ParamsReturnRelatedSource
Provides a simple syntax for making assertions about the properties of a request. By default, the `Request` object is configured with several different types of assertions, which are individually known as _detectors_. Detectors are invoked by calling the `is()` and passing the name of the detector flag, i.e. `$request->is('<name>')`, which returns `true` or `false`, depending on whether or not the the properties (usually headers or data) contained in the request match the detector. The default detectors include the following:
- `'mobile'`: Uses a regular expression to match common mobile browser user agents. - `'ajax'`: Checks to see if the `X-Requested-With` header is present, and matches the value `'XMLHttpRequest'`. - `'flash'`: Checks to see if the user agent is `'Shockwave Flash'`. - `'ssl'`: Verifies that the request is SSL-secured. - `'get'` / `'post'` / `'put'` / `'delete'` / `'head'` / `'options'`: Checks that the HTTP request method matches the one specified. In addition to the above, this method also accepts media type names (see `Media::type()`) to make assertions against the format of the request body (for POST or PUT requests), i.e. `$request->is('json')`. This will return `true` if the client has made a POST request with JSON data. For information about adding custom detectors or overriding the ones in the core, see the `detect()` method. While these detectors are useful in controllers or other similar contexts, they're also useful when performing _content negotiation_, which is the process of modifying the response format to suit the client (see the `'conditions'` field of the `$options` parameter in `Media::type()`).

Parameters

  • string $flag The name of the flag to check, which should be the name of a valid detector (that is either built-in or defined with `detect()`).

Returns

boolean Returns `true` if the detector check succeeds (see the details for the built-in detectors above, or `detect()`), otherwise `false`.

Source

						public function is($flag) {
		$media = $this->_classes['media'];

		if (!isset($this->_detectors[$flag])) {
			if (!in_array($flag, $media::types())) {
				return false;
			}
			return $this->type() == $flag;
		}
		$detector = $this->_detectors[$flag];

		if (!is_array($detector) && is_callable($detector)) {
			return $detector($this);
		}
		if (!is_array($detector)) {
			return (boolean) $this->env($detector);
		}
		list($key, $check) = $detector + array('', '');

		if (is_array($check)) {
			$check = '/' . join('|', $check) . '/i';
		}
		if (Validator::isRegex($check)) {
			return (boolean) preg_match($check, $this->env($key));
		}
		return ($this->env($key) == $check);
	}