PluginLoader.js

/**
* Copyright (C) 2012-2015 KO GmbH <copyright@kogmbh.com>
*
* @licstart
* This file is part of ViewerJS.
*
* ViewerJS is free software: you can redistribute it and/or modify it
* under the terms of the GNU Affero General Public License (GNU AGPL)
* as published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* ViewerJS is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with ViewerJS.  If not, see <http://www.gnu.org/licenses/>.
* @licend
*
* @source: http://viewerjs.org/
* @source: http://github.com/kogmbh/ViewerJS
*/

/*global document, window, Viewer, ODFViewerPlugin, PDFViewerPlugin*/

(function () {
	"use strict";

	var css,
		pluginRegistry = [
		(function() {
			var odfMimetypes = [
				'application/vnd.oasis.opendocument.text',
				'application/vnd.oasis.opendocument.text-flat-xml',
				'application/vnd.oasis.opendocument.text-template',
				'application/vnd.oasis.opendocument.presentation',
				'application/vnd.oasis.opendocument.presentation-flat-xml',
				'application/vnd.oasis.opendocument.presentation-template',
				'application/vnd.oasis.opendocument.spreadsheet',
				'application/vnd.oasis.opendocument.spreadsheet-flat-xml',
				'application/vnd.oasis.opendocument.spreadsheet-template'];
			var odfFileExtensions = [
				'odt',
				'fodt',
				'ott',
				'odp',
				'fodp',
				'otp',
				'ods',
				'fods',
				'ots'];

			return {
				supportsMimetype: function(mimetype) {
					return (odfMimetypes.indexOf(mimetype) !== -1);
				},
				supportsFileExtension: function(extension) {
					return (odfFileExtensions.indexOf(extension) !== -1);
				},
				path: "./ODFViewerPlugin",
				getClass: function() { return ODFViewerPlugin; }
			};
		}()),
		{
			supportsMimetype: function(mimetype) {
				return (mimetype === 'application/pdf');
			},
			supportsFileExtension: function(extension) {
				return (extension === 'pdf');
			},
			path: "./PDFViewerPlugin",
			getClass: function() { return PDFViewerPlugin; }
		},
		(function() {
			var imageMimetypes = [
				'image/jpeg',
				'image/pjpeg',
				'image/gif',
				'image/png',
				'image/bmp'];
			var imageFileExtensions = [
				'png',
				'jpg',
				'jpeg',
				'gif',
				'bmp'];

			return {
				supportsMimetype: function(mimetype) {
					return (imageMimetypes.indexOf(mimetype) !== -1);
				},
				supportsFileExtension: function(extension) {
					return (imageFileExtensions.indexOf(extension) !== -1);
				},
				path: "./ImageViewerPlugin",
				getClass: function() { return ImageViewerPlugin; }
			};
		}()),
		(function() {
			var multimediaMimetypes = [
				'video/mp4',
				'video/ogg',
				'video/webm',
				'audio/aac',
				'audio/mp4',
				'audio/mpeg',
				'audio/ogg',
				'audio/wav',
				'audio/webm'];
			var multimediaFileExtensions = [
				'aac',
				'mp4',
				'm4a',
				'mp3',
				'mpg',
				'mpeg',
				'ogg',
				'wav',
				'webm',
				'm4v',
				'ogv',
				'oga',
				'mp1',
				'mp2'];

			return {
				supportsMimetype: function(mimetype) {
					return (multimediaMimetypes.indexOf(mimetype) !== -1);
				},
				supportsFileExtension: function(extension) {
					return (multimediaFileExtensions.indexOf(extension) !== -1);
				},
				path: "./ImageViewerPlugin",
				getClass: function() { return MultimediaViewerPlugin; }
			};
		}())
	];


	function estimateTypeByHeaderContentType(documentUrl, cb) {
		var xhr = new XMLHttpRequest();
		xhr.onreadystatechange = function() {
			var mimetype, matchingPluginData;
			if (xhr.readyState === 4) {
				if ((xhr.status >= 200 && xhr.status < 300) || xhr.status === 0) {
					mimetype = xhr.getResponseHeader('content-type');

					if (mimetype) {
						pluginRegistry.some(function(pluginData) {
							if (pluginData.supportsMimetype(mimetype)) {
								matchingPluginData = pluginData;
								console.log('Found plugin by mimetype and xhr head: ' + mimetype);
								// store the mimetype globally
								window.mimetype = mimetype;
								return true;
							}
							return false;
						});
					}
				}
				cb(matchingPluginData);
			}
		};
		xhr.open("HEAD", documentUrl, true);
		xhr.send();
	}


