<?php

$__author__   = 'phus.lu@gmail.com';
$__version__  = '1.6.9';
$__password__ = '';

function encode_data($dic) {
    $a = array();
    foreach ($dic as $key => $value) {
       $a[] = $key. '=' . bin2hex($value);
    }
    return join('&', $a);
}

function decode_data($qs) {
    $dic = array();
    foreach (explode('&', $qs) as $kv) {
        $pair = explode('=', $kv, 2);
        $dic[$pair[0]] = $pair[1] ? pack('H*', $pair[1]) : '';
    }
    return $dic;
}

function print_response($status, $headers, $content) {
    $strheaders = encode_data($headers);
    $content_type = $headers['content-type'];
    if ($content_type && substr($content_type, 0, 4) == 'text') {
        $data = '1' . gzcompress(pack('NNN', $status, strlen($strheaders), strlen($content)) . $strheaders . $content);
    } else {
        $data = '0' . pack('NNN', $status, strlen($strheaders), strlen($content)) . $strheaders . $content;
    }
    header('Content-Type: image/gif');
    header('Content-Length: '.strlen($data));
    print($data);
}

function print_notify($method, $url, $status, $content) {
    $content = "<h2>PHP Fetch Server Info</h2><hr noshade='noshade'><p>$method '$url'</p><p>Return Code: $status</p><p>Message: $content</p>";
    $headers = array('content-type' => 'text/html');
    print_response($status, $headers, $content);
}

function error_exit() {
    $status = 200;
    $headers = array('content-type' => 'text/html');
    $content = "<h2>PHP Fetch Server Debug Info</h2><hr noshade='noshade'>";
    foreach (func_get_args() as $key => $value) {
        $content .= '<p>' . var_export($value, true) . '</p>';
    }
    print_response($status, $headers, $content);
    exit(0);
}

class URLFetch {
    protected $body_maxsize = 2097152;
    protected $headers = array();
    protected $body = '';
    protected $body_size = 0;

    function __construct() {
    }

    function urlfetch_curl_readheader($ch, $header) {
        $kv = array_map('trim', explode(':', $header, 2));
        if ($kv[1]) {
            $key = strtolower($kv[0]);
            $value = $kv[1];
            if ($key == 'set-cookie') {
                if (!array_key_exists('set-cookie', $this->headers)) {
                    $this->headers['set-cookie'] = $value;
                } else {
                    $this->headers['set-cookie'] .= "\r\nSet-Cookie: " . $value;
                }
            } else {
                $this->headers[$key] = $kv[1];
            }
        }
        return strlen($header);
    }

    function urlfetch_curl_readbody($ch, $data) {
        $bytes = strlen($data);
        $this->body_size += $bytes;
        $this->body .= $data;
        if ($this->body_size > $this->body_maxsize) {
            return -1;
        }
        return $bytes;
    }

    function urlfetch_curl($url, $payload, $method, $headers, $follow_redirects, $deadline, $validate_certificate) {

        $this->headers = array();
        $this->body = '';
        $this->body_size = 0;

        if ($payload) {
            $headers['content-length'] = strval(strlen($payload));
        }
        $headers['connection'] = 'close';

        $curl_opt = array();

        $curl_opt[CURLOPT_TIMEOUT]        = $deadline;
        $curl_opt[CURLOPT_CONNECTTIMEOUT] = $deadline;
        $curl_opt[CURLOPT_RETURNTRANSFER] = true;
        $curl_opt[CURLOPT_BINARYTRANSFER] = true;
        $curl_opt[CURLOPT_FAILONERROR]    = true;

        if (!$follow_redirects) {
            $curl_opt[CURLOPT_FOLLOWLOCATION] = false;
        }

        if ($deadline) {
            $curl_opt[CURLOPT_CONNECTTIMEOUT] = $deadline;
            $curl_opt[CURLOPT_TIMEOUT] = $deadline;
        }

        if (!$validate_certificate) {
            $curl_opt[CURLOPT_SSL_VERIFYPEER] = false;
            $curl_opt[CURLOPT_SSL_VERIFYHOST] = false;
        }

        switch (strtoupper($method)) {
            case 'HEAD':
                $curl_opt[CURLOPT_NOBODY] = true;
                break;
            case 'GET':
                break;
            case 'POST':
                $curl_opt[CURLOPT_POST] = true;
                $curl_opt[CURLOPT_POSTFIELDS] = $payload;
                break;
            case 'PUT':
            case 'DELETE':
                $curl_opt[CURLOPT_CUSTOMREQUEST] = $method;
                $curl_opt[CURLOPT_POSTFIELDS] = $payload;
                break;
            default:
                print_notify($method, $url, 501, 'Invalid Method');
                exit(-1);
        }

        $header_array = array();
        foreach ($headers as $key => $value) {
            if ($key) {
                $header_array[] = join('-', array_map('ucfirst', explode('-', $key))).': '.$value;
            }
        }
        $curl_opt[CURLOPT_HTTPHEADER] = $header_array;

