1、php加密解密php加密和解密函数可以用来加密一些有用的字符串存放在数据库里，并且通过可逆解密字符串，该函数使用了base64和md5加密和解密。
function encryptdecrypt($key, $string, $decrypt){
if($decrypt){
$decrypted = rtrim(mcrypt_decrypt(mcrypt_rijndael_256, md5($key), base64_decode($string), mcrypt_mode_cbc, md5(md5($key))), "12");
return $decrypted;
}else{
$encrypted = base64_encode(mcrypt_encrypt(mcrypt_rijndael_256, md5($key), $string, mcrypt_mode_cbc, md5(md5($key))));
return $encrypted;
}
}
使用方法如下：
//以下是将字符串“helloweba欢迎您”分别加密和解密 //加密： echo encryptdecrypt('password', 'helloweba欢迎您',0);
//解密： echo encryptdecrypt('password', 'z0jax4qmwcf+db5tnbp/xwdum84snrsxvvpxuaca4bk=',1);
2、php生成随机字符串当我们需要生成一个随机名字，临时密码等字符串时可以用到下面的函数：
function generaterandomstring($length = 10) {
$characters = '0123456789abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz';
$randomstring = '';
for ($i = 0; $i < $length; $i++) {
$randomstring .= $characters[rand(0, strlen($characters) - 1)];
}
return $randomstring;
}
使用方法如下：
echo generaterandomstring(20);
3、php获取文件扩展名（后缀）以下函数可以快速获取文件的扩展名即后缀。
function getextension($filename){
$myext = substr($filename, strrpos($filename, '.'));
return str_replace('.','',$myext);
}
使用方法如下：
$filename = '我的文档.doc';
echo getextension($filename);
4、php获取文件大小并格式化以下使用的函数可以获取文件的大小，并且转换成便于阅读的kb，mb等格式。
function formatsize($size) {
$sizes = array(" bytes", " kb", " mb", " gb", " tb", " pb", " eb", " zb", " yb");
if ($size == 0) {
return('n/a');
} else {
return (round($size/pow(1024, ($i = floor(log($size, 1024)))), 2) . $sizes[$i]);
}
}
使用方法如下：
$thefile = filesize('test_file.mp3');
echo formatsize($thefile);
5、php替换标签字符有时我们需要将字符串、模板标签替换成指定的内容，可以用到下面的函数：
function stringparser($string,$replacer){
$result = str_replace(array_keys($replacer), array_values($replacer),$string);
return $result;
}
使用方法如下：
$string = 'the {b}anchor text{/b} is the {b}actual word{/b} or words used {br}to describe the link {br}itself';
$replace_array = array('{b}' => '<b>','{/b}' => '</b>','{br}' => '<br />');
echo stringparser($string,$replace_array);
6、php列出目录下的文件名如果你想列出目录下的所有文件，使用以下代码即可：
function listdirfiles($dirpath){
if($dir = opendir($dirpath)){
while(($file = readdir($dir))!== false){
if(!is_dir($dirpath.$file))
{
echo "filename: $file<br />";
}
}
}
}
使用方法如下：
listdirfiles('home/some_folder/');
7、php获取当前页面url以下函数可以获取当前页面的url，不管是http还是https:
function curpageurl() {
$pageurl = 'http';
if (!empty($_server['https'])) {$pageurl .= "s";}
$pageurl .= "://";
if ($_server["server_port"] != "80") {
$pageurl .= $_server["server_name"].":".$_server["server_port"].$_server["request_uri"];
} else {
$pageurl .= $_server["server_name"].$_server["request_uri"];
}
return $pageurl;
}
使用方法如下：
echo curpageurl();
8、php强制下载文件有时我们不想让浏览器直接打开文件，如pdf文件，而是要直接下载文件，那么以下函数可以强制下载文件，函数中使用了application/octet-stream头类型。
function download($filename){
if ((isset($filename))&&(file_exists($filename))){
