private async Task ProcessWithDiskCache(HttpContext context, string cacheKey, ImageJobInfo info)
{
var cacheResult = await diskCache.GetOrCreate(cacheKey, info.EstimatedFileExtension, async (stream) =>
{
if (info.HasParams)
{
logger?.LogInformation("DiskCache Miss: Processing image {VirtualPath}{QueryString}", info.FinalVirtualPath, info);
var result = await info.ProcessUncached();
if (result.ResultBytes.Array == null)
{
throw new InvalidOperationException("Image job returned zero bytes.");
}
await stream.WriteAsync(result.ResultBytes.Array, result.ResultBytes.Offset,
result.ResultBytes.Count,
CancellationToken.None);
await stream.FlushAsync();
}
else
{
logger?.LogInformation("DiskCache Miss: Proxying image {VirtualPath}", info.FinalVirtualPath);
await info.CopyPrimaryBlobToAsync(stream);
}
});
if (cacheResult.Result == CacheQueryResult.Miss)
{
GlobalPerf.Singleton.IncrementCounter("diskcache_miss");
}
else if (cacheResult.Result == CacheQueryResult.Hit)
{
GlobalPerf.Singleton.IncrementCounter("diskcache_hit");
}
else if (cacheResult.Result == CacheQueryResult.Failed)
{
GlobalPerf.Singleton.IncrementCounter("diskcache_timeout");
}
// Note that using estimated file extension instead of parsing magic bytes will lead to incorrect content-type
// values when the source file has a mismatched extension.
if (cacheResult.Data != null)
{
if (cacheResult.Data.Length < 1)
{
throw new InvalidOperationException("DiskCache returned cache entry with zero bytes");
}
SetCachingHeaders(context, cacheKey);
await MagicBytes.ProxyToStream(cacheResult.Data, context.Response);
}
else
{
logger?.LogInformation("Serving {0}?{1} from disk cache {2}", info.FinalVirtualPath, info.CommandString, cacheResult.RelativePath);
await ServeFileFromDisk(context, cacheResult.PhysicalPath, cacheKey);
}
}
private async Task ServeFileFromDisk(HttpContext context, string path, string etag)
{
await using var readStream = File.OpenRead(path);
if (readStream.Length < 1)
{
throw new InvalidOperationException("DiskCache file entry has zero bytes");
}
SetCachingHeaders(context, etag);
await MagicBytes.ProxyToStream(readStream, context.Response);
}
private async Task ProcessWithStreamCache(HttpContext context, string cacheKey, ImageJobInfo info)
{
var keyBytes = Encoding.UTF8.GetBytes(cacheKey);
var typeName = streamCache.GetType().Name;
var cacheResult = await streamCache.GetOrCreateBytes(keyBytes, async (cancellationToken) =>
{
if (info.HasParams)
{
logger?.LogDebug("{CacheName} miss: Processing image {VirtualPath}?{Querystring}", typeName, info.FinalVirtualPath, info.ToString());
var result = await info.ProcessUncached();
if (result.ResultBytes.Array == null)
{
throw new InvalidOperationException("Image job returned zero bytes.");
}
return(new Tuple <string, ArraySegment <byte> >(result.ContentType, result.ResultBytes));
}
logger?.LogDebug("{CacheName} miss: Proxying image {VirtualPath}", typeName, info.FinalVirtualPath);
var bytes = await info.GetPrimaryBlobBytesAsync();
return(new Tuple <string, ArraySegment <byte> >(null, bytes));
}, CancellationToken.None, false);
if (cacheResult.Status != null)
{
GlobalPerf.Singleton.IncrementCounter($"{typeName}_{cacheResult.Status}");
}
if (cacheResult.Data != null)
{
await using (cacheResult.Data)
{
if (cacheResult.Data.Length < 1)
{
throw new InvalidOperationException($"{typeName} returned cache entry with zero bytes");
}
SetCachingHeaders(context, cacheKey);
await MagicBytes.ProxyToStream(cacheResult.Data, context.Response);
}
logger?.LogDebug("Serving from {CacheName} {VirtualPath}?{CommandString}", typeName, info.FinalVirtualPath, info.CommandString);
}
else
{
// TODO explore this failure path better
throw new NullReferenceException("Caching failed: " + cacheResult.Status);
}
}
private async Task ProcessWithNoCache(HttpContext context, ImageJobInfo info)
{
// If we're not caching, we should always use the modified date from source blobs as part of the etag
var betterCacheKey = await info.GetExactCacheKey();
if (context.Request.Headers.TryGetValue(HeaderNames.IfNoneMatch, out var etag) && betterCacheKey == etag)
{
GlobalPerf.Singleton.IncrementCounter("etag_hit");
context.Response.StatusCode = StatusCodes.Status304NotModified;
context.Response.ContentLength = 0;
context.Response.ContentType = null;
return;
}
GlobalPerf.Singleton.IncrementCounter("etag_miss");
if (info.HasParams)
{
logger?.LogInformation("Processing image {VirtualPath} with params {CommandString}", info.FinalVirtualPath, info.CommandString);
GlobalPerf.Singleton.IncrementCounter("nocache_processed");
var imageData = await info.ProcessUncached();
var imageBytes = imageData.ResultBytes;
var contentType = imageData.ContentType;
// write to stream
context.Response.ContentType = contentType;
context.Response.ContentLength = imageBytes.Count;
SetCachingHeaders(context, betterCacheKey);
if (imageBytes.Array == null)
{
throw new InvalidOperationException("Image job returned zero bytes.");
}
await context.Response.Body.WriteAsync(imageBytes.Array, imageBytes.Offset, imageBytes.Count);
}
else
{
logger?.LogInformation("Proxying image {VirtualPath} with params {CommandString}", info.FinalVirtualPath, info.CommandString);
GlobalPerf.Singleton.IncrementCounter("nocache_proxied");
await using var sourceStream = (await info.GetPrimaryBlob()).OpenRead();
SetCachingHeaders(context, betterCacheKey);
await MagicBytes.ProxyToStream(sourceStream, context.Response);
}
}
