TiddlyWiki5/core/modules/utils/dom/http.js

/*\
title: $:/core/modules/utils/dom/http.js
type: application/javascript
module-type: utils

Browser HTTP support

\*/
(function(){

/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";

/*
A quick and dirty HTTP function; to be refactored later. Options are:
	url: URL to retrieve
	type: GET, PUT, POST etc
	callback: function invoked with (err,data)
*/
exports.httpRequest = function(options) {
	var type = options.type || "GET",
		headers = options.headers || {accept: "application/json"},
		request = new XMLHttpRequest(),
		data = "",
		f,results;
	// Massage the data hashmap into a string
	if(options.data) {
		if(typeof options.data === "string") { // Already a string
			data = options.data;
		} else { // A hashmap of strings
			results = [];
			$tw.utils.each(options.data,function(dataItem,dataItemTitle) {
				results.push(dataItemTitle + "=" + encodeURIComponent(dataItem));
			});
			data = results.join("&");
		}
	}
	// Set up the state change handler
	request.onreadystatechange = function() {
		if(this.readyState === 4) {
			if(this.status === 200 || this.status === 201 || this.status === 204) {
				// Success!
				options.callback(null,this.responseText,this);
				return;
			}
		// Something went wrong
		options.callback("XMLHttpRequest error code: " + this.status);
		}
	};
	// Make the request
	request.open(type,options.url,true);
	if(headers) {
		$tw.utils.each(headers,function(header,headerTitle,object) {
			request.setRequestHeader(headerTitle,header);
		});
	}
	if(data && !$tw.utils.hop(headers,"Content-type")) {
		request.setRequestHeader("Content-type","application/x-www-form-urlencoded; charset=UTF-8");
	}
	try {
		request.send(data);
	} catch(e) {
		options.callback(e);
	}
	return request;
};

})();