        $curl_opt[CURLOPT_HEADER]         = false;
        $curl_opt[CURLOPT_HEADERFUNCTION] = array(&$this, 'urlfetch_curl_readheader');
        $curl_opt[CURLOPT_WRITEFUNCTION]  = array(&$this, 'urlfetch_curl_readbody');

        //error_exit('curl_opt:', $curl_opt);

        $ch = curl_init($url);
        curl_setopt_array($ch, $curl_opt);
        $ret = curl_exec($ch);
        $this->headers['connection'] = 'close';
        $status_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $errno = curl_errno($ch);
        if( $errno)
        {
            $error =  $errno . ': ' .curl_error($ch);
        }
        curl_close($ch);

        $content_length = 1 * $this->headers["content-length"];

        if ($status_code == 200 && $this->body_size > $this->body_maxsize && $content_length && $this->body_size < $content_length) {
            $status_code = 206;
            $range_start = 0;
            $range_end = $this->body_size - 1;
            $this->headers["content-range"] = "bytes $range_start-$range_end/$content_length";
            $this->headers["content-length"] = $this->body_size;
        }

        //error_exit('urlfetch result:', array('status_code' => $status_code, 'headers' => $this->headers, 'content-size' => $this->body_size, 'error' => $error));

        $response = array('status_code' => $status_code, 'headers' => $this->headers, 'content' => $this->body, 'error' => $error);
        return $response;
    }

    function urlfetch_fopen($url, $payload, $method, $headers, $follow_redirects, $deadline, $validate_certificate) {
        $this->headers = array();
        $this->body = '';
        $this->body_size = 0;

        if ($payload) {
            $headers['content-length'] = strval(strlen($payload));
        }
        $headers['connection'] = 'close';

        $header_string = '';
        foreach ($headers as $key => $value) {
            if ($key) {
                $header_string .= join('-', array_map('ucfirst', explode('-', $key))).': '.$value."\r\n";
            }
        }
        //error_exit('header_string:', $header_string);

        $opt = array();
        $opt['http'] = array();
        $opt['http']['method'] = $method;
        $opt['http']['header'] = $header_string;
        if ($payload) {
            $opt['http']['content'] = $payload;
        }
        $opt['http']['timeout'] = $deadline;
        $opt['ssl'] = array();
        $opt['ssl']['ciphers'] = 'ALL:!AES:!3DES:!RC4:@STRENGTH';

        if (!$follow_redirects) {
            $opt['http']['follow_location'] = false;
        }

        if (!$validate_certificate) {
            $opt['ssl']['verify_peer'] = false;
            $opt['ssl']['capture_peer_cert'] = false;
        }

        $context = stream_context_create($opt);
        if ($context == false) {
            return array('status_code' => 500, 'error' => "stream_context_create fail");
        }

        $fp = @fopen($url, 'rb', false, $context);
        if ($fp == false) {
            return array('status_code' => 500, 'error' => "fopen $url fail");
        }
        $meta = stream_get_meta_data($fp);
        if ($meta == false) {
            return array('status_code' => 500, 'error' => "stream_get_meta_data $url fail");
        }
        //error_exit('meta_data', $meta);
        $response_terms = explode(' ', array_shift($meta['wrapper_data']), 3);
        $status_code = intval($response_terms[1]);
        foreach($meta['wrapper_data'] as $line) {
            $kv = array_map('trim', explode(':', $line, 2));
            if ($kv[1]) {
                $key = strtolower($kv[0]);
                $value = $kv[1];
                if ($key == 'set-cookie') {
                    if (!array_key_exists('set-cookie', $this->headers)) {
                        $this->headers['set-cookie'] = $value;
                    } else {
                        $this->headers['set-cookie'] .= "\r\nset-cookie: " . $value;
                    }
                } else {
                 $this->headers[$key] = $kv[1];
                }
            }
        }
        $content = @file_get_contents($url, false, $context);
        if ($content == false) {
            return array('status_code' => 500, 'error' => "file_get_contents $url fail");
        }
        $this->body_size = strlen($content);
        $this->body = $content;

        $content_length = 1 * $this->headers["content-length"];

        if ($status_code == 200 && $this->body_size > $this->body_maxsize && $content_length && $this->body_size < $content_length) {
            $status_code = 206;
            $range_start = 0;
            $range_end = $this->body_size - 1;
            $this->headers["content-range"] = "bytes $range_start-$range_end/$content_length";
            $this->headers["content-length"] = $this->body_size;
        }

        //error_exit('urlfetch result:', array('status_code' => $status_code, 'headers' => $this->headers, 'content-size' => $this->body_size, 'error' => $error));

