關于CI框架中Session.php源碼分析

2020-03-22 19:28:39

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這篇文章主要介紹了關于CI框架中Session.php源碼分析，有著一定的參考價值，現在分享給大家，有需要的朋友可以參考一下

Session類并不使用PHP本身的session，而是使用類自己的session，這樣做，可以給開發者提供更大的彈性。下面我們就來仔細分析下CI框架的Session類Session.php文件

CI的Session并不是原生的session，正是我前面所有的cookie based session,另外，CI可以根據用戶選擇配置是否將session存入數據庫中，本人很喜歡這個功能，還有就是“閃出數據”的功能，既閃出數據只是對下次服務器請求可以，之后就會被自動清除。常見使用方法有：

$this- session- set_userdata( some_name , some_html' target='_blank'>value //設置session數據

$this- session- userdata( item //獲取session數據

$this- session- unset_userdata( some_name //刪除session數據

$this- session- sess_destroy(); //銷毀session數據

$this- session- set_flashdata( item , value //設置閃存數據

$this- session- flashdata( item //獲取閃存數據

$this- session- keep_flashdata( item //保留閃存數據

/** * CI是 session based cookieclass CI_Session { var $sess_encrypt_cookie = FALSE; //是否對session加密 var $sess_use_database = FALSE; //是否將session存入數據庫 var $sess_table_name = //session存入數據的表名 var $sess_expiration = 7200; //session的過期時間 var $sess_expire_on_close = FALSE; //當瀏覽器窗口關閉時是否自動使session過期 var $sess_match_ip = FALSE;//是否通過用戶的IP地址來讀取 session 的數據 var $sess_match_useragent = TRUE; //是否要按照對應的 User Agent 來讀取 session 數據。 var $sess_cookie_name = ci_session //cookie名稱 var $cookie_prefix = //cookie前綴 var $cookie_path = //cookie路徑 var $cookie_domain = //cookie作用域 var $cookie_secure = FALSE; //是否在安全的https協議下才有效 var $sess_time_to_update = 300; //session cookie多久更新一次 var $encryption_key = //加密key var $flashdata_key = flash  var $time_reference = time  var $gc_probability = 5; //回收session的能力 var $userdata = array(); //用戶session數據保存變量 var $CI; //CI超級句柄 var $now; //當前時間 public function __construct($params = array()) log_message( debug , Session Class Initialized  // 獲取CI超級類 $this- CI = get_instance(); // 獲取config文件中的配置數據 foreach (array( sess_encrypt_cookie , sess_use_database , sess_table_name , sess_expiration , sess_expire_on_close , sess_match_ip , sess_match_useragent , sess_cookie_name , cookie_path , cookie_domain , cookie_secure , sess_time_to_update , time_reference , cookie_prefix , encryption_key ) as $key) $this- $key = (isset($params[$key])) ? $params[$key] : $this- CI- config- item($key); //必須設置encryption_key if ($this- encryption_key == ) show_error( In order to use the Session class you are required to set an encryption key in your config file.  // 加載string helper函數 $this- CI- load- helper( string  // D如果對cookie進行加密，則引入加密類 if ($this- sess_encrypt_cookie == TRUE) $this- CI- load- library( encrypt  // 如果session計入數據庫，則引入db if ($this- sess_use_database === TRUE AND $this- sess_table_name != ) $this- CI- load- database(); // 獲取當前時間 $this- now = $this- _get_time(); // 如果沒有設置session的有效時間，默認兩年 if ($this- sess_expiration == 0) $this- sess_expiration = (60*60*24*365*2); // 獲取cookie名稱 $this- sess_cookie_name = $this- cookie_prefix.$this- sess_cookie_name; // 如果session不存在，創建新會話 if ( ! $this- sess_read()) $this- sess_create(); else $this- sess_update(); // 閃出標記old的閃出數據 $this- _flashdata_sweep(); //將新的閃出數據標記成old 標記成old的數據的數據將會在下次請求時閃出 $this- _flashdata_mark(); //回收/刪除 過期的session $this- _sess_gc(); log_message( debug , Session routines successfully run  // -------------------------------------------------------------------- * 讀取session數據 function sess_read() // 獲取session $session = $this- CI- input- cookie($this- sess_cookie_name); // 沒有session 拜拜 if ($session === FALSE) log_message( debug , A session cookie was not found.  return FALSE; // 如果加密了cookie if ($this- sess_encrypt_cookie == TRUE) $session = $this- CI- encrypt- decode($session); else // encryption was not used, so we need to check the md5 hash $hash = substr($session, strlen($session)-32); // get last 32 chars $session = substr($session, 0, strlen($session)-32); // Does the md5 hash match? This is to prevent manipulation of session data in userspace if ($hash !