curl,fsocketopen,socket 三种函数抓取html页面

<?php
$ch_article = curl_init();
$url        = 'www.baidu.com';
curl_setopt($ch_article, CURLOPT_URL, $url);
curl_setopt($ch_article, CURLOPT_RETURNTRANSFER, 0);
curl_setopt($ch_article, CURLOPT_HEADER, 0);
$article_output = curl_exec($ch_article);
curl_close($ch_article);
echo $article_output;
?>

<?php
$fp = fsockopen("www.baidu.com", 80, $errno, $errstr, 30);
$out = "GET / HTTP/1.1\r\n";
$out .= "Host: www.baidu.com\r\n";
$out .= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
echo fgets($fp, 128);
}
fclose($fp);
?>

<?php
$url='www.baidu.com';
$Port = 80;
$host_ip  = gethostbyname('www.baidu.com');
$Header  .= trim('Host:www.baidu.com')."\r\n";
$Header  .= trim('Connection: Close')."\r\n";
$method   = 'GET';
$Request  = $method." " . '/' . " HTTP/1.1\r\n";
$Request .= $Header;
$Request .= "\r\n";
$sockHttp    = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
$resSockHttp = socket_connect($sockHttp, $host_ip, $Port);
socket_write($sockHttp, $Request, strlen($Request));
$Response = '';
while ($Read_data = socket_read($sockHttp, 4096)){
$Response .= $Read_data;
}
socket_close($sockHttp);
echo $Response;
?>