        $response = array('status_code' => $status_code, 'headers' => $this->headers, 'content' => $this->body, 'error' => $error);
        return $response;
    }
}

function urlfetch($url, $payload, $method, $headers, $follow_redirects, $deadline, $validate_certificate) {
    $urlfetch = new URLFetch();
    if(function_exists('curl_version')) {
        return $urlfetch->urlfetch_curl($url, $payload, $method, $headers, $follow_redirects, $deadline, $validate_certificate);
    } else {
        //error_exit('urlfetch', "Enter urlfetch_fopen($url, $payload, $method, $headers, $follow_redirects, $deadline, $validate_certificate)");
        return $urlfetch->urlfetch_fopen($url, $payload, $method, $headers, $follow_redirects, $deadline, $validate_certificate);
    }
}

function post()
{
    global $__password__;

    $request = @gzuncompress(@file_get_contents('php://input'));
    if ($request === False) {
        return print_notify($method, $url, 500, 'OOPS! gzuncompress php://input error!');
    }
    $request = decode_data($request);

    $method  = $request['method'];
    $url     = $request['url'];
    $payload = $request['payload'];
    $dns     = $request['dns'];

    if ($__password__ && $__password__ != $request['password']) {
        return print_notify($method, $url, 403, 'Wrong password.');
    }

    if (substr($url, 0, 4) != 'http') {
        return print_notify($method, $url, 501, 'Unsupported Scheme');
    }

    $FetchMax     = 3;
    $FetchMaxSize = 1024*1024;
    $Deadline     = array(0 => 16, 1 => 32);
    $deadline     = $Deadline[0];

    $headers = array();
    foreach (explode("\r\n", $request['headers']) as $line) {
        $pair = explode(':', $line, 2);
        $headers[trim($pair[0])] = trim($pair[1]);
    }
    $headers['connection'] = 'close';

    $fetchrange = 'bytes=0-' . strval($FetchMaxSize - 1);
    if (array_key_exists('range', $headers)) {
        preg_match('/(\d+)?-(\d+)?/', $headers['range'], $matches, PREG_OFFSET_CAPTURE);
        $start = $matches[1][0];
        $end = $matches[2][0];
        if ($start || $end) {
            if (!$start and intval($end) > $FetchMaxSize) {
                $end = '1023';
            }
            else if (!$end || intval($end)-intval($start)+1 > $FetchMaxSize) {
                $end = strval($FetchMaxSize-1+intval($start));
            }
            $fetchrange = 'bytes='.$start.'-'.$end;
        }
    }

    if ($dns) {
        preg_match('@://(.+?)[:/]@', $url, $matches, PREG_OFFSET_CAPTURE);
        if ($matches[1][0]) {
            $headers['host'] = $matches[1][0];
            $url = preg_replace('@://.+?([:/])@', "://$dns\\1", $url);
        }
        //error_exit('matches', $matches);
    }

    //error_exit('url', $url, 'headers:', $headers);

    $errors = array();
    for ($i = 0; $i < $FetchMax; $i++) {
        $response = urlfetch($url, $payload, $method, $headers, False, $deadline, False);
        $status_code = $response['status_code'];
        if (200 <= $status_code && $status_code < 400) {
           return print_response($status_code, $response['headers'], $response['content']);
        } else {
            if ($response['error']) {
                $errors[] = $response['error'];
            } else {
                $errors[] = 'URLError: ' . $status_code;
            }
        }
    }

    print_notify($request['method'], $request['url'], 502, 'PHP Fetch Server Failed: ' . var_export($errors, true));
}

function get() {
    global $__version__;

    if (@gzcompress('test') == false) {
        print_notify('GET', $_SERVER['SCRIPT_FILENAME'], 200, 'Error: need zlib moudle!');
        exit(-1);
    }
    
    if (!function_exists('curl_version') && !ini_get('allow_url_fopen')) {
        print_notify('GET', $_SERVER['SCRIPT_FILENAME'], 200, 'Error: need curl moudle or allow_url_fopen!');
        exit(-1);
    }
    
    echo <<<EOF

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>GoAgent {$__version__} is working now</title>
</head>
<body>
    <table width="800" border="0" align="center">
        <tr><td align="center"><hr></td></tr>
        <tr><td align="center">
            <b><h1>GoAgent {$__version__} is working now</h1></b>
        </td></tr>
        <tr><td align="center"><hr></td></tr>

        <tr><td align="center">
            GoAgent is HTTP Porxy written by python and hosting in GAE/PHP.
        </td></tr>
        <tr><td align="center"><hr></td></tr>

        <tr><td align="center">
            For more detail,please refer to <a href="http://code.google.com/p/goagent/">GoAgent Project Homepage</a>.
        </td></tr>
        <tr><td align="center"><hr></td></tr>
    </table>
</body>

EOF;
}

function main() {
    if ($_SERVER['REQUEST_METHOD'] == 'POST') {
        post();
    } else {
        get();
    }
}

main();