From 70bc943c17d5af510533e316f6526b318dd514c6 Mon Sep 17 00:00:00 2001
From: Qstick <qstick@gmail.com>
Date: Tue, 10 Jan 2023 21:45:43 -0600
Subject: [PATCH] Fixed: Correctly combine HttpUri paths with dot segment

---
 .../Http/HttpUriFixture.cs                    | 20 ++++++++++++
 src/NzbDrone.Common/Http/HttpUri.cs           | 31 +++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs b/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs
index f47c59881..3ffb150d9 100644
--- a/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs
+++ b/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs
@@ -52,6 +52,26 @@ namespace NzbDrone.Common.Test.Http
             newUri.FullUri.Should().Be(expected);
         }
 
+        [TestCase("", "./relative", "relative")]
+        [TestCase("/", "./relative", "/relative")]
+        [TestCase("/base", "./relative", "/relative")]
+        [TestCase("/base/sub", "./relative", "/base/relative")]
+        [TestCase("/base/sub/", "./relative", "/base/sub/relative")]
+        [TestCase("base/sub", "./relative", "base/relative")]
+        [TestCase("base/sub/", "./relative", "base/sub/relative")]
+        [TestCase("", "../relative", "relative")]
+        [TestCase("/", "../relative", "/relative")]
+        [TestCase("/base", "../relative", "/relative")]
+        [TestCase("/base/sub", "../relative", "/base/relative")]
+        [TestCase("/base/sub/", "../relative", "/base/sub/relative")]
+        [TestCase("base/sub", "../relative", "base/relative")]
+        [TestCase("base/sub/", "../relative", "base/sub/relative")]
+        public void should_combine_uri_with_dot_segment(string basePath, string relativePath, string expected)
+        {
+            var newUri = new HttpUri(basePath) + new HttpUri(relativePath);
+            newUri.FullUri.Should().Be(expected);
+        }
+
         [TestCase("", "", "")]
         [TestCase("/", "", "/")]
         [TestCase("base", "", "base")]
diff --git a/src/NzbDrone.Common/Http/HttpUri.cs b/src/NzbDrone.Common/Http/HttpUri.cs
index f90e564f5..1a8332f74 100644
--- a/src/NzbDrone.Common/Http/HttpUri.cs
+++ b/src/NzbDrone.Common/Http/HttpUri.cs
@@ -164,6 +164,37 @@ namespace NzbDrone.Common.Http
                 return relativePath;
             }
 
+            if (relativePath.StartsWith("./"))
+            {
+                relativePath = relativePath.TrimStart('.').TrimStart('/');
+
+                var lastIndex = basePath.LastIndexOf("/");
+
+                if (lastIndex > 0)
+                {
+                    basePath = basePath.Substring(0, lastIndex) + "/";
+                }
+            }
+
+            if (relativePath.StartsWith("../"))
+            {
+                relativePath = relativePath.TrimStart('.').TrimStart('/');
+
+                var lastIndex = basePath.LastIndexOf("/");
+
+                if (lastIndex > 0)
+                {
+                    basePath = basePath.Substring(0, lastIndex) + "/";
+                }
+
+                var secondLastIndex = basePath.LastIndexOf("/");
+
+                if (lastIndex > 0)
+                {
+                    basePath = basePath.Substring(0, secondLastIndex) + "/";
+                }
+            }
+
             var baseSlashIndex = basePath.LastIndexOf('/');
 
             if (baseSlashIndex >= 0)