request: function createRequest()

in lib/odata/net-browser.js [185:337]
54 lines of code
12 McCabe index (conditional complexity)

    request: function createRequest() {

        var that = this;


        return function(request, success, error) {

        var result = {};
        var xhr = null;
        var done = false;
        var iframe;

        result.abort = function () {
            iframe = removeIFrame(iframe);
            if (done) {
                return;
            }

            done = true;
            if (xhr) {
                xhr.abort();
                xhr = null;
            }

            error({ message: "Request aborted" });
        };

        var handleTimeout = function () {
            iframe = removeIFrame(iframe);
            if (!done) {
                done = true;
                xhr = null;
                error({ message: "Request timed out" });
            }
        };

        var name;
        var url = request.requestUri;
        var enableJsonpCallback = defined(request.enableJsonpCallback , that.enableJsonpCallback);
        var callbackParameterName = defined(request.callbackParameterName, that.callbackParameterName);
        var formatQueryString = defined(request.formatQueryString, that.formatQueryString);
        if (!enableJsonpCallback || isLocalUrl(url)) {

            xhr = createXmlHttpRequest();
            xhr.onreadystatechange = function () {
                if (done || xhr === null || xhr.readyState !== 4) {
                    return;
                }

                // Workaround for XHR behavior on IE.
                var statusText = xhr.statusText;
                var statusCode = xhr.status;
                if (statusCode === 1223) {
                    statusCode = 204;
                    statusText = "No Content";
                }

                var headers = [];
                readResponseHeaders(xhr, headers);

                var response = { requestUri: url, statusCode: statusCode, statusText: statusText, headers: headers, body: xhr.responseText };

                done = true;
                xhr = null;
                if (statusCode >= 200 && statusCode <= 299) {
                    success(response);
                } else {
                    error({ message: "HTTP request failed", request: request, response: response });
                }
            };

            xhr.open(request.method || "GET", url, true, request.user, request.password);

            // Set the name/value pairs.
            if (request.headers) {
                for (name in request.headers) {
                    xhr.setRequestHeader(name, request.headers[name]);
                }
            }

            // Set the timeout if available.
            if (request.timeoutMS) {
                xhr.timeout = request.timeoutMS;
                xhr.ontimeout = handleTimeout;
            }

            xhr.send(request.body);
        } else {
            if (!canUseJSONP(request)) {
                throw { message: "Request is not local and cannot be done through JSONP." };
            }

            var tick = ticks;
            ticks += 1;
            var tickText = tick.toString();
            var succeeded = false;
            var timeoutId;
            name = "handleJSONP_" + tickText;
            window[name] = function (data) {
                iframe = removeIFrame(iframe);
                if (!done) {
                    succeeded = true;
                    window.clearTimeout(timeoutId);
                    removeCallback(name, tick);

                    // Workaround for IE8 and IE10 below where trying to access data.constructor after the IFRAME has been removed
                    // throws an "unknown exception"
                    if (window.ActiveXObject) {
                        data = window.JSON.parse(window.JSON.stringify(data));
                    }


                    var headers;
                    if (!formatQueryString || formatQueryString == "$format=json") {
                        headers = { "Content-Type": "application/json;odata.metadata=minimal", "OData-Version": "4.0" };
                    } else {
                        // the formatQueryString should be in the format of "$format=xxx", xxx should be one of the application/json;odata.metadata=minimal(none or full)
                        // set the content-type with the string xxx which stars from index 8.
                        headers = { "Content-Type": formatQueryString.substring(8), "OData-Version": "4.0" };
                    }

                    // Call the success callback in the context of the parent window, instead of the IFRAME
                    delay(function () {
                        removeIFrame(iframe);
                        success({ body: data, statusCode: 200, headers: headers });
                    });
                }
            };

            // Default to two minutes before timing out, 1000 ms * 60 * 2 = 120000.
            var timeoutMS = (request.timeoutMS) ? request.timeoutMS : 120000;
            timeoutId = window.setTimeout(handleTimeout, timeoutMS);

            var queryStringParams = callbackParameterName + "=parent." + name;
            if (formatQueryString) {
                queryStringParams += "&" + formatQueryString;
            }

            var qIndex = url.indexOf("?");
            if (qIndex === -1) {
                url = url + "?" + queryStringParams;
            } else if (qIndex === url.length - 1) {
                url = url + queryStringParams;
            } else {
                url = url + "&" + queryStringParams;
            }

            iframe = createIFrame(url);
        }

        return result;
    }
    }()