无法在JavaScript中匹配IP正则表达式

Question

以下是我的代码，我试图在前端验证IP地址，但不知何故，这个Regex不起作用-

var patt = /[0-255].[0-255].[0-255].[0-255]/;
var str = "90.89.99.90";
if(str.match(patt))
  console.log("Valid IP");
else
  console.log("Invalid IP");

它应该输出-有效IP

而这类IP应该返回-无效IP

"fd.45.67.90"、"256.67.67.89"、"@@.45.67.9"等

让我知道我用regex做错了什么。

Answer 1

Regex范围不会按照您的想法执行操作。[x-y]范围包含从x到y的所有ascii字符。

因此，[0-255]匹配从0到2的字符（也称为0、1和2）和5，或者简称为[0125]。

---

要匹配从0到255的数字，可以执行以下操作：

dd?|1dd|2([0-4]d|5[0-5])

想法：

• dd?-一位或两位数字
• 1dd-从100到199的数字
• 2[0-4]d——从200到249的数字
• 25[0-5]-从250到255的数字

---

要匹配整个IP，您可以执行以下操作：

^((dd?|1dd|2([0-4]d|5[0-5])).){3}(dd?|1dd|2([0-4]d|5[0-5]))$

Answer 2

[...]表示一个"字符类"，这意味着它列出了应该匹配的字符；它匹配您列出的任何一个字符。因此，您的正则表达式正在检查每个段是否有一个单个字符，它是0、1、2或5中的任何一个（0-2给我们0、1和2；然后5给我们5，第二个5被忽略）。它应该检查数字（d）和其中1-3个（{1,3}）：

var patt = /d{1,3}.d{1,3}.d{1,3}.d{1,3}/;

您可能还需要^（输入开始）和$（输入结束），这样foo123.123.123.123bar就不匹配：

var patt = /^d{1,3}.d{1,3}.d{1,3}.d{1,3}/$;

当然，这还不足以检查IP是否有效。它只是检查是否有预期的数字；它会很高兴地称CCD_ 31有效。

如果你想正确验证它（例如，数字在有效范围内，过滤掉无效的段组合等），你可以提取这个全面的URL验证正则表达式的IP部分（因为URL可以包含IP地址，所以它涵盖了这一点）。值得庆幸的是，Diego和其他作者对它进行了很好的评论，清楚地确定了哪些比特可以做什么：

//
// Regular Expression for URL validation
//
// Author: Diego Perini
// Updated: 2010/12/05
// License: MIT
//
// Copyright (c) 2010-2013 Diego Perini (http://www.iport.it)
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
// the regular expression composed & commented
// could be easily tweaked for RFC compliance,
// it was expressly modified to fit & satisfy
// these test for an URL shortener:
//
//   http://mathiasbynens.be/demo/url-regex
//
// Notes on possible differences from a standard/generic validation:
//
// - utf-8 char class take in consideration the full Unicode range
// - TLDs have been made mandatory so single names like "localhost" fails
// - protocols have been restricted to ftp, http and https only as requested
//
// Changes:
//
// - IP address dotted notation validation, range: 1.0.0.0 - 223.255.255.255
//   first and last IP address of each class is considered invalid
//   (since they are broadcast/network addresses)
//
// - Added exclusion of private, reserved and/or local networks ranges
//
// - Made starting path slash optional (http://example.com?foo=bar)
//
// - Allow a dot (.) at the end of hostnames (http://example.com.)
//
// Compressed one-line versions:
//
// Javascript version
//
// /^(?:(?:https?|ftp)://)(?:S+(?::S*)?@)?(?:(?!(?:10|127)(?:.d{1,3}){3})(?!(?:169.254|192.168)(?:.d{1,3}){2})(?!172.(?:1[6-9]|2d|3[0-1])(?:.d{1,3}){2})(?:[1-9]d?|1dd|2[01]d|22[0-3])(?:.(?:1?d{1,2}|2[0-4]d|25[0-5])){2}(?:.(?:[1-9]d?|1dd|2[0-4]d|25[0-4]))|(?:(?:[a-zu00a1-uffff0-9]-*)*[a-zu00a1-uffff0-9]+)(?:.(?:[a-zu00a1-uffff0-9]-*)*[a-zu00a1-uffff0-9]+)*(?:.(?:[a-zu00a1-uffff]{2,})).?)(?::d{2,5})?(?:[/?#]S*)?$/i
//
// PHP version
//
// _^(?:(?:https?|ftp)://)(?:S+(?::S*)?@)?(?:(?!(?:10|127)(?:.d{1,3}){3})(?!(?:169.254|192.168)(?:.d{1,3}){2})(?!172.(?:1[6-9]|2d|3[0-1])(?:.d{1,3}){2})(?:[1-9]d?|1dd|2[01]d|22[0-3])(?:.(?:1?d{1,2}|2[0-4]d|25[0-5])){2}(?:.(?:[1-9]d?|1dd|2[0-4]d|25[0-4]))|(?:(?:[a-zx{00a1}-x{ffff}0-9]-*)*[a-zx{00a1}-x{ffff}0-9]+)(?:.(?:[a-zx{00a1}-x{ffff}0-9]-*)*[a-zx{00a1}-x{ffff}0-9]+)*(?:.(?:[a-zx{00a1}-x{ffff}]{2,})).?)(?::d{2,5})?(?:[/?#]S*)?$_iuS
//
var re_weburl = new RegExp(
  "^" +
    // protocol identifier
    "(?:(?:https?|ftp)://)" +
    // user:pass authentication
    "(?:\S+(?::\S*)?@)?" +
    "(?:" +
      // IP address exclusion
      // private & local networks
      "(?!(?:10|127)(?:\.\d{1,3}){3})" +
      "(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})" +
      "(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})" +
      // IP address dotted notation octets
      // excludes loopback network 0.0.0.0
      // excludes reserved space >= 224.0.0.0
      // excludes network & broacast addresses
      // (first & last IP address of each class)
      "(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])" +
      "(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}" +
      "(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))" +
    "|" +
      // host name
      "(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)" +
      // domain name
      "(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*" +
      // TLD identifier
      "(?:\.(?:[a-z\u00a1-\uffff]{2,}))" +
      // TLD may end with dot
      "\.?" +
    ")" +
    // port number
    "(?::\d{2,5})?" +
    // resource path
    "(?:[/?#]\S*)?" +
  "$", "i"
);

Answer 3

这里有一个正则表达式变体（基于上面ndn的答案），它将检查整个输入文本是否是有效的IP:

^(?:(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5])).){3}(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5]))$

参见regex演示

以下是一个可用于从较大文本中提取有效IP的解决方案：

b(?:(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5])).){3}(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5]))b

查看另一个演示

解释：

• ^-字符串的开头（如果只需要在字符串的开头不匹配，则替换为b单词边界）
• (?:(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5])).){3}-出现3次
  • (?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5]))-1或2位序列，或1xx数字（1d{2}）或200-255范围内的整数范围（得益于2(?:[0-4]d|5[0-5])）
  • .-文字周期
• (?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5]))-见上文（仅为IP地址的最后一部分）
• $-字符串结尾（如果您只需要一个完整的单词匹配，请替换为b）

注意：在JS中，您可以使用文字表示法来声明这些regexp，例如：

/b(?:(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5])).){3}(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5]))b/g
/^(?:(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5])).){3}(?:d{1,2}|1d{2}|2(?:[0-4]d|5[0-5]))$/