From fd6d35e1d0a3ceae6080fbf1fe08fb68f01a4395 Mon Sep 17 00:00:00 2001 From: Claus Vium Date: Tue, 22 Jan 2019 21:18:48 +0100 Subject: [PATCH 1/3] Remove unconditional caching, modified since header and use ETags --- .../HttpServer/FileWriter.cs | 2 +- .../HttpServer/HttpResultFactory.cs | 54 ++++++++----------- 2 files changed, 23 insertions(+), 33 deletions(-) diff --git a/Emby.Server.Implementations/HttpServer/FileWriter.cs b/Emby.Server.Implementations/HttpServer/FileWriter.cs index c32c91670a..7aedba9b31 100644 --- a/Emby.Server.Implementations/HttpServer/FileWriter.cs +++ b/Emby.Server.Implementations/HttpServer/FileWriter.cs @@ -21,7 +21,7 @@ namespace Emby.Server.Implementations.HttpServer private long RangeStart { get; set; } private long RangeEnd { get; set; } private long RangeLength { get; set; } - private long TotalContentLength { get; set; } + public long TotalContentLength { get; set; } public Action OnComplete { get; set; } public Action OnError { get; set; } diff --git a/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs b/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs index 8b60d61d41..dee417b43f 100644 --- a/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs +++ b/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs @@ -5,6 +5,7 @@ using System.IO; using System.IO.Compression; using System.Net; using System.Runtime.Serialization; +using System.Security.Cryptography; using System.Text; using System.Threading.Tasks; using System.Xml; @@ -423,13 +424,11 @@ namespace Emby.Server.Implementations.HttpServer /// private object GetCachedResult(IRequest requestContext, IDictionary responseHeaders, Guid cacheKey, string cacheKeyString, DateTime? lastDateModified, TimeSpan? cacheDuration, string contentType) { - responseHeaders["ETag"] = string.Format("\"{0}\"", cacheKeyString); - bool noCache = (requestContext.Headers.Get("Cache-Control") ?? string.Empty).IndexOf("no-cache", StringComparison.OrdinalIgnoreCase) != -1; if (!noCache) { - if (IsNotModified(requestContext, cacheKey, lastDateModified, cacheDuration)) + if (IsNotModified(requestContext, cacheKey)) { AddAgeHeader(responseHeaders, lastDateModified); AddExpiresHeader(responseHeaders, cacheKeyString, cacheDuration); @@ -442,7 +441,7 @@ namespace Emby.Server.Implementations.HttpServer } } - AddCachingHeaders(responseHeaders, cacheKeyString, lastDateModified, cacheDuration); + AddCachingHeaders(responseHeaders, cacheKeyString, cacheDuration); return null; } @@ -532,10 +531,11 @@ namespace Emby.Server.Implementations.HttpServer public async Task GetStaticResult(IRequest requestContext, StaticResultOptions options) { - var cacheKey = options.CacheKey; options.ResponseHeaders = options.ResponseHeaders ?? new Dictionary(StringComparer.OrdinalIgnoreCase); - var contentType = options.ContentType; + var contentType = options.ContentType; + var etag = requestContext.Headers.Get("If-None-Match"); + var cacheKey = etag != null ? new Guid(etag) : Guid.Empty; if (!cacheKey.Equals(Guid.Empty)) { var key = cacheKey.ToString("N"); @@ -554,8 +554,6 @@ namespace Emby.Server.Implementations.HttpServer var factoryFn = options.ContentFactory; var responseHeaders = options.ResponseHeaders; - //var requestedCompressionType = GetCompressionType(requestContext); - var rangeHeader = requestContext.Headers.Get("Range"); if (!isHeadRequest && !string.IsNullOrEmpty(options.Path)) @@ -568,10 +566,21 @@ namespace Emby.Server.Implementations.HttpServer }; AddResponseHeaders(hasHeaders, options.ResponseHeaders); + // Generate an ETag based on identifying information - TODO read contents from filesystem instead? + var responseId = $"{hasHeaders.ContentType}{options.Path}{hasHeaders.TotalContentLength}"; + var hashedId = MD5.Create().ComputeHash(Encoding.Default.GetBytes(responseId)); + hasHeaders.Headers["ETag"] = new Guid(hashedId).ToString("N"); + return hasHeaders; } var stream = await factoryFn().ConfigureAwait(false); + // Generate an etag based on stream content + var streamHash = MD5.Create().ComputeHash(stream); + var newEtag = new Guid(streamHash).ToString("N"); + + // reset position so the response can re-use it -- TODO is this ok? + stream.Position = 0; var totalContentLength = options.ContentLength; if (!totalContentLength.HasValue) @@ -594,6 +603,7 @@ namespace Emby.Server.Implementations.HttpServer }; AddResponseHeaders(hasHeaders, options.ResponseHeaders); + hasHeaders.Headers["ETag"] = newEtag; return hasHeaders; } else @@ -618,6 +628,7 @@ namespace Emby.Server.Implementations.HttpServer }; AddResponseHeaders(hasHeaders, options.ResponseHeaders); + hasHeaders.Headers["ETag"] = newEtag; return hasHeaders; } } @@ -630,16 +641,8 @@ namespace Emby.Server.Implementations.HttpServer /// /// Adds the caching responseHeaders. /// - private void AddCachingHeaders(IDictionary responseHeaders, string cacheKey, DateTime? lastDateModified, TimeSpan? cacheDuration) + private void AddCachingHeaders(IDictionary responseHeaders, string cacheKey, TimeSpan? cacheDuration) { - // Don't specify both last modified and Etag, unless caching unconditionally. They are redundant - // https://developers.google.com/speed/docs/best-practices/caching#LeverageBrowserCaching - if (lastDateModified.HasValue && (string.IsNullOrEmpty(cacheKey) || cacheDuration.HasValue)) - { - AddAgeHeader(responseHeaders, lastDateModified); - responseHeaders["Last-Modified"] = lastDateModified.Value.ToString("r"); - } - if (cacheDuration.HasValue) { responseHeaders["Cache-Control"] = "public, max-age=" + Convert.ToInt32(cacheDuration.Value.TotalSeconds); @@ -692,28 +695,15 @@ namespace Emby.Server.Implementations.HttpServer /// The last date modified. /// Duration of the cache. /// true if [is not modified] [the specified cache key]; otherwise, false. - private bool IsNotModified(IRequest requestContext, Guid cacheKey, DateTime? lastDateModified, TimeSpan? cacheDuration) + private bool IsNotModified(IRequest requestContext, Guid cacheKey) { - //var isNotModified = true; - - var ifModifiedSinceHeader = requestContext.Headers.Get("If-Modified-Since"); - - if (!string.IsNullOrEmpty(ifModifiedSinceHeader) - && DateTime.TryParse(ifModifiedSinceHeader, out DateTime ifModifiedSince) - && IsNotModified(ifModifiedSince.ToUniversalTime(), cacheDuration, lastDateModified)) - { - return true; - } - var ifNoneMatchHeader = requestContext.Headers.Get("If-None-Match"); bool hasCacheKey = !cacheKey.Equals(Guid.Empty); // Validate If-None-Match - if ((hasCacheKey && !string.IsNullOrEmpty(ifNoneMatchHeader))) + if (hasCacheKey && !string.IsNullOrEmpty(ifNoneMatchHeader)) { - ifNoneMatchHeader = (ifNoneMatchHeader ?? string.Empty).Trim('\"'); - if (Guid.TryParse(ifNoneMatchHeader, out var ifNoneMatch) && cacheKey.Equals(ifNoneMatch)) { From 94789860b1217a500e50d74ba5dbec26bb61a8d7 Mon Sep 17 00:00:00 2001 From: Claus Vium Date: Tue, 22 Jan 2019 22:37:26 +0100 Subject: [PATCH 2/3] Trim quotes from If-None-Match --- Emby.Server.Implementations/HttpServer/HttpResultFactory.cs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs b/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs index dee417b43f..370c76ec9a 100644 --- a/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs +++ b/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs @@ -535,7 +535,7 @@ namespace Emby.Server.Implementations.HttpServer var contentType = options.ContentType; var etag = requestContext.Headers.Get("If-None-Match"); - var cacheKey = etag != null ? new Guid(etag) : Guid.Empty; + var cacheKey = etag != null ? new Guid(etag.Trim("\"")) : Guid.Empty; if (!cacheKey.Equals(Guid.Empty)) { var key = cacheKey.ToString("N"); From df5e87409ae08199333da549be118653bc0c2221 Mon Sep 17 00:00:00 2001 From: Claus Vium Date: Tue, 22 Jan 2019 22:40:06 +0100 Subject: [PATCH 3/3] Fix trim input --- Emby.Server.Implementations/HttpServer/HttpResultFactory.cs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs b/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs index 370c76ec9a..0ad4d8406b 100644 --- a/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs +++ b/Emby.Server.Implementations/HttpServer/HttpResultFactory.cs @@ -535,7 +535,7 @@ namespace Emby.Server.Implementations.HttpServer var contentType = options.ContentType; var etag = requestContext.Headers.Get("If-None-Match"); - var cacheKey = etag != null ? new Guid(etag.Trim("\"")) : Guid.Empty; + var cacheKey = etag != null ? new Guid(etag.Trim('\"')) : Guid.Empty; if (!cacheKey.Equals(Guid.Empty)) { var key = cacheKey.ToString("N");