From b34b742cebb162221d55b658bd5fa5ed9afd1643 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=AA=20Trung=20Hi=E1=BA=BFu?= <letrunghieu@example.com>
Date: Wed, 8 Jul 2026 08:59:05 +0700
Subject: [PATCH] refactor: replace regex JSON parsing with
 DataContractJsonSerializer

- Add GitHubRelease DTO and deserialize the GitHub API response properly.

- Use System.Runtime.Serialization.Json.DataContractJsonSerializer (built into .NET Framework 4.8).

- Preserve existing fallback behavior: invalid/empty responses yield no tags.

- Remove Regex using directive.

- dotnet test passes 58/58.

Closes #36.
---
 src/KeePassAutoReload.csproj |  2 ++
 src/UpdateChecker.cs         | 43 +++++++++++++++++++++++++++---------
 2 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/src/KeePassAutoReload.csproj b/src/KeePassAutoReload.csproj
index a53b5be..c137007 100644
--- a/src/KeePassAutoReload.csproj
+++ b/src/KeePassAutoReload.csproj
@@ -19,7 +19,9 @@
     <Reference Include="System" />
     <Reference Include="System.Drawing" />
     <Reference Include="System.Net.Http" />
+    <Reference Include="System.Runtime.Serialization" />
     <Reference Include="System.Windows.Forms" />
+    <Reference Include="System.Xml" />
     <Reference Include="KeePass">
       <HintPath>$(KeePassReferencePath)\KeePass.exe</HintPath>
     </Reference>
diff --git a/src/UpdateChecker.cs b/src/UpdateChecker.cs
index 533f92f..4edf880 100644
--- a/src/UpdateChecker.cs
+++ b/src/UpdateChecker.cs
@@ -4,8 +4,9 @@
 using System.Net;
 using System.Net.Http;
 using System.Reflection;
+using System.Runtime.Serialization;
+using System.Runtime.Serialization.Json;
 using System.Security.Authentication;
-using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -20,6 +21,13 @@ internal sealed class UpdateInfo
         public bool IsUpdateAvailable;
     }
 
+    [DataContract]
+    internal sealed class GitHubRelease
+    {
+        [DataMember]
+        public string tag_name { get; set; }
+    }
+
     internal interface IUpdateClient
     {
         Task<string> DownloadStringAsync(string url, CancellationToken cancellationToken = default);
@@ -110,7 +118,7 @@ public static async Task<UpdateInfo> CheckLatestAsync(IUpdateClient client, Plug
 
             cancellationToken.ThrowIfCancellationRequested();
             string json = await client.DownloadStringAsync(ReleasesApiUrl, cancellationToken);
-            string tagName = GetNewestVersionTag(ExtractJsonStrings(json, "tag_name").ToArray());
+            string tagName = GetNewestVersionTag(ExtractVersionTags(json));
 
             UpdateInfo info = new UpdateInfo();
             info.LatestVersion = tagName;
@@ -188,18 +196,33 @@ private static string BuildChecksumUrl(string tagName)
             return "https://github.com/hieuck/KeePassAutoReload/releases/download/" + tagName + "/SHA256SUMS.txt";
         }
 
-        private static List<string> ExtractJsonStrings(string json, string name)
+        private static string[] ExtractVersionTags(string json)
         {
-            List<string> values = new List<string>();
-            if (string.IsNullOrEmpty(json)) return values;
+            if (string.IsNullOrWhiteSpace(json)) return new string[0];
 
-            MatchCollection matches = Regex.Matches(json, "\"" + Regex.Escape(name) + "\"\\s*:\\s*\"(?<value>(?:\\\\.|[^\"])*)\"");
-            foreach (Match match in matches)
+            try
+            {
+                using (MemoryStream stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(json)))
+                {
+                    DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(List<GitHubRelease>));
+                    List<GitHubRelease> releases = (List<GitHubRelease>)serializer.ReadObject(stream);
+                    if (releases == null) return new string[0];
+
+                    List<string> tags = new List<string>();
+                    foreach (GitHubRelease release in releases)
+                    {
+                        if (release != null && !string.IsNullOrWhiteSpace(release.tag_name))
+                        {
+                            tags.Add(release.tag_name);
+                        }
+                    }
+                    return tags.ToArray();
+                }
+            }
+            catch
             {
-                if (match.Success) values.Add(Regex.Unescape(match.Groups["value"].Value));
+                return new string[0];
             }
-
-            return values;
         }
     }
 }