streams/include/network.php

<?php

use Code\Lib\Libzot;
use Code\Lib\Zotfinger;
use Code\Lib\Webfinger;
use Code\Lib\Channel;    
use Code\Lib\ActivityStreams;
use Code\Lib\Activity;
use Code\Lib\ActivityPub;
use Code\Lib\Queue;
use Code\Lib\System;
use Code\Lib\Keyutils;
use Code\Lib\LDSignatures;
use Code\Lib\Addon;
use Code\Web\HTTPSig;
use Code\Daemon\Run;
use Code\Extend\Hook;

/**
 * @file include/network.php
 * @brief Network related functions.
 */

/**
 * @brief Returns path to CA file.
 *
 * @return string
 */
function get_capath()
{
    return appdirpath() . '/library/cacert.pem';
}

/**
 * @brief fetches an URL.
 *
 * @param string $url
 *    URL to fetch
 * @param bool $binary default false
 *    TRUE if asked to return binary results (file download)
 * @param int $redirects default 0
 *    internal use, recursion counter
 * @param array $opts (optional parameters) associative array with:
 *  * \b timeout => int seconds, default system config value or 60 seconds
 *  * \b headers => array of additional header fields
 *  * \b http_auth => username:password
 *  * \b novalidate => do not validate SSL certs, default is to validate using our CA list
 *  * \b nobody => only return the header
 *  * \b filep => stream resource to write body to. header and body are not returned when using this option.
 *  * \b custom => custom request method: e.g. 'PUT', 'DELETE'
 *  * \b cookiejar => cookie file (write)
 *  * \b cookiefile => cookie file (read)
 *  * \b session => boolean; append session cookie *if* $url is our own site
 *
 * @return array an associative array with:
 *  * \e int \b return_code => HTTP return code or 0 if timeout or failure
 *  * \e boolean \b success => boolean true (if HTTP 2xx result) or false
 *  * \e string \b header => HTTP headers
 *  * \e string \b body => fetched content
 */
function z_fetch_url($url, $binary = false, $redirects = 0, $opts = [])
{

    $ret = array('return_code' => 0, 'success' => false, 'header' => "", 'body' => "");
    $passthru = false;

    $ch = @curl_init($url);
    if (($redirects > 8) || (! $ch)) {
        return $ret;
    }

    if (! array_key_exists('request_target', $opts)) {
        $opts['request_target'] = 'get ' . get_request_string($url);
    }


    @curl_setopt($ch, CURLOPT_HEADER, true);
    @curl_setopt($ch, CURLINFO_HEADER_OUT, true);
    @curl_setopt($ch, CURLOPT_CAINFO, get_capath());
    @curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
    @curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    @curl_setopt($ch, CURLOPT_ENCODING, '');

    $ciphers = @get_config('system', 'curl_ssl_ciphers');
    if ($ciphers) {
        @curl_setopt($ch, CURLOPT_SSL_CIPHER_LIST, $ciphers);
    }

    if (x($opts, 'filep')) {
        @curl_setopt($ch, CURLOPT_FILE, $opts['filep']);
        @curl_setopt($ch, CURLOPT_HEADER, false);
        @curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
        $passthru = true;
    }

    if (x($opts, 'useragent')) {
        @curl_setopt($ch, CURLOPT_USERAGENT, $opts['useragent']);
    } else {
        @curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (compatible; zot)");
    }

    if (x($opts, 'upload')) {
        @curl_setopt($ch, CURLOPT_UPLOAD, $opts['upload']);
    }

    if (x($opts, 'infile')) {
        @curl_setopt($ch, CURLOPT_INFILE, $opts['infile']);
    }

    if (x($opts, 'infilesize')) {
        @curl_setopt($ch, CURLOPT_INFILESIZE, $opts['infilesize']);
    }

    if (x($opts, 'readfunc')) {
        @curl_setopt($ch, CURLOPT_READFUNCTION, $opts['readfunc']);
    }

    // When using the session option and fetching from our own site,
    // append the PHPSESSID cookie to any existing headers.
    // Don't add to $opts['headers'] so that the cookie does not get
    // sent to other sites via redirects

    $instance_headers = ((array_key_exists('headers', $opts) && is_array($opts['headers'])) ? $opts['headers'] : []);

    if (x($opts, 'session')) {
        if (strpos($url, z_root()) === 0) {
            $instance_headers[] = 'Cookie: PHPSESSID=' . session_id();
        }
    }
    if ($instance_headers) {
        @curl_setopt($ch, CURLOPT_HTTPHEADER, $instance_headers);
    }


    if (x($opts, 'nobody')) {
        @curl_setopt($ch, CURLOPT_NOBODY, $opts['nobody']);
    }

    if (x($opts, 'custom')) {
        @curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $opts['custom']);
    }

    if (x($opts, 'timeout') && intval($opts['timeout'])) {
        @curl_setopt($ch, CURLOPT_TIMEOUT, intval($opts['timeout']));
    } else {
        $curl_time = intval(get_config('system', 'curl_timeout', 60));
        @curl_setopt($ch, CURLOPT_TIMEOUT, $curl_time);
    }

    if (x($opts, 'connecttimeout') && intval($opts['connecttimeout'])) {
        @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, intval($opts['connecttimeout']));
    } else {
        $curl_contime = intval(@get_config('system', 'curl_connecttimeout', 60));
        @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $curl_contime);
    }


    if (x($opts, 'http_auth')) {
        // "username" . ':' . "password"
        @curl_setopt($ch, CURLOPT_USERPWD, $opts['http_auth']);
    }

    if (x($opts, 'cookiejar')) {
        @curl_setopt($ch, CURLOPT_COOKIEJAR, $opts['cookiejar']);
    }
    if (x($opts, 'cookiefile')) {
        @curl_setopt($ch, CURLOPT_COOKIEFILE, $opts['cookiefile']);
    }

    if (x($opts, 'cookie')) {
        @curl_setopt($ch, CURLOPT_COOKIE, $opts['cookie']);
    }

    @curl_setopt(
        $ch,
        CURLOPT_SSL_VERIFYPEER,
        ((x($opts, 'novalidate') && intval($opts['novalidate'])) ? false : true)
    );

    $prx = @get_config('system', 'proxy');
    if (strlen($prx)) {
        @curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
        @curl_setopt($ch, CURLOPT_PROXY, $prx);
        $prxusr = @get_config('system', 'proxyuser');
        if (strlen($prxusr)) {
            @curl_setopt($ch, CURLOPT_PROXYUSERPWD, $prxusr);
        }
    }
    if ($binary) {
        @curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
    }


    // don't let curl abort the entire application'
    // if it throws any errors.

