Question

I have spent days working on this and really feel dumb. I have been working on demos and samples that never work when I try it locally with my own url. I have a web service that returns results back in json and am just basically trying to call it using dojo and for now just view the results. I took the search google example and just substituted the url and parameters. Now perhaps I still do not understand the basics so:
– io.script.get vs xhrGet
if using cross domain urls it is better to use io.script.get? correct?
now what is the callbackparam? is this the function that is being called in the webservice?
My webservice url is as follows:
http://xxx.xxx.x.xxx/WcfServices/WcfInstance/Service1.svc/RetrievData?query=Word

when I use the following code I get nothing displayed.

function searchGoogle() {
    // Look up the node we'll stick the text under.
    var targetNode = dojo.byId("rules");

    // The parameters to pass to xhrGet, the url, how to handle it, and the callbacks.
    var jsonpArgs = {
        url: "http://xxx.xxx.x.xxx/WcfServices/WcfInstance/Service1.svc/RetrieveData?",
        callbackParamName: "callback",
        content: {

            query:"dojowords"
        },
        load: function (data) {
            // Set the data from the search into the viewbox in nicely formatted JSON
            targetNode.innerHTML = "<pre>" + dojo.toJson(data, true) + "</pre>";
        },
        error: function (error) {
            targetNode.innerHTML = "An unexpected error occurred: " + error;
        }
    };
    dojo.io.script.get(jsonpArgs);
}
dojo.ready(searchGoogle);

Here is what the webservice results look like:

"{\"rules\":[{\"value\":\"AllState\"},
 {\"value\":\"Cidade de Goa beach\"},{\"value\":\"Euro 2012\"},     
 {\"value\":\"Euro2012\"},{\"value\":\"European&Championship\"},
 {\"value\":\"Holiday  Inn Resort\"},
 {\"value\":\"Holiday Inn Resort goa\"},
 {\"value\":\"Hotel Goa\"},{\"value\":\"Hyatt Goa\"},{\"value\":\"I buy car\"},...

If I get this part correct then at least I know I have data which I can then bind to a datagrid or chart.

Answer 1

dojo.io.script.get is for all cross domain requests.
xhrGet is for same domain requests.

dojo.io.script.get uses a hack which expects jsonp or json padding as a result. This wraps the response of the web service call inside a self executing function. The function name is the callback name. This has to be wired before the call so it knows what already defined function to call when a response comes back.

All of the arguments are well documented http://dojotoolkit.org/reference-guide/1.7/dojo/io/script.html

My guess as to why your service isn’t working is because you wrote the web service and it does not handle jsonp. It is not wrapping its response inside the callbackparamname.

your results should look something like

 callback({json});

where callback is whatever you set up in callbackParamName

you can also remove the ? from your url, that should be handled for you.