# User Agent Class

The User Agent Class provides functions that help identify information about the browser, mobile device, or robot visiting your site. In addition you can get referrer information as well as language and supported character-set information.

- Using the User Agent Class
  - Initializing the Class
  - User Agent Definitions
  - Example
- Class Reference

## Using the User Agent Class

### Initializing the Class

Like most other classes in CodeIgniter, the User Agent class is initialized in your controller using the $this->load->library function:

    $this->load->library('user_agent');

Once loaded, the object will be available using: `$this->agent`

### User Agent Definitions

The user agent name definitions are located in a config file located at: application/config/user_agents.php. You may add items to the various user agent arrays if needed.

### Example

When the User Agent class is initialized it will attempt to determine whether the user agent browsing your site is a web browser, a mobile device, or a robot. It will also gather the platform information if it is available.

    $this->load->library('user_agent');

    if ($this->agent->is_browser())
    {
            $agent = $this->agent->browser().' '.$this->agent->version();
    }
    elseif ($this->agent->is_robot())
    {
            $agent = $this->agent->robot();
    }
    elseif ($this->agent->is_mobile())
    {
            $agent = $this->agent->mobile();
    }
    else
    {
            $agent = 'Unidentified User Agent';
    }

    echo $agent;

    echo $this->agent->platform(); // Platform info (Windows, Linux, Mac, etc.)

## Class Reference

class `CI_User_agent`
  `is_browser`([$key = NULL])

    Parameters: | $key (string) – Optional browser name
    Returns: | TRUE if the user agent is a (specified) browser, FALSE if not
    Return type: | bool

    Returns TRUE/FALSE (boolean) if the user agent is a known web browser.

        if ($this->agent->is_browser('Safari'))
        {
                echo 'You are using Safari.';
        }
        elseif ($this->agent->is_browser())
        {
                echo 'You are using a browser.';
        }

    Note

    The string “Safari” in this example is an array key in the list of browser definitions. You can find this list in application/config/user_agents.php if you want to add new browsers or change the stings.

  `is_mobile`([$key = NULL])

    Parameters: | $key (string) – Optional mobile device name
    Returns: | TRUE if the user agent is a (specified) mobile device, FALSE if not
    Return type: | bool

    Returns TRUE/FALSE (boolean) if the user agent is a known mobile device.

        if ($this->agent->is_mobile('iphone'))
        {
                $this->load->view('iphone/home');
        }
        elseif ($this->agent->is_mobile())
        {
                $this->load->view('mobile/home');
        }
        else
        {
                $this->load->view('web/home');
        }

  `is_robot`([$key = NULL])

    Parameters: | $key (string) – Optional robot name
    Returns: | TRUE if the user agent is a (specified) robot, FALSE if not
    Return type: | bool

    Returns TRUE/FALSE (boolean) if the user agent is a known robot.

    Note

    The user agent library only contains the most common robot definitions. It is not a complete list of bots. There are hundreds of them so searching for each one would not be very efficient. If you find that some bots that commonly visit your site are missing from the list you can add them to your application/config/user_agents.php file.

  `is_referral`()

    Returns: | TRUE if the user agent is a referral, FALSE if not
    Return type: | bool

    Returns TRUE/FALSE (boolean) if the user agent was referred from another site.

  `browser`()

    Returns: | Detected browser or an empty string
    Return type: | string

    Returns a string containing the name of the web browser viewing your site.

  `version`()

    Returns: | Detected browser version or an empty string
    Return type: | string

    Returns a string containing the version number of the web browser viewing your site.

  `mobile`()

    Returns: | Detected mobile device brand or an empty string
    Return type: | string

    Returns a string containing the name of the mobile device viewing your site.

  `robot`()

    Returns: | Detected robot name or an empty string
    Return type: | string

    Returns a string containing the name of the robot viewing your site.

  `platform`()

    Returns: | Detected operating system or an empty string
    Return type: | string

    Returns a string containing the platform viewing your site (Linux, Windows, OS X, etc.).

  `referrer`()

    Returns: | Detected referrer or an empty string
    Return type: | string

    The referrer, if the user agent was referred from another site. Typically you’ll test for this as follows:

        if ($this->agent->is_referral())
        {
                echo $this->agent->referrer();
        }

  `agent_string`()

    Returns: | Full user agent string or an empty string
    Return type: | string

    Returns a string containing the full user agent string. Typically it will be something like this:

        Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.0.4) Gecko/20060613 Camino/1.0.2

  `accept_lang`([$lang = 'en'])

    Parameters: | $lang (string) – Language key
    Returns: | TRUE if provided language is accepted, FALSE if not
    Return type: | bool

    Lets you determine if the user agent accepts a particular language. Example:

        if ($this->agent->accept_lang('en'))
        {
                echo 'You accept English!';
        }

    Note

    This method is not typically very reliable since some browsers do not provide language info, and even among those that do, it is not always accurate.

  `languages`()

    Returns: | An array list of accepted languages
    Return type: | array

    Returns an array of languages supported by the user agent.

  `accept_charset`([$charset = 'utf-8'])

    Parameters: | $charset (string) – Character set
    Returns: | TRUE if the character set is accepted, FALSE if not
    Return type: | bool

    Lets you determine if the user agent accepts a particular character set. Example:

        if ($this->agent->accept_charset('utf-8'))
        {
                echo 'You browser supports UTF-8!';
        }

    Note

    This method is not typically very reliable since some browsers do not provide character-set info, and even among those that do, it is not always accurate.

  `charsets`()

    Returns: | An array list of accepted character sets
    Return type: | array

    Returns an array of character sets accepted by the user agent.

  `parse`($string)

    Parameters: | $string (string) – A custom user-agent string
    Return type: | void

    Parses a custom user-agent string, different from the one reported by the current visitor.