nchizhov / inok-phpagi

src/AGI.php

<?php

namespace Inok\phpagi;

/**
 * phpagi.php : PHP AGI Functions for Asterisk
 * @see https://github.com/welltime/phpagi
 * @filesource http://phpagi.sourceforge.net/
 *
 * $Id: phpagi.php,v 2.20 2010/09/30 02:21:00 masham Exp $
 *
 * Copyright (c) 2003 - 2010 Matthew Asham <matthew@ochrelabs.com>, David Eder <david@eder.us> and others
 * All Rights Reserved.
 *
 * This software is released under the terms of the GNU Lesser General Public License v2.1
 * A copy of which is available from http://www.gnu.org/copyleft/lesser.html
 *
 * We would be happy to list your phpagi based application on the phpagi
 * website.  Drop me an Email if you'd like us to list your program.
 *
 *
 * Written for PHP 4.3.4, should work with older PHP 4.x versions.
 *
 * Please submit bug reports, patches, etc to https://github.com/welltime/phpagi
 *
 *
 * @package phpAGI
 * @version 2.20
 */

/**
 * AGI class
 *
 * @package phpAGI
 * @link http://www.voip-info.org/wiki-Asterisk+agi
 * @example examples/dtmf.php Get DTMF tones from the user and say the digits
 * @example examples/input.php Get text input from the user and say it back
 * @example examples/ping.php Ping an IP address
 */
class AGI
{
  /**
   * Request variables read in on initialization.
   *
   * Often contains any/all of the following:
   *   agi_request - name of agi script
   *   agi_channel - current channel
   *   agi_language - current language
   *   agi_type - channel type (SIP, ZAP, IAX, ...)
   *   agi_uniqueid - unique id based on unix time
   *   agi_callerid - callerID string
   *   agi_dnid - dialed number id
   *   agi_rdnis - referring DNIS number
   *   agi_context - current context
   *   agi_extension - extension dialed
   *   agi_priority - current priority
   *   agi_enhanced - value is 1.0 if started as an EAGI script
   *   agi_accountcode - set by SetAccount in the dialplan
   *   agi_network - value is yes if this is a fastagi
   *   agi_network_script - name of the script to execute
   *
   * NOTE: program arguments are still in $_SERVER['argv'].
   *
   * @var array
   * @access public
   */
  public $request;

  /**
   * Config variables
   *
   * @var array
   * @access public
   */
  public $config;

  /**
   * Asterisk Manager
   *
   * @var AGI_AsteriskManager
   * @access public
   */
  public $asm;

  /**
   * Input Stream
   *
   * @access private
   */
  private $in;

  /**
   * Output Stream
   *
   * @access private
   */
  private $out;

  /**
   * Audio Stream
   *
   * @access public
   */
  public $audio = null;


  /**
   * Application option delimiter
   *
   * @access public
   */
  public $option_delim = ",";

  private $defaultConfig = ["error_handler" => true,
                            "debug" => false,
                            "admin" => null,
                            "tempdir" => AGI_Others::AST_TMP_DIR];

  /**
   * Constructor
   *
   * @param string $config is the name of the config file to parse
   * @param array $optconfig is an array of configuration vars and values, stuffed into $this->config['phpagi']
   */
  public function __construct($config = null, array $optconfig = []) {
    // load config
    if (!is_null($config) && file_exists($config)) {
      $this->config = parse_ini_file($config, true);
    } elseif (file_exists(AGI_Others::DEFAULT_PHPAGI_CONFIG)) {
      $this->config = parse_ini_file(AGI_Others::DEFAULT_PHPAGI_CONFIG, true);
    }

    // If optconfig is specified, stuff values and vars into 'phpagi' config array.
    foreach ($optconfig as $var => $val) {
      $this->config['phpagi'][$var] = $val;
    }

    // add default values to config for uninitialized values
    foreach ($this->defaultConfig as $name => $value) {
      $this->config["phpagi"][$name] = $this->config["phpagi"][$name] ?? $value;
    }

    // festival TTS config
    $this->config['festival']['text2wave'] = $this->config['festival']['text2wave'] ?? $this->which('text2wave');

    // swift TTS config
    $this->config['cepstral']['swift'] = $this->config['cepstral']['swift'] ?? $this->which('swift');

    ob_implicit_flush();

    // open stdin & stdout
    $this->in = defined('STDIN') ? STDIN : fopen('php://stdin', 'r');
    $this->out = defined('STDOUT') ? STDOUT : fopen('php://stdout', 'w');

    // initialize error handler
    if ($this->config['phpagi']['error_handler']) {
      set_error_handler('\\Inok\\phpagi\\AGI_Others::phpagi_error_handler');
      AGI_Others::$phpagi_error_handler_email = $this->config['phpagi']['admin'];
      error_reporting(E_ALL);
    }

    // make sure temp folder exists
    $this->make_folder($this->config['phpagi']['tempdir']);

    // read the request
    $str = fgets($this->in);
    while ($str != "\n") {
      $this->request[substr($str, 0, strpos($str, ':'))] = trim(substr($str, strpos($str, ':') + 1));
      $str = fgets($this->in);
    }

    // open audio if agi detected
    if ($this->request['agi_enhanced'] == '1.0') {
      if (file_exists('/proc/' . getmypid() . '/fd/3')) {
        $this->audio = fopen('/proc/' . getmypid() . '/fd/3', 'r');
      } elseif (file_exists('/dev/fd/3')) {
        // may need to mount fdescfs
        $this->audio = fopen('/dev/fd/3', 'r');
      } else {
        $this->conlog('Unable to open audio stream');
      }

      if ($this->audio) {
        stream_set_blocking($this->audio, 0);
      }
    }

    $this->conlog('AGI Request:');
    $this->conlog(/** @scrutinizer ignore-type */ print_r($this->request, true));
    $this->conlog('PHPAGI internal configuration:');
    $this->conlog(/** @scrutinizer ignore-type */ print_r($this->config, true));
  }

  // *********************************************************************************************************
  // **                             COMMANDS                                                                                            **
  // *********************************************************************************************************

  /**
   * Answer channel if not already in answer state.
   *
   * @link http://www.voip-info.org/wiki-answer
   * @example examples/dtmf.php Get DTMF tones from the user and say the digits
   * @example examples/input.php Get text input from the user and say it back
   * @example examples/ping.php Ping an IP address
   *
   * @return array, see evaluate for return information.  ['result'] is 0 on success, -1 on failure.
   */
  function answer(): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate('ANSWER');
  }

