對 wget 這個 tool 不熟,平常使用 wget 下載一些資料時,可以輕易地使用 --referer 來偽造 HTTP Header 資料,因此能夠通過對方 Server 檢查

wget --referer="REFERER_URL" "TARGET_URL"

然而,上述的 REFERER_URL 和 TARGET_URL 都是固定的位置,如果是會根據 session / cookie 的而改變的話,不曉得還有沒有辦法?對我而言,寫 PHP 比去看 manpage 來得快 XD 所以我就寫成 PHP 囉!或許 wget 也有更方便的下法吧,改天再努力看 manpage

程式碼:

<?php
$output_file = 'result.file';  // 儲存結果
$cookie_file = 'cookie.tmp';  // cookie file
$source_url = 'SOURCE_URL';  // 之後會變成 REFERER_URL
$pattern = '/class="download" href="(.*?)"/';  // 此為一個範例, 用來撈 TARGET_URL

$ch = curl_init();
curl_setopt( $ch , CURLOPT_URL, $source_url );
curl_setopt( $ch , CURLOPT_COOKIEFILE , $cookie_file );
curl_setopt( $ch , CURLOPT_COOKIEJAR , $cookie_file );
curl_setopt( $ch , CURLOPT_RETURNTRANSFER , true );

$result = curl_exec( $ch );

if( preg_match_all( $pattern , $result , $match ) )
{
        if( isset( $match[1][1] ) )
        {  
                $target_url = $match[1][1];  // 請依 pattern 決定
                $referer_url = $source_url;

                curl_setopt( $ch , CURLOPT_URL, $target_url );
                curl_setopt( $ch , CURLOPT_REFERER , $referer_url );
                curl_setopt( $ch , CURLOPT_COOKIEFILE , $cookie_file );
                curl_setopt( $ch , CURLOPT_COOKIEJAR , $cookie_file );
                //curl_setopt( $ch , CURLOPT_RETURNTRANSFER , true );

                $fp = fopen ( $output_file, 'wb' );

                curl_setopt( $ch , CURLOPT_FILE , $fp );

                echo "GO...\n";
                curl_exec( $ch );
                echo "Finish..\n";

                fclose( $fp );
        }   
}

curl_close( $ch );
?>

以上是要從 SOURCE_URL 上頭, 找到下載位置(target_url), 然而, 那個位置卻每次都不一樣, 最重要的是跟 session 有關係並且下載 target_url 時還必須奉上 cookie 資訊, 所以, 先收集一下 cookie 囉!(上述程式並不謹慎, 例如儲存結果的檔案有可能開檔失敗)

後記,無聊又改寫成 tool mode:

<?php

$shortopt = array();

$shortopt['h'] =  array(
    'value' => '' ,
    'text' => '-h, help' );
$shortopt['c:'] =  array(
    'value'    => '' ,
    'text'    => "-c '/tmp/cookie_file' , tmp file for cookie" );
$shortopt['o:'] = array(
    'value'    => '' ,
    'text'    => "-o '/tmp/output_file' , path for result file. default use stdout" );
$shortopt['u:'] = array(
    'value'    => NULL ,
    'text'    => "-u 'http://www.google.com' , source url" );
$shortopt['e:'] = array(
    'value'    => NULL ,
    'text'    => "-e '/class=\"normal-down\" href=\"(.*?)\"/is' , regexp pattern for extract the target url" );
$shortopt['m:'] = array(
    'value'    => '' ,
    'text'    => "-m '1,1' , choose the result matched to be used. e.g. use the match[5][2] is '5,2'" );
$shortopt['d'] = array(
    'value'    => 'true' ,
    'text'    => "-d , disable test mode for showing the target matched by regexp pattern" );

// check function
if( !function_exists( 'getopt' ) )
{
    echo "'getopt' is not supported in current PHP version.\n";
    exit;
}

// help menu
$shortopt_list = '';
$shottopt_help = '';
foreach( $shortopt as $k => $v )
{
    $shortopt_list .= $k;
    $shottopt_help .= "\t".$v['text']."\n";
}

// start to parse...
$parse_arg = getopt( $shortopt_list );

// show help
if( isset( $parse_arg['h'] ) )
{
    echo "Usage> php ".$argv[0]." -h\n";
    echo $shottopt_help;
    exit;
}

// set the value
foreach( $parse_arg as $k => $v )
{
    if( isset( $shortopt[$k] ) )
        $shortopt[$k]['value'] = !strcasecmp( $shortopt[$k]['value'] , 'false' ) ? true : false ;
    else if( isset( $shortopt[$k.':'] ) )
        $shortopt[$k.':']['value'] = $v;
}

// check value (cannot be NULL)
$check_out = '';
foreach( $shortopt as $k => $v )
    if( !isset( $v['value'] ) )
        $check_out .= "\t".$v['text']."\n";
if( !empty( $check_out ) )
{
    echo "Usage> php ".$argv[0]." -h\n";
    echo "Must Set:\n$check_out\n";
    exit;
}

$cookie_file = !empty( $shortopt['c:']['value'] ) ? $shortopt['c:']['value'] : NULL ;
$source_url = $shortopt['u:']['value'];
$output_file = !empty( $shortopt['o:']['value'] ) ? $shortopt['o:']['value'] : NULL ;
$regexp_pattern = $shortopt['e:']['value'];

if( !empty( $shortopt['m:']['value'] ) )
    $shortopt['m:']['value'] = trim( $shortopt['m:']['value'] );
$choose_match = !empty( $shortopt['m:']['value'] ) ? explode( ',' , $shortopt['m:']['value'] ) : NULL;
$test_mode = empty( $choose_match ) || $shortopt['d']['value'];

