I am designing a web app that fetches data every time a user logs into his/her account. The data is an xml file containing image links and some text. I want this data (after image fetch/load from the actual link) to be stored locally so that every time an user opens the app it doesn't have to load everything from scratch. Locally stored contents should load first, then in the background some network processing shall be done so that the newer data is automatically updated. For storing the data I am planning to use SQLite but is there any other efficient way other than this to do the same ?
How does facebook app do this kind of stuff ? Thank you so much
The Facebook app is not really a web app but rather a native Cocoa Touch app.
If you are really creating a web app, your only option is to use localstorage and fetching new data asynchronously using XMLHTTPRequest.
If – on the other hand – your app is a native app, you’ll most likely want to use Core Data for storage and get incremental updates in a separate thread (or using libdispatch in case you’re only targetting post 4.0 devices) using a separate managed object context which you can then merge to the main thread using mergeChangesFromContextDidSaveNotification:.
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Good evening everyone .
I am developing a react native app by interfacing to a database via endpoint (specifically aws).
Now on loading the dashboard I retrieve this data via API , save it in local storage and show it to the user.
Now from the management system, there could be some changes to this data that I show on the app, so what I was interested in knowing was if it was possible to create a sort of listener that calls my API whenever there are changes in the DB. I ask this because I would like to avoid calling the API every time a user lands on the dashboard and I would like to avoid calling the API every XXX minutes if there is no reason (if the data has not changed).
Is there any way to create an event listener? It would also be enough for me to be directed on what exactly to look for.
Thanks in advance for your availability
I am looking at building an offline first React Native Expo app that automatically pushes data to an API when the device gets a connection. However I am struggling to see how if this is possible within Expo and need some guidance.
The app will need to store data from an API for offline use (presumably on first load, which will then be used to populate fields in a form). The form needs to work offline, with the input data stored on the device until it receives a new connection. At that point the app should push the data to an API (whilst the app is in the background). So I need to do multiple things:
Automatically download and store data from an API on first launch.
Store input data - from form fields whilst offline.
Background sync - Upload this user form data when a new connection is received, regardless of whether the app is running in the background or not.
Work on Android and iOS devices.
I have been looking at redux-offline, but unsure if it still supported and/or will satisfy all four requirements?
There is also redux-persist but I can't see how this satisfies the background sync?
Thanks for any help/guidance!
From my point of view, redux-persist is less opinionated compared to redux-offline. I pick redux-persist with useNetInfo hook to listen to network availability.
1. Automatically download and store data from an API on first launch.
When app launch, query initial data and dispatch to redux store and synced automatically to local storage by redux-persist
2. Store input data - from form fields whilst offline.
With useNetInfo, the app can detect network connectivity status, when not connected, dispatch to the redux store with a flag to indicate offline unsynched data.
You need to write a network connectivity listener which is executed when the network state changes and continuously track unsynched data and sync with the database when available and purge those temporary data like form values.
3. Background app sync
Expo SDK provides API https://docs.expo.dev/versions/latest/sdk/background-fetch/
to run continuously a background task at a certain time threshold.
You can sync offline data when the network returns back while the app is background.
Disclaimer: Background tasks run outside of React componentS tree. You can't access redux store data through the react-redux's store component or hooks based API.
redux-persist saves data with Async Storage and you need to directly access data as below.
AsyncStorage.getItem("persist:[REDUCER_CONTAIN_INTERESTED_DATA]")
This seems to be an issue with server state with a client cache. Looks like an ideal case for react-query to solve.
Automatically download and store data from an API on first launch.
This should be taken care of by query prefetching
Store input data - from form fields whilst offline.
Probably needs client state(redux/Zustand etc) for managing state with unverified fields. For storing submitted forms, react-query supports offline caching of 'mutations'.
Background sync - Upload this user form data when a new connection is received, regardless of whether the app is running in the background or not.
Work on Android and iOS devices.
See above.
I am making a mobile app using Cordova and I need to save some sensitive and not so sensitive data inside the phone. I am a bit lost on what is the best way to do it.
I need to save:
A JSON web-token (for authentication).
