CI框架源码阅读---------Input.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 5.1.6 or newer
*
* @package		CodeIgniter
* @author		ExpressionEngine Dev Team
* @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
* @license	 http://codeigniter.com/user_guide/license.html * @link	 http://codeigniter.com * @since		Version 1.0
* @filesource
*/

// ------------------------------------------------------------------------

/**
* Input Class
*
* Pre-processes global input data for security
*
* @package		CodeIgniter
* @subpackage	Libraries
* @category	Input
* @author		ExpressionEngine Dev Team
* @link	 http://codeigniter.com/user_guide/libraries/input.html */
class CI_Input {

/**
* IP address of the current user
* 当前用户的ip地址
* @var string
*/
var $ip_address				= FALSE;
/**
* user agent (web browser) being used by the current user
* 当前用户（web浏览器）代理
* @var string
*/
var $user_agent				= FALSE;
/**
* If FALSE, then $_GET will be set to an empty array
* 如果是FALSE ， $_GET将被设置为空数组
* @var bool
*/
var $_allow_get_array		= TRUE;
/**
* If TRUE, then newlines are standardized
* 如果为TRUR，新行将被标准化
*
* @var bool
*/
var $_standardize_newlines	= TRUE;
/**
* Determines whether the XSS filter is always active when GET, POST or COOKIE data is encountered
* Set automatically based on config setting
* 决定是否总是在GET ,POST , COOKIE数据中进行XSS过滤
* 在配置选项里面配置是否自动开启
*
* @var bool
*/
var $_enable_xss			= FALSE;
/**
* Enables a CSRF cookie token to be set.
* Set automatically based on config setting
* 允许CSRF cookie令牌
*
* @var bool
*/
var $_enable_csrf			= FALSE;
/**
* List of all HTTP request headers
* HTTP请求头部的列表
* @var array
*/
protected $headers			= array();

/**
* Constructor
* 设置是否全局允许XSS处理和是否允许使用$_GET数组
* Sets whether to globally enable the XSS processing
* and whether to allow the $_GET array
*
* @return	void
*/
public function __construct()
{
log_message('debug', "Input Class Initialized");

// 从配置文件中获取是否进行全局允许使用$_GET XSS过滤和csrf保护
$this->_allow_get_array	= (config_item('allow_get_array') === TRUE);
$this->_enable_xss		= (config_item('global_xss_filtering') === TRUE);
$this->_enable_csrf		= (config_item('csrf_protection') === TRUE);

// 清除globals变量，在开启了globals_register的情况下，相当于关闭了此配置。
// 开启一道 安全防护

global $SEC;
$this->security =& $SEC;

// Do we need the UTF-8 class?
if (UTF8_ENABLED === TRUE)
{
global $UNI;
$this->uni =& $UNI;
}

// Sanitize global arrays
$this->_sanitize_globals();
}

// --------------------------------------------------------------------

/**
* Fetch from array
* 从$array获取值，如果设置了xss_clean 那么进行过滤
* This is a helper function to retrieve 检索 values from global arrays
* 这是一个帮助函数用来从全局数组中检索
*
* @access	private
* @param	array
* @param	string
* @param	bool
* @return	string
*/
function _fetch_from_array(&$array, $index = '', $xss_clean = FALSE)
{
if ( ! isset($array[$index]))
{
return FALSE;
}

if ($xss_clean === TRUE)
{
return $this->security->xss_clean($array[$index]);
}

return $array[$index];
}

// --------------------------------------------------------------------

/**
* Fetch an item from the GET array
* 获取过滤后的GET数组
* @access	public
* @param	string
* @param	bool
* @return	string
*/
function get($index = NULL, $xss_clean = FALSE)
{
// Check if a field has been provided
// 检查是否一个字段已经被提供
if ($index === NULL AND ! empty($_GET))
{
$get = array();

