hi,
i have similar problems like shawn: im requesting a service to return
internet-sources for a specific media-type, e.g. video -> amazon.de,
amazon.com, imdb, ofdb, etc...
then i trigger a service for each source, reading and parsing the
source has a duration from 3-30 seconds so there is no chance to
aggregate checking the sources into one service, after all i want to
display some progress too.
currently the whole logic is already separated out in an object which
requests the services and counts to 0 to check if it has finished and
then calls back a passed delegate.
then some aggregating async functions are called, then components are
updated via events, which async callback to return their state.
i can factor out as much as possible, it keeps being some nasty code
in the controller to glue together these async-callbacks....
theres no exact solution im looking for but some best-practices,
design patterns to glue async-stuff or perhaps some of this weird
javascript function-prototyping-closuring ....
perhaps something like function enqueueing....
function doRequestA
function doRequestB
function doRequestC
function callback
Function.prototype.enqueue(QueueIdentifier)
doRequestA.enqueue('a', callback);
doRequestA.enqueue('a', callback);
doRequestA.enqueue('a', callback);
doRequestB.enqueue('a', callback); // same queue
doRequestC.enqueue('c', callback); // new queue
or a more generic queue-impl
var q = new Queue( function() {
//callback-handler initiating just another queue ...
var q2 = new Queue( function() {
// and on and on and on ...
});
doRequestD.enqueue( q2 ) ...
doRequestD.enqueue( q2 ) ...
doRequestD.enqueue( q2 ) ...
});
} );
doRequestA.enqueue( q ).call( ... )
doRequestB.enqueue( q ).call( ... )
doRequestC.enqueue( q ).call( ... )
but thats not very smart either and leads to exactly the same nested
callback-handling...
thanks for the good answers and remarks so far, appreciate any further
comment.
yours, kai
