From 8a84237f138ad81f33bd6be634f530a4238821a1 Mon Sep 17 00:00:00 2001
From: Josh Patra <joshpatra12@gmail.com>
Date: Tue, 3 Feb 2026 23:56:40 -0500
Subject: [PATCH] Fix MediaSources field appending to query string

- Properly parse and modify Fields parameter instead of appending to end
- Fixes 400 BadRequest errors from malformed URLs
- Now correctly adds MediaSources to Fields parameter value
---
 allstarr/Controllers/JellyfinController.cs | 49 ++++++++++++++++++----
 1 file changed, 41 insertions(+), 8 deletions(-)

diff --git a/allstarr/Controllers/JellyfinController.cs b/allstarr/Controllers/JellyfinController.cs
index ff64aee..b4d9a66 100644
--- a/allstarr/Controllers/JellyfinController.cs
+++ b/allstarr/Controllers/JellyfinController.cs
@@ -126,17 +126,50 @@ public class JellyfinController : ControllerBase
             
             // Ensure MediaSources is included in Fields parameter for bitrate info
             var queryString = Request.QueryString.Value ?? "";
-            if (!queryString.Contains("Fields=", StringComparison.OrdinalIgnoreCase))
+            
+            if (!string.IsNullOrEmpty(queryString))
             {
-                // No Fields parameter, add MediaSources
-                queryString = string.IsNullOrEmpty(queryString) 
-                    ? "?Fields=MediaSources" 
-                    : $"{queryString}&Fields=MediaSources";
+                // Parse query string to modify Fields parameter
+                var queryParams = Microsoft.AspNetCore.WebUtilities.QueryHelpers.ParseQuery(queryString);
+                
+                if (queryParams.ContainsKey("Fields"))
+                {
+                    var fieldsValue = queryParams["Fields"].ToString();
+                    if (!fieldsValue.Contains("MediaSources", StringComparison.OrdinalIgnoreCase))
+                    {
+                        // Append MediaSources to existing Fields
+                        var newFields = string.IsNullOrEmpty(fieldsValue) 
+                            ? "MediaSources" 
+                            : $"{fieldsValue},MediaSources";
+                        
+                        // Rebuild query string with updated Fields
+                        var newQueryParams = new Dictionary<string, string>();
+                        foreach (var kvp in queryParams)
+                        {
+                            if (kvp.Key == "Fields")
+                            {
+                                newQueryParams[kvp.Key] = newFields;
+                            }
+                            else
+                            {
+                                newQueryParams[kvp.Key] = kvp.Value.ToString();
+                            }
+                        }
+                        
+                        queryString = "?" + string.Join("&", newQueryParams.Select(kvp => 
+                            $"{Uri.EscapeDataString(kvp.Key)}={Uri.EscapeDataString(kvp.Value)}"));
+                    }
+                }
+                else
+                {
+                    // No Fields parameter, add it
+                    queryString = $"{queryString}&Fields=MediaSources";
+                }
             }
-            else if (!queryString.Contains("MediaSources", StringComparison.OrdinalIgnoreCase))
+            else
             {
-                // Fields parameter exists but doesn't include MediaSources, append it
-                queryString = $"{queryString},MediaSources";
+                // No query string at all
+                queryString = "?Fields=MediaSources";
             }
             
             endpoint = $"{endpoint}{queryString}";