// loop through the full _GET array
// 遍历_GET数组
foreach (array_keys($_GET) as $key)
{
$get[$key] = $this->_fetch_from_array($_GET, $key, $xss_clean);
}
return $get;
}

return $this->_fetch_from_array($_GET, $index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from the POST array
* 获取过滤后的$_POST值
* @access	public
* @param	string
* @param	bool
* @return	string
*/
function post($index = NULL, $xss_clean = FALSE)
{
// Check if a field has been provided
if ($index === NULL AND ! empty($_POST))
{
$post = array();

// Loop through the full _POST array and return it
foreach (array_keys($_POST) as $key)
{
$post[$key] = $this->_fetch_from_array($_POST, $key, $xss_clean);
}
return $post;
}

return $this->_fetch_from_array($_POST, $index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from either the GET array or the POST
* 从get和post中获取值， post优先
* @access	public
* @param	string	The index key
* @param	bool	XSS cleaning
* @return	string
*/
function get_post($index = '', $xss_clean = FALSE)
{
if ( ! isset($_POST[$index]) )
{
return $this->get($index, $xss_clean);
}
else
{
return $this->post($index, $xss_clean);
}
}

// --------------------------------------------------------------------

/**
* Fetch an item from the COOKIE array
* 返回过滤后的COOKIE值
* @access	public
* @param	string
* @param	bool
* @return	string
*/
function cookie($index = '', $xss_clean = FALSE)
{
return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
}

// ------------------------------------------------------------------------

/**
* Set cookie
*
* Accepts six parameter, or you can submit an associative
* array in the first parameter containing all the values.
* 接收6个参数或者接收一个关联数组里面包含所有的值
* @access	public
* @param	mixed
* @param	string	the value of the cookie
* @param	string	the number of seconds until expiration
* @param	string	the cookie domain.  Usually:  .yourdomain.com
* @param	string	the cookie path
* @param	string	the cookie prefix
* @param	bool	true makes the cookie secure
* @return	void
*/
function set_cookie($name = '', $value = '', $expire = '', $domain = '', $path = '/', $prefix = '', $secure = FALSE)
{
// 如果第一个值是数组 将数组中的值分别赋值给留个参数
if (is_array($name))
{
// always leave 'name' in last place, as the loop will break otherwise, due to $$item
foreach (array('value', 'expire', 'domain', 'path', 'prefix', 'secure', 'name') as $item)
{
if (isset($name[$item]))
{
$$item = $name[$item];
}
}
}

// 如果某个参数为默认值但是config.php中的配置不是默认值
// 则使用config.php中的配置值
if ($prefix == '' AND config_item('cookie_prefix') != '')
{
$prefix = config_item('cookie_prefix');
}
if ($domain == '' AND config_item('cookie_domain') != '')
{
$domain = config_item('cookie_domain');
}
if ($path == '/' AND config_item('cookie_path') != '/')
{
$path = config_item('cookie_path');
}
if ($secure == FALSE AND config_item('cookie_secure') != FALSE)
{
$secure = config_item('cookie_secure');
}

if ( ! is_numeric($expire))
{
$expire = time() - 86500;
}
else
{
$expire = ($expire > 0) ? time() + $expire : 0;
}

setcookie($prefix.$name, $value, $expire, $path, $domain, $secure);
}

// --------------------------------------------------------------------

/**
* Fetch an item from the SERVER array
* 返回过滤后的$_SERVER值
* @access	public
* @param	string
* @param	bool
* @return	string
*/
function server($index = '', $xss_clean = FALSE)
{
return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch the IP Address
* 返回当前用户的IP。如果IP地址无效，返回0.0.0.0的IP：
* @return	string
*/
public function ip_address()
{
// 如果已经有了ip_address 则返回
if ($this->ip_address !== FALSE)
{
return $this->ip_address;
}

