Additional adjustments to URL handling

Follow-up to df40ee7216

- Restore opening of non-HTTP URL schemes in link attachments
- Remove scheme whitelist for link attachments, since it's not enforced
  via the API anyway and we prompt before an external application is
  opened. Instead, just block a few schemes (e.g., 'javascript') from
  launching.

TODO:

- Provide some way to change/reset an application association if the
  user checks the box to automatically open that scheme.
- Show an error message if a link attachment with an invalid URL is
  double-clicked

chrome/content/zotero/xpcom/attachments.js

@@ -606,24 +606,13 @@ Zotero.Attachments = new function(){
 		var title = options.title;
 		var collections = options.collections;
 		
-		/* Throw error on invalid URLs
-		 We currently accept the following protocols:
-		 PersonalBrain (brain://)
-		 DevonThink (x-devonthink-item://)
-		 Notational Velocity (nv://)
-		 MyLife Organized (mlo://)
-		 Evernote (evernote://)
-		 OneNote (onenote://)
-		 Kindle (kindle://) 
-		 Logos (logosres:) 
-		 Bear (bear://)
-		 MarginNote (marginnoteapp://)
-		 Zotero (zotero://) */
-
-		var urlRe = /^((https?|zotero|evernote|onenote|brain|nv|mlo|kindle|x-devonthink-item|bear|marginnoteapp|ftp):\/\/|logosres:)[^\s]*$/;
-		var matches = urlRe.exec(url);
+		var matches = url.match(/^([a-z]+):(\/\/)?.+/);
 		if (!matches) {
-			throw ("Invalid URL '" + url + "' in Zotero.Attachments.linkFromURL()");
+			throw new Error(`Invalid URL '${url}'`);
+		}
+		var scheme = matches[1];
+		if (['javascript', 'data', 'chrome', 'resource', 'mailto'].includes(scheme)) {
+			throw new Error(`Invalid scheme '${scheme}'`);
 		}
 		
 		// If no title provided, figure it out from the URL

chrome/content/zotero/xpcom/utilities.js

@@ -187,7 +187,8 @@ Zotero.Utilities = {
 	isHTTPURL: function (url, allowNoScheme = false) {
 		// From https://stackoverflow.com/a/3809435
 		var noSchemeRE = /^[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)/;
-		return /^https?:\/\//.test(url) || (allowNoScheme && noSchemeRE.test(url));
+		return /^https?:\/\//.test(url)
+			|| (allowNoScheme && !url.startsWith('mailto:') && noSchemeRE.test(url));
 	},
 	
 	/**

chrome/content/zotero/xpcom/zotero.js

@@ -1023,17 +1023,32 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 	
 	
 	/**
-	 * Launch an HTTP URL externally, the best way we can
-	 *
-	 * Used only by Standalone
+	 * Launch a URL externally, the best way we can
 	 */
 	this.launchURL = function (url) {
 		if (!Zotero.Utilities.isHTTPURL(url)) {
 			if (Zotero.Utilities.isHTTPURL(url, true)) {
 				url = 'http://' + url;
 			}
+			// Launch non-HTTP URLs
 			else {
-				throw new Error("launchURL() requires an HTTP(S) URL");
+				let matches = url.match(/^([a-z]+):/);
+				if (!matches) {
+					throw new Error(`Invalid URL '${url}'`);
+				}
+				let scheme = matches[1];
+				if (['javascript', 'data', 'chrome', 'resource'].includes(scheme)) {
+					throw new Error(`Invalid scheme '${scheme}'`);
+				}
+				let svc = Components.classes['@mozilla.org/uriloader/external-protocol-service;1']
+					.getService(Components.interfaces.nsIExternalProtocolService);
+				let found = {};
+				let handlerInfo = svc.getProtocolHandlerInfoFromOS(scheme, found);
+				if (!found.value) {
+					throw new Error(`Handler not found for '${scheme}' URLs`);
+				}
+				svc.loadURI(Services.io.newURI(url, null, null));
+				return;
 			}
 		}
 		
@@ -1058,7 +1073,8 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 			
 			let exec = Zotero.File.pathToFile(path);
 			if (!exec.exists()) {
-				throw ("Fallback executable not found -- check extensions.zotero." + pref + " in about:config");
+				throw new Error("Fallback executable not found -- "
+					+ "check extensions.zotero." + pref + " in about:config");
 			}
 			
 			var proc = Components.classes["@mozilla.org/process/util;1"]

test/tests/utilitiesTest.js

@@ -55,6 +55,10 @@ describe("Zotero.Utilities", function() {
 			assert.isFalse(Zotero.Utilities.isHTTPURL('file:///c:/path/to/file.txt'));
 		});
 		
+		it("should return false for mailto URLs in allowNoScheme mode", function () {
+			assert.isFalse(Zotero.Utilities.isHTTPURL('mailto:foo@example.com', true));
+		});
+		
 		it("should return false for zotero: URL", function () {
 			assert.isFalse(Zotero.Utilities.isHTTPURL('zotero://select/library/items/AAAAAAAA'));
 		});