代码来自thinkphp,作者liu21st,我以注释的方式学习这部分代码,只注释的部分函数,之后再完成全部的注释
<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2009 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
/**
* Http 工具类
* 提供一系列的Http方法
* @author liu21st <liu21st@gmail.com>
*/
class Http {
/**
* 采集远程文件
* @access public
* @param string $remote 远程文件名
* @param string $local 本地保存文件名
* @return mixed
*/
static public function curlDownload($remote,$local) {
$cp = curl_init($remote);
$fp = fopen($local,"w");
curl_setopt($cp, CURLOPT_FILE, $fp);
curl_setopt($cp, CURLOPT_HEADER, 0);
curl_exec($cp);
curl_close($cp);
fclose($fp);
}
/**
* 使用 fsockopen 通过 HTTP 协议直接访问(采集)远程文件
* 如果主机或服务器没有开启 CURL 扩展可考虑使用
* fsockopen 比 CURL 稍慢,但性能稳定
* @static
* @access public
* @param string $url 远程URL
* @param array $conf 其他配置信息
* int limit 分段读取字符个数
* string post post的内容,字符串或数组,key=value&形式
* string cookie 携带cookie访问,该参数是cookie内容
* string ip 如果该参数传入,$url将不被使用,ip访问优先
* int timeout 采集超时时间
* bool block 是否阻塞访问,默认为true
* @return mixed
*/
static public function fsockopenDownload($url, $conf = array()) {
$return = '';
//如果不是数据 就返回''
if(!is_array($conf)) return $return;
//解析url
$matches = parse_url($url);
!isset($matches['host']) && $matches['host'] = ''; //如果不存在$matches['host'],就声明这个变量,并赋值为空
!isset($matches['path']) && $matches['path'] = ''; //如果不存在$matches['path'],就声明这个变量,并赋值为空
!isset($matches['query']) && $matches['query'] = ''; //如果不存在$matches['query'],就声明这个变量,并赋值为空
!isset($matches['port']) && $matches['port'] = ''; //如果不存在$matches['port'],就声明这个变量,并赋值为空
$host = $matches['host'];
//如果$matches['path']不为空,其值为$matches['path'].($matches['query'] ? '?'.$matches['query'] : '')
//$matches['query']不为空就拼接上,为空就拼接空
//如果$matches['path']为空,其值为'/'
$path = $matches['path'] ? $matches['path'].($matches['query'] ? '?'.$matches['query'] : '') : '/';
$port = !empty($matches['port']) ? $matches['port'] : 80; //端口不存在就设置成80端口
$conf_arr = array(
'limit' => 0,
'post' => '',
'cookie' => '',
'ip' => '',
'timeout' => 15,
'block' => TRUE,
);
foreach (array_merge($conf_arr, $conf) as $k=>$v) ${$k} = $v; //将用户传入的和程序内的配置数组合并,并且用可变变量完成赋值
if($post) {
if(is_array($post))
{
$post = http_build_query($post); //将$post这个键值对的数组处理成url后面带的参数
}
//请求行,\r\n换行
$out = "POST $path HTTP/1.0\r\n"; //现在的版本都是HTTP/1.1了
//下面都是请求头
$out .= "Accept: */*\r\n"; //
//$out .= "Referer: $boardurl\r\n";
$out .= "Accept-Language: zh-cn\r\n"; //
$out .= "Content-Type: application/x-www-form-urlencoded\r\n"; //post必须加
$out .= "User-Agent: $_SERVER[HTTP_USER_AGENT]\r\n"; //你访问一个php文件,就会产生$_SERVER从里面就能获取这个参数
$out .= "Host: $host\r\n"; //访问的主机
$out .= 'Content-Length: '.strlen($post)."\r\n"; //这个挺关键的
$out .= "Connection: Close\r\n"; //
$out .= "Cache-Control: no-cache\r\n"; //
$out .= "Cookie: $cookie\r\n\r\n"; //
//请求实体,上面是\r\n\r\n,意思就是在请求头与请求实体之间要空一行
$out .= $post;
} else {
//请求行
$out = "GET $path HTTP/1.0\r\n"; //
//请求头
$out .= "Accept: */*\r\n"; //
//$out .= "Referer: $boardurl\r\n";
$out .= "Accept-Language: zh-cn\r\n"; //
$out .= "User-Agent: $_SERVER[HTTP_USER_AGENT]\r\n"; //
$out .= "Host: $host\r\n"; //
$out .= "Connection: Close\r\n"; //
$out .= "Cookie: $cookie\r\n\r\n"; //
}
$fp = @fsockopen(($ip ? $ip : $host), $port, $errno, $errstr, $timeout);
if(!$fp) {
return '';
} else {
stream_set_blocking($fp, $block); //设置程序为阻塞
/*
* PHP函数stream_set_timeout(Stream Functions)作用于读取流时的时间控制。
* fsockopen函数的timeout只管创建连接时的超时,对于连接后读取流时的超时,
* 则需要用到 stream_set_timeout函数。由于国内的网络环境不是很稳定,
* 尤其是连接国外的时候,不想程序出现Fatal error: Maximum execution time of 30 seconds exceeded in …的错误,
* 该函数尤其有用。stream_set_timeout需配合stream_get_meta_data使用,如果没有timeout,
* stream_get_meta_data返回数组中time_out为空,反之为1,可根据此判断是否超时。
*
* */
stream_set_timeout($fp, $timeout);
@fwrite($fp, $out); //沿着打开的通道写数据
$status = stream_get_meta_data($fp);
if(!$status['timed_out']) {
/*
* 可以看出先是返回的http信息,然后是一个空行,然后是html内,下面的代码就是一行一行的读取,直到遇到换行就停止,
*
* HTTP/1.1 200 OK
Content-Type: text/html; charset=GBK
.......
