Include Ruleset ID in /difficulty

Author: MingxuanGame

PerformanceServer/BeatmapDifficultyController.cs

@@ -51,12 +51,19 @@ public async Task<ActionResult<DifficultyAttributes>> CalculateDifficulty([FromB
                 }
             }
 
-            Ruleset ruleset = Helper.GetRuleset(body.RulesetId ?? workingBeatmap.BeatmapInfo.Ruleset.OnlineID);
+            int rulesetId = body.RulesetId ?? workingBeatmap.BeatmapInfo.Ruleset.OnlineID;
+            Ruleset ruleset = Helper.GetRuleset(rulesetId);
             Mod[] mods = body.Mods.Select(m => m.ToMod(ruleset)).ToArray();
             DifficultyAttributes? difficultyAttributes =
                 ruleset.CreateDifficultyCalculator(workingBeatmap).Calculate(mods);
 
-            return Ok(difficultyAttributes);
+            Dictionary<string, object>? attr =
+                JsonConvert.DeserializeObject<Dictionary<string, object>>(
+                    JsonConvert.SerializeObject(difficultyAttributes));
+            if (attr != null)
+                attr["ruleset_id"] = rulesetId;
+
+            return attr != null ? Ok(attr) : BadRequest("Failed to calculate difficulty.");
         }
     }
 }

README.md

@@ -88,7 +88,7 @@ Minimal example:
 }
 ```
 
-Successful Response: `200 OK` with a JSON `PerformanceAttributes` object including (fields differ by ruleset):
+Successful Response: `200 OK` with a JSON `PerformanceAttributes` object with `ruleset_id` including (fields differ by ruleset):
 - `total` (float) Total pp value.
 - Component breakdown fields (aim, speed, flashlight, accuracy, strain, etc.)
 - Embedded `DifficultyAttributes` subset depending on version
@@ -123,7 +123,9 @@ Advanced mods with settings (e.g., DT with speed change) are not yet surfaced he
 - Providing a `checksum` with a cached map triggers integrity verification (MD5). A mismatch forces redownload.
 
 ## Troubleshooting
-| Issue              | Cause                              | Resolution                                               |
-|--------------------|------------------------------------|----------------------------------------------------------|
-| 503 on fetch       | Beatmap not reachable              | Verify ID exists, network, or site availability          |
-| 400 on performance | Invalid statistics / internal null | Ensure ruleset matches beatmap & stats not contradictory |
+| Issue              | Cause                              | Resolution                                                             |
+|--------------------|------------------------------------|------------------------------------------------------------------------|
+| 503 on fetch       | Beatmap not reachable              | Verify ID exists, network, or site availability                        |
+| 400 on performance | Invalid statistics / internal null | Ensure ruleset matches beatmap & stats not contradictory               |
+| 400 on difficulty  | Invalid beatmap / ruleset          | Ensure beatmap is valid & beatmap can be convert into specific ruleset |
+