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Sharing data in between apps in IOS
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I've been doing research on how to share data between applications securely. I'd like to get some info on the correct way to handle this before I do a deep dive on implementation using the wrong method. Just cause you can do something does not necessarily mean you should.
User Case: I am working on a suite of language learning apps that have a shared audio file base of several hundred audio files and json files containing important data corresponding to a language. I'd prefer to allow the user to not have to re-download the language bundle when they use another app in our suite.
1. App Extensions - Document Provider Non-UI Variant
According to the documentation:
The File Provider extension grants access to files outside the host app’s sandbox with the open and move actions. This extension (sometimes shortened here to file provider) also allows the host app to download files without presenting a document picker view controller. This feature lets the host app access previously opened documents using secure URL bookmarks, even if those files are no longer stored on the device.
On the surface this seems like a really solid solution. My main concern stems from the last couple lines where it state that the application can download the files no longer stored on the device. I want the files to be stored locally on the device to prevent constant downloading. If the Document Provider does store the files locally and allow the various applications in the group to access the files, then I think this could work.
2. Shared Keychain Access
Allows you to securely store data to a shared keychain that other applications that are part of a suite of applications can access. All applications that share keychain access must use the same app ID prefix. For an example of shared keychain access in action.
I've looked a little into the documentation of this one, and I think this might be the best fit. My major concern with this solution is whether or not there is a size limit to the data uploaded and if mp3/ogg/json file types are allowed. Most the examples/uses I have found with this solution point to sharing strings and small data, I am not sure if it will handle large data like json or audio files.
I also found this repo that apparently makes dealing with Keychain easier:
3. Custom Pasteboards
The custom pasteboard is best for the purpose of semi-privately sharing custom data between two applications. Custom pasteboards are identified using unique names. They can persist data beyond the application that creates them, allowing a pasteboard to hold onto data after the application is terminated or even after rebooting the device.
When writing or reading data to and from a pasteboard, you must specify a pasteboard type. Pasteboard types typically use a uniform type identifier (UTI) to identify the type of data going into and being retrieved from the pasteboard. See Apple’s UIPasteboard Class Reference documentation for additional information.
Above documentation pulled from this post
My main concern with this solution is that perhaps it is a bit of a hack. Logically a pasteboard seems like something that temporarily holds data and allows sharing between apps, whereas the solution I am looking for needs to be more of a permanent solution.
I'd appreciate any info on best practices towards sharing these types of files between apps. I assume there are plenty of other solutions I've omitted here, so if there is a better alternative I'd love some info on it. If it happens one of the listed solutions I have placed here is a good way to solve this problem I'd love to have some more info on your experience with working with them and if my concerns with them are valid, or nothing to worry about.
Thx in advance. As always, well written answers get up-votes ;)
I believe the best approach would be to enable data sharing by setting up an app group. This is Apple's recommended solution for sharing data between applications and extensions, and I believe for sharing data between apps in general.
See the section "Sharing Data with Your Containing App"
Also see "Adding an App to an App Group":
Related
I am looking for a way to fetch data to my flutter app which can be adjusted and modified dynamically after deploying the app. As an example, if I want to change the images of the carousel depending on promotions or launch new books to the digital library. I need an economic option to host the data in cloud storage and fetch it from there.
I have considered firebase as well as google drive, but have yet to find a good guide. being a beginner and having concerns about security I want some expert advice if possible.
*edit-
Seeing many a tutorial I assume there is no better way than linking file URLs from the
Cloud Storage. So to dynamically change those is it possible to refer the URLs to some excel sheet fields to obtain URLs. Those fields can certainly be adjusted then without any hard coding. but the question is how to refer to such a sheet file? *
I also want to segregate the users into paid and free users, I have successfully proceeded with the authentication with firebase but still don't understand(I do have some concepts but don't know where to do that) how to put them in groups and impose limitations on them about accessing the data. any guidance, links and helpful advice will be cordially appreciated.