  /**
   * Get the status of the specified channel. If no channel name is specified, return the status of the current channel.
   *
   * @link http://www.voip-info.org/wiki-channel+status
   * @param string $channel
   * @return array, see evaluate for return information. ['data'] contains description.
   */
  function channel_status(string $channel = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    $ret = $this->evaluate("CHANNEL STATUS $channel");
    switch ($ret['result']) {
      case -1:
        $ret['data'] = trim("There is no channel that matches $channel");
        break;
      case AGI_Others::AST_STATE_DOWN:
        $ret['data'] = 'Channel is down and available';
        break;
      case AGI_Others::AST_STATE_RESERVED:
        $ret['data'] = 'Channel is down, but reserved';
        break;
      case AGI_Others::AST_STATE_OFFHOOK:
        $ret['data'] = 'Channel is off hook';
        break;
      case AGI_Others::AST_STATE_DIALING:
        $ret['data'] = 'Digits (or equivalent) have been dialed';
        break;
      case AGI_Others::AST_STATE_RING:
        $ret['data'] = 'Line is ringing';
        break;
      case AGI_Others::AST_STATE_RINGING:
        $ret['data'] = 'Remote end is ringing';
        break;
      case AGI_Others::AST_STATE_UP:
        $ret['data'] = 'Line is up';
        break;
      case AGI_Others::AST_STATE_BUSY:
        $ret['data'] = 'Line is busy';
        break;
      case AGI_Others::AST_STATE_DIALING_OFFHOOK:
        $ret['data'] = 'Digits (or equivalent) have been dialed while offhook';
        break;
      case AGI_Others::AST_STATE_PRERING:
        $ret['data'] = 'Channel has detected an incoming call and is waiting for ring';
        break;
      default:
        $ret['data'] = "Unknown ({$ret['result']})";
        break;
    }
    return $ret;
  }

  /**
   * Deletes an entry in the Asterisk database for a given family and key.
   *
   * @link http://www.voip-info.org/wiki-database+del
   * @param string $family
   * @param string $key
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 otherwise.
   */
  function database_del(string $family, string $key): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("DATABASE DEL \"$family\" \"$key\"");
  }

  /**
   * Deletes a family or specific keytree within a family in the Asterisk database.
   *
   * @link http://www.voip-info.org/wiki-database+deltree
   * @param string $family
   * @param string $keytree
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 otherwise.
   */
  function database_deltree(string $family, string $keytree = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    $cmd = "DATABASE DELTREE \"$family\"";
    if ($keytree != '') {
      $cmd .= " \"$keytree\"";
    }
    return $this->evaluate($cmd);
  }

  /**
   * Retrieves an entry in the Asterisk database for a given family and key.
   *
   * @link http://www.voip-info.org/wiki-database+get
   * @param string $family
   * @param string $key
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 failure. ['data'] holds the value
   */
  function database_get(string $family, string $key): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("DATABASE GET \"$family\" \"$key\"");
  }

  /**
   * Adds or updates an entry in the Asterisk database for a given family, key, and value.
   *
   * @param string $family
   * @param string $key
   * @param string $value
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 otherwise
   */
  function database_put(string $family, string $key, string $value): array {

It is generally recommended to explicitly declare the visibility for methods.

    $value = str_replace("\n", '\n', addslashes($value));
    return $this->evaluate("DATABASE PUT \"$family\" \"$key\" \"$value\"");
  }


  /**
   * Sets a global variable, using Asterisk 1.6 syntax.
   *
   * @link http://www.voip-info.org/wiki/view/Asterisk+cmd+Set
   *
   * @param string $pVariable
   * @param string|int|float $pValue
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 otherwise
   */
  function set_global_var(string $pVariable, $pValue): array {

It is generally recommended to explicitly declare the visibility for methods.

    if (is_numeric($pValue)) {
      return $this->evaluate("Set({$pVariable}={$pValue},g);");
    }
    return $this->evaluate("Set({$pVariable}=\"{$pValue}\",g);");
  }


  /**
   * Sets a variable, using Asterisk 1.6 syntax.
   *
   * @link http://www.voip-info.org/wiki/view/Asterisk+cmd+Set
   *
   * @param string $pVariable
   * @param string|int|float $pValue
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 otherwise
   */
  function set_var(string $pVariable, $pValue): array {

It is generally recommended to explicitly declare the visibility for methods.

    if (is_numeric($pValue)) {
      return $this->evaluate("Set({$pVariable}={$pValue});");
    }
    return $this->evaluate("Set({$pVariable}=\"{$pValue}\");");
  }


  /**
   * Executes the specified Asterisk application with given options.
   *
   * @link http://www.voip-info.org/wiki-exec
   * @link http://www.voip-info.org/wiki-Asterisk+-+documentation+of+application+commands
   * @param string $application
   * @param mixed $options
   * @return array, see evaluate for return information. ['result'] is whatever the application returns, or -2 on failure to find application
   */
  function exec(string $application, $options): array {

It is generally recommended to explicitly declare the visibility for methods.

    if (is_array($options)) {
      $options = join('|', $options);
    }
    return $this->evaluate("EXEC $application $options");
  }

  /**
   * Plays the given file and receives DTMF data.
   *
   * This is similar to STREAM FILE, but this command can accept and return many DTMF digits,
   * while STREAM FILE returns immediately after the first DTMF digit is detected.
   *
   * Asterisk looks for the file to play in /var/lib/asterisk/sounds by default.
   *
   * If the user doesn't press any keys when the message plays, there is $timeout milliseconds
   * of silence then the command ends.
   *
   * The user has the opportunity to press a key at any time during the message or the
   * post-message silence. If the user presses a key while the message is playing, the
   * message stops playing. When the first key is pressed a timer starts counting for
   * $timeout milliseconds. Every time the user presses another key the timer is restarted.
   * The command ends when the counter goes to zero or the maximum number of digits is entered,
   * whichever happens first.
   *
   * If you don't specify a time out then a default timeout of 2000 is used following a pressed
   * digit. If no digits are pressed then 6 seconds of silence follow the message.
   *
   * If you don't specify $max_digits then the user can enter as many digits as they want.
   *
   * Pressing the # key has the same effect as the timer running out: the command ends and
   * any previously keyed digits are returned. A side effect of this is that there is no
   * way to read a # key using this command.
   *
   * @param string $filename file to play. Do not include file extension.
   * @param integer $timeout milliseconds
   * @param integer $max_digits
   * @return array, see evaluate for return information. ['result'] holds the digits and ['data'] holds the timeout if present.
   *
   * This differs from other commands with return DTMF as numbers representing ASCII characters.
   * @example examples/ping.php Ping an IP address
   *
   * @link http://www.voip-info.org/wiki-get+data
   */
  function get_data(string $filename, $timeout = null, $max_digits = null): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate(rtrim("GET DATA $filename $timeout $max_digits"));
  }

  /**
   * Fetch the value of a variable.
   *
   * Does not work with global variables. Does not work with some variables that are generated by modules.
   *
   * @link http://www.voip-info.org/wiki-get+variable
   * @link http://www.voip-info.org/wiki-Asterisk+variables
   * @param string $variable name
   * @param boolean $getvalue return the value only
   * @return mixed, see evaluate for return information. ['result'] is 0 if variable hasn't been set, 1 if it has. ['data'] holds the value. returns value if $getvalue is TRUE
   */
  function get_variable(string $variable, bool $getvalue = false) {

It is generally recommended to explicitly declare the visibility for methods.