== md5($session.$this- encryption_key)) log_message( error , The session cookie data did not match what was expected. This could be a possible hacking attempt.  $this- sess_destroy(); return FALSE; // 反序列化存入cookie的session數組 $session = $this- _unserialize($session); // 檢測session的數據 if ( ! is_array($session) OR ! isset($session[ session_id ]) OR ! isset($session[ ip_address ]) OR ! isset($session[ user_agent ]) OR ! isset($session[ last_activity ])) $this- sess_destroy(); return FALSE; // session數據過期了嗎 if (($session[ last_activity ] + $this- sess_expiration) $this- now) $this- sess_destroy(); return FALSE; // 是否是根據用戶ip來讀取session數據 if ($this- sess_match_ip == TRUE AND $session[ ip_address ] != $this- CI- input- ip_address()) $this- sess_destroy(); return FALSE; // 是否根據ua來匹配session數據 if ($this- sess_match_useragent == TRUE AND trim($session[ user_agent ]) != trim(substr($this- CI- input- user_agent(), 0, 120))) $this- sess_destroy(); return FALSE; // 如果session入庫了，這種方式應該更安全點，當然負載大時，就不建議了，數據庫讀寫壓力大 if ($this- sess_use_database === TRUE) $this- CI- db- where( session_id , $session[ session_id  if ($this- sess_match_ip == TRUE) $this- CI- db- where( ip_address , $session[ ip_address  if ($this- sess_match_useragent == TRUE) $this- CI- db- where( user_agent , $session[ user_agent  $query = $this- CI- db- get($this- sess_table_name); // No result? Kill it! if ($query- num_rows() == 0) $this- sess_destroy(); return FALSE; // Is there custom data? If so, add it to the main session array $row = $query- row(); if (isset($row- user_data) AND $row- user_data != ) $custom_data = $this- _unserialize($row- user_data); if (is_array($custom_data)) foreach ($custom_data as $key = $val) $session[$key] = $val; // Session is valid! $this- userdata = $session; unset($session); return TRUE; // -------------------------------------------------------------------- * 將讀取的session數據寫入 function sess_write() // 是否寫入db if ($this- sess_use_database === FALSE) $this- _set_cookie(); return; // set the custom userdata, the session data we will set in a second $custom_userdata = $this- userdata; $cookie_userdata = array(); // Before continuing, we need to determine if there is any custom data to deal with. // Let s determine this by removing the default indexes to see if there s anything left in the array // and set the session data while we re at it foreach (array( session_id , ip_address , user_agent , last_activity ) as $val) unset($custom_userdata[$val]); $cookie_userdata[$val] = $this- userdata[$val]; // Did we find any custom data? If not, we turn the empty array into a string // since there s no reason to serialize and store an empty array in the DB if (count($custom_userdata) === 0) $custom_userdata =  else // Serialize the custom data array so we can store it $custom_userdata = $this- _serialize($custom_userdata); // 更新session記錄 $this- CI- db- where( session_id , $this- userdata[ session_id  $this- CI- db- update($this- sess_table_name, array( last_activity = $this- userdata[ last_activity ], user_data = $custom_userdata)); // Write the cookie. Notice that we manually pass the cookie data array to the // _set_cookie() function. Normally that function will store $this- userdata, but // in this case that array contains custom data, which we do not want in the cookie. $this- _set_cookie($cookie_userdata); // -------------------------------------------------------------------- * 創建一個新的session function sess_create() //保證sessid 安全唯一 $sessid =  while (strlen($sessid) 32) $sessid .