fix: add exception handling to json read

Jellyfin.Plugin.Themerr.Tests/TestThemerrManager.cs

@@ -80,6 +80,14 @@ private void TestGetExistingThemerrDataValue()
 
         Assert.Null(_themerrManager.GetExistingThemerrDataValue("any_key", themerrDataPath));
 
+        // ensure null when the json is invalid
+        themerrDataPath = Path.Combine(
+            Directory.GetCurrentDirectory(),
+            "data",
+            "invalid.json");
+
+        Assert.Null(_themerrManager.GetExistingThemerrDataValue("any_key", themerrDataPath));
+
         // test empty json file
         themerrDataPath = Path.Combine(
             Directory.GetCurrentDirectory(),

Jellyfin.Plugin.Themerr.Tests/data/invalid.json

@@ -0,0 +1,5 @@
+{
+  "downloaded_timestamp": "2023-12-12T04:07:41.7659077Z",
+  "youtube_theme_url": "https://www.youtube.com/watch?v=E8nxMWr2sr4",
+  "dummy_key": "dummy_value"
+},

Jellyfin.Plugin.Themerr/ThemerrManager.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
@@ -68,8 +69,17 @@ public string GetExistingThemerrDataValue(string key, string themerrDataPath)
             }
 
             var jsonString = System.IO.File.ReadAllText(themerrDataPath);
-            dynamic jsonData = JsonConvert.DeserializeObject(jsonString);
-            return jsonData?[key];
+
+            try
+            {
+                dynamic jsonData = JsonConvert.DeserializeObject(jsonString);
+                return jsonData?[key];
+            }
+            catch (JsonReaderException e)
+            {
+                _logger.LogError(e, "Unable to parse themerr data file: {ThemerrDataPath}\n{JsonString}", themerrDataPath, jsonString);
+                return null;
+            }
         }
 
         /// <summary>
@@ -339,18 +349,31 @@ public string CreateThemerrDbLink(string tmdbId, string dbType)
         public string GetYoutubeThemeUrl(string themerrDbUrl, BaseItem item)
         {
             var client = new HttpClient();
+            string jsonString;
 
             try
             {
-                var jsonString = client.GetStringAsync(themerrDbUrl).Result;
-                dynamic jsonData = JsonConvert.DeserializeObject(jsonString);
-                return jsonData?.youtube_theme_url;
+                jsonString = client.GetStringAsync(themerrDbUrl).Result;
+            }
+            catch (HttpRequestException e) when (e.StatusCode == HttpStatusCode.NotFound)
+            {
+                #pragma warning disable S6667
+                _logger.LogWarning(
+                    "ThemerrDB entry not found (404): {ItemName}, contribute:\n  {IssueUrl}",
+                    item.Name,
+                    GetIssueUrl(item));
+                #pragma warning restore S6667
+
+                return string.Empty;
             }
             catch (Exception e)
             {
-                _logger.LogWarning(e, "Missing from ThemerrDB: {ItemTitle}, contribute:\n  {IssueUrl}", item.Name, GetIssueUrl(item));
+                _logger.LogError(e, "Error retrieving from ThemerrDB: {ItemName}", item.Name);
                 return string.Empty;
             }
+
+            dynamic jsonData = JsonConvert.DeserializeObject(jsonString);
+            return jsonData?.youtube_theme_url;
         }
 
         /// <summary>