header("content-length: ".filesize($filename));
header('content-type: application/octet-stream');
header('content-disposition: attachment; filename="' . $filename . '"');
readfile("$filename");
} else {
echo "looks like file does not exist!";
}
}
使用方法如下：
download('/down/test_45f73e852.zip');
9、php截取字符串长度我们经常会遇到需要截取字符串(含中文汉字)长度的情况，比如标题显示不能超过多少字符，超出的长度用…表示，以下函数可以满足你的需求。
/*
utf-8、gb2312都支持的汉字截取函数
cut_str(字符串, 截取长度, 开始长度, 编码);
编码默认为 utf-8
开始长度默认为 0 */ function cutstr($string, $sublen, $start = 0, $code = 'utf-8'){
if($code == 'utf-8'){
$pa = "/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/";
preg_match_all($pa, $string, $t_string);
if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
return join('', array_slice($t_string[0], $start, $sublen));
}else{
$start = $start*2;
$sublen = $sublen*2;
$strlen = strlen($string);
$tmpstr = '';
for($i=0; $i<$strlen; $i++){
if($i>=$start && $i<($start+$sublen)){
if(ord(substr($string, $i, 1))>129){
$tmpstr.= substr($string, $i, 2);
}else{
$tmpstr.= substr($string, $i, 1);
}
}
if(ord(substr($string, $i, 1))>129) $i++;
}
if(strlen($tmpstr)<$strlen ) $tmpstr.= "...";
return $tmpstr;
}
}
使用方法如下：
$str = "jquery插件实现的加载图片和页面效果";
echo cutstr($str,16);
10、php获取客户端真实ip我们经常要用数据库记录用户的ip，以下代码可以获取客户端真实的ip：
//获取用户真实ip function getip() {
if (getenv("http_client_ip") && strcasecmp(getenv("http_client_ip"), "unknown"))
$ip = getenv("http_client_ip");
else
if (getenv("http_x_forwarded_for") && strcasecmp(getenv("http_x_forwarded_for"), "unknown"))
$ip = getenv("http_x_forwarded_for");
else
if (getenv("remote_addr") && strcasecmp(getenv("remote_addr"), "unknown"))
$ip = getenv("remote_addr");
else
if (isset ($_server['remote_addr']) && $_server['remote_addr'] && strcasecmp($_server['remote_addr'], "unknown"))
$ip = $_server['remote_addr'];
else
$ip = "unknown";
return ($ip);
}
使用方法如下：
echo getip();
11、php防止sql注入我们在查询数据库时，出于安全考虑，需要过滤一些非法字符防止sql恶意注入，请看一下函数：
function injcheck($sql_str) {
$check = preg_match('/select|insert|update|delete|'|/*|*|../|./|union|into|load_file|outfile/', $sql_str);
if ($check) {
echo '非法字符！！';
exit;
} else {
return $sql_str;
}
}
使用方法如下：
echo injcheck('1 or 1=1');
12、php页面提示与跳转我们在进行表单操作时，有时为了友好需要提示用户操作结果，并跳转到相关页面，请看以下函数：
function message($msgtitle,$message,$jumpurl){
$str = '<!doctype html>';
$str .= '<html>';
$str .= '<head>';
$str .= '<meta charset="utf-8">';
$str .= '<title>页面提示</title>';
$str .= '<style type="text/css">';
$str .= '*{margin:0; padding:0}a{color:#369; text-decoration:none;}a:hover{text-decoration:underline}body{height:100%; font:12px/18px tahoma, arial, sans-serif; color:#424242; background:#fff}.message{width:450px; height:120px; margin:16% auto; border:1px solid #99b1c4; background:#ecf7fb}.message h3{height:28px; line-height:28px; background:#2c91c6; text-align:center; color:#fff; font-size:14px}.msg_txt{padding:10px; margin-top:8px}.msg_txt h4{line-height:26px; font-size:14px}.msg_txt h4.red{color:#f30}.msg_txt p{line-height:22px}';
