[mapserver-users] URL encoding for map file classexpressions

[Armin Burger]

Thanks,

I tried now to use the complete definition for EXPRESSION, like

- in the map file
  CLASS
    EXPRESSION ([CODE]=312 or [CODE]=313)
  ...

-and in the URL
  ...&map_corineq_class_expression=([CODE]=312+or+[CODE]=313)
or also possible
  ...&map_corineq_class_expression=%28%5BCODE%5D=312+or+%5BCODE%5D=313%29

and it did work fine. Sometimes it's easier than I'm thinking.

Armin


> In PHP you can have URL arguments like:

> http://host/myfile.php?abc[]=expr-1&abc[]=expr-2&abc[]=expr-3

> which will create a PHP array called abc and push each argument onto it,
> so in the example above you would get:

> abc[0] = expr-1
> abc[1] = expr-2
> abc[2] = expr-3

> the [] is synonmous with push

> I hope this helps.
>   -Steve

> ANDREW WOOLEY wrote:
>>
>> Armin,
>>
>> I think that I understand your question.  Pardon me if this is not what
you
>> were asking:
>>
>> The way that I got around this is to use URL friendly characters and then
>> use the PHP function explode().  Following is a snippet of code (pardon
the
>> poor coding):
>>
>> if ($addto)
>> {
>>   if ($expr)
>>     {
>>       $routeid = $routeid . "_" . $expr;
>>      }
>> }
>>
>>  $epr = explode("_", $routeid);
>>
>> for($i = "0"; $i < sizeof($epr); $i++)
>> {
>> if ($i == 0 )
>> {
>> $newexpr = "(";
>> }
>> $newexpr = str_replace ("))", ") or ", $newexpr);
>>
>> $newexpr = $newexpr . "([ID] eq " . $epr[$i] . ")";
>> if ($i == sizeof($epr));
>> {
>> $newexpr = $newexpr . ")";
>> }
>> }
>>
>> echo ("<input type=\"hidden\" name=\"expr\" value=" . $routeid . ">\n");
>>  $oLayer = $map->GetLayerbyName("allbuiltQ");
>> $FirstClass = $oLayer->GetClass(0);
>> $FirstClass->setExpression($newexpr);
>>
>> $oLayer->set("status", 1);
>>
>> The first part of the code checks to see if the user wants to add to the
>> selection and the $routeid is the value from the attribute table for the
>> feature clicked.  Then it explodes the $epr which is the class expression
>> and loops through the resulting array to build the expression string.
Then
>> I set a hidden form variable to be the new expression value so it will be
>> returned on the next form submit and set the class expression.  It works
>> really well and seems to be quite fast.
>>
>> I hope this helps.  Let me know if you have questions.
>>
>> Andrew
>>
>> Andrew Wooley
>> GIS Operations Manager
>> Mountainland Association of Governments
>> Orem, UT
>>
>> phone:  801.229.3844
>> fax:       801.229.3801
>> email:   awooley at mountainland.org
>> web:    www.maps.mountainland.org
>>
>> >>> Armin Burger <armin.burger at territoriumonline.com> 10/31/01 08:47AM
>>>
>> Hi all,
>>
>> I would like to do a query on a layer with a combination of FILTER and
>> EXPRESSION using the query definition via the URL. If I want to query
more
>> than one expression, how would I encode these expressions in the URL?
>>
>> For example:
>> I have the URL part for the LAYER - FILTER tag for the layer 'landcoverq'
>>   &map_landcoverq_filter=%22313%22
>> searching for the number 313 in the field defined with FILTERITEM in the
>> mapfile.
>>
>> and I would like to have the corresponding URL encoding for the
EXPRESSION
>> tag of the class section
>>   EXPRESSION ('[LANCOV_CD]'='215/1' or '[LANCOV_CD]'='215/2' or
>> '[LANCOV_CD]'='220' )
>>
>> Adding all the expressions one by one in the URL with
>>   &map_landcoverq_class_expression=%22215/1%22...
>> selects always only the last one.
>>
>> I think it should be possible but don't how to achieve it. Thanks for any
>> help.
>>
>> Has anyone experiences how queries like that are facilitated using the
>> functionality of PostGIS?
>>
>> Armin
>>
>> --
>> Armin Burger
>> Territorium Online
>> Via Siemens 19 - 39100 Bolzano - Italy
>> _