1 files changed, 39 insertions, 0 deletions
diff --git a/src/Cepis/RateLimitedException.cs b/src/Cepis/RateLimitedException.cs
new file mode 100644
index 0000000..da1e04c
--- /dev/null
+++ b/src/Cepis/RateLimitedException.cs
@@ -0,0 +1,39 @@
+namespace Cepis;
+
+/// <summary>
+/// The API, or the edge in front of it, answered 429 on every attempt.
+/// </summary>
+public sealed class RateLimitedException : CepisException
+{
+    /// <summary>Create the exception with a message and the wait requested.</summary>
+    /// <param name="message">what went wrong</param>
+    /// <param name="retryAfter">
+    /// what the server asked for, or <see langword="null"/> if it did not say
+    /// </param>
+    public RateLimitedException(string message, TimeSpan? retryAfter = null)
+        : base(message)
+    {
+        RetryAfter = retryAfter;
+    }
+
+    /// <summary>Create the exception with a message, the wait and a cause.</summary>
+    /// <param name="message">what went wrong</param>
+    /// <param name="retryAfter">what the server asked for, if anything</param>
+    /// <param name="innerException">the failure underneath</param>
+    public RateLimitedException(string message, TimeSpan? retryAfter, Exception? innerException)
+        : base(message, innerException)
+    {
+        RetryAfter = retryAfter;
+    }
+
+    /// <summary>
+    /// How long the server asked the caller to wait, or <see langword="null"/>
+    /// if it did not say.
+    /// </summary>
+    /// <remarks>
+    /// The client already honoured this across the attempts it made, capped at
+    /// <see cref="CepisClientOptions.BackoffMax"/>. It is exposed here for
+    /// callers who want to reschedule the work.
+    /// </remarks>
+    public TimeSpan? RetryAfter { get; }
+}