We add a refresher to have some force refresh mechanism in place (still, returning cached data when offline!) and a list of the users with a button to update them. Perhaps check a status or flag to determine if it’s worth caching or if the request was just bad.Īll of this looks like the code below in action which goes to your app/services/: This is a general assumption and of course you should not store any failed request! If we are online, our requests run through as desired and for a GET we store that information to our storage, for the important PUT we might want to catch any error case and store it locally then. If you want a little course / intro on different RxJS functionalities just let me know below in the comments!īack to topic. It’s always good to know what the functions return so you can map/change the result according to what you need. They basically help us to transform our Observable data because we are often working with the Ionic Storage which returns a Promise and not an Observable. ![]() I’ve slowly made my way through different operators and how to use them, and I’m far from an expert. Let’s start the fun by creating a new Ionic 4 app, generating a bunch of services that we will need for the different features and finally the Ionic native and Cordova plugins for checking the network and using Ionic Storage:Īnyway, we continue with the class that actually performs the API calls and you’ll most likely already have something like this.Īt this point you can now make use of both of our previous services.įirst of all we can check the internet connection inside our functions to see if we are maybe offline in which case we either directly return the cached result from our storage or otherwise store the PUT request within our offline manager so it can be performed later on.Īlong this and the other classes you have seen quite a few RxJS operators, and if they scare you I can understand you 100%. This post was created with the Ionic 4 Beta 13! While there are caching plugins (that don’t work well with v4 yet) and PWA with service workers you sometimes have specific requirements and therefore this post aims to show how to build your own offline mode system – not 100% like described here perhaps but it will give you a good start in the right direction. Also, we create an offline manager which stores requests made during that time so we can later send out the calls one by one when we are online again. In this article we will build an Ionic 4 offline mode app that caches API data so it can be used as a fallback later. (lldb) 08:07:02.369 myApp Failed to load webpage with error: The request timed out.To build an Ionic 4 Offline Mode app you have to use a package or get creative, but inside the post you will see how everything works to take your app offline and still use it. ![]() (lldb) 08:06:41.223 myApp Resetting plugins due to page load. (lldb) 08:06:34.732 myApp Unlimited access to network resources (lldb) 08:06:34.722 myApp Multi-tasking -> Device: YES, App: YES (lldb) 08:06:34.720 myApp Apache Cordova native platform version 3.7.0 is starting. ![]() 08:06:32.167 myApp DiskCookieStorage changing policy from 2 to 0, cookie file: file:///private/var/mobile/Containers/Data/Application/D288A26E-8124-4636-9B31-EE14F5F9CA1C/Library/Cookies/Cookies.binarycookies (lldb) command script add -s asynchronous -f fruitstrap_b8647a1a6f71f6194d3ceae024d7e3f307673097.safequit_command safequit (lldb) command script add -s asynchronous -f fruitstrap_toexit_command autoexit (lldb) command script add -s asynchronous -f fruitstrap_n_command run (lldb) command script add -f fruitstrap_nnect_command connect (lldb) target create "/Users/en17682/dev/projects/WorkTips/myApp/platforms/ios/build/device/myApp.app"Ĭurrent executable set to '/Users/en17682/dev/projects/WorkTips/myApp/platforms/ios/build/device/myApp.app' (armv7). SDK Path: "/Users/en17682/Library/Developer/Xcode/iOS DeviceSupport/8.1.2 (12B440)/Symbols" (lldb) platform select remote-ios -sysroot '/Users/en17682/Library/Developer/Xcode/iOS DeviceSupport/8.1.2 (12B440)/Symbols'
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