$str .= '</style>';
$str .= '</head>';
$str .= '<body>';
$str .= '<p class="message">';
$str .= '<h3>'.$msgtitle.'</h3>';
$str .= '<p class="msg_txt">';
$str .= '<h4 class="red">'.$message.'</h4>';
$str .= '<p>系统将在 <span style="color:blue;font-weight:bold">3</span> 秒后自动跳转,如果不想等待,直接点击 <a href="{$jumpurl}">这里</a> 跳转</p>';
$str .= "<script>settimeout('location.replace('".$jumpurl."')',2000)</script>";
$str .= '</p>';
$str .= '</p>';
$str .= '</body>';
$str .= '</html>';
echo $str;
}
使用方法如下：
message('操作提示','操作成功！','https://segmentfault.com/');
13、php计算时长我们在处理时间时，需要计算当前时间距离某个时间点的时长，如计算客户端运行时长，通常用hh:mm:ss表示
function changetimetype($seconds) {
if ($seconds > 3600) {
$hours = intval($seconds / 3600);
$minutes = $seconds % 3600;
$time = $hours . ":" . gmstrftime('%m:%s', $minutes);
} else {
$time = gmstrftime('%h:%m:%s', $seconds);
}
return $time;
}
使用方法如下：
$seconds = 3712;
echo changetimetype($seconds);
下面是获取客户端ip，字符串截取，下载等，详情请查看如下代码：
<?php/**
* 获取客户端ip
* @return [string] [description]
*/function getclientip() {
$ip = null; if (isset($_server['http_x_forwarded_for'])) { $arr = explode(',', $_server['http_x_forwarded_for']); $pos = array_search('unknown',$arr); if(false !== $pos) unset($arr[$pos]); $ip = trim($arr[0]);
}elseif (isset($_server['http_client_ip'])) { $ip = $_server['http_client_ip'];
}elseif (isset($_server['remote_addr'])) { $ip = $_server['remote_addr'];
} // ip地址合法验证
$ip = (false !== ip2long($ip)) ? $ip : '0.0.0.0'; return $ip;
}/**
* 获取在线ip
* @return string
*/function getonlineip($format=0) {
global $s_global; if(empty($s_global['onlineip'])) { if(getenv('http_client_ip') && strcasecmp(getenv('http_client_ip'), 'unknown')) { $onlineip = getenv('http_client_ip');
} elseif(getenv('http_x_forwarded_for') && strcasecmp(getenv('http_x_forwarded_for'), 'unknown')) { $onlineip = getenv('http_x_forwarded_for');
} elseif(getenv('remote_addr') && strcasecmp(getenv('remote_addr'), 'unknown')) { $onlineip = getenv('remote_addr');
} elseif(isset($_server['remote_addr']) && $_server['remote_addr'] && strcasecmp($_server['remote_addr'], 'unknown')) { $onlineip = $_server['remote_addr'];
}
preg_match("/[\d\.]{7,15}/", $onlineip, $onlineipmatches); $s_global['onlineip'] = $onlineipmatches[0] ? $onlineipmatches[0] : 'unknown';
} if($format) { $ips = explode('.', $s_global['onlineip']); for($i=0;$i<3;$i++) { $ips[$i] = intval($ips[$i]);
} return sprintf('%03d%03d%03d', $ips[0], $ips[1], $ips[2]);
} else { return $s_global['onlineip'];
}
}/**
* 获取url
* @return [type] [description]
*/function geturl(){
$pageurl = 'http'; if (isset($_server["https"]) && $_server["https"] == "on") { $pageurl .= "s";
} $pageurl .= "://"; if ($_server["server_port"] != "80") { $pageurl .= $_server["http_host"] . ":" . $_server["server_port"] . $_server["request_uri"];