= mt_rand(0, mt_getrandmax()); $sessid .= $this- CI- input- ip_address(); $this- userdata = array( session_id = md5(uniqid($sessid, TRUE)), ip_address = $this- CI- input- ip_address(), user_agent = substr($this- CI- input- user_agent(), 0, 120), last_activity = $this- now, user_data =  // Save the data to the DB if needed if ($this- sess_use_database === TRUE) $this- CI- db- query($this- CI- db- insert_string($this- sess_table_name, $this- userdata)); // Write the cookie $this- _set_cookie(); // -------------------------------------------------------------------- * 更新session function sess_update() // 默認五分鐘更新 if (($this- userdata[ last_activity ] + $this- sess_time_to_update) = $this- now) return; // Save the old session id so we know which record to // update in the database if we need it $old_sessid = $this- userdata[ session_id  $new_sessid =  while (strlen($new_sessid) 32) $new_sessid .= mt_rand(0, mt_getrandmax()); // To make the session ID even more secure we ll combine it with the user s IP $new_sessid .= $this- CI- input- ip_address(); // Turn it into a hash $new_sessid = md5(uniqid($new_sessid, TRUE)); // Update the session data in the session data array $this- userdata[ session_id ] = $new_sessid; $this- userdata[ last_activity ] = $this-  // _set_cookie() will handle this for us if we aren t using database sessions // by pushing all userdata to the cookie. $cookie_data = NULL; // 更新數據庫中幾率 if ($this- sess_use_database === TRUE) // set cookie explicitly to only have our session data $cookie_data = array(); foreach (array( session_id , ip_address , user_agent , last_activity ) as $val) $cookie_data[$val] = $this- userdata[$val]; $this- CI- db- query($this- CI- db- update_string($this- sess_table_name, array( last_activity = $this- now, session_id = $new_sessid), array( session_id = $old_sessid))); // 重新寫入session $this- _set_cookie($cookie_data); // -------------------------------------------------------------------- *銷毀當前所有session數據 function sess_destroy() // Kill the session DB row if ($this- sess_use_database === TRUE isset($this- userdata[ session_id ])) $this- CI- db- where( session_id , $this- userdata[ session_id  $this- CI- db- delete($this- sess_table_name); // Kill the cookie setcookie( $this- sess_cookie_name, addslashes(serialize(array())), ($this- now - 31500000), $this- cookie_path, $this- cookie_domain, // Kill session data $this- userdata = array(); // -------------------------------------------------------------------- * 獲取session數組指定元素的值 function userdata($item) return ( ! isset($this- userdata[$item])) ? FALSE : $this- userdata[$item]; // -------------------------------------------------------------------- * 獲取所有session數據 function all_userdata() return $this- userdata; // -------------------------------------------------------------------- * 添加和修改自定義的session數據 function set_userdata($newdata = array(), $newval = ) if (is_string($newdata)) $newdata = array($newdata = $newval); //支持數組組合方式 if (count($newdata) 0) foreach ($newdata as $key = $val) $this- userdata[$key] = $val; $this- sess_write(); // -------------------------------------------------------------------- * 刪除session數組中的元素， function unset_userdata($newdata = array()) if (is_string($newdata)) $newdata = array($newdata =  if (count($newdata) 0) foreach ($newdata as $key = $val) unset($this- userdata[$key]); $this- sess_write(); // ------------------------------------------------------------------------ * Add or change flashdata, only available * until the next request * @access public * @param mixed * @param string * @return void function set_flashdata($newdata = array(), $newval = ) if (is_string($newdata)) $newdata = array($newdata = $newval); if (count($newdata) 0) foreach ($newdata as $key = $val) $flashdata_key = $this- flashdata_key. :new: .