php session的一些理解

淡淡的烟草味﹌ 2022-05-22 09:18 256阅读 0赞

Session储存在服务器端，根据客户端提供的SessionID来得到这个用户的文件，然后读取文件，取得变量的值，  
SessionID可以使用客户端的Cookie或者Http1.1协议的Query\_String（就是访问的URL的“?”后面的部分）来传送给服务器，然后服务器读取Session的目录  
  
1. session在php.ini配置里的一些默认信息  
\[Session\]  
; Handler used to store/retrieve data.  
session.save\_handler = files  
  
  
; Argument passed to save\_handler. In the case of files, this is the path  
; where data files are stored. Note: Windows users have to change this  
; variable in order to use PHP's session functions.  
session.save\_path = G:\\MYOA\\tmp //默认储存路径  
  
  
; Whether to use cookies.  
session.use\_cookies = 1  
  
  
;session.cookie\_secure =  
  
  
; This option enables administrators to make their users invulnerable to  
; attacks which involve passing session ids in URLs; defaults to 0.  
; session.use\_only\_cookies = 1  
  
  
; Name of the session (used as cookie name).  
session.name = PHPSESSID  
  
  
; Initialize session on request startup.  
session.auto\_start = 0  
  
  
; Lifetime in seconds of cookie or, if 0, until browser is restarted.  
session.cookie\_lifetime = 0  
  
  
; The path for which the cookie is valid.  
session.cookie\_path = /  
  
  
; The domain for which the cookie is valid.  
session.cookie\_domain =  
  
  
; Whether or not to add the httpOnly flag to the cookie, which makes it inaccessible to browser scripting languages such as JavaScript.  
session.cookie\_httponly =  
  
  
; Handler used to serialize data. php is the standard serializer of PHP.  
session.serialize\_handler = php  
  
  
; Define the probability that the 'garbage collection' process is started  
; on every session initialization.  
; The probability is calculated by using gc\_probability/gc\_divisor,  
; e.g. 1/100 means there is a 1% chance that the GC process starts  
; on each request.  
  
  
session.gc\_probability = 1  
session.gc\_divisor = 100  
  
  
; After this number of seconds, stored data will be seen as 'garbage' and  
; cleaned up by the garbage collection process.  
session.gc\_maxlifetime = 36000  
  
  
; PHP 4.2 and less have an undocumented feature/bug that allows you to  
; to initialize a session variable in the global scope, albeit register\_globals  
; is disabled. PHP 4.3 and later will warn you, if this feature is used.  
; You can disable the feature and the warning seperately. At this time,  
; the warning is only displayed, if bug\_compat\_42 is enabled.  
  
  
session.bug\_compat\_42 = 0  
session.bug\_compat\_warn = 1  
  
  
; Check HTTP Referer to invalidate externally stored URLs containing ids.  
; HTTP\_REFERER has to contain this substring for the session to be  
; considered as valid.  
session.referer\_check =  
  
  
; How many bytes to read from the file.  
session.entropy\_length = 0  
  
  
; Specified here to create the session id.  
session.entropy\_file =  
  
  
;session.entropy\_length = 16  
  
  
;session.entropy\_file = /dev/urandom  
  
  
; Set to \{nocache,private,public,\} to determine HTTP caching aspects.  
; or leave this empty to avoid sending anti-caching headers.  
session.cache\_limiter = nocache  
  
  
; Document expires after n minutes.  
session.cache\_expire = 180  
  
  
; trans sid support is disabled by default.  
; Use of trans sid may risk your users security.  
; Use this option with caution.  
; - User may send URL contains active session ID  
; to other person via. email/irc/etc.  
; - URL that contains active session ID may be stored  
; in publically accessible computer.  
; - User may access your site with the same session ID  
; always using URL stored in browser's history or bookmarks.  
session.use\_trans\_sid = 0  
  
  
2. session保存的默认路径在php.ini里可以查找到  
session.save\_path = G:\\MYOA\\tmp  
  
  
3. 如果session有另外的储存模式的话,比如说:储存在memcache的服务器里,这里默认路径就不启作用了.  
  
  
4. 如果保存时不成功,session则会丢失, 比如说:保存在memcahe里,但是php.ini里没有配置php\_memcache.dll组件  
  
  
5. 如果session储存在memcache服务器里,某个文件要引用session,文件头要引用保存的session路径  
  
  
6. session.use\_cookies：默认的值是“1”， 代表SessionID使用Cookie来传递，反之就是使用Query\_String来传递；  
 session.name：这个就是SessionID储存的变量名称，可能是Cookie，也可能是Query\_String来传递，默认值是“PHPSESSID”；   
 session.cookie\_lifetime：这个代表SessionID在客户端Cookie储存的时间，默认是0，代表浏览器一关闭SessionID就作废……就是因为这个所以Session不能永久使用！   
session.gc\_maxlifetime：这个是Session数据在服务器端储存的时间，如果超过这个时间，那么Session数据就自动删除！  
  
  
7. 永久保存session的方法:  
a. session.gc\_maxlifetime=999999999 无穷大  
session.cookie\_lifetime = 99999999 无穷大  
session.save\_path = G:\\MYOA\\tmp  
每一个文件单一设置保存目录(php工作机制)  
 在超过gc\_maxlifetime后,消除session  
  
  
b. session\_start();  
ini\_set('session.save\_path','/tmp/');  
//6个钟头  
ini\_set('session.gc\_maxlifetime',21600);  
 //保存一天  
$lifeTime = 24 \* 3600;  
setcookie(session\_name(), session\_id(), time() + $lifeTime, "/");