    $res = $this->evaluate("GET VARIABLE $variable");
    return $getvalue ? $res['data'] : $res;
  }


  /**
   * Fetch the value of a full variable.
   *
   *
   * @link http://www.voip-info.org/wiki/view/get+full+variable
   * @link http://www.voip-info.org/wiki-Asterisk+variables
   * @param string $variable name
   * @param string $channel channel
   * @param boolean $getvalue return the value only
   * @return mixed, see evaluate for return information. ['result'] is 0 if variable hasn't been set, 1 if it has. ['data'] holds the value.  returns value if $getvalue is TRUE
   */
  function get_fullvariable(string $variable, $channel = false, bool $getvalue = false) {

It is generally recommended to explicitly declare the visibility for methods.

    $req = ($channel == false) ? $variable : $variable . ' ' . $channel;

It seems like you are loosely comparing $channel of type false|string against false; this is ambiguous if the string can be empty. Consider using a strict comparison === instead.

    $res = $this->evaluate('GET FULL VARIABLE ' . $req);
    return $getvalue ? $res['data'] : $res;

  }

  /**
   * Hangup the specified channel. If no channel name is given, hang up the current channel.
   *
   * With power comes responsibility. Hanging up channels other than your own isn't something
   * that is done routinely. If you are not sure why you are doing so, then don't.
   *
   * @link http://www.voip-info.org/wiki-hangup
   * @example examples/dtmf.php Get DTMF tones from the user and say the digits
   * @example examples/input.php Get text input from the user and say it back
   * @example examples/ping.php Ping an IP address
   *
   * @param string $channel
   * @return array, see evaluate for return information. ['result'] is 1 on success, -1 on failure.
   */
  function hangup(string $channel = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("HANGUP $channel");
  }

  /**
   * Does nothing.
   *
   * @link http://www.voip-info.org/wiki-noop
   * @param string $string
   * @return array, see evaluate for return information.
   */
  function noop(string $string = ""): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("NOOP \"$string\"");
  }

  /**
   * Receive a character of text from a connected channel. Waits up to $timeout milliseconds for
   * a character to arrive, or infinitely if $timeout is zero.
   *
   * @link http://www.voip-info.org/wiki-receive+char
   * @param integer $timeout milliseconds
   * @return array, see evaluate for return information. ['result'] is 0 on timeout or not supported, -1 on failure. Otherwise
   * it is the decimal value of the DTMF tone. Use chr() to convert to ASCII.
   */
  function receive_char(int $timeout = -1): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("RECEIVE CHAR $timeout");
  }

  /**
   * Record sound to a file until an acceptable DTMF digit is received or a specified amount of
   * time has passed. Optionally the file BEEP is played before recording begins.
   *
   * @link http://www.voip-info.org/wiki-record+file
   * @param string $file to record, without extension, often created in /var/lib/asterisk/sounds
   * @param string $format of the file. GSM and WAV are commonly used formats. MP3 is read-only and thus cannot be used.
   * @param string $escape_digits
   * @param integer $timeout is the maximum record time in milliseconds, or -1 for no timeout.
   * @param integer $offset to seek to without exceeding the end of the file.
   * @param boolean $beep
   * @param integer $silence number of seconds of silence allowed before the function returns despite the
   * lack of dtmf digits or reaching timeout.
   * @return array, see evaluate for return information. ['result'] is -1 on error, 0 on hangup, otherwise a decimal value of the
   * DTMF tone. Use chr() to convert to ASCII.
   */
  function record_file(string $file, string $format, string $escape_digits = '', int $timeout = -1,

It is generally recommended to explicitly declare the visibility for methods.

                       $offset = null, bool $beep = false, $silence = null): array {
    $cmd = trim("RECORD FILE $file $format \"$escape_digits\" $timeout $offset");
    if ($beep) {
      $cmd .= ' BEEP';
    }
    if (!is_null($silence)) {
      $cmd .= " s=$silence";
    }
    return $this->evaluate($cmd);
  }

  /**
   * Say a given character string, returning early if any of the given DTMF digits are received on the channel.
   *
   * @link https://www.voip-info.org/say-alpha
   * @param string $text
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function say_alpha(string $text, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SAY ALPHA $text \"$escape_digits\"");
  }

  /**
   * Say the given digit string, returning early if any of the given DTMF escape digits are received on the channel.
   *
   * @link http://www.voip-info.org/wiki-say+digits
   * @param integer $digits
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function say_digits(int $digits, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SAY DIGITS $digits \"$escape_digits\"");
  }

  /**
   * Say the given number, returning early if any of the given DTMF escape digits are received on the channel.
   *
   * @link http://www.voip-info.org/wiki-say+number
   * @param integer $number
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function say_number(int $number, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SAY NUMBER $number \"$escape_digits\"");
  }

  /**
   * Say the given character string, returning early if any of the given DTMF escape digits are received on the channel.
   *
   * @link http://www.voip-info.org/wiki-say+phonetic
   * @param string $text
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function say_phonetic(string $text, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SAY PHONETIC $text \"$escape_digits\"");
  }

  /**
   * Say a given time, returning early if any of the given DTMF escape digits are received on the channel.
   *
   * @link http://www.voip-info.org/wiki-say+time
   * @param integer $time number of seconds elapsed since 00:00:00 on January 1, 1970, Coordinated Universal Time (UTC).
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function say_time($time = null, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    if (is_null($time)) {
      $time = time();
    }
    return $this->evaluate("SAY TIME $time \"$escape_digits\"");
  }

  /**
   * Send the specified image on a channel.
   *
   * Most channels do not support the transmission of images.
   *
   * @link http://www.voip-info.org/wiki-send+image
   * @param string $image without extension, often in /var/lib/asterisk/images
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if the image is sent or
   * channel does not support image transmission.
   */
  function send_image(string $image): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SEND IMAGE $image");
  }

  /**
   * Send the given text to the connected channel.
   *
   * Most channels do not support transmission of text.
   *
   * @link http://www.voip-info.org/wiki-send+text
   * @param $text
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if the text is sent or
   * channel does not support text transmission.
   */
  function send_text($text): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SEND TEXT \"$text\"");
  }

  /**
   * Cause the channel to automatically hangup at $time seconds in the future.
   * If $time is 0 then the auto hangup feature is disabled on this channel.
   *
   * If the channel is hangup prior to $time seconds, this setting has no effect.
   *
   * @link http://www.voip-info.org/wiki-set+autohangup
   * @param integer $time until automatic hangup
   * @return array, see evaluate for return information.
   */
  function set_autohangup(int $time = 0): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SET AUTOHANGUP $time");
  }

  /**
   * Changes the caller ID of the current channel.
   *
   * @link http://www.voip-info.org/wiki-set+callerid
   * @param string $cid example: "John Smith"<1234567>
   * This command will let you take liberties with the <caller ID specification> but the format shown in the example above works
   * well: the name enclosed in double quotes followed immediately by the number inside angle brackets. If there is no name then
   * you can omit it. If the name contains no spaces you can omit the double quotes around it. The number must follow the name
   * immediately; don't put a space between them. The angle brackets around the number are necessary; if you omit them the
   * number will be considered to be part of the name.
   * @return array, see evaluate for return information.
   */
  function set_callerid(string $cid): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SET CALLERID $cid");
  }

