a question about local and remote storage of user data. Is there a best practices for the common situation where a user accesses data from an API and can favourite or otherwise personalise the data.
I have seen tutorials, e.g. a movie browsing app, where the use can make a list of favourite movies, where this personalised data is stored locally (e.g. in sqflite) and other tutorials where this data is stored remotely, eg. firebase. And firebase has an offline mode, so that data can be synced later. In that case, is it a common use case to set up local storage as well as cloud storage? Is there a common practice for this situation?
Thanks for any insights.
This is not specifically a Flutter question, more of a general app development question. It's very common to have both local and cloud "storage" but I wouldn't think of it that way. If you're interacting with an API backend I wouldn't consider it as the cloud storage for your app. Instead look at it as a different component within your applications overall architecture. You API/Backend component, this way it's not apart of your app instead it's something your app interacts with.
I assume you know the purpose of your API. Returns your data you want to see, keeps track of user profile information and other sensitive information.
When it comes to local storage I'd say the most common scenarios for local storage is results caching and storing information that the API requires on every session to make the user experience a bit better. See some examples below for both:
On instagram they store your "Feed watermark" which is a string value that is linked to a specific set of results so that when you open the app and request again they return that set of results, plus anything new - Local storage
They also "store locally" (better referred to as caching) a small set of your feeds from your posts, a list of user profiles that has stories on them and your DM's for instant and offline access. This way when the app loads up it has something to show while performing the action to get the new information. - Caching
They also store your login token, that never expires. - Local storage
tl;dr: Yes. If you need data on every session to use your API store that locally in a secure way and use that to interact with your "Cloud storage".
Related
As with many other founders and their start-ups, I'm low on cash and aiming to launch without funding. The app will be dealing with users health data so setting up a server with the correct encryption may be costly. I am also only familiar with JSON, SwiftUI, Swift5 and API programming so setting up a server is outside my scope of expertise.
Therefore, I aim to launch the app with all user data stored locally in SwiftUI CoreData, as to avoid these issues. With enough users i.e. traction, I will then begin to seek funding, at which point I would hope to set up an encrypted server and transfer user data there.
I am worried that if I launch with local storage, I will not be able to transfer each individual users data to an external server, without them having to reenter all of their information.
I was just wondering whether this was possible or not? And if you could provide details that would be very helpful.
PWA application storage (IndexedDB) isn't able to provide data persistence.
In case that PWA is pinned to home screen it is possible to clear all application data from browser by clearing browsing history.
It might be unclear for users that cleaning browser data can affect pinned application and unsynchronised data will be lost.
Is there any way to avoid this?
The only way I see for now - turn back to native apps.
The clear storage mechanism in browsers is to put the user in control of their device.
This is why you as an application should never (native or web) assume your cached assets are cached.
If it is absolutely important to you to make sure you have core assets and data persisted then you need to have some sort of integrity check when the service worker initiates. That way you can restore cached state in case the application goes offline.
You also need to realize the operating system, looking at you iOS, will purge data when it feels like it (think when the available disk space gets critical), which takes you out fo control. It does this for native apps too as far as I know.
I do not know a way around that. The function in Chrome to "clear storage" (for example) does exactly that. I suppose it is reasonable for a user to be able to remove any data from their own device, but I agree it is not a good situation for the developer.
This is not possible.
The Storage API provides a StorageManager.persist() method to request the user explicit permission to persist data until deleted by the user itself:
if (navigator.storage && navigator.storage.persist)
navigator.storage.persist().then(function(persistent) {
if (persistent)
console.log("Storage will not be cleared except by explicit user action");
else
console.log("Storage may be cleared by the UA under storage pressure.");
});
If the local storage is running out of space, the User Agent will start automatically pruning cached resourced except the ones set as "persistent". However if the user itself chooses to clear the local data, there is no way to prevent this.
As far as I am aware, there is no event you can intercept in order to detect a browser clear action from the user.
See API reference doc :
https://developer.mozilla.org/en-US/docs/Web/API/StorageManager/persist
I’m building a new web application which needs to work seamlessly even when there is no internet connection. I’ve selected Angular and am building a PWA as it comes with built-in functionality to make the application work offline. So far, I have the service worker working perfectly and driven by the manifest file, this very nicely caches the static content and I’ve set it to cache a bunch of API requests which I want to use whilst the application is offline.
