From 82abb429e95d57b87e801e5e323b7812203c046c Mon Sep 17 00:00:00 2001
From: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Date: Thu, 26 Jun 2025 17:23:47 +0000
Subject: [PATCH] Fix port number preservation in CSS import URI resolution

- Add test to verify port numbers are preserved when resolving relative CSS imports
- Remove Port = -1 assignment in GetBaseUri() method that was stripping port numbers
- Fixes issue #431 where URIs with port numbers became inaccessible since version 2.7.0

Co-Authored-By: Martin <m@martinnormark.com>
---
 .../ImportRuleCssSourceTests.cs                | 18 ++++++++++++++++++
 .../Sources/ImportRuleCssSource.cs             |  1 -
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/PreMailer.Net/PreMailer.Net.Tests/ImportRuleCssSourceTests.cs b/PreMailer.Net/PreMailer.Net.Tests/ImportRuleCssSourceTests.cs
index 0b9d185..a441b40 100644
--- a/PreMailer.Net/PreMailer.Net.Tests/ImportRuleCssSourceTests.cs
+++ b/PreMailer.Net/PreMailer.Net.Tests/ImportRuleCssSourceTests.cs
@@ -203,6 +203,24 @@ public void ItShould_HandleCircularImports_WithoutInfiniteLoop()
 			_webDownloader.Verify(w => w.DownloadString(It.Is<Uri>(u => u.ToString() == "https://a.com/circular2.css")), Times.Once);
 		}
 
+		[Fact]
+		public void ItShould_PreservePortNumber_WhenResolvingRelativeImports()
+		{
+			var baseUri = new Uri("https://localhost:8080/styles/main.css");
+			var css = "@import \"variables.css\";";
+			var variablesCss = "body { color: red; }";
+
+			_webDownloader
+				.Setup(w => w.DownloadString(It.Is<Uri>(u => u.ToString() == "https://localhost:8080/styles/variables.css")))
+				.Returns(variablesCss);
+
+			var sut = new ImportRuleCssSource();
+
+			var result = sut.GetCss(baseUri, css).ToList();
+
+			_webDownloader.Verify(w => w.DownloadString(It.Is<Uri>(u => u.ToString() == "https://localhost:8080/styles/variables.css")), Times.Once);
+		}
+
 		private string CreateCss(IEnumerable<string> imports)
 		{
 			var builder = new StringBuilder();
diff --git a/PreMailer.Net/PreMailer.Net/Sources/ImportRuleCssSource.cs b/PreMailer.Net/PreMailer.Net/Sources/ImportRuleCssSource.cs
index 0217f61..3cd1ef0 100644
--- a/PreMailer.Net/PreMailer.Net/Sources/ImportRuleCssSource.cs
+++ b/PreMailer.Net/PreMailer.Net/Sources/ImportRuleCssSource.cs
@@ -83,7 +83,6 @@ private static Uri GetBaseUri(Uri downloadUri)
 		{
 			var baseUrl = new UriBuilder(downloadUri)
 			{
-				Port = -1 /* Excludes the port number */,
 				Query = string.Empty
 			};