History Polling: Message-ID-basiert, neuer /api/history/poll Endpoint

Endpoints/HistoryEndpoint.cs

@@ -14,6 +14,7 @@ public static class HistoryEndpoint
     public static void MapHistoryEndpoint(this IEndpointRouteBuilder app)
     {
         app.MapGet("/api/history", HandleHistory);
+        app.MapGet("/api/history/poll", HandlePoll);
     }
 
     private static async Task HandleHistory(HttpContext ctx, DatabaseService db)
@@ -37,4 +38,13 @@ public static class HistoryEndpoint
 
         await ctx.Response.WriteAsJsonAsync(result);
     }
+
+    private static async Task HandlePoll(HttpContext ctx, DatabaseService db)
+    {
+        var afterStr = ctx.Request.Query["afterId"].FirstOrDefault();
+        var afterId = long.TryParse(afterStr, out var a) ? a : 0;
+
+        var messages = await db.GetMessagesAfterId(afterId);
+        await ctx.Response.WriteAsJsonAsync(messages);
+    }
 }