} else { $pageurl .= $_server["http_host"] . $_server["request_uri"];
} return $pageurl;
}/**
* 获取当前站点的访问路径根目录
* @return [type] [description]
*/function getsiteurl() {
$uri = $_server['request_uri']?$_server['request_uri']:($_server['php_self']?$_server['php_self']:$_server['script_name']); return 'http://'.$_server['http_host'].substr($uri, 0, strrpos($uri, '/')+1);
}/**
* 字符串截取，支持中文和其他编码
* @param [string] $str [字符串]
* @param integer $start [起始位置]
* @param integer $length [截取长度]
* @param string $charset [字符串编码]
* @param boolean $suffix [是否有省略号]
* @return [type] [description]
*/function msubstr($str, $start=0, $length=15, $charset="utf-8", $suffix=true) {
if(function_exists("mb_substr")) { return mb_substr($str, $start, $length, $charset);
} elseif(function_exists('iconv_substr')) { return iconv_substr($str,$start,$length,$charset);
} $re['utf-8'] = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/"; $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/"; $re['gbk'] = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/"; $re['big5'] = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
preg_match_all($re[$charset], $str, $match); $slice = join("",array_slice($match[0], $start, $length)); if($suffix) { return $slice."…";
} return $slice;
}/**
* php 实现js escape 函数
* @param [type] $string [description]
* @param string $encoding [description]
* @return [type] [description]
*/function escape($string, $encoding = 'utf-8'){
$return = null; for ($x = 0; $x < mb_strlen($string, $encoding);$x ++)
{ $str = mb_substr($string, $x, 1, $encoding); if (strlen($str) > 1) { // 多字节字符
$return .= "%u" . strtoupper(bin2hex(mb_convert_encoding($str, 'ucs-2', $encoding)));
} else { $return .= "%" . strtoupper(bin2hex($str));
}
} return $return;
}/**
* php 实现 js unescape函数
* @param [type] $str [description]
* @return [type] [description]
*/function unescape($str) {
$str = rawurldecode($str);
preg_match_all("/(?:%u.{4})|.{4};|&#\d+;|.+/u",$str,$r); $ar = $r[0]; foreach($ar as $k=>$v) { if(substr($v,0,2) == "%u"){ $ar[$k] = iconv("ucs-2","utf-8//ignore",pack("h4",substr($v,-4)));
} elseif(substr($v,0,3) == "") { $ar[$k] = iconv("ucs-2","utf-8",pack("h4",substr($v,3,-1)));
} elseif(substr($v,0,2) == "&#") { echo substr($v,2,-1).""; $ar[$k] = iconv("ucs-2","utf-8",pack("n",substr($v,2,-1)));
}
} return join("",$ar);
}/**
* 数字转人名币
* @param [type] $num [description]
* @return [type] [description]
*/function num2rmb ($num) {
$c1 = "零壹贰叁肆伍陆柒捌玖"; $c2 = "分角元拾佰仟万拾佰仟亿"; $num = round($num, 2); $num = $num * 100; if (strlen($num) > 10) { return "oh,sorry,the number is too long!";
} $i = 0; $c = ""; while (1) { if ($i == 0) { $n = substr($num, strlen($num)-1, 1);
} else { $n = $num % 10;