In addition to this, I’ve used localStorage to store attempts to invoke put, post and delete API requests when the user is offline. Once the internet connection is re-established, the requests stored in localStorage are sent to the server.
This far in my proof of concept, the user can access content whilst offline, edit data and the data gets synced with the server once the user’s internet connection is re-established. This is where my quandary begins though. There is API request data cached automatically by the service worker as defined in the manifest file, and there is a separate store of data for data edits whilst offline. This leads to a situation where the user edits some data, saves the data, refreshes the page and the data is served by the service worker cached API.
Is there a built in mechanism to update API data cached automatically by the service worker? I don’t fancy trying to unpick this manually as it seems hacky and I can’t imagine it’ll be future proof as service workers evolve.
If there isn’t a standard way to achieve what I need to do, is it common for developers to take full control of offline data by storing it all in IndexedDB/localStorage manually? i.e. I could invoke API requests and write some code which caches the results in a structured format in IndexedDB to form an offline database, then writes back to the offline database whenever the user edits some data, and uploads any data edits when the user is back online. I don’t envisage any technical problems with doing this, it just seems like a lot of effort to achieve something which I was hoping to be standard functionality.
I’m fairly new to developing with Angular, but have many years of other development experience. So please forgive me if I’m asking obvious questions, I just can’t seem to find a good article on best practices for working with data storage with service workers.
Thanks
I have a project where my users can edit local data when they are offline and I use Cloud Firestore to have a local database cached available. If I understood you correctly, this would be exactly your requirement.
The benefit of this solution is that with just one line of code, you get not only a local db, but also all the changes made offline are automatically synchronised with the server once the client gets online again.
firebase.firestore().enablePersistence()
.catch(function(err) {
// log the error
});
// Subsequent queries will use persistence, if it was enabled successfully
If using this NoSQL database is an option for you I would go with it, otherwise you need to implement the local updates by yourself as there is not a built in solution for that.
Preface:
I'm hoping to upgrade an existing application by adding cloud backup and syncing of the customers data. We want this to be as seamless as possible, but also for the customers only interface to the data to be via the applications front-end interface.
Our application can be connected to the oil pipe of a machine, collects data on the oil condition. When a test has completed we want to push this to the cloud. Because of the distinct test nature of the data (as opposed to one big trend) most IoT platforms don't suit very well, so we're aiming to release a slightly modified version of the application which doesn't have the connection to the sensors and this will be our remote front-end.
Since the existing application uses a relatively simple file structure to store it's data, if we simply replicate these files in the cloud, the remote front-end version can just download these to the same location and it'll work fine. Thus this has lead us to Dropbox (or any recommended more appropriate cloud storage system).
We hope to use the Dropbox API directly in our application to push and pull the files as necessary. All of this so far we believe is perfectly achievable.
Question: Is it possible - and if so how would we go about - to setup a user system with the below requirements
The users personal dropbox is not used
Dropbox is completely hidden from the user
The application vendor has a top level user who has access to all data (for analytic, we do not want to store confidential or sensitive data).
When the user logs in they only have access to their folder and any attackers could not disrupt the overall structure. (We understand that if an attacker got the master account then all is lost, but that is an internal issue to keep it secure. As long as the user accounts are isolated this is okay.)
Alternative Question Is anyone aware of a storage system or IoT system which would better suite this use case? We will still require backups/loss prevention as part of the service.
Im really confused when thinking about my requirement to store data locally for offline viewing.Now i have two options,DOM storage and HTML5 Local storage.
As im a complete newbiew in this particular topic,i need some help of SO Experts and Gurus.
Whats the Advantage and Dis-advantage of these two.?can any one compare these one.,so that i can understand deeply or give some reference links?
DOM Storage or Web Storage is the collective name given to the following types of client storage options available in HTML5. It includes:
localStorage
sessionStorage
Local storage is persistent meaning the stored data will still be there when you close and re-open the browser window.
Session storage is temporary and is available as long as the page session lasts.
There is really no comparison between the two since technically they both are the same.
Try to have a read here http://blog.sebarmeli.com/2010/11/22/understanding-webstorage/, you can easily understand the two objects, their methods, event attributes and their possible use.