  /**
   * Sets the context for continuation upon exiting the application.
   *
   * Setting the context does NOT automatically reset the extension and the priority; if you want to start at the top of the new
   * context you should set extension and priority yourself.
   *
   * If you specify a non-existent context you receive no error indication (['result'] is still 0) but you do get a
   * warning message on the Asterisk console.
   *
   * @link http://www.voip-info.org/wiki-set+context
   * @param string $context
   * @return array, see evaluate for return information.
   */
  function set_context(string $context): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SET CONTEXT $context");
  }

  /**
   * Set the extension to be used for continuation upon exiting the application.
   *
   * Setting the extension does NOT automatically reset the priority. If you want to start with the first priority of the
   * extension you should set the priority yourself.
   *
   * If you specify a non-existent extension you receive no error indication (['result'] is still 0) but you do
   * get a warning message on the Asterisk console.
   *
   * @link http://www.voip-info.org/wiki-set+extension
   * @param string $extension
   * @return array, see evaluate for return information.
   */
  function set_extension(string $extension): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SET EXTENSION $extension");
  }

  /**
   * Enable/Disable Music on hold generator.
   *
   * @link http://www.voip-info.org/wiki-set+music
   * @param boolean $enabled
   * @param string $class
   * @return array, see evaluate for return information.
   */
  function set_music(bool $enabled = true, string $class = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    $enabled = ($enabled) ? 'ON' : 'OFF';
    return $this->evaluate("SET MUSIC $enabled $class");
  }

  /**
   * Set the priority to be used for continuation upon exiting the application.
   *
   * If you specify a non-existent priority you receive no error indication (['result'] is still 0)
   * and no warning is issued on the Asterisk console.
   *
   * @link http://www.voip-info.org/wiki-set+priority
   * @param integer $priority
   * @return array, see evaluate for return information.
   */
  function set_priority(int $priority): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("SET PRIORITY $priority");
  }

  /**
   * Sets a variable to the specified value. The variables so created can later be used by later using ${<variablename>}
   * in the dialplan.
   *
   * These variables live in the channel Asterisk creates when you pickup a phone and as such they are both local and temporary.
   * Variables created in one channel can not be accessed by another channel. When you hang up the phone, the channel is deleted
   * and any variables in that channel are deleted as well.
   *
   * @link http://www.voip-info.org/wiki-set+variable
   * @param string $variable is case sensitive
   * @param string $value
   * @return array, see evaluate for return information.
   */
  function set_variable(string $variable, string $value): array {

It is generally recommended to explicitly declare the visibility for methods.

    $value = str_replace("\n", '\n', addslashes($value));
    return $this->evaluate("SET VARIABLE $variable \"$value\"");
  }

  /**
   * Play the given audio file, allowing playback to be interrupted by a DTMF digit. This command is similar to the GET DATA
   * command but this command returns after the first DTMF digit has been pressed while GET DATA can accumulated any number of
   * digits before returning.
   *
   * @param string $filename without extension, often in /var/lib/asterisk/sounds
   * @param string $escape_digits
   * @param integer $offset
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   * @example examples/ping.php Ping an IP address
   *
   * @link http://www.voip-info.org/wiki-stream+file
   */
  function stream_file(string $filename, string $escape_digits = '', int $offset = 0): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("STREAM FILE $filename \"$escape_digits\" $offset");
  }

  /**
   * Enable or disable TDD transmission/reception on the current channel.
   *
   * @link http://www.voip-info.org/wiki-tdd+mode
   * @param string $setting can be on, off or mate
   * @return array, see evaluate for return information. ['result'] is 1 on success, 0 if the channel is not TDD capable.
   */
  function tdd_mode(string $setting): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("TDD MODE $setting");
  }

  /**
   * Sends $message to the Asterisk console via the 'verbose' message system.
   *
   * If the Asterisk verbosity level is $level or greater, send $message to the console.
   *
   * The Asterisk verbosity system works as follows. The Asterisk user gets to set the desired verbosity at startup time or later
   * using the console 'set verbose' command. Messages are displayed on the console if their verbose level is less than or equal
   * to desired verbosity set by the user. More important messages should have a low verbose level; less important messages
   * should have a high verbose level.
   *
   * @link http://www.voip-info.org/wiki-verbose
   * @param string $message
   * @param integer $level from 1 to 4
   * @return array, see evaluate for return information.
   */
  function verbose(string $message, int $level = 1): array {

It is generally recommended to explicitly declare the visibility for methods.

    $ret = [];
    foreach (explode("\n", str_replace("\r\n", "\n", print_r($message, true))) as $msg) {
      @syslog(LOG_WARNING, $msg);

It seems like you do not handle an error condition for syslog(). This can introduce security issues, and is generally not recommended.

      $ret = $this->evaluate("VERBOSE \"$msg\" $level");
    }
    return $ret;
  }

  /**
   * Waits up to $timeout milliseconds for channel to receive a DTMF digit.
   *
   * @link http://www.voip-info.org/wiki-wait+for+digit
   * @param integer $timeout in milliseconds. Use -1 for the timeout value if you want the call to wait indefinitely.
   * @return array, see evaluate for return information. ['result'] is 0 if wait completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function wait_for_digit(int $timeout = -1): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->evaluate("WAIT FOR DIGIT $timeout");
  }


  // *********************************************************************************************************
  // **                             APPLICATIONS                                                                                        **
  // *********************************************************************************************************

  /**
   * Set absolute maximum time of call.
   *
   * Note that the timeout is set from the current time forward, not counting the number of seconds the call has already been up.
   * Each time you call AbsoluteTimeout(), all previous absolute timeouts are cancelled.
   * Will return the call to the T extension so that you can playback an explanatory note to the calling party (the called party
   * will not hear that)
   *
   * @link http://www.voip-info.org/wiki-Asterisk+-+documentation+of+application+commands
   * @link http://www.dynx.net/ASTERISK/AGI/ccard/agi-ccard.agi
   * @param integer $seconds allowed, 0 disables timeout
   * @return array, see evaluate for return information.
   */
  function exec_absolutetimeout(int $seconds = 0): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->exec('AbsoluteTimeout', $seconds);
  }

  /**
   * Executes an AGI compliant application.
   *
   * @param string $command
   * @param string $args
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or if application requested hangup, or 0 on non-hangup exit.
   */
  function exec_agi(string $command, string $args): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->exec("AGI $command", $args);
  }

  /**
   * Set Language.
   *
   * @param string $language code
   * @return array, see evaluate for return information.
   */
  function exec_setlanguage(string $language = 'en'): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->exec('Set', 'CHANNEL(language)=' . $language);
  }

  /**
   * Do ENUM Lookup.
   *
   * Note: to retrieve the result, use
   *   get_variable('ENUM');
   *
   * @param $exten
   * @return array, see evaluate for return information.
   */
  function exec_enumlookup($exten): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->exec('EnumLookup', $exten);
  }

