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.

* Input Filtering

  * Security Filtering

  * XSS Filtering

* Accessing form data

  * Using POST, GET, COOKIE, or SERVER Data

  * Using the php://input stream

* Class Reference


Input Filtering
===============


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 "PHP_EOL" (\n in UNIX-based OSes,
  \r\n under Windows). This is configurable.


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.

Important:

  The ‘global_xss_filtering’ setting is DEPRECATED and kept solely for
  backwards-compatibility purposes. XSS escaping should be performed
  on *output*, not *input*!


Accessing form data
===================


Using POST, GET, COOKIE, or SERVER Data
---------------------------------------

CodeIgniter comes with 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 main methods are:

* "$this->input->post()"

* "$this->input->get()"

* "$this->input->cookie()"

* "$this->input->server()"


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 read the data
from the **php://input** stream at any time, just by using the
"$raw_input_stream" property:

   $this->input->raw_input_stream;

Additionally if the input stream is form-encoded like $_POST you can
access its values by calling the "input_stream()" method:

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

Similar to other methods such as "get()" and "post()", 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.


Class Reference
===============

class CI_Input

   $raw_input_stream

      Read only property that will return php://input data as is.

      The property can be read multiple times.

   post([$index = NULL[, $xss_clean = NULL]])

      Parameters:
         * **$index** ("mixed") – POST parameter name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         $_POST if no parameters supplied, otherwise the POST value if
         found or NULL if not

      Return type:
         "mixed"

      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 or by setting your
      "$config['global_xss_filtering']" to 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 TRUE.

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

      To return an array of multiple POST parameters, pass all the
      required keys as an array.

         $this->input->post(array('field1', 'field2'));

      Same rule applied here, to retrieve the parameters with XSS
      filtering enabled, set the second parameter to boolean TRUE.

         $this->input->post(array('field1', 'field2'), TRUE);

   get([$index = NULL[, $xss_clean = NULL]])

      Parameters:
         * **$index** ("mixed") – GET parameter name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         $_GET if no parameters supplied, otherwise the GET value if
         found or NULL if not

      Return type:
         "mixed"

      This method is identical to "post()", 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 TRUE.

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

      To return an array of multiple GET parameters, pass all the
      required keys as an array.

         $this->input->get(array('field1', 'field2'));

      Same rule applied here, to retrieve the parameters with XSS
      filtering enabled, set the second parameter to boolean TRUE.

         $this->input->get(array('field1', 'field2'), TRUE);

   post_get($index[, $xss_clean = NULL])

      Parameters:
         * **$index** ("string") – POST/GET parameter name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         POST/GET value if found, NULL if not

      Return type:
         "mixed"

      This method works pretty much the same way as "post()" and
      "get()", only combined. It will search through both POST and GET
      streams for data, looking in POST first, and then in GET:

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

   get_post($index[, $xss_clean = NULL])

      Parameters:
         * **$index** ("string") – GET/POST parameter name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         GET/POST value if found, NULL if not

      Return type:
         "mixed"

      This method works the same way as "post_get()" only it looks for
      GET data first.

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

      Note:

        This method used to act EXACTLY like "post_get()", but it’s
        behavior has changed in CodeIgniter 3.0.

   cookie([$index = NULL[, $xss_clean = NULL]])

      Parameters:
         * **$index** ("mixed") – COOKIE name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         $_COOKIE if no parameters supplied, otherwise the COOKIE
         value if found or NULL if not

      Return type:
         "mixed"

      This method is identical to "post()" and "get()", only it
      fetches cookie data:

         $this->input->cookie('some_cookie');
         $this->input->cookie('some_cookie', TRUE); // with XSS filter

      To return an array of multiple cookie values, pass all the
      required keys as an array.

         $this->input->cookie(array('some_cookie', 'some_cookie2'));

      Note:

        Unlike the Cookie Helper function "get_cookie()", this method
        does NOT prepend your configured "$config['cookie_prefix']"
        value.

   server($index[, $xss_clean = NULL])

      Parameters:
         * **$index** ("mixed") – Value name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         $_SERVER item value if found, NULL if not

      Return type:
         "mixed"

      This method is identical to the "post()", "get()" and "cookie()"
      methods, only it fetches server data ("$_SERVER"):

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

      To return an array of multiple "$_SERVER" values, pass all the
      required keys as an array.

