[OpenLayers-Users] Using Cross Domain JSON to get around a proxy issue

Robert Sanson Robert.Sanson at asurequality.com
Tue Sep 20 00:21:36 EDT 2011

Hi Phil
I just want to use a BBOX, so no cql filters. Does the Script protocol know to return the response to the callback function?

>>> Phil Scadden <p.scadden at gns.cri.nz> 20/09/2011 4:15 p.m. >>>
yes, I've done it with eg.

Instead of
                     wfsProtocol = new OpenLayers.Protocol.WFS.v1_1_0({
                         url: myurl,
                         geometryName: "SHAPE",
                         featurePrefix: myfeaturePrefix,
                         featureType: myfeatureType,
                         srsName: myproj

I use

                     wfsProtocol = new OpenLayers.Protocol.Script({
                         url: myurl,
                         callbackKey: "format_options",
                         callbackPrefix: "callback:",
                         params: {
                             service: "WFS",
                             version: "1.1.0",
                             srsName: myproj
                             request: "GetFeature",
                             featurePrefix: myfeaturePrefix,
                             typeName: myfeatureType,
                             outputFormat: "json"
                         filterToParams: function (filter, params) {
                             // example to demonstrate BBOX serialization
                             delete params.cql_filter;
                             if (filter.type === 
OpenLayers.Filter.Spatial.BBOX) {
                                 params.bbox = filter.value.toArray();
                                 if (filter.projection) {
                             } else if (filter.type === 
OpenLayers.Filter.Spatial.DWITHIN) {
                                 var geom = filter.value.clone();
                                 if (geom.x >= -180 && geom.x <= 360 && 
geom.y >= -180 && geom.y <= 360) { // is this a lat long?
                                     var xx = geom.x;
                                     geom.x = geom.y;
                                     geom.y = xx;
                                 params.cql_filter = 'DWITHIN(SHAPE,' + 
geom.toString() + ',' + filter.distance + ',meters)';
                             } else if (filter.type === 
OpenLayers.Filter.Spatial.INTERSECTS) {
                                 var geom = filter.value;
                                 params.cql_filter = 'INTERSECTS(SHAPE,' 
+ geom.toString() + ')';
                             } else if 
(OpenLayers.Format.QueryStringFilter) {
                                 var format = new 
                                     srsInBBOX: this.srsInBBOX
                                 params = format.writecql(filter, 
params, this.options.url.indexOf('server21') > 0);
                             return params;

The complicated bit the filterToParams. If you dont have any filter, 
then no problem. If you do, they you need to convert the filter to CQL. 
The code above handles spatial filters. I havent attempted others. Gets 
complicated fast. CQL filters dont respect SRS (at least on geoserver). 
You have to make sure that any geometry is transformed to native SRS 
(that's what my application function transformGeometry is doing). You 
also have switch x,y if it is lat/long.

Notice: This email and any attachments are confidential. If received in error please destroy and immediately notify us. Do not copy or disclose the contents.

Users mailing list
Users at lists.osgeo.org 

This email and any attachments are confidential and intended solely for the addressee(s). If you are not the intended recipient, please notify us immediately and then delete this email from your system.

This message has been scanned for Malware and Viruses by Websense Hosted Security.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/openlayers-users/attachments/20110920/51180408/attachment.html

More information about the Users mailing list