    $s = @curl_exec($ch);

    $base = $s;
    $curl_info = @curl_getinfo($ch);
    $http_code = $curl_info['http_code'];
    //logger('fetch_url:' . $http_code . ' data: ' . $s);
    $header = '';

    // For file redirects, set curl to follow location (indicated by $passthru).
    // Then just return success or failure.

    if ($passthru) {
        if ($http_code >= 200 && $http_code < 300) {
            $ret['success'] = true;
        }
        $ret['return_code'] = $http_code;
        @curl_close($ch);
        return $ret;
    }


    // Pull out multiple headers, e.g. proxy and continuation headers
    // allow for HTTP/2.x without fixing code

    while (preg_match('/^HTTP\/[1-3][\.0-9]* [1-5][0-9][0-9]/', $base)) {
        $chunk = substr($base, 0, strpos($base, "\r\n\r\n") + 4);
        $header .= $chunk;
        $base = substr($base, strlen($chunk));
    }

    if ($http_code == 301 || $http_code == 302 || $http_code == 303 || $http_code == 307 || $http_code == 308) {
        $matches = [];
        preg_match('/(Location:|URI:)(.*?)\n/i', $header, $matches);
        $newurl = trim(array_pop($matches));
        if (strpos($newurl, '/') === 0) {
            // We received a redirect to a relative path.
            // Find the base component of the original url and re-assemble it with the new location
            $base = @parse_url($url);
            if ($base) {
                unset($base['path']);
                unset($base['query']);
                unset($base['fragment']);
                $newurl = unparse_url($base) . $newurl;
            }
        }
        if ($newurl) {
            @curl_close($ch);
            return z_fetch_url($newurl, $binary, ++$redirects, $opts);
        }
    }

    $rc = intval($http_code);
    $ret['return_code'] = $rc;
    $ret['success'] = (($rc >= 200 && $rc <= 299) ? true : false);
    if (! $ret['success']) {
        $ret['error'] = curl_error($ch);
        $ret['debug'] = $curl_info;
        $dbg = [
            'url' => $ret['debug']['url'],
            'content_type' => $ret['debug']['content_type'],
            'error_code'  => ((isset($ret['debug']['error_code'])) ? $ret['debug']['error_code'] : 0),
            'request_header' => $ret['debug']['request_header']
        ];
        logger('z_fetch_url: error: ' . $url . ': ' . $ret['error'], LOGGER_DEBUG);
        logger('z_fetch_url: debug: ' . print_r($dbg, true), LOGGER_DATA);
    }
    $ret['body'] = substr($s, strlen($header));
    $ret['header'] = $header;
    $ret['request_target'] = $opts['request_target'];

    if (x($opts, 'debug')) {
        $ret['debug'] = $curl_info;
    }

    @curl_close($ch);
    return($ret);
}


/**
 * @brief Does a curl post request.
 *
 * @param string $url
 *    URL to post
 * @param mixed $params
 *   The full data to post in a HTTP "POST" operation. This parameter can
 *   either be passed as a urlencoded string like 'para1=val1&para2=val2&...'
 *   or as an array with the field name as key and field data as value. If value
 *   is an array, the Content-Type header will be set to multipart/form-data.
 * @param int $redirects = 0
 *    internal use, recursion counter
 * @param array $opts (optional parameters)
 *    'timeout' => int seconds, default system config value or 60 seconds
 *    'http_auth' => username:password
 *    'novalidate' => do not validate SSL certs, default is to validate using our CA list
 *    'filep' => stream resource to write body to. header and body are not returned when using this option.
 *    'custom' => custom request method: e.g. 'PUT', 'DELETE'
 *
 * @return array an associative array with:
 *  * \e int \b return_code => HTTP return code or 0 if timeout or failure
 *  * \e boolean \b success => boolean true (if HTTP 2xx result) or false
 *  * \e string \b header => HTTP headers
 *  * \e string \b body => content
 *  * \e string \b debug => from curl_info()
 */
function z_post_url($url, $params, $redirects = 0, $opts = [])
{

//  logger('url: ' . $url);
//  logger('params: ' . print_r($params,true));
//  logger('opts: ' . print_r($opts,true));

    $ret = array('return_code' => 0, 'success' => false, 'header' => "", 'body' => "");

    $ch = curl_init($url);
    if (($redirects > 8) || (! $ch)) {
        return $ret;
    }

    if (! array_key_exists('request_target', $opts)) {
        $opts['request_target'] = 'post ' . get_request_string($url);
    }


    @curl_setopt($ch, CURLOPT_HEADER, true);
    @curl_setopt($ch, CURLINFO_HEADER_OUT, true);
    @curl_setopt($ch, CURLOPT_CAINFO, get_capath());
    @curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    @curl_setopt($ch, CURLOPT_POST, 1);
    @curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
    @curl_setopt($ch, CURLOPT_ENCODING, '');

    $ciphers = @get_config('system', 'curl_ssl_ciphers');
    if ($ciphers) {
        @curl_setopt($ch, CURLOPT_SSL_CIPHER_LIST, $ciphers);
    }

    if (x($opts, 'filep')) {
        @curl_setopt($ch, CURLOPT_FILE, $opts['filep']);
        @curl_setopt($ch, CURLOPT_HEADER, false);
    }

    if (x($opts, 'useragent')) {
        @curl_setopt($ch, CURLOPT_USERAGENT, $opts['useragent']);
    } else {
        @curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (compatible; zot)");
    }


    $instance_headers = ((array_key_exists('headers', $opts) && is_array($opts['headers'])) ? $opts['headers'] : []);

    if (x($opts, 'session')) {
        if (strpos($url, z_root()) === 0) {
            $instance_headers[] = 'Cookie: PHPSESSID=' . session_id();
        }
    }
    if ($instance_headers) {
        @curl_setopt($ch, CURLOPT_HTTPHEADER, $instance_headers);
    }


    if (x($opts, 'nobody')) {
        @curl_setopt($ch, CURLOPT_NOBODY, $opts['nobody']);
    }

    if (x($opts, 'custom')) {
        @curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $opts['custom']);
        @curl_setopt($ch, CURLOPT_POST, 0);
    }

    if (x($opts, 'timeout') && intval($opts['timeout'])) {
        @curl_setopt($ch, CURLOPT_TIMEOUT, intval($opts['timeout']));
    } else {
        $curl_time = intval(@get_config('system', 'curl_post_timeout', 90));
        @curl_setopt($ch, CURLOPT_TIMEOUT, $curl_time);
    }

    if (x($opts, 'connecttimeout') && intval($opts['connecttimeout'])) {
        @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, intval($opts['connecttimeout']));
    } else {
        $curl_contime = intval(@get_config('system', 'curl_post_connecttimeout', 90));
        @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $curl_contime);
    }

    if (x($opts, 'http_auth')) {
        // "username" . ':' . "password"
        @curl_setopt($ch, CURLOPT_USERPWD, $opts['http_auth']);
    }

    if (x($opts, 'cookiejar')) {
        @curl_setopt($ch, CURLOPT_COOKIEJAR, $opts['cookiejar']);
    }
    if (x($opts, 'cookiefile')) {
        @curl_setopt($ch, CURLOPT_COOKIEFILE, $opts['cookiefile']);
    }
    if (x($opts, 'cookie')) {
        @curl_setopt($ch, CURLOPT_COOKIE, $opts['cookie']);
    }

    @curl_setopt(
        $ch,
        CURLOPT_SSL_VERIFYPEER,
        ((x($opts, 'novalidate') && intval($opts['novalidate'])) ? false : true)
    );

    $prx = get_config('system', 'proxy');
    if (strlen($prx)) {
        @curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
        @curl_setopt($ch, CURLOPT_PROXY, $prx);
        $prxusr = get_config('system', 'proxyuser');
        if (strlen($prxusr)) {
            @curl_setopt($ch, CURLOPT_PROXYUSERPWD, $prxusr);
        }
    }

    // don't let curl abort the entire application
    // if it throws any errors.