$proxy_ips = config_item('proxy_ips');
if ( ! empty($proxy_ips))
{
$proxy_ips = explode(',', str_replace(' ', '', $proxy_ips));
foreach (array('HTTP_X_FORWARDED_FOR', 'HTTP_CLIENT_IP', 'HTTP_X_CLIENT_IP', 'HTTP_X_CLUSTER_CLIENT_IP') as $header)
{
if (($spoof = $this->server($header)) !== FALSE)
{
// Some proxies typically list the whole chain of IP
// addresses through which the client has reached us.
// e.g. client_ip, proxy_ip1, proxy_ip2, etc.
if (strpos($spoof, ',') !== FALSE)
{
$spoof = explode(',', $spoof, 2);
$spoof = $spoof[0];
}

if ( ! $this->valid_ip($spoof))
{
$spoof = FALSE;
}
else
{
break;
}
}
}

$this->ip_address = ($spoof !== FALSE && in_array($_SERVER['REMOTE_ADDR'], $proxy_ips, TRUE))
? $spoof : $_SERVER['REMOTE_ADDR'];
}
else
{
$this->ip_address = $_SERVER['REMOTE_ADDR'];
}

if ( ! $this->valid_ip($this->ip_address))
{
$this->ip_address = '0.0.0.0';
}

return $this->ip_address;
}

// --------------------------------------------------------------------

/**
* Validate IP Address
* 测试输入的IP地址是不是有效，返回布尔值TRUE或者FALSE。
* 注意：$this->input->ip_address()自动测试输入的IP地址本身格式是不是有效。
* @access	public
* @param	string
* @param	string	ipv4 or ipv6
* @return	bool
*/
public function valid_ip($ip, $which = '')
{
$which = strtolower($which);

// First check if filter_var is available
if (is_callable('filter_var'))
{
switch ($which) {
case 'ipv4':
$flag = FILTER_FLAG_IPV4;
break;
case 'ipv6':
$flag = FILTER_FLAG_IPV6;
break;
default:
$flag = '';
break;
}

return (bool) filter_var($ip, FILTER_VALIDATE_IP, $flag);
}

if ($which !== 'ipv6' && $which !== 'ipv4')
{
if (strpos($ip, ':') !== FALSE)
{
$which = 'ipv6';
}
elseif (strpos($ip, '.') !== FALSE)
{
$which = 'ipv4';
}
else
{
return FALSE;
}
}

$func = '_valid_'.$which;
return $this->$func($ip);
}

// --------------------------------------------------------------------

/**
* Validate IPv4 Address
* 验证ipv4地址
* Updated version suggested by Geert De Deckere
*
* @access	protected
* @param	string
* @return	bool
*/
protected function _valid_ipv4($ip)
{
$ip_segments = explode('.', $ip);

// Always 4 segments needed
if (count($ip_segments) !== 4)
{
return FALSE;
}
// IP can not start with 0
if ($ip_segments[0][0] == '0')
{
return FALSE;
}

// Check each segment
foreach ($ip_segments as $segment)
{
// IP segments must be digits and can not be
// longer than 3 digits or greater then 255
if ($segment == '' OR preg_match("/[^0-9]/", $segment) OR $segment > 255 OR strlen($segment) > 3)
{
return FALSE;
}
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Validate IPv6 Address
* 验证ipv6地址
* @access	protected
* @param	string
* @return	bool
*/
protected function _valid_ipv6($str)
{
// 8 groups, separated by :
// 0-ffff per group
// one set of consecutive 0 groups can be collapsed to ::

$groups = 8;
$collapsed = FALSE;

$chunks = array_filter(
preg_split('/(:{1,2})/', $str, NULL, PREG_SPLIT_DELIM_CAPTURE)
);

// Rule out easy nonsense
if (current($chunks) == ':' OR end($chunks) == ':')
{
return FALSE;
}

// PHP supports IPv4-mapped IPv6 addresses, so we'll expect those as well
if (strpos(end($chunks), '.') !== FALSE)
{
$ipv4 = array_pop($chunks);

if ( ! $this->_valid_ipv4($ipv4))
{
return FALSE;
}

$groups--;
}

while ($seg = array_pop($chunks))
{
if ($seg[0] == ':')
{
if (--$groups == 0)
{
return FALSE;	// too many groups
}

if (strlen($seg) > 2)
{
return FALSE;	// long separator
}

if ($seg == '::')
{
if ($collapsed)
{
return FALSE;	// multiple collapsed
}

$collapsed = TRUE;
}
}
elseif (preg_match("/[^0-9a-f]/i", $seg) OR strlen($seg) > 4)
{
return FALSE; // invalid segment
}
}

return $collapsed OR $groups == 1;
}

// --------------------------------------------------------------------

/**
* User Agent
* 返回当前用户正在使用的浏览器的user agent信息。 如果不能得到数据，返回FALSE。
* 一般user_agent为空的时候被认定为手机访问，或者curl的抓取，或则会蜘蛛抓取
* @access	public
* @return	string
*/
function user_agent()
{
if ($this->user_agent !== FALSE)
{
return $this->user_agent;
}