  /**
   * Dial.
   *
   * Dial takes input from ${VXML_URL} to send XML Url to Cisco 7960
   * Dial takes input from ${ALERT_INFO} to set ring cadence for Cisco phones
   * Dial returns ${CAUSECODE}: If the dial failed, this is the errormessage.
   * Dial returns ${DIALSTATUS}: Text code returning status of last dial attempt.
   *
   * @link http://www.voip-info.org/wiki-Asterisk+cmd+Dial
   * @param string $type
   * @param string $identifier
   * @param integer $timeout
   * @param string $options
   * @param string $url
   * @return array, see evaluate for return information.
   */
  function exec_dial(string $type, string $identifier, $timeout = null, $options = null, $url = null): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->exec(
      'Dial', trim("$type/$identifier" . $this->option_delim . $timeout . $this->option_delim . $options . $this->option_delim . $url, $this->option_delim));
  }

  /**
   * Goto.
   *
   * This function takes three arguments: context,extension, and priority, but the leading arguments
   * are optional, not the trailing arguments.  Those goto($z) sets the priority to $z.
   *
   * @param string $a
   * @param string $b ;
   * @param string $c ;
   * @return array, see evaluate for return information.
   */
  function exec_goto(string $a, $b = null, $c = null): array {

It is generally recommended to explicitly declare the visibility for methods.

    return $this->exec('Goto', trim($a . $this->option_delim . $b . $this->option_delim . $c, $this->option_delim));
  }


  // *********************************************************************************************************
  // **                             FAST PASSING                                                                                        **
  // *********************************************************************************************************

  /**
   * Say the given digit string, returning early if any of the given DTMF escape digits are received on the channel.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.voip-info.org/wiki-say+digits
   * @param string $buffer
   * @param integer $digits
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function fastpass_say_digits(string &$buffer, int $digits, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->say_digits($digits, $escape_digits);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer)];
  }

  /**
   * Say the given number, returning early if any of the given DTMF escape digits are received on the channel.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.voip-info.org/wiki-say+number
   * @param string $buffer
   * @param integer $number
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function fastpass_say_number(string &$buffer, int $number, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->say_number($number, $escape_digits);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer)];
  }

  /**
   * Say the given character string, returning early if any of the given DTMF escape digits are received on the channel.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.voip-info.org/wiki-say+phonetic
   * @param string $buffer
   * @param string $text
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function fastpass_say_phonetic(string &$buffer, string $text, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->say_phonetic($text, $escape_digits);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer)];
  }

  /**
   * Say a given time, returning early if any of the given DTMF escape digits are received on the channel.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.voip-info.org/wiki-say+time
   * @param string $buffer
   * @param integer $time number of seconds elapsed since 00:00:00 on January 1, 1970, Coordinated Universal Time (UTC).
   * @param string $escape_digits
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function fastpass_say_time(string &$buffer, $time = null, string $escape_digits = ''): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->say_time($time, $escape_digits);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer)];
  }

  /**
   * Play the given audio file, allowing playback to be interrupted by a DTMF digit. This command is similar to the GET DATA
   * command but this command returns after the first DTMF digit has been pressed while GET DATA can accumulated any number of
   * digits before returning.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.voip-info.org/wiki-stream+file
   * @param string $buffer
   * @param string $filename without extension, often in /var/lib/asterisk/sounds
   * @param string $escape_digits
   * @param integer $offset
   * @return array, see evaluate for return information. ['result'] is -1 on hangup or error, 0 if playback completes with no
   * digit received, otherwise a decimal value of the DTMF tone.  Use chr() to convert to ASCII.
   */
  function fastpass_stream_file(string &$buffer, string $filename, string $escape_digits = '', int $offset = 0): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->stream_file($filename, $escape_digits, $offset);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer),
            'endpos' => 0];
  }

  /**
   * Use festival to read text.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.cstr.ed.ac.uk/projects/festival/
   * @param string $buffer
   * @param string $text
   * @param string $escape_digits
   * @param integer $frequency
   * @return array, see evaluate for return information.
   */
  function fastpass_text2wav(string &$buffer, string $text, string $escape_digits = '', int $frequency = 8000): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->text2wav($text, $escape_digits, $frequency);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer),
            'endpos' => 0];
  }

  /**
   * Use Cepstral Swift to read text.
   * Return early if $buffer is adequate for request.
   *
   * @link http://www.cepstral.com/
   * @param string $buffer
   * @param string $text
   * @param string $escape_digits
   * @param integer $frequency
   * @param $voice
   * @return array, see evaluate for return information.
   */
  function fastpass_swift(string &$buffer, string $text, string $escape_digits = '', int $frequency = 8000, $voice = null): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->swift($text, $escape_digits, $frequency, $voice);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer),
            'endpos' => 0];
  }

  /**
   * Say Punctuation in a string.
   * Return early if $buffer is adequate for request.
   *
   * @param string $buffer
   * @param string $text
   * @param string $escape_digits
   * @param integer $frequency
   * @return array, see evaluate for return information.
   */
  function fastpass_say_punctuation(string &$buffer, string $text, string $escape_digits = '', int $frequency = 8000): array {

It is generally recommended to explicitly declare the visibility for methods.

    if ($buffer == '' || $this->proceedDigits($buffer, $escape_digits)) {
      $res = $this->say_punctuation($text, $escape_digits, $frequency);
      $this->appendBuffer($buffer, $res);
      return $res;
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $this->ordBuffer($buffer)];
  }

  /**
   * Plays the given file and receives DTMF data.
   * Return early if $buffer is adequate for request.
   *
   * This is similar to STREAM FILE, but this command can accept and return many DTMF digits,
   * while STREAM FILE returns immediately after the first DTMF digit is detected.
   *
   * Asterisk looks for the file to play in /var/lib/asterisk/sounds by default.
   *
   * If the user doesn't press any keys when the message plays, there is $timeout milliseconds
   * of silence then the command ends.
   *
   * The user has the opportunity to press a key at any time during the message or the
   * post-message silence. If the user presses a key while the message is playing, the
   * message stops playing. When the first key is pressed a timer starts counting for
   * $timeout milliseconds. Every time the user presses another key the timer is restarted.
   * The command ends when the counter goes to zero or the maximum number of digits is entered,
   * whichever happens first.
   *
   * If you don't specify a time out then a default timeout of 2000 is used following a pressed
   * digit. If no digits are pressed then 6 seconds of silence follow the message.
   *
   * If you don't specify $max_digits then the user can enter as many digits as they want.
   *
   * Pressing the # key has the same effect as the timer running out: the command ends and
   * any previously keyed digits are returned. A side effect of this is that there is no
   * way to read a # key using this command.
   *
   * @link http://www.voip-info.org/wiki-get+data
   * @param string $buffer
   * @param string $filename file to play. Do not include file extension.
   * @param integer $timeout milliseconds
   * @param integer $max_digits
   * @return array, see evaluate for return information. ['result'] holds the digits and ['data'] holds the timeout if present.
   *
   * This differs from other commands with return DTMF as numbers representing ASCII characters.
   */
  function fastpass_get_data(string &$buffer, string $filename, $timeout = null, $max_digits = null): array {

