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CodeIgniter

3.0-dev User Guide

Input Class

The Input Class serves two purposes:

  1. It pre-processes global input data for security.
  2. It provides some helper methods for fetching input data and pre-processing it.

Note

This class is initialized automatically by the system so there is no need to do it manually.

Security Filtering

The security filtering method is called automatically when a new controller is invoked. It does the following:

  • If $config[‘allow_get_array’] is FALSE (default is TRUE), destroys the global GET array.
  • Destroys all global variables in the event register_globals is turned on.
  • Filters the GET/POST/COOKIE array keys, permitting only alpha-numeric (and a few other) characters.
  • Provides XSS (Cross-site Scripting Hacks) filtering. This can be enabled globally, or upon request.
  • Standardizes newline characters to \n(In Windows \r\n)

XSS Filtering

The Input class has the ability to filter input automatically to prevent cross-site scripting attacks. If you want the filter to run automatically every time it encounters POST or COOKIE data you can enable it by opening your application/config/config.php file and setting this:

$config['global_xss_filtering'] = TRUE;

Please refer to the Security class documentation for information on using XSS Filtering in your application.

Using POST, GET, COOKIE, or SERVER Data

CodeIgniter comes with four helper methods that let you fetch POST, GET, COOKIE or SERVER items. The main advantage of using the provided methods rather than fetching an item directly ($_POST['something']) is that the methods will check to see if the item is set and return NULL if not. This lets you conveniently use data without having to test whether an item exists first. In other words, normally you might do something like this:

$something = isset($_POST['something']) ? $_POST['something'] : NULL;

With CodeIgniter’s built in methods you can simply do this:

$something = $this->input->post('something');

The four methods are:

  • $this->input->post()
  • $this->input->get()
  • $this->input->cookie()
  • $this->input->server()

$this->input->post()

The first parameter will contain the name of the POST item you are looking for:

$this->input->post('some_data');

The method returns NULL if the item you are attempting to retrieve does not exist.

The second optional parameter lets you run the data through the XSS filter. It’s enabled by setting the second parameter to boolean TRUE;

$this->input->post('some_data', TRUE);

To return an array of all POST items call without any parameters.

To return all POST items and pass them through the XSS filter set the first parameter NULL while setting the second parameter to boolean;

The method returns NULL if there are no items in the POST.

$this->input->post(NULL, TRUE); // returns all POST items with XSS filter
$this->input->post(); // returns all POST items without XSS filter

$this->input->get()

This method is identical to the post method, only it fetches get data

$this->input->get('some_data', TRUE);

To return an array of all GET items call without any parameters.

To return all GET items and pass them through the XSS filter set the first parameter NULL while setting the second parameter to boolean;

The method returns NULL if there are no items in the GET.

$this->input->get(NULL, TRUE); // returns all GET items with XSS filter
$this->input->get(); // returns all GET items without XSS filtering

$this->input->get_post()

This method will search through both the post and get streams for data, looking first in post, and then in get:

$this->input->get_post('some_data', TRUE);

$this->input->server()

This method is identical to the above methods, only it fetches server server data:

$this->input->server('some_data');

Using the php://input stream

If you want to utilize the PUT, DELETE, PATCH or other exotic request methods, they can only be accessed via a special input stream, that can only be read once. This isn’t as easy as just reading from e.g. the $_POST array, because it will always exist and you can try and access multiple variables without caring that you might only have one shot at all of the POST data.

CodeIgniter will take care of that for you, and you can access data from the php://input stream at any time, just by calling the input_stream() method:

$this->input->input_stream('key');

Similar to the methods above, if the requested data is not found, it will return NULL and you can also decide whether to run the data through xss_clean() by passing a boolean value as the second parameter:

$this->input->input_stream('key', TRUE); // XSS Clean
$this->input->input_stream('key', FALSE); // No XSS filter

Note

You can utilize method() in order to know if you’re reading PUT, DELETE or PATCH data.

$this->input->ip_address()

Returns the IP address for the current user. If the IP address is not valid, the method will return an IP of: 0.0.0.0

echo $this->input->ip_address();

$this->input->valid_ip($ip)

Takes an IP address as input and returns TRUE or FALSE (boolean) if it is valid or not.

Note

The $this->input->ip_address() method above automatically validates the IP address.

if ( ! $this->input->valid_ip($ip))
{
     echo 'Not Valid';
}
else
{
     echo 'Valid';
}

Accepts an optional second string parameter of ‘ipv4’ or ‘ipv6’ to specify an IP format. The default checks for both formats.

$this->input->user_agent()

Returns the user agent (web browser) being used by the current user. Returns FALSE if it’s not available.

echo $this->input->user_agent();

See the User Agent Class for methods which extract information from the user agent string.

$this->input->request_headers()

Useful if running in a non-Apache environment where apache_request_headers() will not be supported. Returns an array of headers.

$headers = $this->input->request_headers();

$this->input->get_request_header()

Returns a single member of the request headers array.

$this->input->get_request_header('some-header', TRUE);

$this->input->is_ajax_request()

Checks to see if the HTTP_X_REQUESTED_WITH server header has been set, and returns a boolean response.

$this->input->is_cli_request()

Checks to see if the STDIN constant is set, which is a failsafe way to see if PHP is being run on the command line.

$this->input->is_cli_request()

$this->input->method()

Returns the $_SERVER[‘REQUEST_METHOD’], optional set uppercase or lowercase (default lowercase).

echo $this->input->method(TRUE); // Outputs: POST
echo $this->input->method(FALSE); // Outputs: post
echo $this->input->method(); // Outputs: post