Ensure external sources for styles only process CSS responses when in…

…lining stylesheets
milkshakesoftware · Nov 7, 2024 · e07d661 · e07d661
1 parent 3c70622
commit e07d661
Show file tree

Hide file tree

Showing 3 changed files with 50 additions and 4 deletions.
diff --git a/PreMailer.Net/Benchmarks/Program.cs b/PreMailer.Net/Benchmarks/Program.cs
@@ -1,17 +1,30 @@
 using AngleSharp;
 using AngleSharp.Html.Parser;
 using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Configs;
+using BenchmarkDotNet.Jobs;
 using BenchmarkDotNet.Running;
+using BenchmarkDotNet.Toolchains.InProcess.NoEmit;
 
 public static class Program
 {
 	public static void Main()
 	{
-		BenchmarkRunner.Run<Realistic>();
+		// Some local environments may run into issues with Windows Defender or 
+		// SentinelOne (and others) when running a benchmark. This ensures we
+		// keep our toolchain within our process and stops the above apps from blocking
+		// our benchmark process, but can slow the execution time.
+		var avSafeConfig = DefaultConfig.Instance
+			.AddJob(
+				Job.ShortRun
+					.WithToolchain(InProcessNoEmitToolchain.Instance)
+					.WithIterationCount(100)
+			);
+
+		BenchmarkRunner.Run<Realistic>(avSafeConfig);
 	}
 }
 
-[SimpleJob(invocationCount: 100, iterationCount: 100)]
 [MemoryDiagnoser]
 public class Realistic
 {
@@ -47,7 +60,7 @@ public void MoveCssInline_AllFlags()
 
 <meta http-equiv=""Content-Type"" content=""text/html; charset=UTF-8"" />
 <title>PreMailer Benchmark</title>
-	
+
 </head>
  
 <body bgcolor=""#123"">

diff --git a/PreMailer.Net/PreMailer.Net/Downloaders/WebDownloader.cs b/PreMailer.Net/PreMailer.Net/Downloaders/WebDownloader.cs
@@ -1,3 +1,4 @@
+using PreMailer.Net.Extensions;
 using System;
 using System.IO;
 using System.Net;
@@ -8,7 +9,7 @@ namespace PreMailer.Net.Downloaders
 	public class WebDownloader : IWebDownloader
 	{
 		private static IWebDownloader _sharedDownloader;
-
+		private const string CssMimeType = "text/css";
 		public static IWebDownloader SharedDownloader
 		{
 			get
@@ -29,8 +30,16 @@ public static IWebDownloader SharedDownloader
 		public string DownloadString(Uri uri)
 		{
 			var request = WebRequest.Create(uri);
+			request.Headers.Add(HttpRequestHeader.Accept, CssMimeType);
+
 			using (var response = request.GetResponse())
 			{
+				// We only support this operation for CSS file/content types coming back
+				// from the response. If we get something different, throw with the unsupported
+				// content type in the message
+				if(response.ParseContentType() != CssMimeType)
+					throw new NotSupportedException($"The Uri type is giving a response in unsupported content type '{response.ContentType}'.");
+
 				switch (response)
 				{
 					case HttpWebResponse httpWebResponse:

diff --git a/PreMailer.Net/PreMailer.Net/Extensions/WebResponseExtensions.cs b/PreMailer.Net/PreMailer.Net/Extensions/WebResponseExtensions.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Net;
+
+namespace PreMailer.Net.Extensions
+{
+	public static class WebResponseExtensions
+	{
+		public static string ParseContentType(this WebResponse response)
+		{
+			if(response == null)
+				throw new NullReferenceException("Malformed response detected when parsing WebResponse Content-Type");
+
+			if(string.IsNullOrEmpty(response.ContentType))
+				throw new NullReferenceException("Malformed Content-Type response detected when parsing WebResponse");
+
+			var results = response.ContentType.Split(';');
+
+			if(results.Length == 0)
+				throw new FormatException("Malformed Content-Type response detected when parsing WebResponse");
+
+			return results[0];
+		}
+	}
+}