Accept-Ranges: bytes
<!DOCTYPE HTML>
把看不到的东西也写出来是这样的
HTTP/1.1 200 OK\r\n
Content-Type: text/html; charset=GBK\r\n
.......
Accept-Ranges: bytes\r\n
\r\n 读到这行满足条件退出
<!DOCTYPE HTML> //指针已经移到了这行开头
*
*
*/
while (!feof($fp)) {
//fgets() 函数从文件指针中读取一行。
if(($header = @fgets($fp)) && ($header == "\r\n" || $header == "\n")) {
break;
}
}
$stop = false;
while(!feof($fp) && !$stop) {
//$limit==0 或者$limit>8102的时候,按照8192读取,否则就按用户设置的$limit读
$data = fread($fp, ($limit == 0 || $limit > 8192 ? 8192 : $limit));
$return .= $data;
if($limit) {
$limit -= strlen($data);
$stop = $limit <= 0; //$limit <=0结果是true还是false会赋值给$stop
}
}
}
@fclose($fp);
return $return;
}
}
/**
* 下载文件
* 可以指定下载显示的文件名,并自动发送相应的Header信息
* 如果指定了content参数,则下载该参数的内容
* @static
* @access public
* @param string $filename 下载文件名
* @param string $showname 下载显示的文件名
* @param string $content 下载的内容
* @param integer $expire 下载内容浏览器缓存时间
* @return void
*/
static public function download ($filename, $showname='',$content='',$expire=180) {
if(is_file($filename)) {
$length = filesize($filename);
}elseif(is_file(UPLOAD_PATH.$filename)) {
$filename = UPLOAD_PATH.$filename;
$length = filesize($filename);
}elseif($content != '') {
$length = strlen($content);
}else {
E($filename.L('下载文件不存在!'));
}
if(empty($showname)) {
$showname = $filename;
}
$showname = basename($showname);
if(!empty($filename)) {
$finfo = new \finfo(FILEINFO_MIME);
$type = $finfo->file($filename);
}else{
$type = "application/octet-stream";
}
//发送Http Header信息 开始下载
header("Pragma: public");
header("Cache-control: max-age=".$expire);
//header('Cache-Control: no-store, no-cache, must-revalidate');
header("Expires: " . gmdate("D, d M Y H:i:s",time()+$expire) . "GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s",time()) . "GMT");
header("Content-Disposition: attachment; filename=".$showname);
header("Content-Length: ".$length);
header("Content-type: ".$type);
header('Content-Encoding: none');
header("Content-Transfer-Encoding: binary" );
if($content == '' ) {
readfile($filename);
}else {
echo($content);
}
exit();
}
/**
* 显示HTTP Header 信息
* @return string
*/
static function getHeaderInfo($header='',$echo=true) {
ob_start();
$headers = getallheaders();
if(!empty($header)) {
$info = $headers[$header];
echo($header.':'.$info."\n"); ;
}else {
foreach($headers as $key=>$val) {
echo("$key:$val\n");
}
}
$output = ob_get_clean();
if ($echo) {
echo (nl2br($output));
}else {
return $output;
}
}
/**
* HTTP Protocol defined status codes
* @param int $num
*/
static function sendHttpStatus($code) {
static $_status = array(
// Informational 1xx
100 => 'Continue',
101 => 'Switching Protocols',
// Success 2xx
200 => 'OK',
201 => 'Created',
202 => 'Accepted',
203 => 'Non-Authoritative Information',
204 => 'No Content',
205 => 'Reset Content',
206 => 'Partial Content',
// Redirection 3xx
300 => 'Multiple Choices',
301 => 'Moved Permanently',
302 => 'Found', // 1.1
303 => 'See Other',
304 => 'Not Modified',
305 => 'Use Proxy',
// 306 is deprecated but reserved
307 => 'Temporary Redirect',
// Client Error 4xx
400 => 'Bad Request',
401 => 'Unauthorized',
402 => 'Payment Required',
403 => 'Forbidden',
404 => 'Not Found',
405 => 'Method Not Allowed',
406 => 'Not Acceptable',
407 => 'Proxy Authentication Required',
408 => 'Request Timeout',
409 => 'Conflict',
410 => 'Gone',
411 => 'Length Required',
412 => 'Precondition Failed',
413 => 'Request Entity Too Large',
414 => 'Request-URI Too Long',
415 => 'Unsupported Media Type',
416 => 'Requested Range Not Satisfiable',
417 => 'Expectation Failed',
// Server Error 5xx
500 => 'Internal Server Error',
501 => 'Not Implemented',
502 => 'Bad Gateway',
503 => 'Service Unavailable',
504 => 'Gateway Timeout',
505 => 'HTTP Version Not Supported',
509 => 'Bandwidth Limit Exceeded'
);
if(isset($_status[$code])) {
header('HTTP/1.1 '.$code.' '.$_status[$code]);
}
}
}//类定义结束