1 files changed, 18 insertions, 24 deletions

diff --git a/Emby.Dlna/DlnaManager.cs b/Emby.Dlna/DlnaManager.cs
index 2ea2c130f..99b3e6e7e 100644
--- a/Emby.Dlna/DlnaManager.cs
+++ b/Emby.Dlna/DlnaManager.cs
@@ -105,9 +105,9 @@ namespace Emby.Dlna
             ArgumentNullException.ThrowIfNull(deviceInfo);
 
             var profile = GetProfiles()
-                .FirstOrDefault(i => i.Identification != null && IsMatch(deviceInfo, i.Identification));
+                .FirstOrDefault(i => i.Identification is not null && IsMatch(deviceInfo, i.Identification));
 
-            if (profile == null)
+            if (profile is null)
             {
                 _logger.LogInformation("No matching device profile found. The default will need to be used. \n{@Profile}", deviceInfo);
             }
@@ -171,8 +171,8 @@ namespace Emby.Dlna
         {
             ArgumentNullException.ThrowIfNull(headers);
 
-            var profile = GetProfiles().FirstOrDefault(i => i.Identification != null && IsMatch(headers, i.Identification));
-            if (profile == null)
+            var profile = GetProfiles().FirstOrDefault(i => i.Identification is not null && IsMatch(headers, i.Identification));
+            if (profile is null)
             {
                 _logger.LogDebug("No matching device profile found. {@Headers}", headers);
             }
@@ -199,6 +199,11 @@ namespace Emby.Dlna
 
             if (headers.TryGetValue(header.Name, out StringValues value))
             {
+                if (StringValues.IsNullOrEmpty(value))
+                {
+                    return false;
+                }
+
                 switch (header.Match)
                 {
                     case HeaderMatchType.Equals:
@@ -208,7 +213,8 @@ namespace Emby.Dlna
                         // _logger.LogDebug("IsMatch-Substring value: {0} testValue: {1} isMatch: {2}", value, header.Value, isMatch);
                         return isMatch;
                     case HeaderMatchType.Regex:
-                        return Regex.IsMatch(value, header.Value, RegexOptions.IgnoreCase);
+                        // Can't be null, we checked above the switch statement
+                        return Regex.IsMatch(value!, header.Value, RegexOptions.IgnoreCase);
                     default:
                         throw new ArgumentException("Unrecognized HeaderMatchType");
                 }
@@ -224,7 +230,7 @@ namespace Emby.Dlna
                 return _fileSystem.GetFilePaths(path)
                     .Where(i => string.Equals(Path.GetExtension(i), ".xml", StringComparison.OrdinalIgnoreCase))
                     .Select(i => ParseProfileFile(i, type))
-                    .Where(i => i != null)
+                    .Where(i => i is not null)
                     .ToList()!; // We just filtered out all the nulls
             }
             catch (IOException)
@@ -265,14 +271,11 @@ namespace Emby.Dlna
         /// <inheritdoc />
         public DeviceProfile? GetProfile(string id)
         {
-            if (string.IsNullOrEmpty(id))
-            {
-                throw new ArgumentNullException(nameof(id));
-            }
+            ArgumentException.ThrowIfNullOrEmpty(id);
 
             var info = GetProfileInfosInternal().FirstOrDefault(i => string.Equals(i.Info.Id, id, StringComparison.OrdinalIgnoreCase));
 
-            if (info == null)
+            if (info is null)
             {
                 return null;
             }
@@ -371,10 +374,7 @@ namespace Emby.Dlna
         {
             profile = ReserializeProfile(profile);
 
-            if (string.IsNullOrEmpty(profile.Name))
-            {
-                throw new ArgumentException("Profile is missing Name");
-            }
+            ArgumentException.ThrowIfNullOrEmpty(profile.Name);
 
             var newFilename = _fileSystem.GetValidFilename(profile.Name) + ".xml";
             var path = Path.Combine(UserProfilesPath, newFilename);
@@ -387,15 +387,9 @@ namespace Emby.Dlna
         {
             profile = ReserializeProfile(profile);
 
-            if (string.IsNullOrEmpty(profile.Id))
-            {
-                throw new ArgumentException("Profile is missing Id");
-            }
+            ArgumentException.ThrowIfNullOrEmpty(profile.Id);
 
-            if (string.IsNullOrEmpty(profile.Name))
-            {
-                throw new ArgumentException("Profile is missing Name");
-            }
+            ArgumentException.ThrowIfNullOrEmpty(profile.Name);
 
             var current = GetProfileInfosInternal().First(i => string.Equals(i.Info.Id, profileId, StringComparison.OrdinalIgnoreCase));
             if (current.Info.Type == DeviceProfileType.System)
@@ -470,7 +464,7 @@ namespace Emby.Dlna
 
             var resource = GetType().Namespace + ".Images." + filename.ToLowerInvariant();
             var stream = _assembly.GetManifestResourceStream(resource);
-            if (stream == null)
+            if (stream is null)
             {
                 return null;
             }