2 files changed, 48 insertions(+), 4 deletions(-)

M src/Anonymizer/Filters/HeaderFilter.cs
M src/Anonymizer/Filters/HeaderFilterOptions.cs

@@ 32,6 32,11 @@ public class HeaderFilter : IFilter
         }
 
         var header = splitted[0];
+        if (_options.KeepHeaders is not null)
+        {
+            return _options.KeepHeaders.Contains(header);
+        }
+
         return !_options.RemoveHeaders.Contains(header);
     }
 }=
\ No newline at end of file

@@ 6,7 6,46 @@
 
 namespace Anonymizer.Filters;
 
-public record HeaderFilterOptions
-(
-    IReadOnlyList<string> RemoveHeaders
-);>
\ No newline at end of file
+/// <summary>
+/// Options for <see cref="HeaderFilter"/>.
+/// </summary>
+public class HeaderFilterOptions
+{
+    /// <summary>
+    /// Gets or sets the headers to remove. <see cref="KeepHeaders"/> is prioritized.
+    /// </summary>
+    public IReadOnlyList<string> RemoveHeaders { get; set; } = new[]
+    {
+        "mv",
+        "stat",
+        "say",
+        "spk",
+        "bn",
+        "inv",
+
+        "qslot",
+        "umi",
+        "msgi2",
+        "qnai2",
+
+        "die",
+
+        "throw",
+
+        "bf",
+        "bf_e",
+        "dm",
+        "finit",
+        "finfo",
+        "ptctl",
+        "suctl", // figure out what it does
+        "ct", // figure out what it does
+    };
+
+    /// <summary>
+    /// Gets or sets the headers to keep. Takes priority before remove headers.
+    /// </summary>
+    public IReadOnlyList<string>? KeepHeaders { get; set; } = null;
+
+    // rdlst, raid, raidmbf, raidbf, in, out, c_info, c_mode
+}<
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