source: Dev/trunk/src/client/dojox/wire/ml/RestHandler.js @ 532

dojo.provide("dojox.wire.ml.RestHandler");

dojo.require("dojox.wire._base");
dojo.require("dojox.wire.ml.util");

dojo.declare("dojox.wire.ml.RestHandler", null, {
        // summary:
        //              A REST service handler
        // description:
        //              This class serves as a base REST service.
        //              Sub-classes may override _getContent() and _getResult() to handle
        //              specific content types.
        contentType: "text/plain",
        handleAs: "text",

        bind: function(method, parameters, deferred, url){
                // summary:
                //              Call a service method with parameters.
                // description:
                //              A service is called with a URL generated by _getUrl() and
                //              an HTTP method specified with 'method'.
                //              For "POST" and "PUT", a content is generated by _getContent().
                //              When data is loaded, _getResult() is used to pass the result to
                //              Deferred.callback().
                // method:
                //              A method name
                // parameters:
                //              An array of parameters
                // deferred:
                //              'Deferred'
                // url:
                //              A URL for the method
                method = method.toUpperCase();
                var self = this;
                var args = {
                        url: this._getUrl(method, parameters, url),
                        contentType: this.contentType,
                        handleAs: this.handleAs,
                        headers: this.headers,
                        preventCache: this.preventCache
                };
                var d = null;
                if(method == "POST"){
                        args.postData = this._getContent(method, parameters);
                        d = dojo.rawXhrPost(args);
                }else if(method == "PUT"){
                        args.putData = this._getContent(method, parameters);
                        d = dojo.rawXhrPut(args);
                }else if(method == "DELETE"){
                        d = dojo.xhrDelete(args);
                }else{ // "GET"
                        d = dojo.xhrGet(args);
                }
                d.addCallbacks(function(result){
                        deferred.callback(self._getResult(result));
                }, function(error){
                        deferred.errback(error);
                });
        },

        _getUrl: function(/*String*/method, /*Array*/parameters, /*String*/url){
                // summary:
                //              Generate a URL
                // description:
                //              If 'method' is "GET" or "DELETE", a query string is generated
                //              from a query object specified to the first parameter in
                //              'parameters' and appended to 'url'.
                //              If 'url' contains variable seguments ("{parameter_name}"),
                //              they are replaced with corresponding parameter values, instead.
                // method:
                //              A method name
                // parameters:
                //              An array of parameters
                // url:
                //              A base URL
                // returns:
                //              A URL
                var query;
                if(method == "GET" || method == "DELETE"){
                        if(parameters.length > 0){
                                query = parameters[0];
                        }
                }else{ // "POST" || "PUT"
                        if(parameters.length > 1){
                                query = parameters[1];
                        }
                }
                if(query){
                        var queryString = "";
                        for(var name in query){
                                var value = query[name];
                                if(value){
                                        value = encodeURIComponent(value);
                                        var variable = "{" + name + "}";
                                        var index = url.indexOf(variable);
                                        if(index >= 0){ // encode in path
                                                url = url.substring(0, index) + value + url.substring(index + variable.length);
                                        }else{ // encode as query string
                                                if(queryString){
                                                        queryString += "&";
                                                }
                                                queryString += (name + "=" + value);
                                        }
                                }
                        }
                        if(queryString){
                                url += "?" + queryString;
                        }
                }
                return url; //String
        },

        _getContent: function(/*String*/method, /*Array*/parameters){
                // summary:
                //              Generate a request content
                // description:
                //              If 'method' is "POST" or "PUT", the first parameter in
                //              'parameters' is returned.
                // method:
                //              A method name
                // parameters:
                //              An array of parameters
                // returns:
                //              A request content
                if(method == "POST" || method == "PUT"){
                        return (parameters ? parameters[0] : null); //anything
                }else{
                        return null; //null
                }
        },

        _getResult: function(/*anything*/data){
                // summary:
                //              Extract a result
                // description:
                //              A response data is returned as is.
                // data:
                //              A response data returned by a service
                // returns:
                //              A result object
                return data; //anything
        }
});