From b29c89cdd48ccb7d0094b1115de7876a095b270e Mon Sep 17 00:00:00 2001
From: Rory& <root@rory.gay>
Date: Sun, 5 Jul 2026 22:26:15 +0200
Subject: More verbose/typed handling for errors resolving homeservers

---
 LibMatrix/LibMatrixException.cs                 |  7 ++++++-
 LibMatrix/Services/HomeserverResolverService.cs | 16 +++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/LibMatrix/LibMatrixException.cs b/LibMatrix/LibMatrixException.cs
index 27cfc2a..e066d6c 100644
--- a/LibMatrix/LibMatrixException.cs
+++ b/LibMatrix/LibMatrixException.cs
@@ -1,6 +1,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Text.Json.Serialization;
 using ArcaneLibs.Extensions;
+
 // ReSharper disable MemberCanBePrivate.Global
 
 namespace LibMatrix;
@@ -12,13 +13,15 @@ public class LibMatrixException : Exception {
     [JsonPropertyName("error")]
     public required string Error { get; set; }
 
-
     public object GetAsObject() => new { errcode = ErrorCode, error = Error };
     public string GetAsJson() => GetAsObject().ToJson(ignoreNull: true);
 
     public override string Message =>
         $"{ErrorCode}: {ErrorCode switch {
+            "M_NOT_FOUND" => "The specified entity could not be found",
             "M_UNSUPPORTED" => "The requested feature is not supported",
+            "RLM_NO_CLIENT_URL" => "Could not resolve client URL",
+            "RLM_NO_SERVER_URL" => "Could not resolve server URL",
             _ => $"Unknown error: {GetAsObject().ToJson(ignoreNull: true)}"
         }}\nError: {Error}";
 
@@ -26,5 +29,7 @@ public class LibMatrixException : Exception {
     public static class ErrorCodes {
         public const string M_NOT_FOUND = "M_NOT_FOUND";
         public const string M_UNSUPPORTED = "M_UNSUPPORTED";
+        public const string RLM_NO_CLIENT_URL = "RLM_NO_CLIENT_URL";
+        public const string RLM_NO_SERVER_URL = "RLM_NO_SERVER_URL";
     }
 }
\ No newline at end of file
diff --git a/LibMatrix/Services/HomeserverResolverService.cs b/LibMatrix/Services/HomeserverResolverService.cs
index ed1d2e3..700cfbb 100644
--- a/LibMatrix/Services/HomeserverResolverService.cs
+++ b/LibMatrix/Services/HomeserverResolverService.cs
@@ -37,16 +37,22 @@ public class HomeserverResolverService {
             var res = new WellKnownUris();
 
             if (client != null)
-                res.Client = (await client)?.TrimEnd('/') ?? throw new Exception($"Could not resolve client URL for {homeserver}.");
+                res.Client = (await client)?.TrimEnd('/') ?? throw new LibMatrixException() {
+                    ErrorCode = LibMatrixException.ErrorCodes.RLM_NO_CLIENT_URL,
+                    Error = $"Could not resolve client URL for {homeserver}."
+                };
 
             if (server != null)
-                res.Server = (await server)?.TrimEnd('/') ?? throw new Exception($"Could not resolve server URL for {homeserver}.");
+                res.Server = (await server)?.TrimEnd('/') ?? throw new LibMatrixException() {
+                    ErrorCode = LibMatrixException.ErrorCodes.RLM_NO_SERVER_URL,
+                    Error = $"Could not resolve server URL for {homeserver}."
+                };
 
             _logger.LogInformation("Resolved well-knowns for {hs}: {json}", homeserver, res.ToJson(indent: false));
             return res;
         });
     }
-    
+
     private async Task<T?> GetFromJsonAsync<T>(string url) {
         try {
             return await _httpClient.GetFromJsonAsync<T>(url);
@@ -56,7 +62,7 @@ public class HomeserverResolverService {
             return default;
         }
     }
-    
+
     private async Task<string?> _tryResolveClientEndpoint(string homeserver) {
         ArgumentNullException.ThrowIfNull(homeserver);
         _logger.LogTrace("Resolving client well-known: {homeserver}", homeserver);
@@ -71,7 +77,7 @@ public class HomeserverResolverService {
         }
         else if (homeserver.StartsWith("http://")) {
             clientWellKnown = await GetFromJsonAsync<ClientWellKnown>($"{homeserver}/.well-known/matrix/client");
-            
+
             if (clientWellKnown is null && await MatrixHttpClient.CheckSuccessStatus($"{homeserver}/_matrix/client/versions"))
                 return homeserver;
         }
-- 
cgit 1.5.1