Re: [Gwt-openlayers-users] WFS Layer

[Edwin C. <com...@gm...>]

Hi Christopher,

Without a proxy it is not possible for OpenLayers to do WFS requests,
because of cross-domain restrictions on Javascript.

Before going into ProxyHost: The recommended way to create a WFS layer
is via WFSProtocol. We are intending to remove the WFS layer
alltogether, as it appears to be the legacy way to talk to a WFS. You
can look at the latest OpenLayers examples
(http://openlayers.org/dev/examples/). For instance:

http://openlayers.org/dev/examples/wfs-states.js

For this you need the code that it is in trunk (but see also below about proxy).

The easiest way to set the proxyHost is to create a setter for it in JSNI code:

public static native void setProxyHost(String host)/*-{

  $wnd.OpenLayers.ProxyHost = host;

}-*/;

and then

setProxyHost("myhost/here");

However, the proxyHost should point at a proxy that is running on the
same domain as the javascript. There is a python proxy included with
the OpenLayers examples. You can try to get that running at the some
domain as the app you are working on.

Currently, the GWT-OL lacks a java proxy servlet, but that should be
added to trunk soon. I can send you a copy of the new build when that
hits trunk.

Greetings,
Edwin

On 11 February 2010 17:55, Christopher Navarro <cna...@gm...> wrote:
> Hi,
>
> I'm trying to read WFS features from a geoserver using gwt-openlayers and I
> can't seem to figure out where I am going wrong.
>
> Using straight OpenLayers/Javascript/HTML I have the following, which works:
>
> // Proxy setup to fix XMLHttpRequest domain matching
> OpenLayers.ProxyHost = "/cgi-bin/proxy.cgi?url=";
>
> // parameters for getting the WFS layer
> var params = { typename: "marketmaker:business_cu" };
> var options = {};
>
> // WFS Layer creation
> var layer = new OpenLayers.Layer.WFS( "WFS",
>           "http://mmweb.ncsa.uiuc.edu:8080/geoserver/wfs",
>           params, options );
>
> // add the layer
> map.addLayer( layer );
>
> My GWT-OpenLayers equivalent is:
>
> // parameters for wfs layer
> WFSParams wfsParams = new WFSParams();
> wfsParams.getJSObject().setProperty( "typename", "marketmaker:business_cu"
> );
>
> // no additional options
> WFSOptions wfsOptions = new WFSOptions();
>
> // WFS layer creation
> WFS wfsLayer = new WFS( "wfs", WFS_URL, wfsParams, wfsOptions );
>
> // add the layer
> map.addLayer( wfsLayer );
>
> Is there some way to inject the value of OpenLayers.ProxyHost using
> GWT-OpenLayers?  I'm not sure if that is the issue.  I am new to javascript
> and perhaps this is wrong, but I tried writing the value of
> OpenLayers.ProxyHost directly into the compiled javascript file that GWT
> creates.  Any help is appreciated.
>
> Regards,
> Chris
>
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