[Twisted-Python] getting all results from DeferredList

[Pet]

On Wed, Jun 30, 2010 at 8:42 PM,  <exarkun at twistedmatrix.com> wrote:
> On 02:41 pm, petshmidt at googlemail.com wrote:
>>Hello,
>>
>>I'm trying to process results from several Deferreds (d1, d2) with
>>DeferredList, merging it into one list and sending back to client.
>
> You might like twisted.internet.defer.gatherResults.
>>
>>While merging works, the client has no results. What is the way to do
>>tasks (db queries in my case) in parallel and then merge results?

I mean, running functions which performs db queries asynchronously and
then merge results

>
> I don't think I understand this part of the question.
>>BTW, are nested runInteraction ok?
>
> Not really.  Twisted APIs are almost all required to be invoked in the
> reactor thread.  Nested runInteraction calls would mean calling
> runInteraction in some other thread, and that's not allowed.


That is why it not worked. I should redesign my application.

Thanks!

>
> Jean-Paul
>>Thanks for help!
>>Pet
>>
>>
>>class Test:
>>    def __init__(self, cursor):
>>        self.cursor = cursor
>>
>>    def test(db, params):
>>        if params.get('query'):
>>            params['q'] = self.someFunc3(db, params)
>>
>>        def processResults(results, out):
>>            #merge results into one
>>            for _, r in results:
>>                out.extend(r)
>>            return out
>>
>>        out = []
>>        d1 = self.cursor.runInteraction(self.someFunc, params)
>>        d2 = self.cursor.runInteraction(self.someFunc2, params)
>>        d = DeferredList([d1,d2])
>>        d.addCallback(processResults, out)
>>        d.addErrback(log.err)
>>        return d
>>
>>class XMLRPCProtokoll(xmlrpc.XMLRPC):
>>    def __init__(self):
>>        self.db = adbapi.ConnectionPool()
>>        xmlrpc.XMLRPC.__init__(self, True)
>>
>>    def xmlrpc_test(self, param):
>>        t = Test(self.db)
>>        return self.db.runInteraction(t.test, param)
>>
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>
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