Code summary of 9 useful PHP functions

一、查看邮件是否已被阅读

　　当你在发送邮件时，你或许很想知道该邮件是否被对方已阅读。这里有段非常有趣的代码片段能够显示对方IP地址记录阅读的实际日期和时间。

代码如下:

<?php
error_reporting
(0);
Header("Content-Type: image/jpeg");
 
//Get IP
if (!empty($_SERVER[&#39;HTTP_CLIENT_IP&#39;]))
{
  $ip=$_SERVER[&#39;HTTP_CLIENT_IP&#39;];
}
elseif (!empty($_SERVER[&#39;HTTP_X_FORWARDED_FOR&#39;]))
{
  $ip=$_SERVER[&#39;HTTP_X_FORWARDED_FOR&#39;];
}
else
{
  $ip=$_SERVER[&#39;REMOTE_ADDR&#39;];
}
 
//Time
$actual_time = time();
$actual_day = date(&#39;Y.m.d&#39;, $actual_time);
$actual_day_chart = date(&#39;d/m/y&#39;, $actual_time);
$actual_hour = date(&#39;H:i:s&#39;, $actual_time);
 
//GET Browser
$browser = $_SERVER[&#39;HTTP_USER_AGENT&#39;];
     
//LOG
$myFile = "log.txt";
$fh = fopen($myFile, &#39;a+&#39;);
$stringData = $actual_day . &#39; &#39; . $actual_hour . &#39; &#39; . $ip . &#39; &#39; . $browser . &#39; &#39; . "\r\n";
fwrite($fh, $stringData);
fclose($fh);
 
//Generate Image (Es. dimesion is 1x1)
$newimage = ImageCreate(1,1);
$grigio = ImageColorAllocate($newimage,255,255,255);
ImageJPEG($newimage);
ImageDestroy($newimage);
     
?>

　　二、从网页中提取关键字

　　一段伟大的代码片段能够轻松的从网页中提取关键字。

$meta = get_meta_tags('http://www.php.cn/');
$keywords = $meta['keywords'];
// Split keywords
$keywords = explode(',', $keywords );
// Trim them
$keywords = array_map( 'trim', $keywords );
// Remove empty values
$keywords = 
array_filter
( $keywords );
 
print_r( $keywords );

　　三、查找页面上的所有链接

　　使用DOM，你可以轻松从任何页面上抓取链接，代码示例如下：

$html = file_get_contents('http://www.php.cn');
 
$dom = new DOMDocument();
@$dom->loadHTML($html);
 
// grab all the on the page
$xpath = new DOMXPath($dom);
$hrefs = $xpath->evaluate("/html/body//a");
 
for ($i = 0; $i < $hrefs->length; $i++) {
       $href = $hrefs->item($i);
       $url = $href->getAttribute(&#39;href&#39;);
       echo $url.&#39;<br />&#39;;
}

　　四、自动转换URL，跳转至超链接

　　在WordPress中，如果你想自动转换URL，跳转至超链接页面，你可以利用内置的函数make_clickable()执行此操作。如果你想基于WordPress之外操作该程序，那么你可以参考wp-includes/formatting.php源代码。

function _make_url_clickable_cb($matches) {
    $ret = '';
    $url = $matches[2];
  
    if ( empty($url) )
        return $matches[0];
    // removed trailing [.,;:] from URL
    if ( in_array(substr($url, -1), array('.', ',', ';', ':')) === true ) {
        $ret = substr($url, -1);
        $url = substr($url, 0, strlen($url)-1);
    }
    return $matches[1] . "<a href=\"$url\" rel=\"nofollow\">$url</a>" . $ret;
}
  
function _make_web_ftp_clickable_cb($matches) {
    $ret = &#39;&#39;;
    $dest = $matches[2];
    $dest = &#39;http://&#39; . $dest;
  
    if ( empty($dest) )
        return $matches[0];
    // removed trailing [,;:] from URL
    if ( in_array(substr($dest, -1), array(&#39;.&#39;, &#39;,&#39;, &#39;;&#39;, &#39;:&#39;)) === true ) {
        $ret = substr($dest, -1);
        $dest = substr($dest, 0, strlen($dest)-1);
    }
    return $matches[1] . "<a href=\"$dest\" rel=\"nofollow\">$dest</a>" . $ret;
}
  
