[Twisted-Python] How to use AmpList?

[Vlad Shevchenko]

Thank you, it helps a lot. I've made a mistake in calling callRemote.

On Mon, Mar 29, 2010 at 4:51 PM, Peter Westlake <peter.westlake at pobox.com>wrote:

>
>
> On Mon, 29 Mar 2010 14:54 +0300, "Vlad Shevchenko"
> <vlad.shevchenko at gmail.com> wrote:
> > No one use AmpList?
> >
> > On Sat, Mar 27, 2010 at 11:45 PM, Vlad Shevchenko
> > <vlad.shevchenko at gmail.com
> > > wrote:
> >
> > > Hi,
> > > can't find any reference of how to use AmpList. What should be passed
> to
> > > callRemote? In command: arguments = Amp.List(...) or arguments =
> [('param',
> > > AmpList(...))]? Responder params?
> > >
> > > Please, advice some refs or examples.
>
> Here's an example. I've missed out the other arguments for clarity. The
> data being passed is a Unix-style environment string. It needs to be
> reformatted to make it suitable for passing in an AmpList, but that's
> just an implementation detail. It's because the AmpList requires the
> dictionary keys to be declared in advance, but I want to be able to pass
> environment variables whose names are only known at run-time. Your code
> might not need to do any of that.
>
> First, the command:
>
>  class RunCmd(amp.Command):
>      arguments = [...,
>                   ('env',  amp.AmpList([('var', amp.String()), ('val',
>                   amp.String())])),
>                   ...]
>
>
> Then the call:
>
>          # env is something like {'PATH': '/bin:/usr/bin', 'HOME':
>          '/home/peter'}
>          # It needs to be converted into a form suitable for AmpList,
>          like this:
>          # [{'var': 'PATH', 'val': '/bin:/usr/bin'}, {'var': 'HOME',
>          'val': '/home/peter'}]
>          #
>          amp_env  = [{'var': var, 'val': val} for (var, val) in
>          env.items()]
>          d = self.protocol.callRemote(commands.RunCmd, ...,
>          env=amp_env, ...)
>
>
> Then the responder:
>
>    def runcmd(..., env, ..):
>        """Implementation of the AMP command RunCmd.
>        ...
>        """
>
>        # The "env" argument represents the environment of a process.
>        # Convert it from the AmpList format back to a Python
>        dictionary.
>        #
>        envd = {}
>        for var in env:
>            envd[var['var']] = var['val']
>        ...
>        return {...}
>
>    commands.RunCmd.responder(runcmd)
>
>
> Peter.
>
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-- 
WBR, Vlad Shevchenko
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