$this->user_agent = ( ! isset($_SERVER['HTTP_USER_AGENT'])) ? FALSE : $_SERVER['HTTP_USER_AGENT'];

return $this->user_agent;
}

// --------------------------------------------------------------------

/**
* Sanitize Globals
* 清理全局数组
* This function does the following:
* 这个函数做了下面的操作：
* Unsets $_GET data (if query strings are not enabled)
* 销毁$_GET （如果query strings 没有开启）
* Unsets all globals if register_globals is enabled
* 销毁所有全局数组如果register_globals开启
*
* Standardizes newline characters to \n
* 标准化换行符\n
* @access	private
* @return	void
*/
function _sanitize_globals()
{
// It would be "wrong" to unset any of these GLOBALS.
// 销毁下面的全局数组将是错误的。
$protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST',
'_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',
'system_folder', 'application_folder', 'BM', 'EXT',
'CFG', 'URI', 'RTR', 'OUT', 'IN');

// Unset globals for securiy.为了安全销毁除了上面之外的全局数组
// This is effectively the same as register_globals = off
// 这样的效果和register_globals是相同的
// 经过下面处理后，所有的非保护的全局变量将被删除掉

foreach (array($_GET, $_POST, $_COOKIE) as $global)
{
if ( ! is_array($global))
{
if ( ! in_array($global, $protected))
{
global $$global;
$$global = NULL;
}
}
else
{
foreach ($global as $key => $val)
{
if ( ! in_array($key, $protected))
{
global $$key;
$$key = NULL;
}
}
}
}

// Is $_GET data allowed? If not we'll set the $_GET to an empty array
// 是否允许$_GET数据？ 如果不允许的话，设置$_GET为空数组
if ($this->_allow_get_array == FALSE)
{
$_GET = array();
}
else
{
if (is_array($_GET) AND count($_GET) > 0)
{
foreach ($_GET as $key => $val)
{
$_GET[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}
}

// Clean $_POST Data
// 过滤$_POST 数组
if (is_array($_POST) AND count($_POST) > 0)
{
foreach ($_POST as $key => $val)
{
$_POST[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}

// Clean $_COOKIE Data
// 过滤$_COOKIE数组
if (is_array($_COOKIE) AND count($_COOKIE) > 0)
{
// Also get rid of specially treated cookies that might be set by a server
// or silly application, that are of no use to a CI application anyway
// but that when present will trip our 'Disallowed Key Characters' alarm
// http://www.ietf.org/rfc/rfc2109.txt // note that the key names below are single quoted strings, and are not PHP variables
unset($_COOKIE['$Version']);
unset($_COOKIE['$Path']);
unset($_COOKIE['$Domain']);

foreach ($_COOKIE as $key => $val)
{
$_COOKIE[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}

// Sanitize PHP_SELF
$_SERVER['PHP_SELF'] = strip_tags($_SERVER['PHP_SELF']);

// CSRF Protection check on HTTP requests
// ＣＳＲＦ保护检测http请求
if ($this->_enable_csrf == TRUE && ! $this->is_cli_request())
{
$this->security->csrf_verify();
}

log_message('debug', "Global POST and COOKIE data sanitized");
}

// --------------------------------------------------------------------

/**
* Clean Input Data
* 过滤input数据
* This is a helper function. It escapes data and
* standardizes newline characters to \n
*
* @access	private
* @param	string
* @return	string
*/
function _clean_input_data($str)
{
if (is_array($str))
{
$new_array = array();
foreach ($str as $key => $val)
{
$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
return $new_array;
}

