Add ResolvePaths ext method

Author: mythz

src/ServiceStack.Text/PathUtils.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text;
 using ServiceStack.Text;
 
@@ -131,6 +132,33 @@ public static string CombineWith(this string path, params object[] thesePaths)
             return StringBuilderThreadStatic.ReturnAndFree(sb);
         }
 
+        public static string ResolvePaths(this string path)
+        {
+            if (path == null || path.IndexOfAny("./", "/.") == -1)
+                return path;
+
+            var parts = path.Split('/').ToList();
+            var combinedPaths = new List<string>();
+            foreach (var part in parts)
+            {
+                if (string.IsNullOrEmpty(part) || part == ".")
+                    continue;
+
+                if (part == ".." && combinedPaths.Count > 0)
+                    combinedPaths.RemoveAt(combinedPaths.Count - 1);
+                else
+                    combinedPaths.Add(part);
+            }
+
+            var resolvedPath = string.Join("/", combinedPaths);
+            if (path[0] == '/')
+                resolvedPath = '/' + resolvedPath;
+
+            return path[path.Length - 1] == '/'
+                ? resolvedPath + '/'
+                : resolvedPath;
+        }
+
         public static string[] ToStrings(object[] thesePaths)
         {
             var to = new string[thesePaths.Length];

tests/ServiceStack.Text.Tests/CombinePathTests.cs

@@ -0,0 +1,53 @@
+using NUnit.Framework;
+
+namespace ServiceStack.Text.Tests
+{
+    public class CombinePathTests
+    {
+        [Test]
+        public void Does_combine_paths()
+        {
+            Assert.That("/a".CombineWith("b"), Is.EqualTo("/a/b"));
+            Assert.That("a".CombineWith("b"), Is.EqualTo("a/b"));
+            Assert.That("/a/b".CombineWith("c"), Is.EqualTo("/a/b/c"));
+            Assert.That("a/b".CombineWith("c"), Is.EqualTo("a/b/c"));
+            Assert.That("/a/b".CombineWith("c/d"), Is.EqualTo("/a/b/c/d"));
+            Assert.That("/a/b".CombineWith("c", "d"), Is.EqualTo("/a/b/c/d"));
+
+            Assert.That("http://example.org/a/b".CombineWith("c", "d"), Is.EqualTo("http://example.org/a/b/c/d"));
+        }
+
+        [Test]
+        public void Does_combine_paths_with_trailing_slashes()
+        {
+            Assert.That("/a/".CombineWith("b"), Is.EqualTo("/a/b"));
+            Assert.That("/a/".CombineWith("b/"), Is.EqualTo("/a/b/"));
+            Assert.That("a/".CombineWith("/b"), Is.EqualTo("a/b"));
+            Assert.That("/a/b/".CombineWith("/c/"), Is.EqualTo("/a/b/c/"));
+            Assert.That("a/b/".CombineWith("c"), Is.EqualTo("a/b/c"));
+            Assert.That("/a/b/".CombineWith("/c/d"), Is.EqualTo("/a/b/c/d"));
+            Assert.That("/a/b/".CombineWith("/c", "/d"), Is.EqualTo("/a/b/c/d"));
+
+            Assert.That("http://example.org/a/b/".CombineWith("/c/", "/d"), Is.EqualTo("http://example.org/a/b/c/d"));
+        }
+
+        [Test]
+        public void Can_resolve_paths()
+        {
+            Assert.That("/a/b/../".ResolvePaths(), Is.EqualTo("/a/"));
+            Assert.That("/a/b/..".ResolvePaths(), Is.EqualTo("/a"));
+            Assert.That("a/b/..".ResolvePaths(), Is.EqualTo("a"));
+
+            Assert.That("a/../b".ResolvePaths(), Is.EqualTo("b"));
+            Assert.That("a/../b/./c".ResolvePaths(), Is.EqualTo("b/c"));
+            Assert.That("a/b/c/d/../..".ResolvePaths(), Is.EqualTo("a/b"));
+            Assert.That("a/b/../../c/d".ResolvePaths(), Is.EqualTo("c/d"));
+
+            Assert.That("a/..".ResolvePaths(), Is.EqualTo(""));
+            Assert.That("a/../..".ResolvePaths(), Is.EqualTo(".."));
+            Assert.That("a/../../".ResolvePaths(), Is.EqualTo("../"));
+            Assert.That("a/../../b".ResolvePaths(), Is.EqualTo("../b"));
+        }
+
+    }
+}