Steps:

1, match the host name and file part in the URL

2, create socket and connect to the target server

3, construct HTTP request and send

4, read HTTP response and parse

5, save Content to file and close the socket connection

The code is implemented as follows:

<?php
/*
 * 使用socket獲取遠(yuǎn)程資源(網(wǎng)頁，圖片等)
 * url 資源URL
 * savepath 資源的保存路徑
 * return true/false
 */
function get_remote_picture($url,$savepath="./"){
    set_time_limit(0);
    $pattern = &#39;/(http:\/\/)?([^\/]+)(.+)/&#39;;
    $res = preg_match($pattern, $url, $matches);
    if($res == 0){
        return false;
    }
    $host = "";//主機(jī)名
    $file = "";//請(qǐng)求的文件
    if(count($matches) == 3){
        $host = $matches[1];
        $file = $matches[2];
    }else if(count($matches) == 4){
        $host = $matches[2];
        $file = $matches[3];
    }else{
        return false;
    }
    $socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP);
    $res = socket_connect($socket,gethostbyname($host),80);
    if(!$res){
        //echo socket_strerror(socket_last_error($socket));
        socket_close($socket);
        return false;
    }
    $request = "";
    $request .= "GET $file HTTP/1.1\r\n";
    $request .= "Host: $host\r\n";
    $request .= "Connection: close\r\n\r\n";
    $len = socket_write($socket,$request);
 
    $response = "";
    while($buf=socket_read($socket,512)){
        if(strlen($buf) == 0){
            break;
        }
        $response .= $buf;
    }
    if(strpos($response,"\r\n\r\n")){
        $arr = explode("\r\n\r\n",$response);
        if(!file_exists($savepath)){
            @mkdir($savepath);
        }
        $savepath = rtrim($savepath,&#39;/&#39;).&#39;/&#39;;
        file_put_contents($savepath.basename($file),$arr[1]);
    }else{
        socket_close($socket);
        return false;
    }
    socket_close($socket);
    return true;
}
 
/* 獲取百度logo */
$url = "http://su.bdimg.com/static/superplus/img/logo_white.png";
$result = get_remote_picture($url);
if($result){
    echo &#39;get remote picture success&#39;;
}else{
    echo &#39;get remote picture failed&#39;;
}