SAML2\Assertion::__construct PHP Method

    public function __construct(\DOMElement $xml = null)
    {
        $this->id = Utils::getContainer()->generateId();
        $this->issueInstant = Temporal::getTime();
        $this->issuer = '';
        $this->authnInstant = Temporal::getTime();
        $this->attributes = array();
        $this->nameFormat = Constants::NAMEFORMAT_UNSPECIFIED;
        $this->certificates = array();
        $this->AuthenticatingAuthority = array();
        $this->SubjectConfirmation = array();
        if ($xml === null) {
            return;
        }
        if (!$xml->hasAttribute('ID')) {
            throw new \Exception('Missing ID attribute on SAML assertion.');
        }
        $this->id = $xml->getAttribute('ID');
        if ($xml->getAttribute('Version') !== '2.0') {
            /* Currently a very strict check. */
            throw new \Exception('Unsupported version: ' . $xml->getAttribute('Version'));
        }
        $this->issueInstant = Utils::xsDateTimeToTimestamp($xml->getAttribute('IssueInstant'));
        $issuer = Utils::xpQuery($xml, './saml_assertion:Issuer');
        if (empty($issuer)) {
            throw new \Exception('Missing <saml:Issuer> in assertion.');
        }
        $this->issuer = new XML\saml\Issuer($issuer[0]);
        if ($this->issuer->Format === Constants::NAMEID_ENTITY) {
            $this->issuer = $this->issuer->value;
        }
        $this->parseSubject($xml);
        $this->parseConditions($xml);
        $this->parseAuthnStatement($xml);
        $this->parseAttributes($xml);
        $this->parseEncryptedAttributes($xml);
        $this->parseSignature($xml);
    }