    $s = @curl_exec($ch);

    $base = $s;
    $curl_info = @curl_getinfo($ch);
    $http_code = $curl_info['http_code'];

    $header = '';

    // Pull out multiple headers, e.g. proxy and continuation headers
    // allow for HTTP/2.x without fixing code

    while (preg_match('/^HTTP\/[1-3][\.0-9]* [1-5][0-9][0-9]/', $base)) {
        $chunk = substr($base, 0, strpos($base, "\r\n\r\n") + 4);
        $header .= $chunk;
        $base = substr($base, strlen($chunk));
    }

    // would somebody take lighttpd and just shoot it?

    if ($http_code == 417) {
        curl_close($ch);
        if ($opts) {
            if ($opts['headers']) {
                $opts['headers'][] = 'Expect:';
            } else {
                $opts['headers'] = array('Expect:');
            }
        } else {
            $opts = array('headers' => array('Expect:'));
        }
        return z_post_url($url, $params, ++$redirects, $opts);
    }

    if ($http_code == 301 || $http_code == 302 || $http_code == 303 || $http_code == 307 || $http_code == 308) {
        $matches = [];
        preg_match('/(Location:|URI:)(.*?)\n/', $header, $matches);
        $newurl = trim(array_pop($matches));
        if (strpos($newurl, '/') === 0) {
            // We received a redirect to a relative path.
            // Find the base component of the original url and re-assemble it with the new location
            $base = @parse_url($url);
            if ($base) {
                unset($base['path']);
                unset($base['query']);
                unset($base['fragment']);
                $newurl = unparse_url($base) . $newurl;
            }
        }
        if ($newurl) {
            curl_close($ch);
            if ($http_code == 303) {
                return z_fetch_url($newurl, false, ++$redirects, $opts);
            } else {
                return z_post_url($newurl, $params, ++$redirects, $opts);
            }
        }
    }
    $rc = intval($http_code);
    $ret['return_code'] = $rc;
    $ret['success'] = (($rc >= 200 && $rc <= 299) ? true : false);
    if (! $ret['success']) {
        $ret['error'] = curl_error($ch);
        $ret['debug'] = $curl_info;
        $dbg = [
            'url' => $ret['debug']['url'],
            'content_type' => $ret['debug']['content_type'],
            'error_code'  => $ret['debug']['error_code'],
            'request_header' => $ret['debug']['request_header']
        ];
        logger('z_post_url: error: ' . $url . ': ' . $ret['error'], LOGGER_DEBUG);
        logger('z_post_url: debug: ' . print_r($dbg, true), LOGGER_DATA);
    }

    $ret['body'] = substr($s, strlen($header));
    $ret['header'] = $header;
    $ret['request_target'] = $opts['request_target'];

    if (x($opts, 'debug')) {
        $ret['debug'] = $curl_info;
    }

    curl_close($ch);
    return($ret);
}

function z_curl_error($ret)
{
    $output = EMPTY_STR;
    if (isset($ret['debug'])) {
        $output .= datetime_convert() . EOL;
        $output .= t('url: ') . $ret['debug']['url'] . EOL;
        $output .= t('error_code: ') . $ret['debug']['error_code'] . EOL;
        $output .= t('error_string: ') . $ret['error'] . EOL;
        $output .= t('content-type: ') . $ret['debug']['content_type'] . EOL;
    }
    return $output;
}

function json_return_and_die($x, $content_type = 'application/json', $debug = false)
{
    header("Content-type: $content_type");
    if ($debug) {
        logger('returned_json: ' . json_encode($x, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES), LOGGER_DATA);
    }
    echo json_encode($x);
    killme();
}

function as_return_and_die($obj, $channel)
{

    $x = array_merge(['@context' => [
        ACTIVITYSTREAMS_JSONLD_REV,
        'https://w3id.org/security/v1',
        Activity::ap_schema()
        ]], $obj);

    $headers = [];
    $headers['Content-Type'] = 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"' ;
    $x['signature'] = LDSignatures::sign($x, $channel);
    $ret = json_encode($x, JSON_UNESCAPED_SLASHES);
    logger('data: ' . jindent($ret), LOGGER_DATA);
    $headers['Date'] = datetime_convert('UTC', 'UTC', 'now', 'D, d M Y H:i:s \\G\\M\\T');
    $headers['Digest'] = HTTPSig::generate_digest_header($ret);
    $headers['(request-target)'] = strtolower($_SERVER['REQUEST_METHOD']) . ' ' . $_SERVER['REQUEST_URI'];

    $h = HTTPSig::create_sig($headers, $channel['channel_prvkey'], Channel::url($channel));
    HTTPSig::set_headers($h);

    echo $ret;
    killme();
}


/**
 * @brief Send HTTP status header.
 *
 * @param int $val
 *    integer HTTP status result value
 * @param string $msg
 *    optional message
 */
function http_status($val, $msg = '')
{
    if ($val >= 400) {
        $msg = (($msg) ? $msg : 'Error');
    }
    if ($val >= 200 && $val < 300) {
        $msg = (($msg) ? $msg : 'OK');
    }

    logger(App::$query_string . ':' . $val . ' ' . $msg);
    header($_SERVER['SERVER_PROTOCOL'] . ' ' . $val . ' ' . $msg);
}


/**
 * @brief Send HTTP status header and exit.
 *
 * @param int $val
 *    integer HTTP status result value
 * @param string $msg
 *    optional message
 * @return void does not return, process is terminated
 */
function http_status_exit($val, $msg = '')
{
    http_status($val, $msg);
    killme();
}

/*
 *
 * Takes the output of parse_url and builds a URL from it
 *
 */

function unparse_url($parsed_url)
{
    $scheme   = isset($parsed_url['scheme']) ? $parsed_url['scheme'] . '://' : '';
    $host     = isset($parsed_url['host']) ? $parsed_url['host'] : '';
    $port     = ((isset($parsed_url['port']) && intval($parsed_url['port'])) ? ':' . intval($parsed_url['port']) : '');
    $user     = isset($parsed_url['user']) ? $parsed_url['user'] : '';
    $pass     = isset($parsed_url['pass']) ? ':' . $parsed_url['pass']  : '';
    $pass     = ($user || $pass) ? "$pass@" : '';
    $path     = isset($parsed_url['path']) ? $parsed_url['path'] : '';
    $query    = isset($parsed_url['query']) ? '?' . $parsed_url['query'] : '';
    $fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : '';
    return "$scheme$user$pass$host$port$path$query$fragment";
}





/**
 * @brief Convert an XML document to a normalised, case-corrected array used by webfinger.
 *
 * @param string|array|SimpleXMLElement $xml_element
 * @param[in,out] int $recursion_depth
 * @return NULL|string|array
 */
function convert_xml_element_to_array($xml_element, &$recursion_depth = 0)
{

    // If we're getting too deep, bail out
    if ($recursion_depth > 512) {
        return(null);
    }

    if (
        !is_string($xml_element) &&
            !is_array($xml_element) &&
            (get_class($xml_element) == 'SimpleXMLElement')
    ) {
        $xml_element_copy = $xml_element;
        $xml_element = get_object_vars($xml_element);
    }

    if (is_array($xml_element)) {
        $result_array = [];
        if (count($xml_element) <= 0) {
            return (trim(strval($xml_element_copy)));
        }

        foreach ($xml_element as $key => $value) {
            $recursion_depth++;
            $result_array[strtolower($key)] =
                convert_xml_element_to_array($value, $recursion_depth);
            $recursion_depth--;
        }
        if ($recursion_depth == 0) {
            $temp_array = $result_array;
            $result_array = array(
                strtolower($xml_element_copy->getName()) => $temp_array,
            );
        }

        return ($result_array);
    } else {
        return (trim(strval($xml_element)));
    }
}



function z_dns_check($h, $check_mx = 0)
{

    // dns_get_record() has issues on some platforms
    // so allow somebody to ignore it completely
    // Use config values from memory as this can be called during setup
    // before a database or even any config structure exists.

    if (is_array(App::$config) && array_path_exists('system/do_not_check_dns', App::$config) && App::$config['system']['do_not_check_dns']) {
        return true;
    }

    // This will match either Windows or Mac ('Darwin')
    if (stripos(PHP_OS, 'win') !== false) {
        return true;
    }

    // BSD variants have dns_get_record() but it only works reliably without any options
    if (stripos(PHP_OS, 'bsd') !== false) {
        return((@dns_get_record($h) || filter_var($h, FILTER_VALIDATE_IP)) ? true : false);
    }

