RosettaCodeData/Task/HTTP/JavaScript/http-4.js

66 lines
1.8 KiB
JavaScript

/**
* @name _http
* @description Generic API Client using XMLHttpRequest
* @param {string} url The URI/URL to connect to
* @param {string} method The HTTP method to invoke- GET, POST, etc
* @param {function} callback Once the HTTP request has completed, responseText is passed into this function for execution
* @param {object} params Query Parameters in a JavaScript Object (Optional)
*
*/
function _http(url, method, callback, params) {
var xhr,
reqUrl;
xhr = new XMLHttpRequest();
xhr.onreadystatechange = function xhrProc() {
if (xhr.readyState == 4 && xhr.status == 200) {
callback(xhr.responseText);
}
};
/** If Query Parameters are present, handle them... */
if (typeof params === 'undefined') {
reqUrl = url;
} else {
switch (method) {
case 'GET':
reqUrl = url + procQueryParams(params);
break;
case 'POST':
reqUrl = url;
break;
default:
}
}
/** Send the HTTP Request */
if (reqUrl) {
xhr.open(method, reqUrl, true);
xhr.setRequestHeader("Accept", "application/json");
if (method === 'POST') {
xhr.send(params);
} else {
xhr.send();
}
}
/**
* @name procQueryParams
* @description Return function that converts Query Parameters from a JavaScript Object to a proper URL encoded string
* @param {object} params Query Parameters in a JavaScript Object
*
*/
function procQueryParams(params) {
return "?" + Object
.keys(params)
.map(function (key) {
return key + "=" + encodeURIComponent(params[key])
})
.join("&")
}
}