         $this->input->server(array('SERVER_PROTOCOL', 'REQUEST_URI'));

   input_stream([$index = NULL[, $xss_clean = NULL]])

      Parameters:
         * **$index** ("mixed") – Key name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         Input stream array if no parameters supplied, otherwise the
         specified value if found or NULL if not

      Return type:
         "mixed"

      This method is identical to "get()", "post()" and "cookie()",
      only it fetches the *php://input* stream data.

   set_cookie($name = ''[, $value = ''[, $expire = ''[, $domain = ''[, $path = '/'[, $prefix = ''[, $secure = NULL[, $httponly = NULL[, $samesite = NULL]]]]]]]])

      Parameters:
         * **$name** ("mixed") – Cookie name or an array of parameters

         * **$value** ("string") – Cookie value

         * **$expire** ("int") – Cookie expiration time in seconds

         * **$domain** ("string") – Cookie domain

         * **$path** ("string") – Cookie path

         * **$prefix** ("string") – Cookie name prefix

         * **$secure** ("bool") – Whether to only transfer the cookie
           through HTTPS

         * **$httponly** ("bool") – Whether to only make the cookie
           accessible for HTTP requests (no JavaScript)

         * **$samesite** ("string") – SameSite attribute (‘Lax’,
           ‘Strict’, ‘None’)

      Return type:
         "void"

      Sets a cookie containing the values you specify. There are two
      ways to pass information to this method so that a cookie can be
      set: Array Method, and Discrete Parameters:

      **Array Method**

      Using this method, an associative array is passed to the first
      parameter:

         $cookie = array(
                 'name'          => 'The Cookie Name',
                 'value'         => 'The Value',
                 'expire'        => 86500,
                 'domain'        => '.some-domain.com',
                 'path'          => '/',
                 'prefix'        => 'myprefix_',
                 'secure'        => TRUE,
                 'samesite'      => 'Strict'
         );

         $this->input->set_cookie($cookie);

      **Notes**

      Only the name and value are required. To delete a cookie set it
      with the expiration blank.

      The expiration is set in **seconds**, which will be added to the
      current time. Do not include the time, but rather only the
      number of seconds from *now* that you wish the cookie to be
      valid. If the expiration is set to zero the cookie will only
      last as long as the browser is open.

      For site-wide cookies regardless of how your site is requested,
      add your URL to the **domain** starting with a period, like
      this: .your-domain.com

      The path is usually not needed since the method sets a root
      path.

      The prefix is only needed if you need to avoid name collisions
      with other identically named cookies for your server.

      The *httponly* and *secure* flags, when omitted, will default to
      your "$config['cookie_httponly']" and "$config['cookie_secure']"
      settings. The *samesite* parameter can be "'Lax'", "'Strict'" or
      "'None'". If not set, the same-site cookie attribute will
      default to "'Lax'".

      **Discrete Parameters**

      If you prefer, you can set the cookie by passing data using
      individual parameters:

         $this->input->set_cookie($name, $value, $expire, $domain, $path, $prefix, $secure, $samesite);

   ip_address()

      Returns:
         Visitor’s IP address or ‘0.0.0.0’ if not valid

      Return type:
         "string"

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

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

      Important:

        This method takes into account the "$config['proxy_ips']"
        setting and will return the reported HTTP_X_FORWARDED_FOR,
        HTTP_CLIENT_IP, HTTP_X_CLIENT_IP or HTTP_X_CLUSTER_CLIENT_IP
        address for the allowed IP addresses.

   valid_ip($ip[, $which = ''])

      Parameters:
         * **$ip** ("string") – IP address

         * **$which** ("string") – IP protocol (‘ipv4’ or ‘ipv6’)

      Returns:
         TRUE if the address is valid, FALSE if not

      Return type:
         "bool"

      Takes an IP address as input and returns TRUE or FALSE (boolean)
      depending on whether 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.

   user_agent([$xss_clean = NULL])

      Returns:
         User agent string or NULL if not set

      Parameters:
         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Return type:
         "mixed"

      Returns the user agent string (web browser) being used by the
      current user, or NULL 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.

   request_headers([$xss_clean = FALSE])

      Parameters:
         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         An array of HTTP request headers

      Return type:
         "array"

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

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

   get_request_header($index[, $xss_clean = FALSE])

      Parameters:
         * **$index** ("string") – HTTP request header name

         * **$xss_clean** ("bool") – Whether to apply XSS filtering

      Returns:
         An HTTP request header or NULL if not found

      Return type:
         "string"

      Returns a single member of the request headers array or NULL if
      the searched header is not found.

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

   is_ajax_request()

      Returns:
         TRUE if it is an Ajax request, FALSE if not

      Return type:
         "bool"

      Checks to see if the HTTP_X_REQUESTED_WITH server header has
      been set, and returns boolean TRUE if it is or FALSE if not.

   is_cli_request()

      Returns:
         TRUE if it is a CLI request, FALSE if not

      Return type:
         "bool"

      Checks to see if the application was run from the command-line
      interface.

      Note:

        This method checks both the PHP SAPI name currently in use and
        if the "STDIN" constant is defined, which is usually a
        failsafe way to see if PHP is being run via the command line.

         $this->input->is_cli_request()

      Note:

        This method is DEPRECATED and is now just an alias for the
        "is_cli()" function.

   method([$upper = FALSE])

      Parameters:
         * **$upper** ("bool") – Whether to return the request method
           name in upper or lower case

      Returns:
         HTTP request method

      Return type:
         "string"

      Returns the "$_SERVER['REQUEST_METHOD']", with the option to set
      it in uppercase or lowercase.

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