file:// in allow-navigation crashes on iOS

[ankon]

Bug Report

Problem

Using <allow-navigation href="file://"></allow-navigation> crashes parseWhitelistUrlForATS on iOS.

TypeError: Cannot read property 'indexOf' of null
    at parseWhitelistUrlForATS (.../.cordova/platforms/ios/cordova/lib/prepare.js:1056:27)
    at .../.cordova/platforms/ios/cordova/lib/prepare.js:982:23
    at Array.reduce (<anonymous>)
    at processAccessAndAllowNavigationEntries (.../.cordova/platforms/ios/cordova/lib/prepare.js:973:10)
    at writeATSEntries (.../.cordova/platforms/ios/cordova/lib/prepare.js:1099:16)
    at updateProject (.../.cordova/platforms/ios/cordova/lib/prepare.js:215:15)
    at .../.cordova/platforms/ios/cordova/lib/prepare.js:59:20
    at _fulfilled (.../.cordova/node_modules/q/q.js:854:54)
    at .../.cordova/node_modules/q/q.js:883:30
    at Promise.promise.promiseDispatch (.../.cordova/node_modules/q/q.js:816:13)"

What is expected to happen?

"Nothing", as the setting is the default.

What does actually happen?

An error that indexOf isn't a function on undefined :)

Information

cordova-ios/bin/templates/scripts/cordova/lib/prepare.js

Lines 1051 to 1068 in 5e688ca

	if (!retObj.Hostname) {
	// check origin, if it allows subdomains (wildcard in hostname), we set NSIncludesSubdomains to YES. Default is NO
	var subdomain1 = '/*.'; // wildcard in hostname
	var subdomain2 = '*://*.'; // wildcard in hostname and protocol
	var subdomain3 = '*://'; // wildcard in protocol only
	if (href.pathname.indexOf(subdomain1) === 0) {
	retObj.NSIncludesSubdomains = true;
	retObj.Hostname = href.pathname.substring(subdomain1.length);
	} else if (href.pathname.indexOf(subdomain2) === 0) {
	retObj.NSIncludesSubdomains = true;
	retObj.Hostname = href.pathname.substring(subdomain2.length);
	} else if (href.pathname.indexOf(subdomain3) === 0) {
	retObj.Hostname = href.pathname.substring(subdomain3.length);
	} else {
	// Handling "scheme:*" case to avoid creating of a blank key in NSExceptionDomains.
	return null;
	}
	}

As per the documentation the value file:// is the default (https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-whitelist/), but when using that value !retObject.HostName is true-ish, but there is no href.pathname.

Version information

cordova-ios 5.0.0.

Checklist

• I searched for existing GitHub issues
• I updated all Cordova tooling to most recent version
• I included all the necessary information above

[purplecabbage]

I have added a potential fix for the crash. In the mean time, there is no benefit to adding 'file://' to your whitelist since it is already allowed. If you feel you must, then please use 'file://*'