It is generally recommended to explicitly declare the visibility for methods.

    if (is_null($max_digits) || strlen($buffer) < $max_digits) {
      if ($buffer == '') {
        $res = $this->get_data($filename, $timeout, $max_digits);
        if ($res['code'] == AGI_Others::AGIRES_OK) {
          $buffer .= $res['result'];
        }
        return $res;
      }
      while (is_null($max_digits) || strlen($buffer) < $max_digits) {
        $res = $this->wait_for_digit();
        if ($res['code'] != AGI_Others::AGIRES_OK) {
          return $res;
        }
        if ($res['result'] == ord('#')) {
          break;
        }
        $buffer .= chr($res['result']);
      }
    }
    return ['code' => AGI_Others::AGIRES_OK,
            'result' => $buffer];
  }

  // *********************************************************************************************************
  // **                             DERIVED                                                                                             **
  // *********************************************************************************************************

  /**
   * Menu.
   *
   * This function presents the user with a menu and reads the response
   *
   * @param array $choices has the following structure:
   *   array('1'=>'*Press 1 for this', // festival reads if prompt starts with *
   *           '2'=>'some-gsm-without-extension',
   *           '*'=>'*Press star for help');
   * @param int $timeout
   * @return mixed key pressed on success, -1 on failure
   */
  function menu(array $choices, int $timeout = 2000) {

It is generally recommended to explicitly declare the visibility for methods.

    $keys = join('', array_keys($choices));
    $choice = null;
    while (is_null($choice)) {
      foreach ($choices as $prompt) {
        if ($prompt[0] == '*') {
          $ret = $this->text2wav(substr($prompt, 1), $keys);
        } else {
          $ret = $this->stream_file($prompt, $keys);
        }

        if ($ret['code'] != AGI_Others::AGIRES_OK || $ret['result'] == -1) {
          $choice = -1;
          break;
        }

        if ($ret['result'] != 0) {
          $choice = chr($ret['result']);
          break;
        }
      }

      if (is_null($choice)) {
        $ret = $this->get_data('beep', $timeout, 1);
        if ($ret['code'] != AGI_Others::AGIRES_OK || $ret['result'] == -1) {
          $choice = -1;
        } elseif ($ret['result'] != '' && strpos(' ' . $keys, $ret['result'])) {
          $choice = $ret['result'];
        }
      }
    }
    return $choice;
  }

  /**
   * setContext - Set context, extension and priority.
   *
   * @param string $context
   * @param string $extension
   * @param int $priority
   */
  function setContext(string $context, string $extension = 's', int $priority = 1) {

It is generally recommended to explicitly declare the visibility for methods.

    $this->set_context($context);
    $this->set_extension($extension);
    $this->set_priority($priority);
  }

  /**
   * Parse caller id.
   *
   * @param string $callerid
   * @return array('Name'=>$name, 'Number'=>$number)
   * @example examples/dtmf.php Get DTMF tones from the user and say the digits
   * @example examples/input.php Get text input from the user and say it back
   *
   * "name" <proto:user@server:port>
   *
   */
  function parse_callerid($callerid = null): array {

It is generally recommended to explicitly declare the visibility for methods.

    if (is_null($callerid)) {
      $callerid = $this->request['agi_callerid'];
    }

    $ret = ['name' => '',
            'protocol' => '',
            'username' => '',
            'host' => '',
            'port' => ''];
    $callerid = trim($callerid);

    if ($callerid[0] == '"' || $callerid[0] == "'") {
      $d = $callerid[0];
      $callerid = explode($d, substr($callerid, 1));
      $ret['name'] = array_shift($callerid);
      $callerid = join($d, $callerid);
    }

    $callerid = explode('@', trim($callerid, '<> '));
    $username = explode(':', array_shift($callerid));
    if (count($username) == 1) {
      $ret['username'] = $username[0];
    } else {
      $ret['protocol'] = array_shift($username);
      $ret['username'] = join(':', $username);
    }

    $callerid = join('@', $callerid);
    $host = explode(':', $callerid);
    if (count($host) == 1) {
      $ret['host'] = $host[0];
    } else {
      $ret['host'] = array_shift($host);
      $ret['port'] = join(':', $host);
    }

    return $ret;
  }

  /**
   * Use festival to read text.
   *
   * @param string $text
   * @param string $escape_digits
   * @param integer $frequency
   * @return array | bool, see evaluate for return information.
   * @example examples/dtmf.php Get DTMF tones from the user and say the digits
   * @example examples/input.php Get text input from the user and say it back
   * @example examples/ping.php Ping an IP address
   *
   * @link http://www.cstr.ed.ac.uk/projects/festival/
   */
  function text2wav(string $text, string $escape_digits = '', int $frequency = 8000) {

It is generally recommended to explicitly declare the visibility for methods.

    $text = trim($text);
    if ($text == '') {
      return true;
    }

    $hash = md5($text);
    $fname = $this->config['phpagi']['tempdir'] . DIRECTORY_SEPARATOR;
    $fname .= 'text2wav_' . $hash;

    // create wave file
    if (!file_exists("$fname.wav")) {
      // write text file
      if (!file_exists("$fname.txt")) {
        $fp = fopen("$fname.txt", 'w');
        fputs($fp, $text);
        fclose($fp);
      }

      shell_exec("{$this->config['festival']['text2wave']} -F $frequency -o $fname.wav $fname.txt");
    } else {
      touch("$fname.txt");
      touch("$fname.wav");
    }

    // stream it
    $ret = $this->stream_file($fname, $escape_digits);

    // clean up old files
    $delete = time() - 2592000; // 1 month
    foreach (glob($this->config['phpagi']['tempdir'] . DIRECTORY_SEPARATOR . 'text2wav_*') as $file) {
      if (filemtime($file) < $delete) {
        unlink($file);
      }
    }

    return $ret;
  }

  /**
   * Use Cepstral Swift to read text.
   *
   * @link http://www.cepstral.com/
   * @param string $text
   * @param string $escape_digits
   * @param integer $frequency
   * @param $voice
   * @return array | bool, see evaluate for return information.
   */
  function swift(string $text, string $escape_digits = '', int $frequency = 8000, $voice = null) {

It is generally recommended to explicitly declare the visibility for methods.

    if (!is_null($voice)) {
      $voice = "-n $voice";
    } elseif (isset($this->config['cepstral']['voice'])) {
      $voice = "-n {$this->config['cepstral']['voice']}";
    }

    $text = trim($text);
    if ($text == '') {
      return true;
    }

    $hash = md5($text);
    $fname = $this->config['phpagi']['tempdir'] . DIRECTORY_SEPARATOR;
    $fname .= 'swift_' . $hash;

