CollabVMAuthServer/CollabVMAuthServer/Utilities.cs

using System.Net;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Text.RegularExpressions;

namespace Computernewb.CollabVMAuthServer;

public enum LogLevel
{
    DEBUG,
    INFO,
    WARN,
    ERROR,
    FATAL
}


public static class Utilities
{
    public static JsonSerializerOptions JsonSerializerOptions => new JsonSerializerOptions
    {
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
    };
    public static void Log(LogLevel level, string msg)
    {
#if !DEBUG
        if (level == LogLevel.DEBUG)
            return;
#endif
        StringBuilder logstr = new StringBuilder();
        logstr.Append("[");
        logstr.Append(DateTime.Now.ToString("G"));
        logstr.Append("] [");
        switch (level)
        {
            case LogLevel.DEBUG:
                logstr.Append("DEBUG");
                break;
            case LogLevel.INFO:
                logstr.Append("INFO");
                break;
            case LogLevel.WARN:
                logstr.Append("WARN");
                break;
            case LogLevel.ERROR:
                logstr.Append("ERROR");
                break;
            case LogLevel.FATAL:
                logstr.Append("FATAL");
                break;
            default:
                throw new ArgumentException("Invalid log level");
        }
        logstr.Append("] ");
        logstr.Append(msg);
        switch (level)
        {
            case LogLevel.DEBUG:
            case LogLevel.INFO:
                Console.WriteLine(logstr.ToString());
                break;
            case LogLevel.WARN:
            case LogLevel.ERROR:
            case LogLevel.FATAL:
                Console.Error.Write(logstr.ToString());
                break;
        }
    }

    public static bool ValidateUsername(string username)
    {
        return username.Length >= 3 &&
               username.Length <= 20 &&
               username[0] != ' ' &&
               username[^1] != ' ' &&
               new Regex("^[a-zA-Z0-9 \\-_\\.]+$").IsMatch(username);
    }

    public static bool ValidatePassword(string password)
    {
        return password.Length > 8 &&
               new Regex("[a-z]").IsMatch(password) &&
               new Regex("[A-Z]").IsMatch(password) &&
               new Regex("[!@#$%^&*()\\-_=+\\\\|\\[\\];:'\\\",<.>/?`~]").IsMatch(password) &&
               new Regex("[0-9]").IsMatch(password);
    }

    public static string RandomString(int length)
    {
        const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        StringBuilder str = new StringBuilder();
        Random rand = new Random();
        for (int i = 0; i < length; i++)
        {
            str.Append(chars[rand.Next(chars.Length)]);
        }
        return str.ToString();
    }

    public static IPAddress? GetIP(HttpContext ctx)
    {
        if (Program.Config.HTTP.UseXForwardedFor)
        {
            if (!Program.Config.HTTP.TrustedProxies.Contains(ctx.Connection.RemoteIpAddress.ToString()))
            {
                Utilities.Log(LogLevel.WARN,
                    $"An IP address not allowed to proxy connections ({ctx.Connection.RemoteIpAddress.ToString()}) attempted to connect. This means your server port is exposed to the internet.");
                return null;
            }

            if (ctx.Request.Headers["X-Forwarded-For"].Count == 0)
            {
                Utilities.Log(LogLevel.WARN, $"Missing X-Forwarded-For header in request from {ctx.Connection.RemoteIpAddress.ToString()}. This is probably a misconfiguration of your reverse proxy.");
                return null;
            }

            if (!IPAddress.TryParse(ctx.Request.Headers["X-Forwarded-For"][0], out var ip)) return null;
            return ip;
        }
        else return ctx.Connection.RemoteIpAddress;
    }

    public static bool IsSessionExpired(Session session)
    {
        return DateTime.Now > session.LastUsed.AddDays(Program.Config.Accounts.SessionExpiryDays);
    }
}