What is the use of php curl? The 6 most commonly used examples of php curl classics

<?php
    /***
    *   php curl 案例
    *   下载网络上一个HTTPS资源
    */
    //初始化
    $curlobj = curl_init();  
     //设置访问的url
    curl_setopt($curlobj, CURLOPT_URL, "https://ajax.aspnetcdn.com/ajax/jquery.validate/1.12.0/jquery.validate.js" ); 
    //执行后不直接打印出
    curl_setopt($curlobj, CURLOPT_RETURNTRANSFER, true);  

    //设置https 支持
    date_default_timezone_get(&#39;PRC&#39;);   //使用cookies时，必须先设置时区
    curl_setopt($curlobj, CURLOPT_SSL_VERIFYPEER, 0);  //终止从服务端验证

    $output = curl_exec($curlobj);  //执行获取内容
    curl_close($curlobj);          //关闭curl

    //创建一个文件 
    $myfile = fopen(&#39;testfile.html&#39;, &#39;w&#39;);    //将获取的网站内容保存到文件中
    fwrite($myfile, $output);    //关闭文件资源
    fclose($myfile);?>

<?php  
     $ch = curl_init();  
     curl_setopt($ch, CURLOPT_URL, "http://localhost/mytest/phpinfo.php");  
     curl_setopt($ch, CURLOPT_HEADER, false);  
     curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); //如果把这行注释掉的话，就会直接输出  
     $result=curl_exec($ch);  
     curl_close($ch);  
     ?>

<?php  
     $ch = curl_init();  
     curl_setopt($ch, CURLOPT_URL, "http://blog.51yip.com");  
     curl_setopt($ch, CURLOPT_HEADER, false);  
     curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);  
     curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, TRUE);  
     curl_setopt($ch, CURLOPT_PROXY, 125.21.23.6:8080);  
     //url_setopt($ch, CURLOPT_PROXYUSERPWD, &#39;user:password&#39;);如果要密码的话，加上这个  
     $result=curl_exec($ch);  
     curl_close($ch);  
     ?>

 <?php  
     $ch = curl_init();  
     /***在这里需要注意的是，要提交的数据不能是二维数组或者更高 
     *例如array(&#39;name&#39;=>serialize(array(&#39;tank&#39;,&#39;zhang&#39;)),&#39;sex&#39;=>1,&#39;birth&#39;=>&#39;20101010&#39;) 
     *例如array(&#39;name&#39;=>array(&#39;tank&#39;,&#39;zhang&#39;),&#39;sex&#39;=>1,&#39;birth&#39;=>&#39;20101010&#39;)这样会报错的*/
     $data = array(&#39;name&#39; => &#39;test&#39;, &#39;sex&#39;=>1,&#39;birth&#39;=>&#39;20101010&#39;);  
     curl_setopt($ch, CURLOPT_URL, &#39;http://localhost/mytest/curl/upload.php&#39;);  
     curl_setopt($ch, CURLOPT_POST, 1);  
     curl_setopt($ch, CURLOPT_POSTFIELDS, $data);  
     curl_exec($ch);  
     ?>
     在 upload.php文件中，print_r($_POST);利用curl就能抓取出upload.php输出的内容Array ( [name] => test [sex] => 1 [birth] => 20101010 )

  <?php  
     $ch = curl_init();  
     curl_setopt($ch, CURLOPT_URL, "http://club-china");  
     /*CURLOPT_USERPWD主要用来破解页面访问控制的 
     *例如平时我们所以htpasswd产生页面控制等。*/
     //curl_setopt($ch, CURLOPT_USERPWD, &#39;231144:2091XTAjmd=&#39;);  
     curl_setopt($ch, CURLOPT_HTTPGET, 1);  
     curl_setopt($ch, CURLOPT_REFERER, "http://club-china");  
     curl_setopt($ch, CURLOPT_HEADER, 0);  
     $result=curl_exec($ch);  
     curl_close($ch);  
     ?>

<?php   

    function checklogin( $user, $password )  
     {  
     if ( emptyempty( $user ) || emptyempty( $password ) )  
     {  
     return 0;  
     }  
     $ch = curl_init( );  
     curl_setopt( $ch, CURLOPT_REFERER, "http://mail.sina.com.cn/index.html" );  
     curl_setopt( $ch, CURLOPT_HEADER, true );  
     curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );  
     curl_setopt( $ch, CURLOPT_USERAGENT, USERAGENT );  
     curl_setopt( $ch, CURLOPT_COOKIEJAR, COOKIEJAR );  
     curl_setopt( $ch, CURLOPT_TIMEOUT, TIMEOUT );  
     curl_setopt( $ch, CURLOPT_URL, "http://mail.sina.com.cn/cgi-bin/login.cgi" );  
     curl_setopt( $ch, CURLOPT_POST, true );  
     curl_setopt( $ch, CURLOPT_POSTFIELDS, "&logintype=uid&u=".urlencode( $user )."&psw=".$password );  
     $contents = curl_exec( $ch );  
     curl_close( $ch );  
     if ( !preg_match( "/Location: (.*)\\\\/cgi\\\\/index\\\\.php\\\\?check_time=(.*)\\n/", $contents, $matches ) )  
     {  
     return 0;  
     }else{  
     return 1;  
     }  
     }   

     define( "USERAGENT", $_SERVER[&#39;HTTP_USER_AGENT&#39;] );  
     define( "COOKIEJAR", tempnam( "/tmp", "cookie" ) );  
     define( "TIMEOUT", 500 );   

     echo checklogin("zhangying215","xtaj227");  
     ?>  

打开/tmp下面的cookie文件看一下

# Netscape HTTP Cookie File
# http://curl.haxx.se/rfc/cookie_spec.html# This file was generated by libcurl! Edit at your own risk.

mail.sina.com.cn    FALSE    /    FALSE    0    SINAMAIL-WEBFACE-SESSID    65223c4bd8900284ed463d2a3e1ac182
#HttpOnly_.sina.com.cn    TRUE    /    FALSE    0    SUE    es%3D8d96db0820c6c79922ad57d422f575e8%26ev%3Dv0%26es2%3Dcddfb8400dc5ca95902367ddcd7f57dd.sina.com.cn    TRUE    /    FALSE    0    SUP    cv%3D1%26bt%3D1286900433%26et%3D1286986833%26lt%3D1%26uid%3D1445632344%26user%3D%25E5%25BC%25A0%25E6%2598%25A02001%26ag%3D2%26name%3Dzhangying20015%2540sina.com%26nick%3D%25E5%25BC%25A0%25E6%2598%25A02001%26sex%3D1%26ps%3D0%26email%3Dzhangying20015%2540sina.com%26dob%3D1982-07-18#HttpOnly_.sina.com.cn    TRUE    /    FALSE    0    SID    BihcallomxMx-QZxzGrOlcSQx%2F0B%2F0cmr.NyQ%2F0B%2FcmGGalmarlmcHrcGlSmrmxmfxal_CBZ%2F_afugCmmGirBYHm0Bc%40fr5ciZiGG5i#HttpOnly_.sina.com.cn    TRUE    /    FALSE    0    SPRIAL    bfb4102951fd5892a3fd5b42d442cd26
#HttpOnly_.sina.com.cn    TRUE    /    FALSE    0    SINA_USER    %D5%C5%D2001