epub.js/src/request.js

var RSVP = require('rsvp');
var URI = require('urijs');
var core = require('./core');

function request(url, type, withCredentials, headers) {
	var supportsURL = (typeof window != "undefined") ? window.URL : false; // TODO: fallback for url if window isn't defined
	var BLOB_RESPONSE = supportsURL ? "blob" : "arraybuffer";
	var uri;

	var deferred = new RSVP.defer();

	var xhr = new XMLHttpRequest();

	//-- Check from PDF.js:
	//   https://github.com/mozilla/pdf.js/blob/master/web/compatibility.js
	var xhrPrototype = XMLHttpRequest.prototype;

	var header;

	if (!('overrideMimeType' in xhrPrototype)) {
		// IE10 might have response, but not overrideMimeType
		Object.defineProperty(xhrPrototype, 'overrideMimeType', {
			value: function xmlHttpRequestOverrideMimeType(mimeType) {}
		});
	}
	if(withCredentials) {
		xhr.withCredentials = true;
	}

	xhr.onreadystatechange = handler;
	xhr.onerror = err;

	xhr.open("GET", url, true);

	for(header in headers) {
		xhr.setRequestHeader(header, headers[header]);
	}

	if(type == "json") {
		xhr.setRequestHeader("Accept", "application/json");
	}

	// If type isn't set, determine it from the file extension
	if(!type) {
		uri = URI(url);
		type = uri.suffix();
	}

	if(type == 'blob'){
		xhr.responseType = BLOB_RESPONSE;
	}


	if(core.isXml(type)) {
		// xhr.responseType = "document";
		xhr.overrideMimeType('text/xml'); // for OPF parsing
	}

	if(type == 'xhtml') {
		// xhr.responseType = "document";
	}

	if(type == 'html' || type == 'htm') {
		// xhr.responseType = "document";
	 }

	if(type == "binary") {
		xhr.responseType = "arraybuffer";
	}

	xhr.send();

	function err(e) {
		console.error(e);
		deferred.reject(e);
	}

	function handler() {
		if (this.readyState === XMLHttpRequest.DONE) {

			if (this.status === 200 || this.responseXML ) { //-- Firefox is reporting 0 for blob urls
				var r;

				if (!this.response && !this.responseXML) {
					deferred.reject({
						status: this.status,
						message : "Empty Response",
						stack : new Error().stack
					});
					return deferred.promise;
				}

				if (this.status === 403) {
					deferred.reject({
						status: this.status,
						response: this.response,
						message : "Forbidden",
						stack : new Error().stack
					});
					return deferred.promise;
				}

				if((this.responseType == '' || this.responseType == 'document')
						&& this.responseXML){
					r = this.responseXML;
				} else
				if(core.isXml(type)){
					// xhr.overrideMimeType('text/xml'); // for OPF parsing
					// If this.responseXML wasn't set, try to parse using a DOMParser from text
					r = core.parse(this.response, "text/xml");
				}else
				if(type == 'xhtml'){
					r = core.parse(this.response, "application/xhtml+xml");
				}else
				if(type == 'html' || type == 'htm'){
					r = core.parse(this.response, "text/html");
				}else
				if(type == 'json'){
					r = JSON.parse(this.response);
				}else
				if(type == 'blob'){

					if(supportsURL) {
						r = this.response;
					} else {
						//-- Safari doesn't support responseType blob, so create a blob from arraybuffer
						r = new Blob([this.response]);
					}

				}else{
					r = this.response;
				}

				deferred.resolve(r);
			} else {

				deferred.reject({
					status: this.status,
					message : this.response,
					stack : new Error().stack
				});

			}
		}
	}

	return deferred.promise;
};

module.exports = request;