function _make_email_clickable_cb($matches) {
    $email = $matches[2] . &#39;@&#39; . $matches[3];
    return $matches[1] . "<a href=\"mailto:$email\">$email</a>";
}
  
function make_clickable($ret) {
    $ret = &#39; &#39; . $ret;
    // in testing, using arrays here was found to be faster
    $ret = preg_replace_callback(&#39;#([\s>])([\w]+?://[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is&#39;, &#39;_make_url_clickable_cb&#39;, $ret);
    $ret = preg_replace_callback(&#39;#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is&#39;, &#39;_make_web_ftp_clickable_cb&#39;, $ret);
    $ret = preg_replace_callback(&#39;#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i&#39;, &#39;_make_email_clickable_cb&#39;, $ret);
  
    // this one is not in an array because we need it to run last, for cleanup of accidental links within links
    $ret = preg_replace("#(<a( [^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i", "$1$3</a>", $ret);
    $ret = trim($ret);
    return $ret;
}

　　五、创建数据URL

　　数据URL可以直接嵌入到HTML/CSS/JS中，以节省大量的 HTTP请求。 下面的这段代码可利用$file轻松创建数据URL。

function data_uri($file, $mime) {
  $contents=file_get_contents($file);
  $base64=base64_encode($contents);
  echo "data:$mime;base64,$base64";
}

　　六、从服务器上下载&保存一个远程图片 

　　当你在搭建网站时，从远程服务器下载某张图片并且将其保存在自己的服务器上，这一操作会经常用到。代码如下：

$image = file_get_contents('http://www.url.com/image.jpg');
file_put_contents('/images/image.jpg', $image); //Where to save the image

　　七、移除Remove Microsoft Word HTML Tag

　　当你使用Microsoft Word会创建许多Tag，比如font，span，style，class等。这些标签对于Word本身而言是非常有用的，但是当你从Word粘贴至网页时，你会发现很多无用的Tag。因此，下面的这段代码可帮助你删除所有无用的Word HTML Tag。

function cleanHTML($html) {
/// <summary>
/// Removes all FONT and SPAN tags, and all Class and Style attributes.
/// Designed to get rid of non-standard Microsoft Word HTML tags.
/// </summary>
// start by completely removing all unwanted tags
 
$html = ereg_replace("<(/)?(font|span|del|ins)[^>]*>","",$html);
 
// then run another pass over the html (twice), removing unwanted attributes
 
$html = ereg_replace("<([^>]*)(class|lang|style|size|face)=("[^"]*"|&#39;[^&#39;]*&#39;|[^>]+)([^>]*)>","<\1>",$html);
$html = ereg_replace("<([^>]*)(class|lang|style|size|face)=("[^"]*"|&#39;[^&#39;]*&#39;|[^>]+)([^>]*)>","<\1>",$html);
 
return $html
}

　　八、检测浏览器语言

　　如果你的网站上有多种语言，那么可以使用这段代码作为默认的语言来检测浏览器语言。该段代码将返回浏览器客户端使用的初始语言。

function get_client_language($availableLanguages, $default='en'){
    if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
        $langs=explode(',',$_SERVER['HTTP_ACCEPT_LANGUAGE']);
 
        foreach ($langs as $value){
            $choice=substr($value,0,2);
            if(in_array($choice, $availableLanguages)){
                return $choice;
            }
        }
    } 
    return $default;
}

　　九、显示Facebook 粉丝数量

　　如果你的网站或者博客上有内链的Facebook页面，你或许想知道拥有多少粉丝。这段代码将帮助你查看Facebook粉丝数，记住，别忘了在你的页面ID第二行添加该段代码。

<?php
    $page_id = "YOUR PAGE-ID";
    $xml = @simplexml_load_file("http://api.facebook.com/restserver.php?method=facebook.fql.query&query=SELECT%20fan_count%20FROM%20page%20WHERE%20page_id=".$page_id."") or die ("a lot");
    $fans = $xml->page->fan_count;
    echo $fans;
?>

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