    // Otherwise we will assume dns_get_record() works as documented

    $opts = DNS_A + DNS_CNAME + DNS_AAAA;
    if ($check_mx) {
        $opts += DNS_MX;
    }

    return((@dns_get_record($h, $opts) || filter_var($h, FILTER_VALIDATE_IP)) ? true : false);
}

/**
 * @brief Validates a given URL.
 *
 * Take a URL from the wild, prepend http:// if necessary and check DNS to see
 * if it's real (or check if is a valid IP address).
 *
 * @see z_dns_check()
 *
 * @param[in,out] string $url URL to check
 * @return bool Return true if it's OK, false if something is wrong with it
 */
function validate_url(&$url)
{

    // no naked subdomains (allow localhost for tests)
    if (strpos($url, '.') === false && strpos($url, '/localhost/') === false) {
        return false;
    }

    if (substr($url, 0, 4) != 'http') {
        $url = 'http://' . $url;
    }

    $h = @parse_url($url);

    if (($h) && z_dns_check($h['host'])) {
        return true;
    }

    return false;
}

/**
 * @brief Checks that email is an actual resolvable internet address.
 *
 * @param string $addr
 * @return bool
 */
function validate_email($addr)
{

    if (get_config('system', 'disable_email_validation')) {
        return true;
    }

    if (! strpos($addr, '@')) {
        return false;
    }

    $h = substr($addr, strpos($addr, '@') + 1);

    if (($h) && z_dns_check($h, true)) {
        return true;
    }

    return false;
}

/**
 * @brief Check if email address is allowed to register here.
 *
 * Compare against our list (wildcards allowed).
 *
 * @param string $email
 * @return bool Returns false if not allowed, true if allowed or if allowed list is
 * not configured.
 */
function allowed_email($email)
{

    $domain = strtolower(substr($email, strpos($email, '@') + 1));
    if (! $domain) {
        return false;
    }

    $str_allowed = get_config('system', 'allowed_email');
    $str_not_allowed = get_config('system', 'not_allowed_email');

    if (! $str_allowed && ! $str_not_allowed) {
        return true;
    }

    $return = false;
    $found_allowed = false;
    $found_not_allowed = false;

    $fnmatch = function_exists('fnmatch');

    $allowed = explode(',', $str_allowed);

    if (count($allowed)) {
        foreach ($allowed as $a) {
            $pat = strtolower(trim($a));
            if (($fnmatch && fnmatch($pat, $email)) || ($pat == $domain)) {
                $found_allowed = true;
                break;
            }
        }
    }

    $not_allowed = explode(',', $str_not_allowed);

    if (count($not_allowed)) {
        foreach ($not_allowed as $na) {
            $pat = strtolower(trim($na));
            if (($fnmatch && fnmatch($pat, $email)) || ($pat == $domain)) {
                $found_not_allowed = true;
                break;
            }
        }
    }

    if ($found_allowed) {
        $return = true;
    } elseif (!$str_allowed && !$found_not_allowed) {
        $return = true;
    }

    return $return;
}



function parse_xml_string($s, $strict = true)
{
    if ($strict) {
        if (! strstr($s, '<?xml')) {
            return false;
        }

        $s2 = substr($s, strpos($s, '<?xml'));
    } else {
        $s2 = $s;
    }

    libxml_use_internal_errors(true);


    $x = @simplexml_load_string($s2);
    if ($x === false) {
        logger('libxml: parse: error: ' . $s2, LOGGER_DATA);
        foreach (libxml_get_errors() as $err) {
            logger('libxml: parse: ' . $err->code . ' at ' . $err->line
                . ':' . $err->column . ' : ' . $err->message, LOGGER_DATA);
        }
        libxml_clear_errors();
    }

    return $x;
}


function sxml2array($xmlObject, $out = array ())
{
    foreach ((array) $xmlObject as $index => $node) {
        $out[$index] = ( is_object($node) ) ? sxml2array($node) : $node;
    }

    return $out;
}

/**
 * @brief xml2[] will convert the given XML text to an array in the XML structure.
 *
 * Link: http://www.bin-co.com/php/scripts/xml2array/
 * Portions significantly re-written by mike@macgirvin.com
 * (namespaces, lowercase tags, get_attribute default changed, more...)
 *
 * Examples: $array =  xml2array(file_get_contents('feed.xml'));
 *           $array =  xml2array(file_get_contents('feed.xml', true, 1, 'attribute'));
 *
 * @param string $contents The XML text
 * @param bool $namespaces true or false include namespace information in the returned array as array elements
 * @param int $get_attributes 1 or 0. If this is 1 the function will get the attributes as well as the tag values - this results in a different array structure in the return value.
 * @param string $priority Can be 'tag' or 'attribute'. This will change the way the resulting array sturcture. For 'tag', the tags are given more importance.
 *
 * @return array The parsed XML in an array form. Use print_r() to see the resulting array structure.
 */
function xml2array($contents, $namespaces = true, $get_attributes = 1, $priority = 'attribute')
{
    if (!$contents) {
        return [];
    }

    if (!function_exists('xml_parser_create')) {
        logger('xml2array: parser function missing');
        return [];
    }

    libxml_use_internal_errors(true);
    libxml_clear_errors();

    if ($namespaces) {
        $parser = @xml_parser_create_ns("UTF-8", ':');
    } else {
        $parser = @xml_parser_create();
    }

    if (! $parser) {
        logger('xml2array: xml_parser_create: no resource');
        return [];
    }

    xml_parser_set_option($parser, XML_OPTION_TARGET_ENCODING, "UTF-8");
    // http://minutillo.com/steve/weblog/2004/6/17/php-xml-and-character-encodings-a-tale-of-sadness-rage-and-data-loss
    xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
    xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, 1);
    @xml_parse_into_struct($parser, trim($contents), $xml_values);
    @xml_parser_free($parser);

    if (! $xml_values) {
        logger('xml2array: libxml: parse error: ' . $contents, LOGGER_DATA);
        foreach (libxml_get_errors() as $err) {
            logger('libxml: parse: ' . $err->code . " at " . $err->line . ":" . $err->column . " : " . $err->message, LOGGER_DATA);
        }
        libxml_clear_errors();

        return;
    }

    //Initializations
    $xml_array = [];
    $parents = [];
    $opened_tags = [];
    $arr = [];

    $current = &$xml_array; // Reference

    // Go through the tags.
    $repeated_tag_index = []; // Multiple tags with same name will be turned into an array
    foreach ($xml_values as $data) {
        unset($attributes, $value); // Remove existing values, or there will be trouble

        // This command will extract these variables into the foreach scope
        // tag(string), type(string), level(int), attributes(array).
        extract($data); // We could use the array by itself, but this cooler.

