How to use socket to get remote pictures in php

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获取远程资源(网页，图片等)
 * url 资源URL
 * savepath 资源的保存路径
 * 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 = "";//主机名
    $file = "";//请求的文件
    if(count($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;
}
 
/* 获取百度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;;
}