Proyectos de Subversion Moodle

<?php

/**

 * Custom XML parser for signed and/or encrypted XML Docs

 *

 * @author  Donal McMullan  donal@catalyst.net.nz

 * @version 0.0.1

 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License

 * @package mnet

 */

/**

 * Custom XML parser class for signed and/or encrypted XML Docs

 */

class mnet_encxml_parser {

    /** @var resource|false|XMLParser — a resource handle for the new XML parser. */

    private $parser;

    /** @var int unique ID for each tag. */

    private $tag_number;

    /** @var string digest string. */

    private $digest;

    /** @var string remote_timestamp string. */

    public $remote_timestamp;

    /** @var string remote_wwwroot string. */

    public $remote_wwwroot;

    /** @var string signature string. */

    public $signature;

    /** @var string data_object string. */

    public $data_object;

    /** @var string URI value inside the RETRIEVALMETHOD xml tag. */

    private $key_URI;

    /** @var bool true if $chiper has a value, otherwise false. */

    public $payload_encrypted;

    /** @var array the chiper string. */

    public $cipher = [];

    /** @var array error information with code and string keys. */

    public $error = [];

    /** @var string The remote error string, specified in the discard_data(). */

    public $remoteerror;

    /** @var stdClass error started status. */

    private $errorstarted;

    /**

     * Constructor creates and initialises parser resource and calls initialise

     *

     * @return bool True

     */

    public function __construct() {

        return $this->initialise();

    }

    /**

     * Old syntax of class constructor. Deprecated in PHP7.

     *

     * @deprecated since Moodle 3.1

     */

    public function mnet_encxml_parser() {

        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);

        self::__construct();

    }

    /**

     * Set default element handlers and initialise properties to empty.

     *

     * @return bool True

     */

    function initialise() {

        $this->parser = xml_parser_create();

        xml_set_element_handler($this->parser, [$this, "start_element"], [$this, "end_element"]);

        xml_set_character_data_handler($this->parser, [$this, "discard_data"]);

        $this->tag_number        = 0; // Just a unique ID for each tag

        $this->digest            = '';

        $this->remote_timestamp  = '';

        $this->remote_wwwroot    = '';

        $this->signature         = '';

        $this->data_object       = '';

        $this->key_URI           = '';

        $this->payload_encrypted = false;

        $this->cipher            = array();

        $this->error             = array();

        $this->remoteerror       = null;

        $this->errorstarted      = false;

        return true;

    }

    /**

     * Parse a block of XML text

     *

     * The XML Text will be an XML-RPC request which is wrapped in an XML doc

     * with a signature from the sender. This envelope may be encrypted and

     * delivered within another XML envelope with a symmetric key. The parser

     * should first decrypt this XML, and then place the XML-RPC request into

     * the data_object property, and the signature into the signature property.

     *

     * See the W3C's {@link http://www.w3.org/TR/xmlenc-core/ XML Encryption Syntax and Processing}

     * and {@link http://www.w3.org/TR/2001/PR-xmldsig-core-20010820/ XML-Signature Syntax and Processing}

     * guidelines for more detail on the XML.

     *

     * -----XML-Envelope---------------------------------

     * |                                                |

     * |    Symmetric-key--------------------------     |

     * |    |_____________________________________|     |

     * |                                                |

     * |    Encrypted data-------------------------     |

     * |    |                                     |     |

     * |    |  -XML-Envelope------------------    |     |

     * |    |  |                             |    |     |

     * |    |  |  --Signature-------------   |    |     |

     * |    |  |  |______________________|   |    |     |

     * |    |  |                             |    |     |

     * |    |  |  --Signed-Payload--------   |    |     |

     * |    |  |  |                      |   |    |     |

     * |    |  |  |   XML-RPC Request    |   |    |     |

     * |    |  |  |______________________|   |    |     |

     * |    |  |                             |    |     |

     * |    |  |_____________________________|    |     |

     * |    |_____________________________________|     |

     * |                                                |

     * |________________________________________________|

     *

     * @param   string  $data   The XML that you want to parse

     * @return  bool            True on success - false on failure

     */

    function parse($data) {

        $p = xml_parse($this->parser, $data);

        if ($p == 0) {

            // Parse failed

            $errcode = xml_get_error_code($this->parser);

            $errstring = xml_error_string($errcode);

            $lineno = xml_get_current_line_number($this->parser);

            if ($lineno !== false) {

                $error = array('lineno' => $lineno);

                $lineno--; // Line numbering starts at 1.

                while ($lineno > 0) {

                    $data = strstr($data, "\n");

                    $lineno--;

                }

                $data .= "\n"; // In case there's only one line (no newline)

                $line = substr($data, 0, strpos($data, "\n"));

                $error['code']   = $errcode;

                $error['string'] = $errstring;

                $error['line']   = $line;

                $this->error[] = $error;

            } else {

                $this->error[] = array('code' => $errcode, 'string' => $errstring);

            }

        }

        if (!empty($this->remoteerror)) {

            return false;

        }

        if (count($this->cipher) > 0) {

            $this->cipher = array_values($this->cipher);

            $this->payload_encrypted = true;

        }

        return (bool)$p;

    }

    /**

     * Destroy the parser and free up any related resource.