        $result = [];
        $attributes_data = [];

        if (isset($value)) {
            if ($priority == 'tag') {
                $result = $value;
            } else {
                $result['value'] = $value; // Put the value in a assoc array if we are in the 'Attribute' mode
            }
        }

        //Set the attributes too.
        if (isset($attributes) and $get_attributes) {
            foreach ($attributes as $attr => $val) {
                if ($priority == 'tag') {
                    $attributes_data[$attr] = $val;
                } else {
                    $result['@attributes'][$attr] = $val; // Set all the attributes in a array called 'attr'
                }
            }
        }

        // See tag status and do the needed.
        if ($namespaces && strpos($tag, ':')) {
            $namespc = substr($tag, 0, strrpos($tag, ':'));
            $tag = strtolower(substr($tag, strlen($namespc) + 1));
            $result['@namespace'] = $namespc;
        }
        $tag = strtolower($tag);

        if ($type == "open") {   // The starting of the tag '<tag>'
            $parent[$level - 1] = &$current;
            if (!is_array($current) or (!in_array($tag, array_keys($current)))) { // Insert New tag
                $current[$tag] = $result;
                if ($attributes_data) {
                    $current[$tag . '_attr'] = $attributes_data;
                }
                $repeated_tag_index[$tag . '_' . $level] = 1;

                $current = &$current[$tag];
            } else { // There was another element with the same tag name
                if (isset($current[$tag][0])) { // If there is a 0th element it is already an array
                    $current[$tag][$repeated_tag_index[$tag . '_' . $level]] = $result;
                    $repeated_tag_index[$tag . '_' . $level]++;
                } else { // This section will make the value an array if multiple tags with the same name appear together
                    $current[$tag] = array($current[$tag],$result); // This will combine the existing item and the new item together to make an array
                    $repeated_tag_index[$tag . '_' . $level] = 2;

                    if (isset($current[$tag . '_attr'])) { // The attribute of the last(0th) tag must be moved as well
                        $current[$tag]['0_attr'] = $current[$tag . '_attr'];
                        unset($current[$tag . '_attr']);
                    }
                }
                $last_item_index = $repeated_tag_index[$tag . '_' . $level] - 1;
                $current = &$current[$tag][$last_item_index];
            }
        } elseif ($type == "complete") { // Tags that ends in 1 line '<tag />'
            //See if the key is already taken.
            if (!isset($current[$tag])) { //New Key
                $current[$tag] = $result;
                $repeated_tag_index[$tag . '_' . $level] = 1;
                if ($priority == 'tag' and $attributes_data) {
                    $current[$tag . '_attr'] = $attributes_data;
                }
            } else { // If taken, put all things inside a list(array)
                if (isset($current[$tag][0]) and is_array($current[$tag])) { // If it is already an array...
                    // ...push the new element into that array.
                    $current[$tag][$repeated_tag_index[$tag . '_' . $level]] = $result;

                    if ($priority == 'tag' and $get_attributes and $attributes_data) {
                        $current[$tag][$repeated_tag_index[$tag . '_' . $level] . '_attr'] = $attributes_data;
                    }
                    $repeated_tag_index[$tag . '_' . $level]++;
                } else { // If it is not an array...
                    $current[$tag] = array($current[$tag],$result); //...Make it an array using using the existing value and the new value
                    $repeated_tag_index[$tag . '_' . $level] = 1;
                    if ($priority == 'tag' and $get_attributes) {
                        if (isset($current[$tag . '_attr'])) { // The attribute of the last(0th) tag must be moved as well
                            $current[$tag]['0_attr'] = $current[$tag . '_attr'];
                            unset($current[$tag . '_attr']);
                        }

                        if ($attributes_data) {
                            $current[$tag][$repeated_tag_index[$tag . '_' . $level] . '_attr'] = $attributes_data;
                        }
                    }
                    $repeated_tag_index[$tag . '_' . $level]++; // 0 and 1 indexes are already taken
                }
            }
        } elseif ($type == 'close') { // End of tag '</tag>'
            $current = &$parent[$level - 1];
        }
    }

    return($xml_array);
}


function email_header_encode($in_str, $charset = 'UTF-8', $header = 'Subject')
{
    $out_str = $in_str;
    $need_to_convert = false;

    for ($x = 0; $x < strlen($in_str); $x++) {
        if ((ord($in_str[$x]) == 0) || ((ord($in_str[$x]) > 128))) {
            $need_to_convert = true;
            break;
        }
    }

    if (! $need_to_convert) {
        return $in_str;
    }

    if ($out_str && $charset) {
        // define start delimimter, end delimiter and spacer
        $end = "?=";
        $start = "=?" . $charset . "?B?";
        $spacer = $end . PHP_EOL . " " . $start;

        // determine length of encoded text within chunks
        // and ensure length is even
        $length = 75 - strlen($start) - strlen($end) - (strlen($header) + 2);

        /*
            [EDIT BY danbrown AT php DOT net: The following
            is a bugfix provided by (gardan AT gmx DOT de)
            on 31-MAR-2005 with the following note:
            "This means: $length should not be even,
            but divisible by 4. The reason is that in
            base64-encoding 3 8-bit-chars are represented
            by 4 6-bit-chars. These 4 chars must not be
            split between two encoded words, according
            to RFC-2047.
        */
        $length = $length - ($length % 4);

        // encode the string and split it into chunks
        // with spacers after each chunk
        $out_str = base64_encode($out_str);
        $out_str = chunk_split($out_str, $length, $spacer);

        // remove trailing spacer and
        // add start and end delimiters
        $spacer = preg_quote($spacer, '/');
        $out_str = preg_replace("/" . $spacer . "$/", "", $out_str);
        $out_str = $start . $out_str . $end;
    }
    return $out_str;
}

/**
 * @brief
 *
 * @param string $webbie
 * @param string $protocol (optional) default empty
 * @param bool $verify (optional) default true, verify HTTP signatures on Zot discovery packets.
 * @return bool
 */
function discover_by_webbie($webbie, $protocol = '', $verify = true)
{

    $result   = [];

    $network  = null;

    $x = Webfinger::exec($webbie);

    $address = EMPTY_STR;

    if ($x && array_key_exists('subject', $x) && strpos($x['subject'], 'acct:') === 0) {
        $address = str_replace('acct:', '', $x['subject']);
    }
    if ($x && array_key_exists('aliases', $x) && count($x['aliases'])) {
        foreach ($x['aliases'] as $a) {
            if (strpos($a, 'acct:') === 0) {
                $address = str_replace('acct:', '', $a);
                break;
            }
        }
    }

    if ($x && array_key_exists('links', $x) && is_array($x['links'])) {

		// look for Nomad first

		foreach ($x['links'] as $link) {
			if (array_key_exists('rel',$link)) {
				$apurl = null;

				// If we discover zot - don't search further; grab the info and get out of
				// here.

				if (in_array($link['rel'], [ PROTOCOL_NOMAD ]) && ((! $protocol) || (in_array(strtolower($protocol), [ 'nomad' ])))) {
					logger('nomad found for ' . $webbie, LOGGER_DEBUG);
					$record = Zotfinger::exec($link['href'], null, $verify);

					// Check the HTTP signature

					if ($verify) {

						$hsig = $record['signature'];
						if($hsig && ($hsig['signer'] === $url || $hsig['signer'] === $link['href']) && $hsig['header_valid'] === true && $hsig['content_valid'] === true) {
							$hsig_valid = true;
						}

						if(! $hsig_valid) {
							logger('http signature not valid: ' . print_r($hsig,true));
							continue;
						}
					}

					$x = Libzot::import_xchan($record['data']);
					if($x['success']) {
						return $x['hash'];
					}
				}
			}
		}

		// if we reached this point, nomad wasn't found.

        foreach ($x['links'] as $link) {
            if (array_key_exists('rel', $link)) {
                $apurl = null;

                // If we discover zot - don't search further; grab the info and get out of
                // here.

                if ($link['rel'] === PROTOCOL_ZOT6 && ((! $protocol) || (strtolower($protocol) === 'zot6'))) {
                    logger('zot6 found for ' . $webbie, LOGGER_DEBUG);
                    $record = Zotfinger::exec($link['href'], null, $verify);

                    // Check the HTTP signature

                    if ($verify) {
                        $hsig = $record['signature'];
                        if ($hsig && ($hsig['signer'] === $url || $hsig['signer'] === $link['href']) && $hsig['header_valid'] === true && $hsig['content_valid'] === true) {
                            $hsig_valid = true;
                        }

