我对PHP会话的理解正确吗? [英] Is my understanding of PHP sessions correct?
问题描述
我一直对会话在内部的工作方式很感兴趣，但是我对C的知识很少(并且不确定在PHP源代码中的位置).
I've been interested in how sessions work internally, but I have little knowledge of C (and am unsure where to look in the PHP source for this).
这是我目前对会话的了解:
This is what I understand of sessions at the moment:
- 启动会话时，会为用户分配一个存储在cookie中的会话ID.
- 保存会话数据(通过
$_SESSION)时，会将其与相关的会话ID和到期时间一起存储在文件系统中.
- When you start a session the user gets assigned a session id which is stored in a cookie.
- When session data is saved (via
$_SESSION) it is stored on the filesystem, with the relevant session id and an expiry time.
这是正确的吗?另外，创建会话ID的方法是什么?我认为这是基于时间的，但是如果两个用户同时发送请求该怎么办?内部有哪些方法可以防止它们获得相同的ID?
Is this correct? Also what is the method in which session id are created? I assume it's based on time but what if two users send a request at the same time? What methods are in place internally to prevent them getting the same id?
谢谢
推荐答案
我对内部会话处理过程的了解如下:
My understanding is of the internal session handling process is the following:
当调用 session_start 时，PHP会从客户端中查找通过POST发送的参数， GET或Cookie(取决于配置；请参见 session.use_cookies ， session.use_only_cookies 和
When session_start is called, PHP is looking for a parameter from the client that was sent via POST, GET, or in a cookie (depending on the configuration; see session.use_cookies, session.use_only_cookies, and session.use_trans_sid) with the name of the value of session.name to use the session ID of an already started session.
如果找到有效的会话ID，它将尝试从存储中检索会话数据(请参阅
If it finds a valid session ID, it tries to retrieve the session data from the storage (see session.save_handler) to load the data into $_SESSION. If it can’t find an ID or its usage is forbidden, PHP generates a new ID using a hash function (see session.hash_function) on data of a source that generates random data (see session.entropy_file).
在运行时结束时或调用 session_write_close 时，$_SESSION中的会话数据为存放到指定的存储器中.
At the end of the runtime or when session_write_close is called, the session data in $_SESSION is stored away into the designated storage.
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