1.fsockopen方式，可post图片：
//例子：socket_post('http://site.com/', array('key1'=>'value1', 'key2'=>'value2'), array('filekey'=>'filepath'))
function socket_post($url, $postdata=array(), $files=array())
{
$boundary = '-------'.substr(md5(rand(0,32000)),0,10);
$encoded = "";
if($postdata){
while(list($k,$v) = each($postdata)){
$encoded .= "--$boundary\r\nContent-Disposition: form-data; name=\"".rawurlencode($k)."\"\r\n\r\n";
$encoded .= rawurlencode($v)."\r\n";
}
}
if($files){
foreach($files as $name=>$file){
$ext= strtolower(strrchr($file,"."));
switch($ext){
case '.gif':
$type = "image/gif";
break;
case '.jpg':
$type = "image/jpeg";
break;
case '.png':
$type = "image/png";
break;
default:
$type = "image/jpeg";
}
$encoded .= "--$boundary\r\nContent-Disposition:
form-data; name=\"".rawurlencode($name)."\";
filename=\"$file\"\r\nContent-Type: $type\r\n\r\n";
$encoded .= join("", file($file));
$encoded .= "\r\n";
}
}
$encoded .= "--$boundary--\r\n";
$length = strlen($encoded);
$uri = parse_url($url);
$fp = fsockopen($uri['host'], $uri['port'] ? $uri['port'] : 80);
if(!$fp)
return "Failed to open socket to ".$uri['host'];
fputs($fp, sprintf("POST %s%s%s HTTP/1.0\r\n", $uri['path'], $uri['query'] ? "?" : "", $uri['query']));
fputs($fp, "Host: ".$uri['host']."\r\n");
fputs($fp, "Content-type: multipart/form-data; boundary=$boundary\r\n");
fputs($fp, "Content-length: $length\r\n");
fputs($fp, "Connection: close\r\n\r\n");
fputs($fp, $encoded);
$results = "";
while(!feof($fp)){
$results .= fgets($fp,1024);
}
fclose($fp);
return preg_replace('/^HTTP(.*?)\r\n\r\n/s','',$results);
}
2.file_get_contents方式，不能post文件：
function Post($url, $post = null)
{
$context = array();
if (is_array($post))
{
ksort($post);
$context['http'] = array
(
'method' => 'POST',
'header'=>'Content-type: application/x-www-form-urlencoded',
'content' => http_build_query($post, '', '&'),
);
}
return file_get_contents($url, false, stream_context_create($context));
}