Building cool hybrid mobile apps - Lessons from Basecamp

Basecamp has successfully utilized hybrid techniques for building their iOS and Android apps. The following links are worth a perusal to understand the techniques they used.

https://signalvnoise.com/posts/3743-hybrid-sweet-spot-native-navigation-web-content

https://signalvnoise.com/posts/3438-drawing-the-nativeweb-line-in-basecamp-for-iphone

https://signalvnoise.com/posts/3766-hybrid-how-we-took-basecamp-multi-platform-with-a-tiny-team


PhoneGap on its blog has made an interesting distinction between two types of Hybrid applications -

1. Web Hybrid: This is the default approach that PhoneGap takes. You package your apps as HMTL5/CSS3 and then run the app in a thin native web view container. All the UI controls are HTML or JavaScript controls.
2. Native Hybrid: In this approach, you build a native app and use native controls for navigation, menus, etc. But most of the content pages are HTML views rendered in a web view. The HTML content can come from the local store or the server. 

Apple enforcing HTTPS connections using TLS v1.2

In iOS 9, Apple has implemented a new security feature called as ATS (App Transport Security), which is enabled by default.

So what is ATS? In simple words, ATS enforces all HTTP requests to be made on SSH - i.e. any API call your app makes to the backend servers must be on HTTPS. If you want to make an unsecured HTTP call, then you have to explicitly list down those exceptions in your Infoplist file.

ATS also enforces the latest protocol version of TLS - i.e. Transport Layer Security version 1.2. This can cause issues if your server is using HTTPS, but an older version of TLS. In such cases, you have two options - either upgrade your server to use the latest TLS protocol or add an exception to your app for these URLs.

More details on ATS can be found here. 

Updating content in an iOS app

Any mobile app needs to have a design strategy for updating content from the server. We were exploring multiple options for retrieving content from the server and updating the local cache in our iOS app.

After considerable research, we have found that iOS 7 provides a very neat design for background fetching of new content - one that uses silent push events to raise events in the client app. Even if the app is not running, it would be launched in the background (with UI invisible, rendered off-screen) to process the event. The following article gives a very good overview of the technique.

http://www.objc.io/issue-5/multitasking.html

Some snippets from the above article:

A Remote Notification is really just a normal Push Notification with the content-available flag set. You might send a push with an alert message informing the user that something has happened, while you update the UI in the background. 
But Remote Notifications can also be silent, containing no alert message or sound, used only to update your app’s interface or trigger background work. You might then post a local notification when you’ve finished downloading or processing the new content. 

 iOS 7 adds a new application delegate method, which is called when a push notification with the content-available key is received. Again, the app is launched into the background and given 30 seconds to fetch new content and update its UI, before calling the completion handler.

How is the App launched in the background? 
If your app is currently suspended, the system will wake it before callingapplication: performFetchWithCompletionHandler:. If your app is not running, the system will launch it, calling the usual delegate methods, includingapplication: didFinishLaunchingWithOptions:. You can think of it as the app running exactly the same way as if the user had launched it from Springboard, except the UI is invisible, rendered offscreen.