A response from server (I save this to populate my page in case the GET request fails).
Coordinates information when user is logging data to the app (for later upload to a server from with in the app). These will be many separate logs, and can be large in size for local storage ~5-10 MB.
Till now i have been successfully saving everything I need to the local storage but I don't think that is the correct way to do it. So that is why I need some help in deciding what is the best course to take from security point of view.
Saving server response is just for better UI experience and static in size so I guess local storage is a good option to use.
But web-tokens and GPS logs is sensitive information and I dont want to keep it in the local storage as it is accessible from outside the app.
What other options do I have?
Cordova still doesn't have encrypted storage.
Is saving to files a good approach? This here says that data contained inside cordova.file.applicationStorageDirectory is private to the app.So can I use it to save the logs and the token?
The plugin also lists the file systems for Android and iOS and lists which of those are private.
I am currently working with android phones but want to extend the app to iOS later. I have never worked with file systems and caches before so I am a bit lost.
How does the Dropbox Datastore API differ from similar offerings like Parse? One difference that I see is that my users pay for server storage instead of me. Are there other differences?
Disclaimer: I'm a Dropbox engineer who worked on the Datastore API, and know about the Parse API only indirectly. Weigh my opinion appropriately. Major differences I know of (pro and con):
Dropbox Datastores are free to the developer, and free the user for the first 5MB per-app (after which their Dropbox quota applies). Parse charges developers based on how many API requests they’re making.
Parse has minimal offline support, while Dropbox has full offline operation. With Dropbox, if the developer modifies data while offline, those modifications will be reflected in subsequent queries (with Parse, those changes are not reflected). Dropbox provides on-device query logic (unlike Parse) so that apps can continue to generate the views they need to, even when there’s no Internet available. In addition, Parse does not provide conflict resolution or querying offline.
Parse provides the ability to share data between users, and global data for all users of the app. Dropbox Datastores only support per-user data (for each app) for now (sharing is on the roadmap).
I would also add that:
Parse is full feature of backend of as service. You can find a pretty complete list of the other player in this field: http://en.wikipedia.org/wiki/Backend_as_a_service. They provide feature like:
Data service
User registration/auth
Push notification
Social
The dropbox Datastore APIs is more focusing on data services. (You also got the User part for free too?) Also it works full offline.
The Parse framework can store data that can be ready by any user in the application.
The Dropbox datastore, store data for each user, and you can't accesss data from other user. That's the main difference.
So easy to get lost in this since you have to read between the lines. My take is that with Datastore you are working with objects stored offline locally as json. I'm hoping they will soon release a Xamarin Android component - they released an IOS component last month. Since Xamarin targets both Android and IOS and Winphone, who knows why they made a dedicated IOS DLL for Xamarin but I digress. With Parse, it appears to me their intent is the always-connected-device. Sure you can save queries locally and you can save (save eventually) locally where Parse will push to the server when it is connected. But saving "eventually" and saving queries for offline work is a different design than just saving and letting Parse do it all in the background for you - which it does not unless I have missed something that would make this attractive to me. I cannot see Parse useable for devices that you know will be sometimes-connected, without a lot of code to make this happen and sync.
Well, the topic says it all. I'm dabbling with windows 8 app development using html/css/javascript and I'm having a hard time finding information on how to dynamically manipulate the live tiles.
There is a lot of information out there on how to create multiple tile xml files and launch them after each other but if anyone had a good resource, or even better, a first-hand explanation, on how to create these tiles programatically to, say, make a countdown tile, it would be greatly appreciated.
There's no way to programmatically update the text/image on a live tile directly in real time.
The only APIs available are those in the Windows.UI.Notifications namespace, such as are shown in the Sending a tile update Quickstart.
You can use the notification queue, as shown here, to provide multiple updates that will automatically cycle, or you can use an external service, such as Windows Azure Mobile Services to send tile updates. Using push notifications from an external service will probably get you closest to the behavior you're looking for, since it will not rely on the app being active in order to update the tile. Be aware, however, that the app will need to run at least once in order to create the channel URI that's needed for the external service to update the tile.
For more info on Windows Store app development, register for Generation App.