$ch = curl_init();
curl_setopt( $ch , CURLOPT_URL, $source_url );

if( !empty( $cookie_file ) )
{
    curl_setopt( $ch , CURLOPT_COOKIEFILE , $cookie_file );
    curl_setopt( $ch , CURLOPT_COOKIEJAR , $cookie_file );
}
curl_setopt( $ch , CURLOPT_RETURNTRANSFER , true );

$result = curl_exec( $ch );

if( preg_match_all( $regexp_pattern , $result , $matches ) )
{
    $target_url = getTargetURL( $matches , $choose_match );
    if( $test_mode || empty( $target_url ) )
    {
        echo "Matched Target URL: \n";
        print_r( $matches );
        echo "Choose option(Cannot be empty):".$shortopt['m:']['value']."\n";
        echo "Target(Cannot be empty):$target_url\n";
    }
    else
    {
        curl_setopt( $ch , CURLOPT_URL, $target_url );
        curl_setopt( $ch , CURLOPT_REFERER , $source_url );

        if( !empty( $cookie_file ) )
        {
            curl_setopt( $ch , CURLOPT_COOKIEFILE , $cookie_file );
            curl_setopt( $ch , CURLOPT_COOKIEJAR , $cookie_file );
        }

        if( !empty( $output_file ) )
        {
            echo "Target URL:$target_url\n";
            echo "Referer URL:$source_url\n";

            if( ( $fp = fopen ( $output_file , 'wb' ) ) == NULL )
            {
                echo "ERROR: Cannot open the output file to write:$output_file\n";
                exit;
            }
            curl_setopt( $ch , CURLOPT_FILE , $fp );

            echo "Begin...\n";
            curl_exec( $ch );
            echo "...Finish\n";
            fclose( $fp );
        }
        else
        {
            curl_exec( $ch );
        }
    }
}
curl_close( $ch );
exit;

function getTargetURL( $matches , $choose )
{
    if( !isset( $matches ) )
        return NULL;
    if( is_array( $matches ) && is_array( $choose ) && count( $choose ) > 0 )
    {
        $index = array_shift( $choose );
        if( isset( $matches[ $index ] ) )
            return getTargetURL( $matches[ $index ] , $choose );
        return NULL;
    }

    if( !is_array( $matches ) )
        return $matches;
    else if( isset( $matches[ $choose ] ) )
        return $matches[ $choose ];
    return NULL;
}
?>

用法:

單純以抓 Yahoo! New 為例

尚未指定 -m
# php my_wget.php -u 'http://tw.yahoo.com' -e '/<h3><a href="([^"]+)" title="([^"]+)"/is'

Matched Target URL:
Array
(
    [0] => Array
        (
            [0] => <h3><a href="news/a/h1/t/*http://tw.news.yahoo.com/article/url/d/a/100628/5/289yr.html" title="莫拉克風災 學者:無關暖化"
            [1] => <h3><a href="news/a/h2/t/*http://tw.news.yahoo.com/article/url/d/a/100628/69/289tr.html" title="立院藏七寶 總價數億元"
        )

    [1] => Array
        (
            [0] => news/a/h1/t/*http://tw.news.yahoo.com/article/url/d/a/100628/5/289yr.html
            [1] => news/a/h2/t/*http://tw.news.yahoo.com/article/url/d/a/100628/69/289tr.html
        )

    [2] => Array
        (
            [0] => 莫拉克風災 學者:無關暖化
            [1] => 立院藏七寶 總價數億元
        )

)
Choose option(Cannot be empty):
Target(Cannot be empty):

指定 -m '1,1'
# php my_wget.php -u 'http://tw.yahoo.com' -e '/<h3><a href="([^"]+)" title="([^"]+)"/is' -m '1,1'

Matched Target URL:
Array
(
    [0] => Array
        (
            [0] => <h3><a href="news/a/h1/t/*http://tw.news.yahoo.com/article/url/d/a/100628/5/289yr.html" title="莫拉克風災 學者:無關暖化"
            [1] => <h3><a href="news/a/h2/t/*http://tw.news.yahoo.com/article/url/d/a/100628/69/289tr.html" title="立院藏七寶 總價數億元"
        )

    [1] => Array
        (
            [0] => news/a/h1/t/*http://tw.news.yahoo.com/article/url/d/a/100628/5/289yr.html
            [1] => news/a/h2/t/*http://tw.news.yahoo.com/article/url/d/a/100628/69/289tr.html
        )

    [2] => Array
        (
            [0] => 莫拉克風災 學者:無關暖化
            [1] => 立院藏七寶 總價數億元
        )

)
Choose option(Cannot be empty):1,1
Target(Cannot be empty):news/a/h2/t/*http://tw.news.yahoo.com/article/url/d/a/100628/69/289tr.html

正式要下載請記得加 -d (disable test) , 但此例不適用, 因為抓出來的 url 並不完整, 開頭只是 "news/a/h2/t/*....."
# php my_wget.php -u 'http://tw.yahoo.com' -e '/<h3><a href="([^"]+)" title="([^"]+)"/is' -m '1,1' -d

輸出到檔案
# php my_wget.php -u 'http://tw.yahoo.com' -e '/<h3><a href="([^"]+)" title="([^"]+)"/is' -m '1,1' -d -o '/tmp/output'

需要 cookie
# php my_wget.php -u 'http://tw.yahoo.com' -e '/<h3><a href="([^"]+)" title="([^"]+)"/is' -m '1,1' -d -o '/tmp/output' -c '/tmp/cookie'


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