    // create wave file
    if (!file_exists("$fname.wav")) {
      // write text file
      if (!file_exists("$fname.txt")) {
        $fp = fopen("$fname.txt", 'w');
        fputs($fp, $text);
        fclose($fp);
      }

      shell_exec("{$this->config['cepstral']['swift']} -p audio/channels=1,audio/sampling-rate=$frequency $voice -o $fname.wav -f $fname.txt");
    }

    // stream it
    $ret = $this->stream_file($fname, $escape_digits);

    // clean up old files
    $delete = time() - 2592000; // 1 month
    foreach (glob($this->config['phpagi']['tempdir'] . DIRECTORY_SEPARATOR . 'swift_*') as $file) {
      if (filemtime($file) < $delete) {
        unlink($file);
      }
    }

    return $ret;
  }

  /**
   * Text Input.
   *
   * Based on ideas found at http://www.voip-info.org/wiki-Asterisk+cmd+DTMFToText
   *
   * Example:
   *                  UC   H     LC   i        ,     SP   h     o        w    SP   a    r        e     SP   y        o        u     ?
   *   $string = '*8'.'44*'.'*5'.'444*'.'00*'.'0*'.'44*'.'666*'.'9*'.'0*'.'2*'.'777*'.'33*'.'0*'.'999*'.'666*'.'88*'.'0000*';
   *
   * @link http://www.voip-info.org/wiki-Asterisk+cmd+DTMFToText
   * @example examples/input.php Get text input from the user and say it back
   *
   * @param string $mode
   * @return string
   */
  function text_input(string $mode = 'NUMERIC'): string {

It is generally recommended to explicitly declare the visibility for methods.

    $alpha = ['k0' => ' ',
              'k00' => ',',
              'k000' => '.',
              'k0000' => '?',
              'k00000' => '0',
              'k1' => '!',
              'k11' => ':',
              'k111' => ';',
              'k1111' => '#',
              'k11111' => '1',
              'k2' => 'A',
              'k22' => 'B',
              'k222' => 'C',
              'k2222' => '2',
              'k3' => 'D',
              'k33' => 'E',
              'k333' => 'F',
              'k3333' => '3',
              'k4' => 'G',
              'k44' => 'H',
              'k444' => 'I',
              'k4444' => '4',
              'k5' => 'J',
              'k55' => 'K',
              'k555' => 'L',
              'k5555' => '5',
              'k6' => 'M',
              'k66' => 'N',
              'k666' => 'O',
              'k6666' => '6',
              'k7' => 'P',
              'k77' => 'Q',
              'k777' => 'R',
              'k7777' => 'S',
              'k77777' => '7',
              'k8' => 'T',
              'k88' => 'U',
              'k888' => 'V',
              'k8888' => '8',
              'k9' => 'W',
              'k99' => 'X',
              'k999' => 'Y',
              'k9999' => 'Z',
              'k99999' => '9'];
    $symbol = ['k0' => '=',
               'k1' => '<',
               'k11' => '(',
               'k111' => '[',
               'k1111' => '{',
               'k11111' => '1',
               'k2' => '@',
               'k22' => '$',
               'k222' => '&',
               'k2222' => '%',
               'k22222' => '2',
               'k3' => '>',
               'k33' => ')',
               'k333' => ']',
               'k3333' => '}',
               'k33333' => '3',
               'k4' => '+',
               'k44' => '-',
               'k444' => '*',
               'k4444' => '/',
               'k44444' => '4',
               'k5' => "'",
               'k55' => '`',
               'k555' => '5',
               'k6' => '"',
               'k66' => '6',
               'k7' => '^',
               'k77' => '7',
               'k8' => "\\",
               'k88' => '|',
               'k888' => '8',
               'k9' => '_',
               'k99' => '~',
               'k999' => '9'];
    $text = '';
    do {
      $command = false;
      $result = $this->get_data('beep');
      foreach (explode('*', $result['result']) as $code) {
        if ($command) {
          switch ($code[0]) {
            case '2':
              $text = substr($text, 0, strlen($text) - 1);
              break; // backspace
            case '5':
              $mode = 'LOWERCASE';
              break;
            case '6':
              $mode = 'NUMERIC';
              break;
            case '7':
              $mode = 'SYMBOL';
              break;
            case '8':
              $mode = 'UPPERCASE';
              break;
            case '9':
              $text = explode(' ', $text);
              unset($text[count($text) - 1]);
              $text = join(' ', $text);
              break; // backspace a word
          }
          $code = substr($code, 1);
          $command = false;
        }
        if ($code == '') {
          $command = true;
        } elseif ($mode == 'NUMERIC') {
          $text .= $code;
        } elseif ($mode == 'UPPERCASE' && isset($alpha['k' . $code])) {
          $text .= $alpha['k' . $code];
        } elseif ($mode == 'LOWERCASE' && isset($alpha['k' . $code])) {
          $text .= strtolower($alpha['k' . $code]);
        } elseif ($mode == 'SYMBOL' && isset($symbol['k' . $code])) {
          $text .= $symbol['k' . $code];
        }
      }
      $this->say_punctuation($text);
    } while (substr($result['result'], -2) == '**');
    return $text;
  }

  /**
   * Say Punctuation in a string.
   *
   * @param string $text
   * @param string $escape_digits
   * @param integer $frequency
   * @return array, see evaluate for return information.
   */
  function say_punctuation(string $text, string $escape_digits = '', int $frequency = 8000): array {

It is generally recommended to explicitly declare the visibility for methods.

    $ret = "";
    for ($i = 0; $i < strlen($text); $i++) {
      switch ($text[$i]) {
        case ' ':
          $ret .= 'SPACE ';
          break;
        case ',':
          $ret .= 'COMMA ';
          break;
        case '.':
          $ret .= 'PERIOD ';
          break;
        case '?':
          $ret .= 'QUESTION MARK ';
          break;
        case '!':
          $ret .= 'EXPLANATION POINT ';
          break;
        case ':':
          $ret .= 'COLON ';
          break;
        case ';':
          $ret .= 'SEMICOLON ';
          break;
        case '#':
          $ret .= 'POUND ';
          break;
        case '=':
          $ret .= 'EQUALS ';
          break;
        case '<':
          $ret .= 'LESS THAN ';
          break;
        case '(':
          $ret .= 'LEFT PARENTHESIS ';
          break;
        case '[':
          $ret .= 'LEFT BRACKET ';
          break;
        case '{':
          $ret .= 'LEFT BRACE ';
          break;
        case '@':
          $ret .= 'AT ';
          break;
        case '$':
          $ret .= 'DOLLAR SIGN ';
          break;
        case '&':
          $ret .= 'AMPERSAND ';
          break;
        case '%':
          $ret .= 'PERCENT ';
          break;
        case '>':
          $ret .= 'GREATER THAN ';
          break;
        case ')':
          $ret .= 'RIGHT PARENTHESIS ';
          break;
        case ']':
          $ret .= 'RIGHT BRACKET ';
          break;
        case '}':
          $ret .= 'RIGHT BRACE ';
          break;
        case '+':
          $ret .= 'PLUS ';
          break;
        case '-':
          $ret .= 'MINUS ';
          break;
        case '*':
          $ret .= 'ASTERISK ';
          break;
        case '/':
          $ret .= 'SLASH ';
          break;
        case "'":
          $ret .= 'SINGLE QUOTE ';
          break;
        case '`':
          $ret .= 'BACK TICK ';
          break;
        case '"':
          $ret .= 'QUOTE ';
          break;
        case '^':
          $ret .= 'CAROT ';
          break;
        case "\\":
          $ret .= 'BACK SLASH ';
          break;
        case '|':
          $ret .= 'BAR ';
          break;
        case '_':
          $ret .= 'UNDERSCORE ';
          break;
        case '~':
          $ret .= 'TILDE ';
          break;
        default:
          $ret .= $text[$i] . ' ';
          break;
      }
    }
    return $this->text2wav($ret, $escape_digits, $frequency);
  }