                        if (! $hsig_valid) {
                            logger('http signature not valid: ' . print_r($hsig, true));
                            continue;
                        }
                    }

                    $x = Libzot::import_xchan($record['data']);
                    if ($x['success']) {
                        return $x['hash'];
                    }
                }
                if ($link['rel'] === 'self' && ($link['type'] === 'application/activity+json' || strpos($link['type'], 'ld+json') !== false) && ((! $protocol) || (strtolower($protocol) === 'activitypub'))) {
                    $ap = ActivityPub::discover($link['href']);
                    if ($ap) {
                        return $ap;
                    }
                }
            }
        }
    }

	if (strpos($webbie, 'http') === 0 && !$x) {
        $record = Zotfinger::exec($webbie, null, $verify);

        // Check the HTTP signature

		if ($record) {
            if ($verify) {
                $hsig = $record['signature'];
                if ($hsig && ($hsig['signer'] === $url || $hsig['signer'] === $webbie) && $hsig['header_valid'] === true && $hsig['content_valid'] === true) {
                    $hsig_valid = true;
                }

                if (! $hsig_valid) {
                    logger('http signature not valid: ' . print_r($hsig, true));
                    return false;
                }
            }

            $x = Libzot::import_xchan($record['data']);
            if ($x['success']) {
                return $x['hash'];
            }
		}
	}

    if (strpos($webbie, 'http') === 0) {
        $ap = ActivityPub::discover($webbie);
        if ($ap) {
            return $ap;
        }
    }

    logger('webfinger: ' . print_r($x, true), LOGGER_DATA, LOG_INFO);

    $arr = [
            'address'   => $webbie,
            'protocol'  => $protocol,
            'success'   => false,
            'xchan'     => '',
            'webfinger' => $x
    ];
    /**
     * @hooks discover_channel_webfinger
     *   Called when performing a webfinger lookup.
     *   * \e string \b address - The webbie
     *   * \e string \b protocol
     *   * \e array \b webfinger - The result from webfinger_rfc7033()
     *   * \e boolean \b success - The return value, default false
     */
    Hook::call('discover_channel_webfinger', $arr);
    if ($arr['success']) {
        return $arr['xchan'];
    }

    return false;
}

/**
 * @brief Fetch and return a webfinger for a webbie.
 * No longer used - see Code/Lib/Webfinger.php
 *
 * @param string $webbie - The resource
 * @return bool|string false or associative array from result JSON
 */
function webfinger_rfc7033($webbie)
{

    if (strpos($webbie, '@')) {
        $lhs = substr($webbie, 0, strpos($webbie, '@'));
        $rhs = substr($webbie, strpos($webbie, '@') + 1);
        $resource = urlencode('acct:' . $webbie);
    } else {
        $m = parse_url($webbie);
        if ($m) {
            if ($m['scheme'] !== 'https') {
                return false;
            }

            $rhs = $m['host'] . ((isset($m['port']) && intval($m['port'])) ? ':' . intval($m['port']) : '');
            $resource = urlencode($webbie);
        } else {
            return false;
        }
    }
    logger('fetching url from resource: ' . $rhs . ':' . $webbie);

    $counter = 0;
    $s = z_fetch_url(
        'https://' . $rhs . '/.well-known/webfinger?f=&resource=' . $resource . (($zot) ? '&zot=1' : ''),
        false,
        $counter,
        [ 'headers' => [ 'Accept: application/jrd+json, application/json, */*' ] ]
    );

    if ($s['success']) {
        $j = json_decode($s['body'], true);
        return($j);
    }

    return false;
}

function do_delivery($deliveries, $force = false)
{

    // $force is set if a site that wasn't responding suddenly returns to life.
    // Try and shove through everything going to that site while it's responding.

    if (! (is_array($deliveries) && count($deliveries))) {
        return;
    }


    $x = q("select count(outq_hash) as total from outq where outq_delivered = 0");
    if (intval($x[0]['total']) > intval(get_config('system', 'force_queue_threshold', 3000)) && (! $force)) {
        logger('immediate delivery deferred.', LOGGER_DEBUG, LOG_INFO);
        foreach ($deliveries as $d) {
            Queue::update($d);
        }
        return;
    }


    $interval = ((get_config('system', 'delivery_interval') !== false)
            ? intval(get_config('system', 'delivery_interval')) : 2 );

    $deliveries_per_process = intval(get_config('system', 'delivery_batch_count'));

    if ($deliveries_per_process <= 0) {
        $deliveries_per_process = 1;
    }


    $deliver = [];
    foreach ($deliveries as $d) {
        if (! $d) {
            continue;
        }

        $deliver[] = $d;

        if (count($deliver) >= $deliveries_per_process) {
            Run::Summon([ 'Deliver',$deliver ]);
            $deliver = [];
            if ($interval) {
                @time_sleep_until(microtime(true) + (float) $interval);
            }
        }
    }

    // catch any stragglers

    if ($deliver) {
        Run::Summon([ 'Deliver',$deliver ]);
    }
}


function get_site_info()
{

    $register_policy = array('REGISTER_CLOSED', 'REGISTER_APPROVE', 'REGISTER_OPEN');

    $sql_extra = '';

    $r = q("select * from channel left join account on account_id = channel_account_id where ( account_roles & 4096 ) > 0 and account_default_channel = channel_id");


    if ($r) {
        $admin = [];
        foreach ($r as $rr) {
            if ($rr['channel_pageflags'] & PAGE_HUBADMIN) {
                $admin[] = array( 'name' => $rr['channel_name'], 'address' => Channel::get_webfinger($rr), 'channel' => z_root() . '/channel/' . $rr['channel_address']);
            }
        }
        if (! $admin) {
            foreach ($r as $rr) {
                $admin[] = array( 'name' => $rr['channel_name'], 'address' => Channel::get_webfinger($rr), 'channel' => z_root() . '/channel/' . $rr['channel_address']);
            }
        }
    } else {
        $admin = false;
    }

    $def_service_class = get_config('system', 'default_service_class');
    if ($def_service_class) {
        $service_class = get_config('service_class', $def_service_class);
    } else {
        $service_class = false;
    }

    $visible_plugins = Addon::list_visible();

    if (@is_dir('.git') && function_exists('shell_exec')) {
        $commit = trim(@shell_exec('git log -1 --format="%h"'));
    }
    if (! isset($commit) || strlen($commit) > 16) {
        $commit = '';
    }

    $site_info = get_config('system', 'info');
    $site_name = get_config('system', 'sitename');
    if (! get_config('system', 'hidden_version_siteinfo')) {
        $version = System::get_project_version();

        if (@is_dir('.git') && function_exists('shell_exec')) {
            $commit = trim(@shell_exec('git log -1 --format="%h"'));
        }

        if (! isset($commit) || strlen($commit) > 16) {
            $commit = '';
        }
    } else {
        $version = $commit = '';
    }

    //Statistics
//  $channels_total_stat = intval(get_config('system','channels_total_stat'));
//  $channels_active_halfyear_stat = intval(get_config('system','channels_active_halfyear_stat'));
//  $channels_active_monthly_stat = intval(get_config('system','channels_active_monthly_stat'));
//  $local_posts_stat = intval(get_config('system','local_posts_stat'));
//  $local_comments_stat = intval(get_config('system','local_comments_stat'));
//  $hide_in_statistics = intval(get_config('system','hide_in_statistics'));

    $site_expire = intval(get_config('system', 'default_expire_days'));

    load_config('feature_lock');
    $locked_features = [];
    if (is_array(App::$config['feature_lock']) && count(App::$config['feature_lock'])) {
        foreach (App::$config['feature_lock'] as $k => $v) {
            if ($k === 'config_loaded') {
                continue;
            }

