From a86fc3866056908d4ac1b67786be05d6bc2764dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Thu, 2 Feb 2023 10:13:54 +0100
Subject: [PATCH] feat: add packet filters

---
 .../Models/Filters/CompoundFilter.cs          | 46 +++++++++++++
 .../Models/Filters/ContainsFilter.cs          | 36 +++++++++++
 .../Models/Filters/FilterCreator.cs           | 64 +++++++++++++++++++
 src/PacketLogger/Models/Filters/IFilter.cs    | 27 ++++++++
 .../Models/Filters/PacketHeaderFilter.cs      | 54 ++++++++++++++++
 .../Models/Filters/SendRecvFilter.cs          | 44 +++++++++++++
 .../Models/Filters/StartsWithFilter.cs        | 35 ++++++++++
 7 files changed, 306 insertions(+)
 create mode 100644 src/PacketLogger/Models/Filters/CompoundFilter.cs
 create mode 100644 src/PacketLogger/Models/Filters/ContainsFilter.cs
 create mode 100644 src/PacketLogger/Models/Filters/FilterCreator.cs
 create mode 100644 src/PacketLogger/Models/Filters/IFilter.cs
 create mode 100644 src/PacketLogger/Models/Filters/PacketHeaderFilter.cs
 create mode 100644 src/PacketLogger/Models/Filters/SendRecvFilter.cs
 create mode 100644 src/PacketLogger/Models/Filters/StartsWithFilter.cs

diff --git a/src/PacketLogger/Models/Filters/CompoundFilter.cs b/src/PacketLogger/Models/Filters/CompoundFilter.cs
new file mode 100644
index 0000000..fe48f5f
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/CompoundFilter.cs
@@ -0,0 +1,46 @@
+//
+//  CompoundFilter.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using PacketLogger.Models.Packets;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// A filter created from multiple filters joined by "OR".
+/// </summary>
+public class CompoundFilter : IFilter
+{
+    private readonly bool _negate;
+    private readonly IFilter[] _filters;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CompoundFilter"/> class.
+    /// </summary>
+    /// <param name="negate">Whether to negate the result (false - whitelist, true - blacklist).</param>
+    /// <param name="filters">The filters to use.</param>
+    public CompoundFilter(bool negate, params IFilter[] filters)
+    {
+        _negate = negate;
+        _filters = filters;
+    }
+
+    /// <inheritdoc />
+    public string FilterString => "Many";
+
+    /// <inheritdoc />
+    public bool Match(PacketInfo packet)
+    {
+        foreach (var filter in _filters)
+        {
+            if (filter.Match(packet))
+            {
+                return !_negate;
+            }
+        }
+
+        return _negate;
+    }
+}
\ No newline at end of file
diff --git a/src/PacketLogger/Models/Filters/ContainsFilter.cs b/src/PacketLogger/Models/Filters/ContainsFilter.cs
new file mode 100644
index 0000000..c7e3504
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/ContainsFilter.cs
@@ -0,0 +1,36 @@
+//
+//  ContainsFilter.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using PacketLogger.Models.Packets;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// Filters packets that contain the given string.
+/// </summary>
+public class ContainsFilter : IFilter
+{
+    private readonly string _contains;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ContainsFilter"/> class.
+    /// </summary>
+    /// <param name="contains">The string to filter.</param>
+    public ContainsFilter(string contains)
+    {
+        _contains = contains;
+    }
+
+    /// <inheritdoc />
+    public string FilterString => _contains;
+
+    /// <inheritdoc />
+    public bool Match(PacketInfo packet)
+    {
+        return packet.PacketString.Contains(_contains, StringComparison.OrdinalIgnoreCase);
+    }
+}
\ No newline at end of file
diff --git a/src/PacketLogger/Models/Filters/FilterCreator.cs b/src/PacketLogger/Models/Filters/FilterCreator.cs
new file mode 100644
index 0000000..e258076
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/FilterCreator.cs
@@ -0,0 +1,64 @@
+//
+//  FilterCreator.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Diagnostics;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// A builder/creator of <see cref="IFilter"/>.
+/// </summary>
+public static class FilterCreator
+{
+    /// <summary>
+    /// A type of a filter.
+    /// </summary>
+    public enum FilterType
+    {
+        /// <summary>
+        /// <see cref="PacketHeaderFilter"/>.
+        /// </summary>
+        PacketHeader,
+
+        /// <summary>
+        /// <see cref="ContainsFilter"/>.
+        /// </summary>
+        Contains,
+
+        /// <summary>
+        /// <see cref="StartsWithFilter"/>.
+        /// </summary>
+        StartsWith
+    }
+
+    /// <summary>
+    /// Information about a filter to create.
+    /// </summary>
+    /// <param name="Type">The type of the filter.</param>
+    /// <param name="Value">The value.</param>
+    public record FilterData(FilterType Type, string Value);
+
+    /// <summary>
+    /// Build a filter of the given type and value.
