I found a somewhat simple pattern that seems to work for me:
function processSequential(r, processFn) {
function getNext() {
var res = r.read();
if (res)
processFn(res, getNext);
else
r.once('readable', getNext);
}
getNext();
}
And calling it:
processSequential(r, function(buf, cb) {
// do stuff
cb();
});
I'm thinking about putting this into an npm module.
On 02/07/2013, at 11.38, Gil Pedersen <[email protected]> wrote:
> Thanks, this looks like a somewhat interesting pattern. Looking at it, things
> quickly get complicated:
>
> I need to loop, so I'll wrap it in a method, calling it recursively.
> I don't want to call doAsync when bytes === null.
> I can't "kick" when bytes === null, since I get an infinite recursive loop.
> Depending on internal stream state, kicking will not always trigger a
> 'readable' emit, leading to a stall.
>
> I really wish this was simpler :-/
>
> On 02/07/2013, at 09.28, Floby <[email protected]> wrote:
>
>> I'd use some kind of withReadable(stream, fn) helper
>>
>> var bytes = stream.read(2);
>> doAsync(bytes, function(err, res) {
>> withReadable(stream, function () {
>> // stream is readable for sure
>> });
>> });
>>
>> function withReadable(stream, callback) {
>> stream.once(callback);
>> stream.read(0);
>> }
>>
>>
>> On Monday, 1 July 2013 15:23:44 UTC+2, Gil Pedersen wrote:
>> Hi,
>>
>> I have a case where I want to consume a Readable, by:
>>
>> 1. Read n bytes.
>> 2. Process buffer using a function with an async callback.
>> 3. When callback completes, goto 1.
>>
>> I fail to see any simple solution to what I feel must be a somewhat common
>> use case. The standard "on('readable', function() { this.read(); ... })"
>> doesn't apply, as I have no way of deferring future 'readable' emits once I
>> have returned from the handler.
>>
>> Can it really be that the most sensible solution is to fall back to the old
>> API, using pause() and resume()? or have I missed something?
>>
>> Regards,
>> Gil
>
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