WPS Client implementation in our desktop

Question

How to implement wps client in our system and also specify requirements needed?
How to specify the proxy to the

OpenLayers.ProxyHost = 'proxy.cgi?url=';

var map, client, intersect, buffer;

function init() {

map = new OpenLayers.Map('map', {
    allOverlays: true,
    center: [114, 16],
    zoom: 4,
    layers: [new OpenLayers.Layer.Vector()]
});

var features = [new OpenLayers.Feature.Vector(OpenLayers.Geometry.fromWKT(
    'LINESTRING(117 22,112 18,118 13, 115 8)'
))];
var geometry = OpenLayers.Geometry.fromWKT(
    'POLYGON((110 20,120 20,120 10,110 10,110 20),(112 17,118 18,118 16,112 15,112 17))'
);

map.baseLayer.addFeatures(features);
map.baseLayer.addFeatures([new OpenLayers.Feature.Vector(geometry)]);

client = new OpenLayers.WPSClient({
    servers: {
        opengeo: 'http://demo.opengeo.org/geoserver/wps'
    }
});

// Create a process and configure it
intersect = client.getProcess('opengeo', 'JTS:intersection');    
intersect.configure({
    // spatial input can be a feature or a geometry or an array of
    // features or geometries
    inputs: {
        a: features,
        b: geometry
    }
});

// Create another process which chains the previous one and execute it
buffer = client.getProcess('opengeo', 'JTS:buffer');
buffer.execute({
    inputs: {
        geom: intersect.output(),
        distance: 1
    },
    success: function(outputs) {
        // outputs.result is a feature or an array of features for spatial
        // processes.
        map.baseLayer.addFeatures(outputs.result);
    }
});

// Instead of creating a process and executing it, we could call execute on
// the client directly if we are only dealing with a single process:
/*
client.execute({
    server: "opengeo",
    process: "JTS:intersection",
    // spatial input can be a feature or a geometry or an array of
    // features or geometries
    inputs: {
        a: features,
        b: geometry
    },
    success: function(outputs) {
        // outputs.result is a feature or an array of features for spatial
        // processes.
        map.baseLayer.addFeatures(outputs.result);
    }
});
*/
}

Answer 1

For remote ajax requests, you need proxy living on the server, to pass your server requests to the server in a different domain.

The proxy.cgi script is part of OpenLayers distribution, you can find (and configure!) it in examples directory. Just copy it out into your server's cgi-bin directory.

I do not know much about the WPSClient implementation you have here. In OpenLayers, there is OpenLayers.Format.WPSExecute and other classes, which can help you out with building of the request and parsing the response.