     */

    function free_resource() {

        $free = xml_parser_free($this->parser);

    }

    /**

     * Set the character-data handler to the right function for each element

     *

     * For each tag (element) name, this function switches the character-data

     * handler to the function that handles that element. Note that character

     * data is referred to the handler in blocks of 1024 bytes.

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $name   The name of the tag, e.g. method_call

     * @param   array   $attrs  The tag's attributes (if any exist).

     * @return  bool            True

     */

    function start_element($parser, $name, $attrs) {

        $this->tag_number++;

        $handler = 'discard_data';

        switch(strtoupper($name)) {

            case 'DIGESTVALUE':

                $handler = 'parse_digest';

                break;

            case 'SIGNATUREVALUE':

                $handler = 'parse_signature';

                break;

            case 'OBJECT':

                $handler = 'parse_object';

                break;

            case 'RETRIEVALMETHOD':

                $this->key_URI = $attrs['URI'];

                break;

            case 'TIMESTAMP':

                $handler = 'parse_timestamp';

                break;

            case 'WWWROOT':

                $handler = 'parse_wwwroot';

                break;

            case 'CIPHERVALUE':

                $this->cipher[$this->tag_number] = '';

                $handler = 'parse_cipher';

                break;

            case 'FAULT':

                $handler = 'parse_fault';

            default:

                break;

        }

        xml_set_character_data_handler($this->parser, [$this, $handler]);

        return true;

    }

    /**

     * Add the next chunk of character data to the remote_timestamp string

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function parse_timestamp($parser, $data) {

        $this->remote_timestamp .= $data;

        return true;

    }

    /**

     * Add the next chunk of character data to the cipher string for that tag

     *

     * The XML parser calls the character-data handler with 1024-character

     * chunks of data. This means that the handler may be called several times

     * for a single tag, so we use the concatenate operator (.) to build the

     * tag content into a string.

     * We should not encounter more than one of each tag type, except for the

     * cipher tag. We will often see two of those. We prevent the content of

     * these two tags being concatenated together by counting each tag, and

     * using its 'number' as the key to an array of ciphers.

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function parse_cipher($parser, $data) {

        $this->cipher[$this->tag_number] .= $data;

        return true;

    }

    /**

     * Add the next chunk of character data to the remote_wwwroot string

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function parse_wwwroot($parser, $data) {

        $this->remote_wwwroot .= $data;

        return true;

    }

    /**

     * Add the next chunk of character data to the digest string

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function parse_digest($parser, $data) {

        $this->digest .= $data;

        return true;

    }

    /**

     * Add the next chunk of character data to the signature string

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function parse_signature($parser, $data) {

        $this->signature .= $data;

        return true;

    }

    /**

     * Add the next chunk of character data to the data_object string

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function parse_object($parser, $data) {

        $this->data_object .= $data;

        return true;

    }

    /**

     * Discard the next chunk of character data

     *

     * This is used for tags that we're not interested in.

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $data   The content of the current tag (1024 byte chunk)

     * @return  bool            True

     */

    function discard_data($parser, $data) {

        if (!$this->errorstarted) {

            // Not interested

            return true;

        }

        $data = trim($data);

        if (isset($this->errorstarted->faultstringstarted) && !empty($data)) {

            $this->remoteerror .= ', message: ' . $data;

        } else if (isset($this->errorstarted->faultcodestarted)) {

            $this->remoteerror = 'code: ' . $data;

            unset($this->errorstarted->faultcodestarted);

        } else if ($data == 'faultCode') {

            $this->errorstarted->faultcodestarted = true;

        } else if ($data == 'faultString') {

            $this->errorstarted->faultstringstarted = true;

        }

        return true;

    }

    function parse_fault($parser, $data) {

        $this->errorstarted = new StdClass;

        return true;

    }

    /**

     * Switch the character-data handler to ignore the next chunk of data

     *

     * @param   mixed   $parser The XML parser

     * @param   string  $name   The name of the tag, e.g. method_call

     * @return  bool            True

     */

    function end_element($parser, $name) {

        $ok = xml_set_character_data_handler($this->parser, [$this, "discard_data"]);

        return true;

    }

}