  /**
   * Create a new AGI_AsteriskManager.
   */
  function &new_AsteriskManager(): AGI_AsteriskManager {
    $this->asm = new AGI_AsteriskManager(null, $this->config['asmanager']);
    $this->asm->setPagi($this);
    $this->config['asmanager'] = &$this->asm->config['asmanager'];
    return $this->asm;
  }


  // *********************************************************************************************************
  // **                             PRIVATE                                                                                             **
  // *********************************************************************************************************


  /**
   * Evaluate an AGI command.
   *
   * @access private
   * @param string $command
   * @return array ('code'=>$code, 'result'=>$result, 'data'=>$data)
   */
  private function evaluate(string $command): array {
    $broken = ['code' => 500,
               'result' => -1,
               'data' => ''];

    // write command
    if (!@fwrite($this->out, trim($command) . "\n")) {
      return $broken;
    }
    fflush($this->out);

    // Read result.  Occasionally, a command return a string followed by an extra new line.
    // When this happens, our script will ignore the new line, but it will still be in the
    // buffer.  So, if we get a blank line, it is probably the result of a previous
    // command.  We read until we get a valid result or asterisk hangs up.  One offending
    // command is SEND TEXT.
    $count = 0;
    do {
      $str = trim(fgets($this->in, 4096));
    } while ($str == '' && $count++ < 5);

    if ($count >= 5) {
      //          $this->conlog("evaluate error on read for $command");
      return $broken;
    }

    // parse result
    $ret['code'] = substr($str, 0, 3);

$ret was never initialized. Although not strictly required by PHP, it is generally a good practice to add $ret = array(); before regardless.

    $str = trim(substr($str, 3));

    if ($str[0] == '-') { // we have a multiline response!
      $count = 0;
      $str = substr($str, 1) . "\n";
      $line = fgets($this->in, 4096);
      while (substr($line, 0, 3) != $ret['code'] && $count < 5) {
        $str .= $line;
        $line = fgets($this->in, 4096);
        $count = (trim($line) == '') ? $count + 1 : 0;
      }
      if ($count >= 5) {
        //            $this->conlog("evaluate error on multiline read for $command");
        return $broken;
      }
    }

    $ret['result'] = null;
    $ret['data'] = '';
    if ($ret['code'] != AGI_Others::AGIRES_OK) { // some sort of error
      $ret['data'] = $str;
      $this->conlog(/** @scrutinizer ignore-type */ print_r($ret, true));
    } else { // normal AGIRES_OK response
      $parse = explode(' ', trim($str));
      $in_token = false;
      foreach ($parse as $token) {
        if ($in_token) { // we previously hit a token starting with ')' but not ending in ')'
          $ret['data'] .= ' ' . trim($token, '() ');
          if ($token[strlen($token) - 1] == ')') {
            $in_token = false;
          }
        } elseif ($token[0] == '(') {
          if ($token[strlen($token) - 1] != ')') {
            $in_token = true;
          }
          $ret['data'] .= ' ' . trim($token, '() ');
        } elseif (strpos($token, '=')) {
          $token = explode('=', $token);
          $ret[$token[0]] = $token[1];
        } elseif ($token != '') {
          $ret['data'] .= ' ' . $token;
        }
      }
      $ret['data'] = trim($ret['data']);
    }

    // log some errors
    if ($ret['result'] < 0) {
      $this->conlog("$command returned {$ret['result']}");
    }

    return $ret;
  }

  /**
   * Log to console if debug mode.
   *
   * @param string $str
   * @param integer $vbl verbose level
   * @example examples/ping.php Ping an IP address
   *
   */
  function conlog(string $str, int $vbl = 1) {

It is generally recommended to explicitly declare the visibility for methods.

    static $busy = false;

    if ($this->config['phpagi']['debug'] != false) {
      if (!$busy) { // no conlogs inside conlog!!!
        $busy = true;
        $this->verbose($str, $vbl);
        $busy = false;

The assignment to $busy is dead and can be removed.

      }
    }
  }

  /**
   * Find an executable in the path.
   *
   * @access private
   * @param string $cmd command to find
   * @param string $checkpath path to check
   * @return string the path to the command
   */
  private function which(string $cmd, $checkpath = null) {
    if (is_null($checkpath)) {
      $chpath = getenv('PATH');
      if ($chpath === false) {
        $chpath = '/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:' .
          '/usr/X11R6/bin:/usr/local/apache/bin:/usr/local/mysql/bin';
      }
    } else {
      $chpath = $checkpath;
    }

    foreach (explode(':', $chpath) as $path) {
      if (is_executable("$path/$cmd")) {
        return "$path/$cmd";
      }
    }

    return false;

The expression return false returns the type false which is incompatible with the documented return type string.

  }

  /**
   * Make a folder recursively.
   *
   * @access private
   * @param string $folder
   * @param integer $perms
   * @return boolean
   */
  private function make_folder(string $folder, int $perms = 0755): bool {
    $f = explode(DIRECTORY_SEPARATOR, $folder);
    $base = '';
    for ($i = 0; $i < count($f); $i++) {

It seems like you are calling the size function count() as part of the test condition. You might want to compute the size beforehand, and not on each iteration.

      $base .= $f[$i];
      if ($f[$i] != '' && !file_exists($base)) {
        if (mkdir($base, $perms) == false) {

It seems like you are loosely comparing two booleans. Considering using the strict comparison === instead.

          return (false);
        }
      }
      $base .= DIRECTORY_SEPARATOR;
    }
    return (true);
  }

  private function proceedDigits(string $buffer, string $escapeDigits): bool {
    if ($escapeDigits != "" && $buffer != "") {
      if (!strpos(chr(255) . $escapeDigits, $buffer[strlen($buffer) - 1])) {
        return true;
      }
    }
    return false;
  }

  private function ordBuffer(string $buffer): int {
    return ord($buffer[strlen($buffer) - 1]);
  }

  private function appendBuffer(string &$buffer, array $res) {
    if ($res['code'] == AGI_Others::AGIRES_OK && $res['result'] > 0) {
      $buffer .= chr($res['result']);
    }
  }
}