|
|
|
@ -5,12 +5,15 @@ The Application Context
|
|
|
|
|
|
|
|
|
|
.. versionadded:: 0.9 |
|
|
|
|
|
|
|
|
|
One of the design ideas behind Flask is that there are two different |
|
|
|
|
“states” in which code is executed. The application setup state in which |
|
|
|
|
the application implicitly is on the module level. It starts when the |
|
|
|
|
:class:`Flask` object is instantiated, and it implicitly ends when the |
|
|
|
|
first request comes in. While the application is in this state a few |
|
|
|
|
assumptions are true: |
|
|
|
|
One of the design ideas behind Flask is that there are at least two |
|
|
|
|
different “states” in which code is executed: |
|
|
|
|
|
|
|
|
|
1. The application setup state, in which the application implicitly is |
|
|
|
|
on the module level. |
|
|
|
|
|
|
|
|
|
This state starts when the :class:`Flask` object is instantiated, and |
|
|
|
|
it implicitly ends when the first request comes in. While the |
|
|
|
|
application is in this state, a few assumptions are true: |
|
|
|
|
|
|
|
|
|
- the programmer can modify the application object safely. |
|
|
|
|
- no request handling happened so far |
|
|
|
@ -18,18 +21,21 @@ assumptions are true:
|
|
|
|
|
modify it, there is no magic proxy that can give you a reference to |
|
|
|
|
the application object you're currently creating or modifying. |
|
|
|
|
|
|
|
|
|
In contrast, during request handling, a couple of other rules exist: |
|
|
|
|
2. In contrast, in the request handling state, a couple of other rules |
|
|
|
|
exist: |
|
|
|
|
|
|
|
|
|
- while a request is active, the context local objects |
|
|
|
|
(:data:`flask.request` and others) point to the current request. |
|
|
|
|
- any code can get hold of these objects at any time. |
|
|
|
|
|
|
|
|
|
There is a third state which is sitting in between a little bit. |
|
|
|
|
3. There is also a third state somewhere in between 'module-level' and |
|
|
|
|
'request-handling': |
|
|
|
|
|
|
|
|
|
Sometimes you are dealing with an application in a way that is similar to |
|
|
|
|
how you interact with applications during request handling; just that there |
|
|
|
|
is no request active. Consider, for instance, that you're sitting in an |
|
|
|
|
interactive Python shell and interacting with the application, or a |
|
|
|
|
command line application. |
|
|
|
|
how you interact with applications during request handling, but without |
|
|
|
|
there being an active request. Consider, for instance, that you're |
|
|
|
|
sitting in an interactive Python shell and interacting with the |
|
|
|
|
application, or a command line application. |
|
|
|
|
|
|
|
|
|
The application context is what powers the :data:`~flask.current_app` |
|
|
|
|
context local. |
|
|
|
|