/* We strip slashes if magic quotes is on to keep things consistent
如果小于PHP5.4版本，并且get_magic_quotes_gpc开启了，则去掉斜线。
NOTE: In PHP 5.4 get_magic_quotes_gpc() will always return 0 and
it will probably not exist in future versions at all。
注意：在PHP5.4及之后版本，get_magic_quotes_gpc()将总是返回0，
在后续版本中可能会移除该特性
*/
if ( ! is_php('5.4') && get_magic_quotes_gpc())
{
$str = stripslashes($str);
}

// Clean UTF-8 if supported 如果支持清理utf8
if (UTF8_ENABLED === TRUE)
{
$str = $this->uni->clean_string($str);
}

// Remove control characters
$str = remove_invisible_characters($str);

// Should we filter the input data?
if ($this->_enable_xss === TRUE)
{
$str = $this->security->xss_clean($str);
}

// Standardize newlines if needed
if ($this->_standardize_newlines == TRUE)
{
if (strpos($str, "\r") !== FALSE)
{
$str = str_replace(array("\r\n", "\r", "\r\n\n"), PHP_EOL, $str);
}
}

return $str;
}

// --------------------------------------------------------------------

/**
* Clean Keys
* 过滤键值
* This is a helper function. To prevent malicious users
* from trying to exploit keys we make sure that keys are
* only named with alpha-numeric text and a few other items.
*
* @access	private
* @param	string
* @return	string
*/
function _clean_input_keys($str)
{
if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str))
{
exit('Disallowed Key Characters.');
}

// Clean UTF-8 if supported
if (UTF8_ENABLED === TRUE)
{
$str = $this->uni->clean_string($str);
}

return $str;
}

// --------------------------------------------------------------------

/**
* Request Headers
* 返回请求头（header）数组。
* In Apache, you can simply call apache_request_headers(), however for
* people running other webservers the function is undefined.
*
* @param	bool XSS cleaning
*
* @return array
*/
public function request_headers($xss_clean = FALSE)
{
// Look at Apache go!
if (function_exists('apache_request_headers'))
{
$headers = apache_request_headers();
}
else
{
$headers['Content-Type'] = (isset($_SERVER['CONTENT_TYPE'])) ? $_SERVER['CONTENT_TYPE'] : @getenv('CONTENT_TYPE');

foreach ($_SERVER as $key => $val)
{
if (strncmp($key, 'HTTP_', 5) === 0)
{
$headers[substr($key, 5)] = $this->_fetch_from_array($_SERVER, $key, $xss_clean);
}
}
}

// take SOME_HEADER and turn it into Some-Header
foreach ($headers as $key => $val)
{
$key = str_replace('_', ' ', strtolower($key));
$key = str_replace(' ', '-', ucwords($key));

$this->headers[$key] = $val;
}

return $this->headers;
}

// --------------------------------------------------------------------

/**
* Get Request Header
* 返回请求头（request header）数组中某一个元素的值
* Returns the value of a single member of the headers class member
*
* @param 	string		array key for $this->headers
* @param	boolean		XSS Clean or not
* @return 	mixed		FALSE on failure, string on success
*/
public function get_request_header($index, $xss_clean = FALSE)
{
if (empty($this->headers))
{
$this->request_headers();
}

if ( ! isset($this->headers[$index]))
{
return FALSE;
}

if ($xss_clean === TRUE)
{
return $this->security->xss_clean($this->headers[$index]);
}

return $this->headers[$index];
}

// --------------------------------------------------------------------

/**
* Is ajax Request?
* 判断是否为ajax请求
* Test to see if a request contains the HTTP_X_REQUESTED_WITH header
*
* @return 	boolean
*/
public function is_ajax_request()
{
return ($this->server('HTTP_X_REQUESTED_WITH') === 'XMLHttpRequest');
}

// --------------------------------------------------------------------

/**
* Is cli Request?
* 判断是否来自cli请求
* Test to see if a request was made from the command line
*
* @return 	bool
*/
public function is_cli_request()
{
return (php_sapi_name() === 'cli' OR defined('STDIN'));
}

}

/* End of file Input.php */
/* Location: ./system/core/Input.php */