From e39b20707bfffd6487329723d51a9f83750c7dbd Mon Sep 17 00:00:00 2001
From: Katherine Marsee <ksmarsee@gmail.com>
Date: Fri, 19 Jan 2024 22:41:51 -0500
Subject: [PATCH] Add Profile field support to HTTP ContentType (resolves #127)

---
 .../ActivityPub.Client/ActivityPubClient.cs   | 24 +++++++++++++----
 .../Util/ActivityPubOptions.cs                | 27 ++++++++++++-------
 2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/Source/ActivityPub.Client/ActivityPubClient.cs b/Source/ActivityPub.Client/ActivityPubClient.cs
index 1b473ce..896e69f 100644
--- a/Source/ActivityPub.Client/ActivityPubClient.cs
+++ b/Source/ActivityPub.Client/ActivityPubClient.cs
@@ -33,7 +33,10 @@ public ActivityPubClient(ActivityPubOptions apOptions, IJsonLdSerializer jsonLdS
         // https://stackoverflow.com/questions/47176104/c-sharp-add-accept-header-to-httpclient
         foreach (var mimeType in apOptions.RequestContentTypes)
         {
-            var mediaType = new MediaTypeWithQualityHeaderValue(mimeType);
+            var mediaType = new MediaTypeWithQualityHeaderValue(mimeType.MediaType);
+            if (mimeType.Profile != "") {
+                mediaType.Parameters.Add(new NameValueHeaderValue("profile", mimeType.Profile));
+            }
             _httpClient.DefaultRequestHeaders.Accept.Add(mediaType);
         }
     }
@@ -83,9 +86,9 @@ private async Task<ASType> Get(Uri uri, Type targetType, int? maxRecursion, Canc
         if (!resp.IsSuccessStatusCode)
             throw new ApplicationException($"Request failed: got status {resp.StatusCode}");
 
-        var mediaType = resp.Content.Headers.ContentType?.MediaType;
-        if (mediaType == null || !_apOptions.ResponseContentTypes.Contains(mediaType))
-            throw new ApplicationException($"Request failed: unsupported content type {mediaType}");
+        var contentType = resp.Content.Headers.ContentType;
+        if (contentType == null || !_apOptions.ResponseContentTypes.Any(expectedContentType => IsContentTypeMatch(contentType, expectedContentType)))
+            throw new ApplicationException($"Request failed: unsupported content type {contentType?.MediaType}");
 
         var json = await resp.Content.ReadAsStringAsync(cancellationToken);
         var jsonObj = _jsonLdSerializer.Deserialize(json, targetType);
@@ -100,6 +103,17 @@ private async Task<ASType> Get(Uri uri, Type targetType, int? maxRecursion, Canc
         return obj;
     }
 
+    private static bool IsContentTypeMatch(MediaTypeHeaderValue actual, ActivityPubOptions.ContentType expected) {
+        if (!expected.MediaType.Equals(actual.MediaType)) {
+            return false;
+        }
+
+        var actualProfile = actual.Parameters.FirstOrDefault(p => p.Name.Equals("profile"))?.Value ?? "";
+
+        return string.Equals(actualProfile, expected.Profile,
+            StringComparison.OrdinalIgnoreCase);
+    }
+
 
     #region Dispose
 
@@ -130,4 +144,4 @@ protected virtual void Dispose(bool disposing)
     private bool _disposed;
 
     #endregion
-}
\ No newline at end of file
+}
diff --git a/Source/ActivityPub.Common/Util/ActivityPubOptions.cs b/Source/ActivityPub.Common/Util/ActivityPubOptions.cs
index 8a05a61..aee2f12 100644
--- a/Source/ActivityPub.Common/Util/ActivityPubOptions.cs
+++ b/Source/ActivityPub.Common/Util/ActivityPubOptions.cs
@@ -13,11 +13,12 @@ public class ActivityPubOptions
     ///     This maps to the Content-Type header.
     /// </summary>
     /// <seealso href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type" />
-    public HashSet<string> ResponseContentTypes { get; set; } =
+    public HashSet<ContentType> ResponseContentTypes { get; set; } =
     [
-        "application/activity+json",
-        "application/ld+json",
-        "application/json"
+        new ContentType("application/ld+json", "https://www.w3.org/ns/activitystreams"),
+        new ContentType("application/activity+json", ""),
+        new ContentType("application/ld+json", ""),
+        new ContentType("application/json", "")
     ];
 
     /// <summary>
@@ -25,10 +26,18 @@ public class ActivityPubOptions
     ///     This maps to the Accept header.
     /// </summary>
     /// <seealso href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept" />
-    public List<string> RequestContentTypes { get; set; } =
+    public List<ContentType> RequestContentTypes { get; set; } =
     [
-        "application/activity+json",
-        "application/ld+json",
-        "application/json"
+        new ContentType("application/ld+json", "https://www.w3.org/ns/activitystreams"),
+        new ContentType("application/activity+json", ""),
+        new ContentType("application/ld+json", ""),
+        new ContentType("application/json", "")
     ];
-}
\ No newline at end of file
+
+    /// <summary>
+    ///     A Record that contains the MediaType and Profile for the HTTP Content-Type and Accept Headers
+    /// </summary>
+    /// <param name="MediaType">A MIME type for the header</param>
+    /// <param name="Profile">A profile to append to the MIME type, leave empty for none</param>
+    public record struct ContentType(string MediaType, string Profile);
+}