	function doEstimateTypeByFileExtension(extension) {
		var matchingPluginData;

		pluginRegistry.some(function(pluginData) {
			if (pluginData.supportsFileExtension(extension)) {
				matchingPluginData = pluginData;
				return true;
			}
			return false;
		});

		return matchingPluginData;
	}


	function estimateTypeByFileExtension(extension) {
		var matchingPluginData = doEstimateTypeByFileExtension(extension)

		if (matchingPluginData) {
			console.log('Found plugin by parameter type: ' + extension);
			
			// this is needed for the Multimedia Plugin
			window.mimetype = getMimeByExtension(extension);
		}

		return matchingPluginData;
	}


	function estimateTypeByFileExtensionFromPath(documentUrl) {
		// See to get any path from the url and grep what could be a file extension
		var documentPath = documentUrl.split('?')[0],
			extension = documentPath.split('.').pop(),
			matchingPluginData = doEstimateTypeByFileExtension(extension)

		if (matchingPluginData) {
			console.log('Found plugin by file extension from path: ' + extension);
		}

		return matchingPluginData;
	}


	function parseSearchParameters(location) {
		var parameters = {},
			search = location.search || "?";

		search.substr(1).split('&').forEach(function (q) {
			// skip empty strings
			if (!q) {
				return;
			}
			// if there is no '=', have it handled as if given key was set to undefined
			var s = q.split('=', 2);
			parameters[decodeURIComponent(s[0])] = decodeURIComponent(s[1]);
		});

		return parameters;
	}
	
	function getMimeByExtension(ext) {
		var extToMimes = {
			'aac' : 'audio/aac',
			'mp4' : 'video/mp4',
			'm4a' : 'audio/mp4',
			'mp3' : 'audio/mpeg',
			'mpg' : 'video/mpeg',
			'mpeg': 'video/mpeg',
			'ogg' : 'video/ogg',
			'wav' : 'audio/wav',
			'webm': 'video/webm',
			'm4v' : 'video/mp4',
			'ogv' : 'video/ogg',
			'oga' : 'audio/ogg',
			'mp1' : 'audio/mpeg',
			'mp2' : 'audio/mpeg'
		};
		
		if (extToMimes.hasOwnProperty(ext)) {
           return extToMimes[ext];
        }
        return false;
	}


	window.onload = function () {
		var viewer,
			documentUrl = document.location.hash.substring(1),
			parameters = parseSearchParameters(document.location),
			Plugin;

		if (documentUrl) {
			// try to guess the title as filename from the location, if not set by parameter
			if (!parameters.title) {
				parameters.title = documentUrl.replace(/^.*[\\\/]/, '');
			}

			parameters.documentUrl = documentUrl;

			// trust the server most
			estimateTypeByHeaderContentType(documentUrl, function(pluginData) {
				if (!pluginData) {
					if (parameters.type) {
						pluginData = estimateTypeByFileExtension(parameters.type);
					} else {
						// last ressort: try to guess from path
						pluginData = estimateTypeByFileExtensionFromPath(documentUrl);
					}
				}

				if (pluginData) {
					if (String(typeof loadPlugin) !== "undefined") {
						loadPlugin(pluginData.path, function () {
							Plugin = pluginData.getClass();
							viewer = new Viewer(new Plugin(), parameters);
						});
					} else {
						Plugin = pluginData.getClass();
						viewer = new Viewer(new Plugin(), parameters);
					}
				} else {
					viewer = new Viewer();
				}
			});
		} else {
			viewer = new Viewer();
		}
	};

	css = /**@type{!HTMLStyleElement}*/(document.createElementNS(document.head.namespaceURI, 'style'));
	css.setAttribute('media', 'screen');
	css.setAttribute('type', 'text/css');
	css.appendChild(document.createTextNode(viewer_css));
	document.head.appendChild(css);

	css = /**@type{!HTMLStyleElement}*/(document.createElementNS(document.head.namespaceURI, 'style'));
	css.setAttribute('media', 'only screen and (max-device-width: 800px) and (max-device-height: 800px)');
	css.setAttribute('type', 'text/css');
	css.setAttribute('viewerTouch', '1');
	css.appendChild(document.createTextNode(viewerTouch_css));
	document.head.appendChild(css);

}());