$key; $this- set_userdata($flashdata_key, $val); // ------------------------------------------------------------------------ * CI支持閃出數據也就是說 Session數據只對下次服務器請求可用,有時候如果你還想在下個請求后的請求還有效。。。 * keep_flashdata功能就是講持續保持閃出數據，使其在下個請求也有效 function keep_flashdata($key) //將閃出數據標記成new $old_flashdata_key = $this- flashdata_key. :old: .$key; $value = $this- userdata($old_flashdata_key); $new_flashdata_key = $this- flashdata_key. :new: .$key; $this- set_userdata($new_flashdata_key, $value); // ------------------------------------------------------------------------ * 獲取閃出數據 function flashdata($key) $flashdata_key = $this- flashdata_key. :old: .$key; return $this- userdata($flashdata_key); // ------------------------------------------------------------------------ * 將閃出數據標記成old，以便_flashdata_sweep清除數據 function _flashdata_mark() $userdata = $this- all_userdata(); foreach ($userdata as $name = $value) $parts = explode( :new: , $name); if (is_array($parts) count($parts) === 2) $new_name = $this- flashdata_key. :old: .$parts[1]; $this- set_userdata($new_name, $value); $this- unset_userdata($name); // ------------------------------------------------------------------------ * 將標記成old的閃出數據閃出 function _flashdata_sweep() $userdata = $this- all_userdata(); foreach ($userdata as $key = $value) if (strpos($key, :old: )) $this- unset_userdata($key); //獲取當前時間 function _get_time() if (strtolower($this- time_reference) == gmt ) $now = time(); $time = mktime(gmdate( H , $now), gmdate( i , $now), gmdate( s , $now), gmdate( m , $now), gmdate( d , $now), gmdate( Y , $now)); else $time = time(); return $time; // -------------------------------------------------------------------- * 寫入session cookie function _set_cookie($cookie_data = NULL) if (is_null($cookie_data)) $cookie_data = $this- userdata; // 序列化數組 $cookie_data = $this- _serialize($cookie_data); //加密數據 if ($this- sess_encrypt_cookie == TRUE) $cookie_data = $this- CI- encrypt- encode($cookie_data); else // if encryption is not used, we provide an md5 hash to prevent userside tampering $cookie_data = $cookie_data.md5($cookie_data.$this- encryption_key); //sess_expire_on_close為TRUE則，瀏覽器關閉，session失效 $expire = ($this- sess_expire_on_close === TRUE) ? 0 : $this- sess_expiration + time(); // Set the cookie setcookie( $this- sess_cookie_name, $cookie_data, $expire, $this- cookie_path, $this- cookie_domain, $this- cookie_secure // -------------------------------------------------------------------- * 序列化數組 function _serialize($data) if (is_array($data)) foreach ($data as $key = $val) if (is_string($val)) $data[$key] = str_replace( // , {{slash}} , $val); else if (is_string($data)) $data = str_replace( // , {{slash}} , $data); return serialize($data); // -------------------------------------------------------------------- * 反序列化數組 function _unserialize($data) $data = @unserialize(strip_slashes($data)); if (is_array($data)) foreach ($data as $key = $val) if (is_string($val)) $data[$key] = str_replace( {{slash}} , // , $val); return $data; return (is_string($data)) ? str_replace( {{slash}} , // , $data) : $data; // -------------------------------------------------------------------- * 回收/刪除數據庫中失效的session信息 function _sess_gc() if ($this- sess_use_database != TRUE) return; srand(time()); if ((rand() % 100) $this- gc_probability) $expire = $this- now - $this- sess_expiration; $this- CI- db- where( last_activity {$expire}  $this- CI- db- delete($this- sess_table_name); log_message( debug , Session garbage collection performed. }

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