            $locked_features[$k] = intval($v);
        }
    }

    $protocols = [ 'nomad', 'zot6' ];
    if (get_config('system', 'activitypub', ACTIVITYPUB_ENABLED)) {
        $protocols[] = 'activitypub';
    }

    $data = [
        'url'                          => z_root(),
        'platform'                     => System::get_project_name(),
        'site_name'                    => (($site_name) ? $site_name : ''),
        'version'                      => $version,
        'addon_version'                => defined('ADDON_VERSION') ? ADDON_VERSION : 'unknown',
        'commit'                       => $commit,
        'protocols'                    => $protocols,
        'plugins'                      => $visible_plugins,
        'register_policy'              => $register_policy[get_config('system', 'register_policy')],
        'invitation_only'              => (bool) (defined('INVITE_WORKING') && intval(get_config('system', 'invitation_only'))),
        'language'                     => get_config('system', 'language'),
        'expiration'                   => $site_expire,
        'default_service_restrictions' => $service_class,
        'locked_features'              => $locked_features,
        'admin'                        => $admin,
        'dbdriver'                     => DBA::$dba->getdriver() . ' ' . ((ACTIVE_DBTYPE == DBTYPE_POSTGRES) ? 'postgres' : 'mysql'),
        'lastpoll'                     => get_config('system', 'lastpoll'),
        'ebs'                          => System::ebs(), // bit.ly/3DGCmki
        'info'                         => (($site_info) ? $site_info : '')

    ];


    return $data;
}

/**
 * @brief
 *
 * @param string $url
 * @return bool
 */
function check_siteallowed($url)
{

    $retvalue = true;

    if (! (isset($url) && $url)) {
        return false;
    }

    $arr = [ 'url' => $url ];
    /**
     * @hooks check_siteallowed
     *   Used to over-ride or bypass the site black/white block lists.
     *   * \e string \b url
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('check_siteallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    // your own site is always allowed
    if (strpos($url, z_root()) !== false) {
        return $retvalue;
    }

    $bl1 = get_config('system', 'allowed_sites');
    $bl2 = get_config('system', 'denied_sites');

    if (is_array($bl1) && $bl1) {
        if (! (is_array($bl2) && $bl2)) {
            $retvalue = false;
        }
        foreach ($bl1 as $bl) {
            if ($bl === '*') {
                $retvalue = true;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return true;
            }
        }
    }
    if (is_array($bl2) && $bl2) {
        foreach ($bl2 as $bl) {
            if ($bl === '*') {
                $retvalue = false;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return false;
            }
        }
    }

    return $retvalue;
}

/**
 * @brief
 *
 * @param string $url
 * @return bool
 */
function check_pubstream_siteallowed($url)
{

    $retvalue = true;

    $arr = array('url' => $url);
    /**
     * @hooks check_siteallowed
     *   Used to over-ride or bypass the site black/white block lists.
     *   * \e string \b url
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('pubstream_check_siteallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    // your own site is always allowed
    if (strpos($url, z_root()) !== false) {
        return $retvalue;
    }

    $bl1 = get_config('system', 'pubstream_allowed_sites');
    $bl2 = get_config('system', 'pubstream_denied_sites');

    if (is_array($bl1) && $bl1) {
        if (! (is_array($bl2) && $bl2)) {
            $retvalue = false;
        }
        foreach ($bl1 as $bl) {
            if ($bl === '*') {
                $retvalue = true;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return true;
            }
        }
    }
    if (is_array($bl2) && $bl2) {
        foreach ($bl2 as $bl) {
            if ($bl === '*') {
                $retvalue = false;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return false;
            }
        }
    }

    return $retvalue;
}



/**
 * @brief
 *
 * @param string $hash
 * @return bool
 */
function check_channelallowed($hash)
{

    $retvalue = true;

    $arr = [ 'hash' => $hash ];
    /**
     * @hooks check_channelallowed
     *   Used to over-ride or bypass the channel black/white block lists.
     *   * \e string \b hash
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('check_channelallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    $bl1 = get_config('system', 'allowed_channels');
    $bl2 = get_config('system', 'denied_channels');

    if (is_array($bl1) && $bl1) {
        if (! (is_array($bl2) && $bl2)) {
            $retvalue = false;
        }
        foreach ($bl1 as $bl) {
            if ($bl === '*') {
                $retvalue = true;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return true;
            }
        }
    }
    if (is_array($bl2) && $bl2) {
        foreach ($bl2 as $bl) {
            if ($bl === '*') {
                $retvalue = false;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return false;
            }
        }
    }

    return $retvalue;
}


/**
 * @brief
 *
 * @param string $hash
 * @return bool
 */
function check_pubstream_channelallowed($hash)
{

    $retvalue = true;

    $arr = array('hash' => $hash);
    /**
     * @hooks check_channelallowed
     *   Used to over-ride or bypass the channel black/white block lists.
     *   * \e string \b hash
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('check_pubstream_channelallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    $bl1 = get_config('system', 'pubstream_allowed_channels');
    $bl2 = get_config('system', 'pubstream_denied_channels');

    if (is_array($bl1) && $bl1) {
        if (! (is_array($bl2) && $bl2)) {
            $retvalue = false;
        }
        foreach ($bl1 as $bl) {
            if ($bl === '*') {
                $retvalue = true;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return true;
            }
        }
    }
    if (is_array($bl2) && $bl2) {
        foreach ($bl2 as $bl) {
            if ($bl === '*') {
                $retvalue = false;
            }
            if ($bl && (strpos($url, $bl) !== false || wildmat($bl, $url))) {
                return false;
            }
        }
    }

    return $retvalue;
}


function deliverable_singleton($channel_id, $xchan)
{

    if (array_key_exists('xchan_hash', $xchan)) {
        $xchan_hash = $xchan['xchan_hash'];
    } elseif (array_key_exists('hubloc_hash', $xchan)) {
        $xchan_hash = $xchan['hubloc_hash'];
    } else {
        return true;
    }

    $r = q(
        "select abook_instance from abook where abook_channel = %d and abook_xchan = '%s' limit 1",
        intval($channel_id),
        dbesc($xchan_hash)
    );
    if ($r) {
        if (! $r[0]['abook_instance']) {
            return true;
        }
        if (strpos($r[0]['abook_instance'], z_root()) !== false) {
            return true;
        }
    }
    return false;
}



function get_repository_version($branch = 'release')
{

    $path = "https://raw.codeberg.page/streams/" . PLATFORM_NAME . "/@$branch/version.php";

    $x = z_fetch_url($path);
    if ($x['success']) {
        $y = preg_match('/define(.*?)STD_VERSION(.*?)([0-9.].*)\'/', $x['body'], $matches);
        if ($y) {
            return $matches[3];
        }
    }
    return '?.?';
}

/**
 * @brief Get translated network name.
 *
 * @param string $s Network string, see boot.php
 * @return string Translated name of the network
 */
function network_to_name($s)
{

    $nets = array(
        NETWORK_FEED        => t('RSS/Atom'),
        NETWORK_ACTIVITYPUB => t('ActivityPub'),
        NETWORK_DIASPORA    => t('Diaspora'),
        NETWORK_NOMAD       => t('Nomad'),
        NETWORK_ZOT6        => t('Zot6'),
    );

    /**
     * @hooks network_to_name
     * @deprecated
     */
    Hook::call('network_to_name', $nets);

