深入PHP的Email地址邮箱验证的内部函数filter_var FILTER_VALIDATE_EMAIL实现

目录

1、在ThinkPHP 验证邮箱地址的函数。

2、在PHP源代码中查看该函数实现

3、提取之后编写个PHP测试脚本进行测试。

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1、在ThinkPHP 验证邮箱地址的函数。

下载了ThinkPHP 5.1源代码，地址：https://github.com/HubQin/thinkPHP5.1-source-code-reading

在里面搜索“email”（忽略大小写），结果如下：

然后分别搜索"filter"和"FILTER_VALIDATE_EMAIL"。

filter的结果太多了，好像没有有用的信息。

在看看FILTER_VALIDATE_EMAIL的结果：

只有一条记录。

然后去Google去搜索“PHP FILTER_VALIDATE_EMAIL”。

去W3school看看使用示例：

filter_var是什么函数，怎么直接调用就可以了。在TP5.1中的搜索“filter_var”不存在，那就继续Google。

但都是些用法，没有看到其内部实现。

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2、在PHP源代码中查看该函数实现

考虑看看PHP源代码。于是下载了PHP 5.4.45的源代码。下载地址：https://www.php.net/distributions/php-5.4.45.tar.bz2

在源代码中搜索“FILTER_VALIDATE_EMAIL”，很多结果。关键看该函数的内部实现。

FILTER_VALIDATE_EMAIL旁边的标志有个"php_filter_validate_email"，于是继续搜索"php_filter_validate_email"。

打开./ext/filter/logical_filters.c

void php_filter_validate_email(PHP_INPUT_FILTER_PARAM_DECL) /* {{{ */
{
    /*
     * The regex below is based on a regex by Michael Rushton.
     * However, it is not identical.  I changed it to only consider routeable
     * addresses as valid.  Michael's regex considers a@b a valid address
     * which conflicts with section 2.3.5 of RFC 5321 which states that:
     *
     *   Only resolvable, fully-qualified domain names (FQDNs) are permitted
     *   when domain names are used in SMTP.  In other words, names that can
     *   be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
     *   in Section 5) are permitted, as are CNAME RRs whose targets can be
     *   resolved, in turn, to MX or address RRs.  Local nicknames or
     *   unqualified names MUST NOT be used.
     *
     * This regex does not handle comments and folding whitespace.  While
     * this is technically valid in an email address, these parts aren't
     * actually part of the address itself.
     *
     * Michael's regex carries this copyright:
     *
     * Copyright © Michael Rushton 2009-10
     * http://squiloople.com/
     * Feel free to use and redistribute this code. But please keep this copyright notice.
     *
     */
    const char regexp[] = "/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD";

    pcre       *re = NULL;
    pcre_extra *pcre_extra = NULL;
    int preg_options = 0;
    int         ovector[150]; /* Needs to be a multiple of 3 */
    int         matches;

    /* The maximum length of an e-mail address is 320 octets, per RFC 2821. */
    if (Z_STRLEN_P(value) > 320) {
        RETURN_VALIDATION_FAILED
    }

    re = pcre_get_compiled_regex((char *)regexp, &pcre_extra, &preg_options TSRMLS_CC);
    if (!re) {
        RETURN_VALIDATION_FAILED
    }
    matches = pcre_exec(re, NULL, Z_STRVAL_P(value), Z_STRLEN_P(value), 0, 0, ovector, 3);


    /* 0 means that the vector is too small to hold all the captured substring offsets */
    if (matches < 0) {
        RETURN_VALIDATION_FAILED
    }

}

从代码中可以看出，首先检查输入的字符长度不能超过320个。然后就用正则表达式匹配了。

这里的正则表达式好像用了ASCII码16进制，看不懂。

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3、提取之后编写个PHP测试脚本进行测试。

都是正则表达式应该是通用的编写个测试脚本试试。

$expr = "/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD";

if(preg_match($expr,"[email protected]")){
    echo "Matched\n";
}else{
    echo "Invalided\n";
}

 

运行结果：

将[email protected]改成sw@opensourcecom，看看结果：

需要进行更多的验证。