathSegments = requestUri.GetRequestPathSegments();
var attachment = new AttachmentInfo
{
ID = pathSegments.Length > 3 && pathSegments[3].IsValidUUID() ? pathSegments[3].ToLower() : "",
ServiceName = pathSegments.Length > 1 && !pathSegments[1].IsValidUUID() ? pathSegments[1] : "",
SystemID = pathSegments.Length > 1 && pathSegments[1].IsValidUUID() ? pathSegments[1].ToLower() : "",
ContentType = pathSegments.Length > 2 ? pathSegments[2].Replace("=", "/") : "",
Filename = pathSegments.Length > 4 && pathSegments[3].IsValidUUID() ? pathSegments[4].UrlDecode() : "",
IsThumbnail = false
};
if (string.IsNullOrWhiteSpace(attachment.ID) || string.IsNullOrWhiteSpace(attachment.Filename))
{
throw new InvalidRequestException();
}
// check "If-Modified-Since" request to reduce traffict
var eTag = "file#" + attachment.ID;
var noneMatch = context.GetHeaderParameter("If-None-Match");
var modifiedSince = context.GetHeaderParameter("If-Modified-Since") ?? context.GetHeaderParameter("If-Unmodified-Since");
if (eTag.IsEquals(noneMatch) && modifiedSince != null)
{
context.SetResponseHeaders((int)HttpStatusCode.NotModified, eTag, modifiedSince.FromHttpDateTime().ToUnixTimestamp(), "public", context.GetCorrelationID());
await context.FlushAsync(cancellationToken).ConfigureAwait(false);
if (Global.IsDebugLogEnabled)
{
context.WriteLogs(this.Logger, "Http.Downloads", $"Response to request with status code 304 to reduce traffic ({requestUri})");
}
return;
}
// get info & check permissions
attachment = await context.GetAsync(attachment.ID, cancellationToken).ConfigureAwait(false);
if (!await context.CanDownloadAsync(attachment, cancellationToken).ConfigureAwait(false))
{
throw new AccessDeniedException();
}
// check existed
var cacheKey = attachment.ContentType.IsStartsWith("image/") && "true".IsEquals(UtilityService.GetAppSetting("Files:Cache:Images", "true")) && Global.Cache != null
? $"Image#{attachment.Filename.ToLower().GenerateUUID()}"
: null;
var hasCached = cacheKey != null && await Global.Cache.ExistsAsync(cacheKey, cancellationToken).ConfigureAwait(false);
FileInfo fileInfo = null;
if (!hasCached)
{
fileInfo = new FileInfo(attachment.GetFilePath());
if (!fileInfo.Exists)
{
if (Global.IsDebugLogEnabled)
{
context.WriteLogs(this.Logger, "Http.Downloads", $"Not found: {requestUri} => {fileInfo.FullName}");
}
context.ShowHttpError((int)HttpStatusCode.NotFound, "Not Found", "FileNotFoundException", context.GetCorrelationID());
return;
}
}
// flush the file to output stream, update counter & logs
if (hasCached)
{
var lastModified = await Global.Cache.GetAsync <long>($"{cacheKey}:time", cancellationToken).ConfigureAwait(false);
var bytes = await Global.Cache.GetAsync <byte[]>(cacheKey, cancellationToken).ConfigureAwait(false);
using (var stream = UtilityService.CreateMemoryStream(bytes))
{
await context.WriteAsync(stream, attachment.ContentType, attachment.IsReadable()?null : attachment.Filename, eTag, lastModified, "public", TimeSpan.FromDays(366), null, context.GetCorrelationID(), cancellationToken).ConfigureAwait(false);
}
if (Global.IsDebugLogEnabled)
{
context.WriteLogs(this.Logger, "Http.Downloads", $"Successfully flush a cached image ({requestUri})");
}
}
else
{
await context.WriteAsync(fileInfo, attachment.IsReadable()?null : attachment.Filename, eTag, cancellationToken).ConfigureAwait(false);
if (cacheKey != null)
{
await Task.WhenAll
(
Global.Cache.SetAsFragmentsAsync(cacheKey, await UtilityService.ReadBinaryFileAsync(fileInfo, cancellationToken).ConfigureAwait(false), 1440, cancellationToken),
Global.Cache.SetAsync($"{cacheKey}:time", fileInfo.LastWriteTime.ToUnixTimestamp(), 1440, cancellationToken),
Global.IsDebugLogEnabled?context.WriteLogsAsync(this.Logger, "Http.Downloads", $"Update an image file into cache successful ({requestUri})") : Task.CompletedTask
).ConfigureAwait(false);
}
if (Global.IsDebugLogEnabled)
{
context.WriteLogs(this.Logger, "Http.Downloads", $"Successfully flush a file [{requestUri} => {fileInfo.FullName}]");
}
}
await context.UpdateAsync(attachment, attachment.IsReadable()? "Direct" : "Download", cancellationToken).ConfigureAwait(false);
}
