PHP之mb_check_encoding使用方法分享

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mb_check_encoding

• (PHP 4 >= 4.4.3, PHP 5 >= 5.1.3, PHP 7)

• mb_check_encoding — Check if the string is valid for the specified encoding

• mb_check_encoding — 检查字符串在指定的编码里是否有效

Description

bool mb_check_encoding ([ string $var = NULL [, string $encoding = mb_internal_encoding() ]] )
// Checks if the specified byte stream is valid for the specified encoding. 
// It is useful to prevent so-called "Invalid Encoding Attack".

// 检查指定的字节流在指定的编码里是否有效。它能有效避免所谓的“无效编码攻击（Invalid Encoding Attack）”。

Parameters

var

• The byte stream to check. If it is omitted, this function checks all the input from the beginning of the request.

• 要检查的字节流。如果省略了这个参数，此函数会检查所有来自最初请求所有的输入。

encoding

• The expected encoding.

• 期望的编码。

Return Values

• Returns TRUE on success or FALSE on failure.

• 成功时返回 TRUE， 或者在失败时返回 FALSE。

Examples

<?php
/**
 * Created by PhpStorm.
 * User: zhangrongxiang
 * Date: 2018/1/27
 * Time: 下午2:59
 */

/**纯数字和英文字母组合*/
$utf8Str = "I have 4 books and 2 magazines to check out. ";
echo ( mb_check_encoding( $utf8Str, 'utf-8' ) ) . PHP_EOL; //

输出1 echo ( mb_check_encoding( $utf8Str, 'gbk' ) ) . PHP_EOL; //输出1 echo bin2hex( $utf8Str ) . PHP_EOL; //492068617665203420626f6f6b7320616e642032206d6167617a696e657320746f20636865636b206f75742e20 $gbkStr = mb_convert_encoding( $utf8Str, 'gbk', 'utf-8' ); echo bin2hex( $gbkStr ) . PHP_EOL; //492068617665203420626f6f6b7320616e642032206d6167617a696e657320746f20636865636b206f75742e20 /**gbk编码的字符串 --> 设置文件编码为gbk*/ $str = '博客园和github。'; echo mb_check_encoding( $str, 'utf-8' ) . PHP_EOL; //输出空 echo mb_check_encoding( $str, 'gbk' ) . PHP_EOL; //输出1 /**utf-8编码的字符串 --> 设置文件编码为utf-8*/ $str = '博客园和github。'; echo mb_check_encoding( $str, 'utf-8' ) . PHP_EOL; //1 echo mb_check_encoding( $str, 'gbk' ) . PHP_EOL; //输出空 $utf8Str = '我abc是谁.'; echo mb_check_encoding( $utf8Str, 'utf-8' ) . PHP_EOL; //输出1 //如果有中文标点符号则为空！！！ echo mb_check_encoding( $utf8Str, 'gbk' ) . PHP_EOL; //输出1 /**自定义检测字符串编码是否为utf-8*/ function is_utf8( $str ) { return (bool) preg_match( '//u', serialize($str) ); } echo 'hello 中国!' .is_utf8( 'hello 中国!' ) . PHP_EOL; //1 function check_utf8( $str ) { $len = strlen( $str ); for ( $i = 0; $i < $len; $i ++ ) { $c = ord( $str[ $i ] ); if ( $c > 128 ) { if ( ( $c > 247 ) ) { return false; } elseif ( $c > 239 ) { $bytes = 4; } elseif ( $c > 223 ) { $bytes = 3; } elseif ( $c > 191 ) { $bytes = 2; } else { return false; } if ( ( $i + $bytes ) > $len ) { return false; } while ( $bytes > 1 ) { $i ++; $b = ord( $str[ $i ] ); if ( $b < 128 || $b > 191 ) { return false; } $bytes --; } } } return true; } // end of check_utf8 echo check_utf8("hello 中国").PHP_EOL; // 1 echo check_utf8( "\x00\xE3").PHP_EOL; //空 /** check a strings encoded value */ function checkEncoding( $string, $string_encoding ) { $fs = $string_encoding == 'UTF-8' ? 'UTF-32' : $string_encoding; $ts = $string_encoding == 'UTF-32' ? 'UTF-8' : $string_encoding; return $string === mb_convert_encoding( mb_convert_encoding( $string, $fs, $ts ), $ts, $fs ); } /* test 1 variables */ $string = "\x00\x81"; $encoding = "Shift_JIS"; /* test 1 mb_check_encoding (test for bad byte stream) */ if ( true === mb_check_encoding( $string, $encoding ) ) { echo 'valid (' . $encoding . ') encoded byte stream!' . PHP_EOL; } else { echo 'invalid (' . $encoding . ') encoded byte stream!' . PHP_EOL; } /* test 1 checkEncoding (test for bad byte sequence(s)) */ if ( true === checkEncoding( $string, $encoding ) ) { echo 'valid (' . $encoding . ') encoded byte sequence!' . PHP_EOL; } else { echo 'invalid (' . $encoding . ') encoded byte sequence!' . PHP_EOL; } /* test 2 */ /* test 2 variables */ $string = "\x00\xE3"; $encoding = "UTF-8"; /* test 2 mb_check_encoding (test for bad byte stream) */ if ( true === mb_check_encoding( $string, $encoding ) ) { echo 'valid (' . $encoding . ') encoded byte stream!' . PHP_EOL; } else { echo 'invalid (' . $encoding . ') encoded byte stream!' . PHP_EOL; } /* test 2 checkEncoding (test for bad byte sequence(s)) */ if ( true === checkEncoding( $string, $encoding ) ) { echo 'valid (' . $encoding . ') encoded byte sequence!' . PHP_EOL; } else { echo 'invalid (' . $encoding . ') encoded byte sequence!' . PHP_EOL; }

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