On Mon, Jan 16, 2012 at 1:54 PM, <[email protected]> wrote: > On 14 Jan, 09:30 am, [email protected] wrote: > >I have been looking at JPCalderones example of using web.request with > >JSON > >which seems much like what I want. > > > >One thing I am not clear about is if I get a lot of queries coming in > >more > >or less simultaneously and I am using cooperate to allow other > >functions to > >run, will I need to guard against my data in a list being overwritten > >by > >subsequent requests. > > > >The way I see it the functions to read data and and store it in my list > >are > >in danger of impacting each other. > > > >The response is being built cooperatively bit by bit to permit other > >functions to run so it could happen that the next request overwrites my > >list where the database query is being stored. > > Any time you have shared mutable state, you have this possibility. You > do need to take measures to avoid making one request destroy the state > associated with another request. > >If this is a danger, then I need to prevent this, which seems to imply > >that > >I will need to block each request and not service another request until > >the > >previous one has completed. > > Serializing (ie, not processing a second request until the first is > completed) processing is one way to accomplish this. > > However, another way to accomplish it is to not have shared mutable > state. A quick skim of your code suggests you don't actually have much, > if any, shared mutable state. > > The list holding your database results is a local variable, and each > request builds its own (as far as I can tell). There is no danger of > different requests interfering with each other in this case. > > Jean-Paul > > _______________________________________________ > Twisted-web mailing list > [email protected] > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-web > Thanks for the reply.
I think I must have been asleep when I asked this. Someone else pointed this out to me earlier on but I did not have time to get to a computer before you replied. Thanks anyway. I shall glue this to me screen for the next week or so. John Aherne
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