    $search  = array_keys($nets);
    $replace = array_values($nets);

    return str_replace($search, $replace, $s);
}

/**
 * @brief Send a text email message.
 *
 * @param array $params an associative array with:
 *  * \e string \b fromName        name of the sender
 *  * \e string \b fromEmail       email of the sender
 *  * \e string \b replyTo         replyTo address to direct responses
 *  * \e string \b toEmail         destination email address
 *  * \e string \b messageSubject  subject of the message
 *  * \e string \b htmlVersion     html version of the message
 *  * \e string \b textVersion     text only version of the message
 *  * \e string \b additionalMailHeader  additions to the smtp mail header
 */
function z_mail($params)
{

    if (! $params['fromEmail']) {
        $params['fromEmail'] = get_config('system', 'from_email');
        if (! $params['fromEmail']) {
            $params['fromEmail'] = 'Administrator' . '@' . App::get_hostname();
        }
    }
    if (! $params['fromName']) {
        $params['fromName'] = get_config('system', 'from_email_name');
        if (! $params['fromName']) {
            $params['fromName'] = System::get_site_name();
        }
    }
    if (! $params['replyTo']) {
        $params['replyTo'] = get_config('system', 'reply_address');
        if (! $params['replyTo']) {
            $params['replyTo'] = 'noreply' . '@' . App::get_hostname();
        }
    }

    $params['sent']   = false;
    $params['result'] = false;

    /**
     * @hooks email_send
     *   * \e params @see z_mail()
     */
    Hook::call('email_send', $params);

    if ($params['sent']) {
        logger('notification: z_mail returns ' . (($params['result']) ? 'success' : 'failure'), LOGGER_DEBUG);
        return $params['result'];
    }

    $fromName = email_header_encode(html_entity_decode($params['fromName'], ENT_QUOTES, 'UTF-8'), 'UTF-8');
    $messageSubject = email_header_encode(html_entity_decode($params['messageSubject'], ENT_QUOTES, 'UTF-8'), 'UTF-8');

    $messageHeader =
        $params['additionalMailHeader'] .

        "From: $fromName <{$params['fromEmail']}>" . PHP_EOL .
        "Reply-To: $fromName <{$params['replyTo']}>" . PHP_EOL .
        "Content-Type: text/plain; charset=UTF-8";

    // send the message
    $res = mail(
        $params['toEmail'],                             // send to address
        $messageSubject,                                // subject
        $params['textVersion'],
        $messageHeader                                  // message headers
    );
    logger('notification: z_mail returns ' . (($res) ? 'success' : 'failure'), LOGGER_DEBUG);
    return $res;
}


/**
 * @brief Discover the best API path available for the project servers.
 *
 * @param string $host
 * @return string
 */
function probe_api_path($host)
{

    $schemes = ['https', 'http' ];
    $paths   = ['/api/z/1.0/version', '/api/red/version' ];

    foreach ($schemes as $scheme) {
        foreach ($paths as $path) {
            $curpath = $scheme . '://' . $host . $path;
            $x = z_fetch_url($curpath);
            if ($x['success'] && ! strpos($x['body'], 'not implemented')) {
                return str_replace('version', '', $curpath);
            }
        }
    }

    return '';
}

function service_plink($contact, $guid)
{

    $plink = '';

    $m = parse_url($contact['xchan_url']);
    if ($m) {
        $url = $m['scheme'] . '://' . $m['host'] . ((isset($m['port']) && intval($m['port'])) ? ':' . intval($m['port']) : '');
    } else {
        $url = 'https://' . substr($contact['xchan_addr'], strpos($contact['xchan_addr'], '@') + 1);
    }

    $handle = substr($contact['xchan_addr'], 0, strpos($contact['xchan_addr'], '@'));

    $plink = $url . '/channel/' . $handle . '?f=&mid=' . $guid;

    $x = [ 'xchan' => $contact, 'guid' => $guid, 'url' => $url, 'plink' => $plink ];
    /**
     * @hooks service_plink
     *   * \e array \b xchan
     *   * \e string \b guid
     *   * \e string \b url
     *   * \e string \b plink will get returned
     */
    Hook::call('service_plink', $x);

    return $x['plink'];
}


/**
 * @brief
 *
 * @param array $mimeTypes
 * @param string $acceptedTypes by default false will use $_SERVER['HTTP_ACCEPT']
 * @return array|NULL
 */
function getBestSupportedMimeType($mimeTypes = null, $acceptedTypes = false)
{
    // Values will be stored in this array
    $AcceptTypes = [];

    if ($acceptedTypes === false) {
        $acceptedTypes = ((isset($_SERVER['HTTP_ACCEPT']) && $_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : EMPTY_STR);
    }

    // Accept header is case insensitive, and whitespace isn’t important
    $accept = strtolower(str_replace(' ', '', $acceptedTypes));
    // divide it into parts in the place of a ","
    $accept = explode(',', $accept);
    foreach ($accept as $a) {
        // the default quality is 1.
        $q = 1;
        // check if there is a different quality
        if (strpos($a, ';q=')) {
            // divide "mime/type;q=X" into two parts: "mime/type" i "X"
            list($a, $q) = explode(';q=', $a);
        }
        // mime-type $a is accepted with the quality $q
        // WARNING: $q == 0 means, that mime-type isn’t supported!
        $AcceptTypes[$a] = $q;
    }
    arsort($AcceptTypes);

    // if no parameter was passed, just return parsed data
    if (!$mimeTypes) {
        return $AcceptTypes;
    }

    $mimeTypes = array_map('strtolower', (array)$mimeTypes);

    // let’s check our supported types:
    foreach ($AcceptTypes as $mime => $q) {
        if ($q && in_array($mime, $mimeTypes)) {
            return $mime;
        }
    }

    // no mime-type found
    return null;
}

/**
 * @brief Perform caching for jsonld normaliser.
 *
 * @param string $url
 * @return mixed|bool|array
 */
function jsonld_document_loader($url)
{

    require_once('library/jsonld/jsonld.php');

    $recursion = 0;

    $x = debug_backtrace();
    if ($x) {
        foreach ($x as $n) {
            if ($n['function'] === __FUNCTION__) {
                $recursion++;
            }
        }
    }
    if ($recursion > 5) {
        logger('jsonld bomb detected at: ' . $url);
        killme();
    }


    $cachepath = 'cache/ldcache';
    if (! is_dir($cachepath)) {
        os_mkdir($cachepath, STORAGE_DEFAULT_PERMISSIONS, true);
    }

    $filename = $cachepath . '/' . urlencode($url);
    if (file_exists($filename) && filemtime($filename) > time() - (12 * 60 * 60)) {
        return json_decode(file_get_contents($filename));
    }

    $r = jsonld_default_document_loader($url);
    if ($r) {
        file_put_contents($filename, json_encode($r));
        return $r;
    }

    logger('not found');
    if (file_exists($filename)) {
        return json_decode(file_get_contents($filename));
    }

    return [];
}


function is_https_request()
{

    $https = false;

    if (array_key_exists('HTTPS', $_SERVER) && $_SERVER['HTTPS']) {
        $https = true;
    } elseif (array_key_exists('SERVER_PORT', $_SERVER) && intval($_SERVER['SERVER_PORT']) === 443) {
        $https = true;
    } elseif (array_key_exists('HTTP_X_FORWARDED_PROTO', $_SERVER) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
        $https = true; // technically this is not true, but pretending it is will allow reverse proxies to work
    }

    return $https;
}

/**
 * @brief Given a URL, return everything after the host portion, but exclude any fragments.
 * example https://foobar.com/gravy?g=5&y=6
 * returns /gravy?g=5&y=6
 * example https:://foobar.com/gravy?g=5&y=6#fragment
 * also returns /gravy?g=5&y=6
 * result always returns the leading slash
 */

function get_request_string($url)
{

    $m = parse_url($url);
    if ($m) {
        return ( (isset($m['path']) ? $m['path'] : '/' ) . (isset($m['query']) ? '?' . $m['query'] : EMPTY_STR) );
    }

    return EMPTY_STR;
}