} $p1 = substr($c1, 3 * $n, 3); $p2 = substr($c2, 3 * $i, 3); if ($n != '0' || ($n == '0' && ($p2 == '亿' || $p2 == '万' || $p2 == '元'))) { $c = $p1 . $p2 . $c;
} else { $c = $p1 . $c;
} $i = $i + 1; $num = $num / 10; $num = (int)$num; if ($num == 0) { break;
}
} $j = 0; $slen = strlen($c); while ($j < $slen) { $m = substr($c, $j, 6); if ($m == '零元' || $m == '零万' || $m == '零亿' || $m == '零零') { $left = substr($c, 0, $j); $right = substr($c, $j + 3); $c = $left . $right; $j = $j-3; $slen = $slen-3;
} $j = $j + 3;
} if (substr($c, strlen($c)-3, 3) == '零') { $c = substr($c, 0, strlen($c)-3);
} // if there is a '0' on the end , chop it out
return $c . "整";
}/**
* 特殊的字符
* @param [type] $str [description]
* @return [type] [description]
*/function makesemiangle($str) {
$arr = array( '０' => '0', '１' => '1', '２' => '2', '３' => '3', '４' => '4', '５' => '5', '６' => '6', '７' => '7', '８' => '8', '９' => '9', 'ａ' => 'a', 'ｂ' => 'b', 'ｃ' => 'c', 'ｄ' => 'd', 'ｅ' => 'e', 'ｆ' => 'f', 'ｇ' => 'g', 'ｈ' => 'h', 'ｉ' => 'i', 'ｊ' => 'j', 'ｋ' => 'k', 'ｌ' => 'l', 'ｍ' => 'm', 'ｎ' => 'n', 'ｏ' => 'o', 'ｐ' => 'p', 'ｑ' => 'q', 'ｒ' => 'r', 'ｓ' => 's', 'ｔ' => 't', 'ｕ' => 'u', 'ｖ' => 'v', 'ｗ' => 'w', 'ｘ' => 'x', 'ｙ' => 'y', 'ｚ' => 'z', 'ａ' => 'a', 'ｂ' => 'b', 'ｃ' => 'c', 'ｄ' => 'd', 'ｅ' => 'e', 'ｆ' => 'f', 'ｇ' => 'g', 'ｈ' => 'h', 'ｉ' => 'i', 'ｊ' => 'j', 'ｋ' => 'k', 'ｌ' => 'l', 'ｍ' => 'm', 'ｎ' => 'n', 'ｏ' => 'o', 'ｐ' => 'p', 'ｑ' => 'q', 'ｒ' => 'r', 'ｓ' => 's', 'ｔ' => 't', 'ｕ' => 'u', 'ｖ' => 'v', 'ｗ' => 'w', 'ｘ' => 'x', 'ｙ' => 'y', 'ｚ' => 'z', '（' => '(', '）' => ')', '〔' => '[', '〕' => ']', '【' => '[', '】' => ']', '〖' => '[', '〗' => ']', '｛' => '{', '｝' => '}', '《' => '<', '》' => '>', '％' => '%', '＋' => '+', '—' => '-', '－' => '-', '～' => '-', '：' => ':', '。' => '.', '、' => ',', '，' => '.', '、' => '.', '；' => ';', '？' => '?', '！' => '!', '…' => '-', '‖' => '|', '”' => '"', '“' => '"', ''' => '`', '‘' => '`', '｜' => '|', '〃' => '"',
' ' => ' ','．' => '.');
return strtr($str, $arr);
}
/**
* 下载
* @param [type] $filename [description]
* @param string $dir [description]
* @return [type] [description]
*/
function downloads($filename,$dir='./'){
$filepath = $dir.$filename;
if (!file_exists($filepath)){
header("content-type: text/html; charset=utf-8");
echo "file not found!";
exit;
} else {
$file = fopen($filepath,"r");
header("content-type: application/octet-stream");
header("accept-ranges: bytes");
header("accept-length: ".filesize($filepath));
header("content-disposition: attachment; filename=".$filename);
echo fread($file, filesize($filepath));
fclose($file);
}
}
/**
* 创建一个目录树
* @param [type] $dir [description]
* @param integer $mode [description]
* @return [type] [description]
*/
function mkdirs($dir, $mode = 0777) {
if (!is_dir($dir)) {
mkdirs(dirname($dir), $mode);
return mkdir($dir, $mode);
}
return true;
}
相关推荐：
php中字符串操作函数的总结
php删除文件夹操作函数和几种方式实例代码汇总
php常用的字符串操作函数总结
以上就是常用的php操作函数分享的详细内容。