Simple ftp

C#/forSpbu/SimpleFtp.Client/Client.cs

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+using System.Net.Sockets;
+using SimpleFtp.Protocol;
+
+namespace SimpleFtp.Client;
+
+public class FtpClient
+{
+    private readonly TcpClient _client = new TcpClient();
+    private StreamReader? _reader;
+    private StreamWriter? _writer;
+
+    private FtpClient(string hostname, int port)
+    {
+        Hostname = hostname;
+        Port = port;
+    }
+
+    public string Hostname { get; private set; }
+    public int Port { get; private set; }
+
+    public static async Task<FtpClient> Connect(string hostname, int port)
+    {
+        var client = new FtpClient(hostname, port);
+        await client._client.ConnectAsync(hostname, port);
+        client._reader = new StreamReader(client._client.GetStream());
+        client._writer = new StreamWriter(client._client.GetStream());
+        client._writer.AutoFlush = true;
+        return client;
+    }
+
+    public Response SendRequest(Request request)
+    {
+        _writer?.Write(request.ToString());
+        var data = _reader?.ReadLine() + "\n";
+        return ResponseFactory.Create(data);
+    }
+
+    public void Disconnect()
+    {
+        _client.Close();
+    }
+}

C#/forSpbu/SimpleFtp.Client/Program.cs

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+using SimpleFtp.Client;
+using SimpleFtp.Protocol;
+
+var client = await FtpClient.Connect("localhost", 32768);
+Console.WriteLine("Connected");
+while (true)
+{
+    var command = Console.ReadLine();
+    if (command == "exit")
+    {
+        client.Disconnect();
+        break;
+    }
+
+    if (command == null)
+    {
+        Console.WriteLine("Incorrect command");
+        continue;
+    }
+
+    try
+    {
+        var request = RequestFactory.Create(command + "\n");
+        var response = client.SendRequest(request);
+        Console.Write(response.ToString());
+    }
+    catch (RequestParseException)
+    {
+        Console.WriteLine("Incorrect command");
+    }
+}

C#/forSpbu/SimpleFtp.Client/SimpleFtp.Client.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net7.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <RootNamespace>SimpleFtpClient</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\SimpleFtp.Protocol\SimpleFtp.Protocol.csproj" />
+    </ItemGroup>
+
+</Project>

C#/forSpbu/SimpleFtp.Protocol/Request/GetRequest.cs

@@ -0,0 +1,16 @@
+namespace SimpleFtp.Protocol;
+
+public class GetRequest : Request
+{
+    public string Path { get; private set; }
+
+    public GetRequest(string path)
+    {
+        Path = path;
+    }
+
+    public override string ToString()
+    {
+        return "2 " + Path + "\n";
+    }
+}

C#/forSpbu/SimpleFtp.Protocol/Request/ListRequest.cs

@@ -0,0 +1,16 @@
+namespace SimpleFtp.Protocol;
+
+public class ListRequest : Request
+{
+    public string Path { get; private set; }
+
+    public ListRequest(string path)
+    {
+        Path = path;
+    }
+
+    public override string ToString()
+    {
+        return "1 " + Path + "\n";
+    }
+}

C#/forSpbu/SimpleFtp.Protocol/Request/Request.cs

@@ -0,0 +1,6 @@
+namespace SimpleFtp.Protocol;
+
+public abstract class Request
+{
+    public abstract override string ToString();
+}

C#/forSpbu/SimpleFtp.Protocol/Request/RequestFactory.cs

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+using System.Text.RegularExpressions;
+
+namespace SimpleFtp.Protocol;
+
+public static partial class RequestFactory
+{
+    private const string GetPattern = "2 (?<path>[1-9a-zA-Z./\\\\]+)\n";
+    private const string ListPattern = "1 (?<path>[1-9a-zA-Z./\\\\]+)\n";
+
+    public static Request Create(string request)
+    {
+        if (GetRegex().IsMatch(request))
+        {
+            var match = GetRegex().Match(request);
+            return new GetRequest(match.Groups["path"].Value);
+        }
+        if (ListRegex().IsMatch(request))
+        {
+            var match = ListRegex().Match(request);
+            return new ListRequest(match.Groups["path"].Value);
+        }
+
+        throw new RequestParseException();
+    }
+
+    [GeneratedRegex(GetPattern)]
+    private static partial Regex GetRegex();
+
+    [GeneratedRegex(ListPattern)]
+    private static partial Regex ListRegex();
+}

