利用PUT方式上传文件的方法研究

虽然没有POST方法使用广泛，但是PUT方法却是向服务器上传文件最有效率的方法。POST上传文件时，我们通常需要将所有的信息组合成 multipart 传送过去，然后服务器再解码这些信息，解码过程则必不可少的会消耗内存和CPU资源，这种现象在上传大文件时尤其明显。而PUT方法则允许你通过与服务器建立的socket链接传递文件的内容，而不附带其他的信息。

最近一个项目上需要利用这种方式来进行文件的上传，下面介绍一下在 Apache + PHP 的环境下如何进行PUT方式的文件上传。

Apache 有一个模块 mod_actions，先看看官方的说明：

This module has two directives. The Action directive lets you run CGI scripts whenever a file of a certain MIME content type is requested. The Script directive lets you run CGI scripts whenever a particular method is used in a request. This makes it much easier to execute scripts that process files.

也就是说，这个模块可以指定对于特定 MIME 类型的文件处理，或者对于特定脚本的请求进行指定的处理。我用到的就是 Script 这个选项。

在Apache 配置文件的 Directory 中指定

Script PUT /receive.php

这个含义就是，对于所有对服务器的PUT请求，都交给根目录下的 receive.php 去处理，当然我们也可以选择 perl 或者其他的CGI脚本来进行处理。

接下来就是这个 receive.php 脚本的编写了，他的主要任务就是将请求的文件写到指定的位置

<?php
/**
* Process The PUT File, receive and move a file to corresponsed location
* Created by shiqiang<cocowool@gmail.com> at 2010-05-24
*
**/

class Receive {
    var $default_log_file = "logs/error.log";
    var $default_server_info = "logs/server.log";
    var $default_header_info = "logs/header.log";
    var $default_prefix = "/data1/vhosts";    //Default project location prefix;
    var $default_module = "test.cn";
    var $max_filesize = 2048000;
    var $request_uri;

    function Receive(){
        $this->request_uri = $_SERVER['REQUEST_URI'];
    }
    function saveFile(){
        //receive data and save
        $putdata = fopen("php://input", "r");

        $path = $this->getPath($this->request_uri);
        $fp = fopen($path, 'w');
        while($data = fread($putdata, 1024) ){
            fwrite($fp, $data);
        }

        fclose($fp);
        fclose($putdata);

        //Log The filesize check and limit check
        if( filesize($path) != $_SERVER['CONTENT_LENGTH'] ){
            $this->errorLog( "[warn] " . date("Y-m-d H:i:s") . " The file's ($path) size dosen't match Server Filesize = " . filesize($path) . "; Put Filesize = " . $_SERVER['CONTENT_LENGTH']. "\r\n" );
            header('HTTP/1.1 526 Receive Data Error');
        }

        if( filesize($path) > $this->max_filesize ){
            $this->errorLog( "[warn] " . date("Y-m-d H:i:s") . " The file's ($path) size exceed the system limit");
        }
    }

    //Log Error Info
    function errorLog( $info ){
        $f = fopen($this->default_log_file, 'a+');
        fwrite($f, $info);
        flcose($f);
    }

    function serverLog(){
        $f = fopen($this->default_server_info, 'w');
        $info = $_SERVER;
        $str = "The Last Request Server Info:\r\n";
        foreach ($info as $key => $value){
            $str .= "$key = $value\r\n";
        }
        $str .= $this->getPath($this->request_uri) . "\r\n";
        $str .= "PHP_UPLOADED_FILE_NAME=" . $PHP_UPLOADED_FILE_NAME . "\r\n";
        fwrite($f , $str);
        fclose($f);
    }

    //Log the Request Header info
    function headerLog(){
        $f = fopen($this->default_header_info, 'w');
        $info = get_headers();
        $str = "The Last Request header Info:\r\n";
        foreach ($info as $key => $value){
            $str .= "$key = $value\r\n";
        }
        fwrite($f , $str);
        fclose($f);
    }

    //get the path where the file should be
    function getPath($uri){
        $module = $this->defalt_module;    //Default storage module

        $referer = $this->request_uri;
        preg_match('/(?<=\/)(.*?)(?=\/)/s', $referer, $match);

        if( !empty($match) && !empty($match[0]) ){
            $module = $match[0];
        }

        $path = $this->default_prefix;
        $path .= '/' . $module . '/htdocs';
        $fullpath = substr($uri, strlen($match[0]) + 1, strlen($uri) );

        $arr = explode('/', ltrim($fullpath, '/'));
        foreach($arr as $v){
            if( !strstr($v, '.') ){
                $path .= '/' . $v;
                //exec("echo $path >> dir.txt");
                if( !is_dir($path) ){
                    //For php > 5.0
                    //mkdir($path, "0766", true);
                    mkdir($path, 0766);
                }
            }else{
                $path .= '/' . $v;
            }
        }

        return $path;
    }

}

$instance = new Receive();
$instance->serverLog();
//$instance->headerLog();
$instance->saveFile();

?>