验证IP地址的最佳方法是什么？ [英] What is the best way of validating an IP Address?

问题描述

我有一种验证参数IP地址的方法。作为一个整体发展新手，我想知道是否有更好的方法。

I have a method to validate a parameter IP Address. Being new to development as a whole I would like to know if there is a better way of doing this.

/// <summary>
/// Check IP Address, will accept 0.0.0.0 as a valid IP
/// </summary>
/// <param name="strIP"></param>
/// <returns></returns>
public Boolean CheckIPValid(String strIP)
{
    //  Split string by ".", check that array length is 3
    char chrFullStop = '.';
    string[] arrOctets = strIP.Split(chrFullStop);
    if (arrOctets.Length != 4)
    {
        return false;
    }
    //  Check each substring checking that the int value is less than 255 and that is char[] length is !> 2
    Int16 MAXVALUE = 255;
    Int32 temp; // Parse returns Int32
    foreach (String strOctet in arrOctets)
    {
        if (strOctet.Length > 3)
        {
            return false;
        }

        temp = int.Parse(strOctet);
        if (temp > MAXVALUE)
        {
            return false;
        }
    }
    return true;
}

它很简单（我能做到）但它似乎可以解决问题。

Its simple (I could do it) but it seems to do the trick.

推荐答案

限制与 IPAddress.TryParse 方法是验证字符串是否为字符串可以转换为IP地址，因此如果它提供了一个字符串值，如5，它会将其视为0.0.0.5。

The limitation with IPAddress.TryParse method is that it verifies if a string could be converted to IP address, thus if it is supplied with a string value like "5", it consider it as "0.0.0.5".

另一种验证IPv4的方法可能如下：

Another approach to validate an IPv4 could be following :

public bool ValidateIPv4(string ipString)
{
    if (String.IsNullOrWhiteSpace(ipString))
    {
        return false;
    }

    string[] splitValues = ipString.Split('.');
    if (splitValues.Length != 4)
    {
        return false;
    }

    byte tempForParsing;

    return splitValues.All(r => byte.TryParse(r, out tempForParsing));
}

可以测试如下：

List<string> ipAddresses = new List<string>
{
    "2",
    "1.2.3",
    "1.2.3.4",
    "255.256.267.300",
    "127.0.0.1",
};
foreach (var ip in ipAddresses)
{
    Console.WriteLine($"{ip} ==> {ValidateIPv4(ip)}");
}

输出将是：

2 ==> False
1.2.3 ==> False
1.2.3.4 ==> True
255.256.267.300 ==> False
127.0.0.1 ==> True

您还可以使用 IPAddress.TryParse 但它有局限性，可能导致解析不正确。

You can also use IPAddress.TryParse but it has the limitations and could result in incorrect parsing.

System.Net.IPAddress.TryParse方法

请注意，如果TryParse成功解析输入，则返回true，
但这并不一定意味着生成的IP地址
是有效的。 请勿使用此方法验证IP地址。

但这适用于包含至少包含的普通字符串三个点。类似于：

But this would work with normal string containing at least three dots. Something like:

string addrString = "192.168.0.1";
IPAddress address;
if (IPAddress.TryParse(addrString, out address)) {
       //Valid IP, with address containing the IP
} else {
       //Invalid IP
}

使用 IPAddress.TryParse ，您可以查看存在三个点，然后调用 TryParse 喜欢：

With IPAddress.TryParse you can check for existence of three dots and then call TryParse like:

public static bool ValidateIPv4(string ipString)
{
    if (ipString.Count(c => c == '.') != 3) return false;
    IPAddress address;
    return IPAddress.TryParse(ipString, out address);
}

这篇关于验证IP地址的最佳方法是什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！