php发送http请求的几种方式

1.curl仍然是最好的HTTP库，没有之一。 可以解决任何复杂的应用场景中的HTTP 请求
2. 文件流式的HTTP请求比较适合处理简单的HTTP POST/GET请求，但不适用于复杂的HTTP请求
3. PECL_HTTP扩展写代码更加简洁，省事， 但成熟度不好，编程接口不统一，文档和实例匮乏。 

1、file_get_contents 发送get请求

<?php
/**
 * 发送post请求
 * @param string $url 请求地址
 * @param array $post_data post键值对数据
 * @return string
 */
function send_post($url, $post_data) {
    $postdata = http_build_query($post_data);
    $options = array(
        'http' => array(
            'method' => 'POST',
            'header' => 'Content-type:application/x-www-form-urlencoded',
            'content' => $postdata,
            'timeout' => 15 * 60 // 超时时间（单位:s）
        )
    );
    $context = stream_context_create($options);
    $result = file_get_contents($url, false, $context);
    return $result;
}

$post_data = array(
    'username' => 'abcdef',
    'password' => '123456'
);
send_post('http://xxx.com', $post_data);

2、通过CURL发送get请求

<?php
$ch=curl_init('http://www.xxx.com/xx.html');
curl_setopt($ch,CURLOPT_RETURNTRANSFER,true);
curl_setopt($ch,CURLOPT_BINARYTRANSFER,true);
$output=curl_exec($ch);
$fh=fopen("out.html",'w');
fwrite($fh,$output);
fclose($fh);

3、通过fsocket发送get请求

/**
 * Socket版本
 * 使用方法：
 * $post_string = "app=socket&version=beta";
 * request_by_socket('blog.snsgou.com', '/restServer.php', $post_string);
 */
function request_by_socket($remote_server,$remote_path,$post_string,$port = 80,$timeout = 30) {
    $socket = fsockopen($remote_server, $port, $errno, $errstr, $timeout);
    if (!$socket) die("$errstr($errno)");
    fwrite($socket, "POST $remote_path HTTP/1.0");
    fwrite($socket, "User-Agent: Socket Example");
    fwrite($socket, "HOST: $remote_server");
    fwrite($socket, "Content-type: application/x-www-form-urlencoded");
    fwrite($socket, "Content-length: " . （strlen($post_string) + 8） . "");
    fwrite($socket, "Accept:*/*");
    fwrite($socket, "");
    fwrite($socket, "mypost=$post_string");
    fwrite($socket, "");
    $header = "";
    while ($str = trim(fgets($socket, 4096))) {
        $header .= $str;
    }

    $data = "";
    while (!feof($socket)) {
        $data .= fgets($socket, 4096);
    }

    return $data;
}