get_meta_tags（）连接被拒绝

Question

In my php code i am using get_meta_tags() to fetch meta information from the site. But my proxy server is refusing connections and i am getting the following error:

Warning: get_meta_tags(http://www.espncricinfo.com/) [function.get-meta-tags]: failed to open stream: No connection could be made because the target machine actively refused it

Can anyone tell me how to by pass the proxy in my php code?

I tried setting proxy in Eclipse XDebug configuration but i don't think that is the right way to do it.

In curl i specified the proxy as curl_setopt($ch, CURLOPT_PROXY, "host:port"); which worked fine but in php i don't know the procedure. Any help would be appreciated.

-Adithya

Answer 1

By default PHP doesn't use a proxy. To bypass via a proxy, you can add a proxy for all functions using the http stream wrapper ^Docs (that wrapper is taking care for "filenames" starting with http:// or https:// ) like in your get_meta_tags ^Docs function example.

There are many HTTP context options ^Docs , the one you're looking for is proxy .

As get_meta_tags does not accept a context parameter (only a filename parameter), you need to change the so called default context which is (normally) used by PHP functions accepting a filename parameter. It's set with stream_context_get_default ^Docs .

$opts = array(
    'http' => array(
        'proxy' => 'tcp://127.0.0.1:8000'
    )
);
stream_context_get_default($opts);

Unfortunately get_meta_tags looks like an exception to the general rule to use stream wrappers at all (at least with my PHP 5.3.8 version). But no worries, you can slip the data you would like to obtain the meta tags from into get_meta_tags with using the default context.

This can be done with the data:// stream wrapper ^Docs . A little helper function takes care for the conversion:

/**
 * obtain $filename content as data:// URI
 * 
 * @link http://php.net/manual/en/wrappers.data.php
 *
 * @param string $filename
 * @return string data:// URI
 */
function filename_data_uri($filename)
{
    $buffer = file_get_contents($filename);

    $mime = 'text/plain';
    # obtain mime type and charset from http response (if available)
    if (isset($http_response_header))
        foreach($http_response_header as $header)
            sscanf($header, 'Content-Type: %[^]]', $mime)
    ;

    return "data://$mime;base64,".base64_encode($buffer);       
};

This function allows to obtain contents from an URL with file_get_contents which makes use of the default stream context. That is the one the proxy was configured for.

You then can combine this with get_meta_tags :

$url = 'http://www.espncricinfo.com/';
$url = filename_data_uri($url);
$meta_tags = get_meta_tags($url);

get_meta_tags now operates on the contents of $url which has been already fetched with the filename_data_uri function while using the proxy. The full example:

$url = 'http://www.espncricinfo.com/';
$proxy = 'tcp://host:port';

// configure default context to use proxy
$opts['http']['proxy'] = $proxy;
$resource = stream_context_get_default($opts);

// obtain url contents with default context
$data = filename_data_uri($url);
$meta_tags = get_meta_tags($data);
print_r($meta_tags);

/**
 * obtain $filename content as data:// URI
 * 
 * @link http://php.net/manual/en/wrappers.data.php
 *
 * @param string $filename
 * @return string data:// URI
 */
function filename_data_uri($filename)
{
    $buffer = file_get_contents($filename);

    $mime = 'text/plain';
    # obtain mime type and charset from http response (if available)
    if (isset($http_response_header))
        foreach($http_response_header as $header)
            sscanf($header, 'Content-Type: %[^]]', $mime)
    ;

    return "data://$mime;base64,".base64_encode($buffer);       
};