Zinc Callback Limit

> 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?

> 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.

> 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.

> Sven
>
> --
> Sven Van Caekenberghe
> http://stfx.eu
> Smalltalk is the Red Pill
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> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside

> On 05/14/2012 12:22 PM, Mark Smith wrote:
>> 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?
>
> Other than increasing the limit like Sven suggests if you can use jQuery you could:
>
> 1. In your component create a callback dictionary in an inst var with a randomly chosen id # as the key and each checkbox's callback as the value.
> 2. Assign the id # as the html id for the checkbox.
> 3. Set a onclick handler on a div that contains the checkboxes that posts the callback id # when it is clicked and triggers just one callback in your seaside app.
> 4. have the container div callback in your seaside app lookup which checkbox callback to run from the dictionary in step 1 and run the checkbox callback.