[Cartoweb-users] Creating a filter plugin

[Oliver Christen]

do you use persistant query result?



> Hello Oliver,
> 
> thanks. Everything is working now. After a few test, I found out that 
> initializeRequest (not handlePreDrawing) needs to be used. Otherwise, 
> the query plugin will not recognize the changed map object and return 
> all results. Unfortunately, this causes another side effect: If a query 
> result exists and the filter is changed, an error is triggered 
> ("Attribute query returned no results") if none of the existing query 
> results fits the new filter. If at least one result fits the filter, all 
> are kept.
> 
> Do you have any idea, how I could synchronize the query results if the 
> filter changes?
> 
> Regards,
> Dirk
> 
> 
> 
> Oliver Christen wrote:
>> see comments below
>>
>>>
>>> 1. How do I transfer an array of FilterRequest objects? Do I need a 
>>> separate class in the common part?
>>
>> yes, you need to define a class whose structure correspond to your 
>> array of FilterRequest Object
>>
>> have a look at existing "common" part of existing plugin for example 
>> (outline is a easy one)
>>
>>>
>>> 2. How should the wsdl for the FilterRequest class look like? Probably
>>>
>>>      <complexType name="FilterRequest">
>>>        <all>
>>>          <element name="layerId" type="xsd:string"/>
>>>          <element name="filter" type="xsd:string"/>
>>>        </all>
>>>      </complexType>
>>
>> you only need the wsdl part if you use cartoweb in Soap mode. If you 
>> use it in direct mode, you can ignore the wsdl.
>> again, for example, have a look at the outline plugin
>>
>>>
>>> But how do I handle the array of requests?
>>
>> the root element need to be an array, and its children will be of 
>> FilterRequest type
>>
>>>
>>> 3. Which function on the server side should I use to handle the 
>>> request and set the filter strings?
>>
>> Since you seem to want to set the data of layers on the fly, you must 
>> act before the handleDrawing function. I would do it in the 
>> handlePreDrawing stage.
>> (see http://www.cartoweb.org/doc/misc/plugins_diagram.pdf)
>>
>> then it is just a matter of using mapOverlay to set the change you 
>> have passed in your FilterRequests.
>>
>>>
>>> And finally a general question:
>>> I would like to prevent that Cartoweb fails and shows an error 
>>> message if the provided filter is wrong, e.g. syntax errors. Supposed 
>>> a user provides an incorrect filter string, can I somehow test the 
>>> filter and ignore it?
>>>
>>
>> a wrong provider will most certainly trigger a mapserver error.
>>
>> maybe you can catch it in the handlePostDrawing, but im not sure, i 
>> never tried to handle mapserver errors.
>>
>> regards
>> Oliver
>>
>>
>