0、基本例子
一般流程:

$to_url=$_GET['url'];
print_r($_GET);
if(substr($to_url,0,1)=='/'){
 $to_url="http://www.amazon.com".$to_url;
}
echo $to_url;
//初始化
$ch = curl_init();
//设置选项，包括URL
curl_setopt($ch, CURLOPT_URL, $to_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
//执行并获取HTML文档内容
$output = curl_exec($ch);
$output=preg_replace("#href=\"#","href=\"http://in2.qq-ex.com/amazon.php?url=",$output);
// 释放curl句柄
curl_close($ch);
echo $output;
// 指定代理地址
curl_setopt($ch, CURLOPT_PROXY, '11.11.11.11:8080');
// 如果需要的话，提供用户名和密码
curl_setopt($ch, CURLOPT_PROXYUSERPWD,'user:pass');

1、测试网站是否运行正常

 if (isDomainAvailible('http://gz.itownet.cn')) 
 { 
 echo "Up and running!"; 
 } 
 else 
 { 
 echo "Woops, nothing found there."; 
 } 
 
 //returns true, if domain is availible, false if not 
 function isDomainAvailible($domain) 
 { 
 //check, if a valid url is provided 
 if(!filter_var($domain, FILTER_VALIDATE_URL)) 
 { 
 return false; 
 } 
 
 //initialize curl 
 $curlInit = curl_init($domain); 
 curl_setopt($curlInit,CURLOPT_CONNECTTIMEOUT,10); 
 curl_setopt($curlInit,CURLOPT_HEADER,true); 
 curl_setopt($curlInit,CURLOPT_NOBODY,true); 
 curl_setopt($curlInit,CURLOPT_RETURNTRANSFER,true); 
 
 //get answer 
 $response = curl_exec($curlInit); 
 
 curl_close($curlInit); 
 
 if ($response) return true; 
 
 return false; 
 } 

2、可以代替file_gecontents的操作

function file_get_contents_curl($url) { 
 $ch = curl_init(); 
 
 curl_setopt($ch, CURLOPT_HEADER, 0); 
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); //Set curl to return the data instead of printing it to the browser. 
 curl_setopt($ch, CURLOPT_URL, $url); 
 
 $data = curl_exec($ch); 
 curl_close($ch); 
 
 return $data; 
} 

3、保存某个网站下的所有图片

 function getImages($html) { 
 $matches = array(); 
 $regex = '~http://somedomain.com/images/(.*?)\.jpg~i'; 
 preg_match_all($regex, $html, $matches); 
 foreach ($matches[1] as $img) { 
 saveImg($img); 
 } 
} 
 
function saveImg($name) { 
 $url = 'http://somedomain.com/images/'.$name.'.jpg'; 
 $data = get_data($url); 
 file_put_contents('photos/'.$name.'.jpg', $data); 
} 
 
$i = 1; 
$l = 101; 
 
while ($i < $l) { 
 $html = get_data('http://somedomain.com/id/'.$i.'/'); 
 getImages($html); 
 $i += 1; 
} 

4、FTP应用

// open a file pointer 
$file = fopen("/path/to/file", "r"); 
 
// the url contains most of the info needed 
$url = "ftp://username:password@mydomain.com:21/path/to/new/file"; 
 
$ch = curl_init(); 
 
curl_setopt($ch, CURLOPT_URL, $url); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
 
// upload related options 
curl_setopt($ch, CURLOPT_UPLOAD, 1); 
curl_setopt($ch, CURLOPT_INFILE, $fp); 
curl_setopt($ch, CURLOPT_INFILESIZE, filesize("/path/to/file")); 
 
// set for ASCII mode (e.g. text files) 
curl_setopt($ch, CURLOPT_FTPASCII, 1); 
 
$output = curl_exec($ch); 
curl_close($ch); 

5、使用curl发送JSON数据

$data = array("name" => "Hagrid", "age" => "36"); 
$data_string = json_encode($data); 
 
$ch = curl_init('http://api.local/rest/users'); 
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST"); 
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
curl_setopt($ch, CURLOPT_HTTPHEADER, array( 
 'Content-Type: application/json', 
 'Content-Length: ' . strlen($data_string)) 
); 
 
$result = curl_exec($ch);