+    /// </summary>
+    /// <param name="type">The type of the filter to build.</param>
+    /// <param name="value">The value of the filter.</param>
+    /// <returns>A filter.</returns>
+    public static IFilter BuildFilter(FilterType type, string value)
+    {
+        switch (type)
+        {
+            case FilterType.Contains:
+                return new ContainsFilter(value);
+            case FilterType.PacketHeader:
+                return new PacketHeaderFilter(value);
+            case FilterType.StartsWith:
+                return new StartsWithFilter(value);
+        }
+
+        throw new UnreachableException();
+    }
+}
\ No newline at end of file
diff --git a/src/PacketLogger/Models/Filters/IFilter.cs b/src/PacketLogger/Models/Filters/IFilter.cs
new file mode 100644
index 0000000..da05228
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/IFilter.cs
@@ -0,0 +1,27 @@
+//
+//  IFilter.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using PacketLogger.Models.Packets;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// Filter a packet.
+/// </summary>
+public interface IFilter
+{
+    /// <summary>
+    /// The string to filter.
+    /// </summary>
+    public string FilterString { get; }
+
+    /// <summary>
+    /// Match the given packet.
+    /// </summary>
+    /// <param name="packet">The packet info.</param>
+    /// <returns>Whether to keep the packet.</returns>
+    public bool Match(PacketInfo packet);
+}
\ No newline at end of file
diff --git a/src/PacketLogger/Models/Filters/PacketHeaderFilter.cs b/src/PacketLogger/Models/Filters/PacketHeaderFilter.cs
new file mode 100644
index 0000000..246a990
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/PacketHeaderFilter.cs
@@ -0,0 +1,54 @@
+//
+//  PacketHeaderFilter.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Reflection.Emit;
+using System.Reflection.PortableExecutable;
+using PacketLogger.Models.Packets;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// Filters packets that start with the given header.
+/// </summary>
+public class PacketHeaderFilter : IFilter
+{
+    private readonly string _header;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="PacketHeaderFilter"/> class.
+    /// </summary>
+    /// <param name="header">The header to filter.</param>
+    public PacketHeaderFilter(string header)
+    {
+        _header = header.Trim();
+    }
+
+    /// <inheritdoc />
+    public string FilterString => _header;
+
+    /// <inheritdoc/>
+    public bool Match(PacketInfo packet)
+    {
+        var packetString = packet.PacketString;
+
+        var split = ' ';
+        if (packetString.StartsWith('#'))
+        {
+            packetString = packetString.Substring(1);
+            split = '^';
+        }
+
+        var splitted = packetString.Split(split, 2);
+
+        if (splitted.Length >= 1)
+        {
+            return string.Compare(splitted[0], _header, StringComparison.OrdinalIgnoreCase) == 0;
+        }
+
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/src/PacketLogger/Models/Filters/SendRecvFilter.cs b/src/PacketLogger/Models/Filters/SendRecvFilter.cs
new file mode 100644
index 0000000..c5dd385
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/SendRecvFilter.cs
@@ -0,0 +1,44 @@
+//
+//  SendRecvFilter.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using NosSmooth.PacketSerializer.Abstractions.Attributes;
+using PacketLogger.Models.Packets;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// Filter using different matches for sent and received packets.
+/// </summary>
+public class SendRecvFilter : IFilter
+{
+    private readonly IFilter _sendFilter;
+    private readonly IFilter _recvFilter;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SendRecvFilter"/> class.
+    /// </summary>
+    /// <param name="sendFilter">The filter for sent packets.</param>
+    /// <param name="recvFilter">The filter for received packets.</param>
+    public SendRecvFilter(IFilter sendFilter, IFilter recvFilter)
+    {
+        _sendFilter = sendFilter;
+        _recvFilter = recvFilter;
+    }
+
+    /// <inheritdoc />
+    public string FilterString => "SendRecv";
+
+    /// <inheritdoc />
+    public bool Match(PacketInfo packet)
+    {
+        if (packet.Source == PacketSource.Server)
+        {
+            return _recvFilter.Match(packet);
+        }
+
+        return _sendFilter.Match(packet);
+    }
+}
\ No newline at end of file
diff --git a/src/PacketLogger/Models/Filters/StartsWithFilter.cs b/src/PacketLogger/Models/Filters/StartsWithFilter.cs
new file mode 100644
index 0000000..2ecdd64
--- /dev/null
+++ b/src/PacketLogger/Models/Filters/StartsWithFilter.cs
@@ -0,0 +1,35 @@
+//
+//  StartsWithFilter.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using PacketLogger.Models.Packets;
+
+namespace PacketLogger.Models.Filters;
+
+/// <summary>
+/// Filters packets that start with the given string.
+/// </summary>
+public class StartsWithFilter : IFilter
+{
+    private string _startsWith;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="StartsWithFilter"/> class.
+    /// </summary>
+    /// <param name="startsWith">The string to filter.</param>
+    public StartsWithFilter(string startsWith)
+    {
+        _startsWith = startsWith;
+    }
+
+    /// <inheritdoc />
+    public string FilterString => _startsWith;
+
+    /// <inheritdoc />
+    public bool Match(PacketInfo packet)
+    {
+        return packet.PacketString.StartsWith(_startsWith);
+    }
+}
\ No newline at end of file
-- 
2.48.1