[Twisted-Python] How can I change the default behaviour?

[Bob Ippolito]

On May 8, 2005, at 10:01 PM, Leslie Huyan wrote:

>    I encountered one problem to dig into twisted.
>    If I have 2 methods in the call back chain, however I don't want  
> the result of the first one to pass to the second one as its  
> arguments, what should I do?
>    For example:
>    defer.addCallbacks(request.write, html)
>    defer.addCallbacks(request.setHeader, key, value)

The solution to this problem is to write a callback that does what  
you need to do and attach that to the deferred:

def doStuff(result):
     request.write(html)
     request.setHeader(key, value)
     return result
defer.addCallback(doStuff)

By the way, your example is not going to work (at all) because the  
method you want is "addCallback" and the first argument passed to the  
callback is going to be the deferred result.  request.write(result,  
html) and request.setHeader(result, key, value) aren't going to do  
what you want.

-bob