C#/forSpbu/SimpleFtp.Protocol/Request/RequestParseException.cs

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+namespace SimpleFtp.Protocol;
+
+public class RequestParseException : FormatException
+{
+}

C#/forSpbu/SimpleFtp.Protocol/Response/GetResponse.cs

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+namespace SimpleFtp.Protocol;
+
+public class GetResponse : Response
+{
+    private readonly byte[]? _file;
+    private int Size => _file?.Length ?? -1;
+
+    public GetResponse(byte[] fileBytes)
+    {
+        _file = fileBytes;
+    }
+
+    public GetResponse()
+    {
+    }
+
+    public override string ToString() => Size + " " + System.Text.Encoding.UTF8.GetString(_file ?? Array.Empty<byte>()) + "\n";
+}

C#/forSpbu/SimpleFtp.Protocol/Response/ListResponse.cs

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+namespace SimpleFtp.Protocol;
+
+public class ListResponse : Response
+{
+    private readonly IEnumerable<(string name, bool isDir)>? _list;
+
+    private int Size => _list?.Count() ?? -1;
+
+    public ListResponse(IEnumerable<(string name, bool isDir)> dirList)
+    {
+        _list = dirList;
+    }
+
+    public ListResponse()
+    {
+    }
+
+    public override string ToString() => 
+        Size + " " + 
+            string.Join(' ', (_list ?? Array.Empty<(string name, bool isDir)>())
+                .Select<(string name, bool isDir), string>(x => x.name + " " + x.isDir)) + "\n";
+}

C#/forSpbu/SimpleFtp.Protocol/Response/Response.cs

@@ -0,0 +1,6 @@
+namespace SimpleFtp.Protocol;
+
+public abstract class Response
+{
+    public abstract override string ToString();
+}

C#/forSpbu/SimpleFtp.Protocol/Response/ResponseFactory.cs

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+using System.Text;
+using System.Text.RegularExpressions;
+
+namespace SimpleFtp.Protocol;
+
+public static partial class ResponseFactory
+{
+    private const string ListPattern = "(?<size>[0-9]+) ((?<names>[1-9a-zA-Z./\\\\]+) (?<isDirs>False|True) )*((?<names>[1-9a-zA-Z./\\\\]+) (?<isDirs>False|True))+\n";
+    private const string GetPattern = "(?<size>[0-9]+) (?<content>.+)\n";
+
+    public static Response Create(string response)
+    {
+        if (ListRegex().IsMatch(response))
+        {
+            var match = ListRegex().Match(response);
+
+            var isDirs = match.Groups["isDirs"].Captures.Select(x => x.Value == "True").ToArray();
+            var names = match.Groups["names"].Captures.Select(x => x.Value).ToArray();
+            if (!int.TryParse(match.Groups["size"].Value, out var size) || names.Length != size)
+            {
+                throw new ResponseParseException();
+            }
+
+            var list = new (string, bool)[size];
+            for (int i = 0; i < size; i++)
+            {
+                list[i] = (names[i], isDirs[i]);
+            }
+            return new ListResponse(list);
+        }
+        if (GetRegex().IsMatch(response))
+        {
+            var match = GetRegex().Match(response);
+
+            var content = match.Groups["content"].Value;
+            if (!int.TryParse(match.Groups["size"].Value, out _))
+            {
+                throw new ResponseParseException();
+            }
+
+            return new GetResponse(Encoding.ASCII.GetBytes(content));
+        }
+
+        throw new ResponseParseException();
+    }
+
+
+    [GeneratedRegex(ListPattern)]
+    private static partial Regex ListRegex();
+
+    [GeneratedRegex(GetPattern)]
+    private static partial Regex GetRegex();
+}

C#/forSpbu/SimpleFtp.Protocol/Response/ResponseParseException.cs

@@ -0,0 +1,5 @@
+namespace SimpleFtp.Protocol;
+
+public class ResponseParseException : FormatException
+{
+}

C#/forSpbu/SimpleFtp.Protocol/SimpleFtp.Protocol.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net7.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>

C#/forSpbu/SimpleFtp.Server/Program.cs

@@ -0,0 +1,11 @@
+using SimpleFtp;
+using SimpleFtp.Protocol;
+
+var server = new FtpServer();
+var cancellation = new CancellationTokenSource();
+Task.Run(() => server.Listen(cancellation));
+var input = Console.ReadLine();
+if (input == "exit")
+{
+    cancellation.Cancel();
+}