How do I gracefully interrupt loading of a certain URL in Cordova's InAppBrowser and open it in the system browser?

Question

I am using Cordova's inappbrowser plugin to display web parts in my app. On the website, there are sharing links, e.g. for WhatsApp:

<a href="whatsapp://send?text=Check this out">Share on WhatsApp</a>

Now when clicking these links in inappbrowser, it simply tries to load whatsapp://send?... as a URL and displays an error page.

What I want to do instead is open links that start with whatsapp:// using the given system's browser/URI handler so it resembles the behavior when clicking such link in the system's browser. To do that, I did the following:

urlChanged = function(event) {
    // when a "whatsapp://" link is clicked, open it in the system browser
    if(event.url.startsWith("whatsapp://")) {
        window.open(event.url, "_system");
        return;
    } 
}
// Add an "loadstart" event listener to the inappbrowser:    
browser.addEventListener("loadstart", urlChanged);

So far, this somewhat works, but with quirks:

1. While the event immediately fires when the user clicks a WhatsApp link (checked that by firing an alert), it takes like two or three seconds for the system browser to actually open.
2. While waiting these 2-3 seconds and when returning to the app, the user sees an inappbrowser error page that the whatsapp:// link could not be opened ("unknown url scheme").

To mitigate point 2, I also tried the following in the event listener, without success (the behavior is exactly the same):

urlChanged = function(event) {
    if(event.url.startsWith("whatsapp://")) {
        // stop loading the whatsapp:// link in inappbrowser
        browser.stop(); 
        // go back in history to display page where whatsapp:// link was on
        browser.history.back(); 
        window.open(event.url, "_system");
        return;
    } 
}
browser.addEventListener("loadstart", urlChanged);

Can you guide me how to solve points 1 and 2?

Answer 1

So I ended up with the following code:

openWithSystemBrowser = function(url) {
    window.open(url, "_system");
    location.href = "index.html";
};

shareOnWhatsapp = function(url) {
    openWithSystemBrowser(url);
};

/**
 * Handles URL changes in in-app browser, e.g. to handle logouts or
 * unsuccessful logins
 */
urlChanged = function(event) {
    if(event.url.startsWith("http://whatsapp://")) {
        shareOnWhatsapp(event.url.substr("http://".length));
        return;
    }
    if(event.url.startsWith("whatsapp://")) {
        shareOnWhatsapp(event.url);
        return;
    }
};

This is of course slightly lame as you're always brought back to index.html, but for my purposes it was enough. Interested to see if anyone's found a more elegant solution.

It also solved the 2-3 second delay before opening the system browser, but I don't have any clue why, frankly.

Answer 2

I found an approach with a better user experience: When loading an external URL in the system browser, I close the InAppBrowser and reopen it with the last internal URL.

var appUrl = 'https://www.my-website.com';

var app = {

    currentUrl: appUrl,

    initialize: function() {
        document.addEventListener('deviceready', this.onDeviceReady.bind(this), false);
    },

    onDeviceReady: function() {
        app.openBrowser();
    },

    openBrowser: function() {
        var target = '_blank';
        var options = [
            "location=no",
            "clearcache=no",
            "clearsessioncache=no",
            "footer=no",
            "hardwareback=no",
            "hideurlbar=yes",
            "zoom=no",
            "hidenavigationbuttons=no",
            "toolbar=yes",
            "hidespinner=yes",
            "toolbarcolor=#000000",
            "toolbartranslucent=no",
            "navigationbuttoncolor=#ffffff",
            "closebuttoncolor=#000000",
            "closebuttoncaption="
        ];

        browser = cordova.InAppBrowser.open(app.currentUrl, target, options.join());

        // reopen the browser if it was closed via "Done" button
        browser.addEventListener('exit', function(){ app.openBrowser(); } );

        // open external urls in system browser window
        browser.addEventListener('loadstart', function(event){ app.handleUrl(event.url, browser); });
    },

    handleUrl: function(url, browser) {
        var extension = url.split('.').pop();

        // load internal urls that are not pdf files in the app browser
        if (extension != 'pdf' && url.startsWith(appUrl)) {
            app.currentUrl = url;
            return;
        }

        // open website in system browser window
        var ref = cordova.InAppBrowser.open(url, '_system', 'location=no');

        // since the inapp browser is loading the website too, close it and open it again with the last internal url visited
        browser.close();
        app.openBrowser();

        return;
    }
};

app.initialize();