Application processors, hooks

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Problem

How to use application processors, loadhooks and unload hooks?

Solution

web.py application allows adding processors which can do some processing before and after executing the requests

def my_processor(handler):
    print 'before handling'
    result = handler()
    print 'after handling'
    return result

app.add_processor(my_processor)

Load hooks and unload hooks can be used to do actions at begining and end of requests.

def my_loadhook():
    print "my load hook"

def my_unloadhook():
    print "my unload hook"

app.add_processor(web.loadhook(my_loadhook))
app.add_processor(web.unloadhook(my_unloadhook))

you can write or use global variables in hook function, for example: web.header()

def my_loadhook():
    web.header('Content-type', "text/html; charset=utf-8")

app.add_processor(web.loadhook(my_loadhook))

###Tip: and also can use web.ctx or web.input() in hook.

def my_loadhook():
    input = web.input()
    print input