[Seaside] Zinc Callback Limit

Mark Smith mark.smith at objectbynature.com
Mon May 14 20:49:20 UTC 2012


On 14 May 2012, at 20:50, Sven Van Caekenberghe wrote:

> Hi Mark,
> 
> On 14 May 2012, at 21:22, Mark Smith wrote:
> 
>> Hi all,
>> 
>> I realise that this might not be typical usage however I have an application with a lot of checkboxes, well over 100, and have run into a small problem using the ZnZincServerAdaptor. When the form is submitted, by clicking the submit button, the final callback isn't executed, and the server appears to drop the connection.
>> 
>> The following reliably replicates the issue –
>> 
>> renderContentOn: html
>> 	html form: [
>> 		(1 to: 256) do: [ :aNumber |
>> 			html checkbox
>> 				callback: [ :aValue | ].
>> 			html
>> 				space;
>> 				text: 'checkbox', aNumber asString;
>> 				break ].
>> 		html submitButton
>> 			callback: [
>> 				self inform: 'clicked' ];
>> 			value: 'click' ]
>> 
>> Although the exact number of fields/callbacks needed seems to vary. I arrived at 256 by a binary search.
>> 
>> Unfortunately that's as far as I've got :).
>> 
>> Does anyone have any suggestions?
> 
> Yes, this is part of Zn server protecting itself against general resource overconsumption as well as against a well-known, recently discovered attack vector. This is hardcoded at ZnConstants class>>#maximumNumberOfDictionaryEntries to 256.

Thanks Sven :). That makes a lot of sense. 256 seems like a good limit.

> You could overwrite it. In any case, you are the first one hitting the limit ;-)

When I have more time I might try to redesign the application so that it doesn't present quite so many checkboxes at one time ;).

> Sven
> 
> --
> Sven Van Caekenberghe
> http://stfx.eu
> Smalltalk is the Red Pill
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