From 885d0d276c738df6a74e02318159bfe8638840ac Mon Sep 17 00:00:00 2001
From: NZSmartie <nzsmartie@gmail.com>
Date: Thu, 7 Sep 2017 22:19:27 +1200
Subject: [PATCH] Include full uri in CORELink format when Authoraty does not
 match.

---
 CoAPNet/CoreLinkFormat.cs      | 24 ++++++++++++++++--------
 CoAPNet/Utils/UriExtensions.cs | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 8 deletions(-)
 create mode 100644 CoAPNet/Utils/UriExtensions.cs

diff --git a/CoAPNet/CoreLinkFormat.cs b/CoAPNet/CoreLinkFormat.cs
index 8308d98..1120f1c 100644
--- a/CoAPNet/CoreLinkFormat.cs
+++ b/CoAPNet/CoreLinkFormat.cs
@@ -18,6 +18,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using CoAPNet.Utils;
 
 namespace CoAPNet
 {
@@ -217,14 +218,21 @@ public static List<CoapResourceMetadata> Parse(string message)
 
         private static readonly Uri _throwAwayUri = new Uri("coap://localhost/");
 
-        public static string ToCoreLinkFormat(CoapResourceMetadata resource)
+        public static string ToCoreLinkFormat(CoapResourceMetadata resource, Uri baseUri = null)
         {
             var message = new StringBuilder();
             try
             {
-                message.Append(resource.UriReference.IsAbsoluteUri
-                    ? $"<{resource.UriReference.AbsolutePath}>"
-                    : $"<{new Uri(_throwAwayUri, resource.UriReference).AbsolutePath}>");
+                if (baseUri == null)
+                    baseUri = _throwAwayUri;
+
+                var uri = resource.UriReference.IsAbsoluteUri
+                    ? resource.UriReference
+                    : new Uri(baseUri, resource.UriReference);
+
+                message.Append(CoapUri.Compare(uri, baseUri, UriComponents.HostAndPort, UriFormat.SafeUnescaped, StringComparison.OrdinalIgnoreCase) == 0
+                    ? $"<{uri.AbsolutePath}>"
+                    : $"<{uri}>");
 
                 if(resource.InterfaceDescription.Count > 0)
                 message.AppendFormat(";if=\"{0}\"", string.Join(" ", resource.InterfaceDescription));
@@ -248,8 +256,8 @@ public static string ToCoreLinkFormat(CoapResourceMetadata resource)
                 if (resource.Rel.Count > 1)
                     message.AppendFormat(";rel=\"{0}\"", string.Join(" ", resource.Rel));
 
-                if ((resource.Anchor ?? string.Empty) != string.Empty)
-                    message.Append($";anchor={resource.Anchor}");
+                if (!string.IsNullOrEmpty(resource.Anchor))
+                    message.Append($";anchor=\"{resource.Anchor}\"");
 
                 if ((resource.HrefLang ?? string.Empty) != string.Empty)
                     message.Append($";hreflang={resource.HrefLang?.ToLower()}");
@@ -317,9 +325,9 @@ public static string ToCoreLinkFormat(CoapResourceMetadata resource)
             return message.ToString();
         }
 
-        public static string ToCoreLinkFormat(IEnumerable<CoapResourceMetadata> resources)
+        public static string ToCoreLinkFormat(IEnumerable<CoapResourceMetadata> resources, Uri baseUri = null)
         {
-            return string.Join(",", resources.Select(ToCoreLinkFormat));
+            return string.Join(",", resources.Select(r => ToCoreLinkFormat(r, baseUri)));
         }
     }
 }
diff --git a/CoAPNet/Utils/UriExtensions.cs b/CoAPNet/Utils/UriExtensions.cs
new file mode 100644
index 0000000..c7eda67
--- /dev/null
+++ b/CoAPNet/Utils/UriExtensions.cs
@@ -0,0 +1,33 @@
+using System;
+using System.Linq;
+
+namespace CoAPNet.Utils
+{
+    // TODO: This helper class will be redundant in .Net Core 2.0 through sub-classing HttpStyleUriParser and adding CoAP defaults.
+    public static class CoapUri
+    {
+        private static readonly string[] _schemes = {"coap", "coaps"};
+
+        public static int Compare(Uri uri1, Uri uri2, UriComponents partsToCompare, UriFormat compareFormat, StringComparison comparisonType)
+        {
+            // Setup Default ports before performing comparasons.
+            if (_schemes.Contains(uri1.Scheme.ToLower()) && uri1.Port == -1)
+                uri1 = new UriBuilder(uri1)
+                {
+                    Port = uri1.Scheme == "coap" 
+                        ? Coap.Port 
+                        : Coap.PortDTLS
+                }.Uri;
+
+            if (_schemes.Contains(uri2.Scheme.ToLower()) && uri2.Port == -1)
+                uri2 = new UriBuilder(uri2)
+                {
+                    Port = uri2.Scheme == "coap"
+                        ? Coap.Port
+                        : Coap.PortDTLS
+                }.Uri;
+
+            return Uri.Compare(uri1, uri2, partsToCompare, compareFormat, comparisonType);
+        }
+    }
+}
\ No newline at end of file