在Python和Apache mod_wsgi的全局变量 [英] Global variables in Python and Apache mod_wsgi

问题描述

我知道有存在的框架，但我试图用WSGI直接提高我自己的理解。

I know there are frameworks that exist, but I am trying to use wsgi directly to improve my own understanding.

我有我的WSGI处理程序，并在最顶端我已经声明的变量 I = 0 。

I have my wsgi handler, and up at the top I have declared a variable i = 0.

在我的应用程序（ENVIRON，start_response）功能，我宣布全局I ，然后我增加 I 每当一个按钮为pressed。

In my application(environ, start_response) function, I declare global i, then I increment i whenever a button is pressed.

这是我的理解，这个变量的状态为preserved只要服务器在运行，所以Web应用程序的所有用户看到相同的 I

It is my understanding that the state of this variable is preserved as long as the server is running, so all users of the web app see the same i.

如果我宣布 I 的应用函数内部，那么的值I 复位为0的请求作出的任何时间。

If I declare i inside the application function, then the value of i resets to 0 any time a request is made.

我想知道，你怎么了preserve I 单个用户的请求之间，但又不希望它$不同用户的会话pserved p $？因此，一个用户可以让多个帖子，而 I 将增加，但如果另一个用户访问Web应用程序，他们开始与 I = 0 。

I'm wondering, how do you preserve i between a single user's requests, but not have it preserved across different users' sessions? So, a single user can make multiple posts, and i will increment, but if another user visits the web app, they start with i=0.

我知道你能 I 存储在岗位之间的数据库，但有可能只保留 I 在岗位之间的记忆？

And I know you could store i in a database between posts, but is it possible to just keep i in memory between posts?

推荐答案

Web的应用程序一般都是无共享。在WSGI的背景下，这意味着你不知道有多少次你的应用程序（和它的计数器）将被实例化;这样的选择是到它作为您的应用程序的容器WSGI服务器。

Web-apps are generally "shared-nothing". In the context of WSGI, that means you have no idea how many times your application (and the counter with it) will be instantiated; that choice is up to the WSGI server which acts as your app's container.

如果您希望用户会话的一些概念，你必须明确地实现它，通常在饼干上。如果你要坚持，你需要明确地支持它的组成部分;这可以是一个共享的数据库，也可以背驮式Cookie的会话。

If you want some notion of user sessions, you have to implement it explicitly, typically on top of cookies. If you want persistence, you need a component that explicitly supports it; that can be a shared database, or it can piggy-back on your cookie sessions.

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