REST_Controller::_detect_output_format PHP Метод

    protected function _detect_output_format()
    {
        // Concatenate formats to a regex pattern e.g. \.(csv|json|xml)
        $pattern = '/\\.(' . implode('|', array_keys($this->_supported_formats)) . ')($|\\/)/';
        $matches = [];
        // Check if a file extension is used e.g. http://example.com/api/index.json?param1=param2
        if (preg_match($pattern, $this->uri->uri_string(), $matches)) {
            return $matches[1];
        }
        // Get the format parameter named as 'format'
        if (isset($this->_get_args['format'])) {
            $format = strtolower($this->_get_args['format']);
            if (isset($this->_supported_formats[$format]) === TRUE) {
                return $format;
            }
        }
        // Get the HTTP_ACCEPT server variable
        $http_accept = $this->input->server('HTTP_ACCEPT');
        // Otherwise, check the HTTP_ACCEPT server variable
        if ($this->config->item('rest_ignore_http_accept') === FALSE && $http_accept !== NULL) {
            // Check all formats against the HTTP_ACCEPT header
            foreach (array_keys($this->_supported_formats) as $format) {
                // Has this format been requested?
                if (strpos($http_accept, $format) !== FALSE) {
                    if ($format !== 'html' && $format !== 'xml') {
                        // If not HTML or XML assume it's correct
                        return $format;
                    } elseif ($format === 'html' && strpos($http_accept, 'xml') === FALSE) {
                        // HTML or XML have shown up as a match
                        // If it is truly HTML, it wont want any XML
                        return $format;
                    } else {
                        if ($format === 'xml' && strpos($http_accept, 'html') === FALSE) {
                            // If it is truly XML, it wont want any HTML
                            return $format;
                        }
                    }
                }
            }
        }
        // Check if the controller has a default format
        if (empty($this->rest_format) === FALSE) {
            return $this->rest_format;
        }
        // Obtain the default format from the configuration
        return $this->_get_default_output_format();
    }