According to what you are looking for, I highly recommend you to use Firebase Remote Config, which is a cloud tool that allows you to modify your app's functionality and appearance without forcing users to download an update. You define in-app default values that control the functionality and appearance of your app when you use Remote Config. Then, for all app users or for subsets of your user base, you may utilize the Firebase console or the Remote Config backend APIs to modify in-app default values.
Your program can control when updates are applied, and it can check for updates regularly and apply them with minimal performance impact.
Remote Config comes with a client library that takes care of essential functions like fetching parameter values and caching them while still allowing you to manage when new values are active and how they affect the user experience in your app.
Here is a tutorial that uses Flutter and Firebase Remote Config that could also help you.
I am new to iPhone app development and have a question about storing data. I've spent quite sometime learning about core data but still confused about the concept of persistence store.
What I understand is that core data is just a way of managing the data you downloaded from an external database. But given that core data is backed by SQLite, does that mean there exists a SQLite db in-memory while running? If so, does that mean when I use core data it will be more effective if I download a huge data set at start? But what about apps such as twitter or Facebook that require constant update of data, is a straight $NSURLConnection$ sufficient in these cases? If core data is used, will the extra overheads (i.e. data objects) be of any burden for such frequent request of update?
I would also like to find out some common ways of setting up an online database for iPhone app? Is it usually MySQL servers with a homemade Python wrapper that translates the data into JSON? Any standard server provider would provide the whole package? Or open source code?
Many many thanks!
I'm going to go through and try to address each of your questions, let me know if I missed one!
Firstly, Core Data can be used to store information generated in your app as well, there is nothing keeping you from using it in one way or another.
The way I understand it working is that the file, or other storage mechanism Core Data uses, exists regardless of whether or not your app is running. For a user to have to wait for a large database to be downloaded and loaded into a local database without being able to interact with your application is not the best way to do it in my opinion, people react negatively unresponsive UI. When a user may run your app for the first time, its possible you may need to get a larger set of data, but if any of it is generic and can be preloaded that is ideal, the rest should be downloaded as the user attempts to access it.
Facebook and Twitter applications work just as you understand in that a connection is established and the information is pulled from the appropriate site, the only thing they store is profile information, as far as I know. I would hesitate to use Core Data to store peoples information as eventually yes, there would be a significant amount of overhead caused by having to store peoples news feed or messages going back months on end.
As for setting up on online database that is something I'm unfamiliar with, so hopefully someone else can provide some insight on that, or if I find something I think may be of use, I will post back here for you. This part may actually merit its own separate question.
Let me know if you need to me elaborate on anything!
Basically I want to know if apps work and store data independent of one another or if there is a possibility for one app to modify another. Also...
In what folder are apps and their data saved on a phone?
If I modify data locally in an app, will the data be saved in a public place where other apps have access or is it saved to a folder specific to that app?
iOS is kinda not that mature in inter-app communication.
Data can be shared between apps using the system clipboard and transmitted over the network through mediums such as email and webservices.
iOS devices also provide a straightforward and well defined method for apps to send messages and data via URLs and filetype handlers. These techniques diverge into two categories:
Custom URL prefixes, e.g. someapp://something/somethingelse?somestuff=whatever
Custom file type handlers by file extension (e.g. *.txt) or by MIME type (e.g. text/plain).
Custom URL prefixes are useful for when two apps have established a specific protocol, while custom file type handlers are much more general, and are designed in a way that allows any app to register itself and participate. This article describes the latter: custom file type handlers for chemical data. If you register your app for a certain filetype it will look like so -
Reg. your second part of question - If I modify data locally in an app, will the data be saved in a public place where other apps have access or is it saved to a folder specific to that app?
As such, each application is restricted in terms of where it can store data on the file system of the device. iOS achieves this by allowing applications to read and write only to their own Documents and tmp directories. Within these two directories the corresponding application can create files and also sub-directories to any required level of depth. This area constitutes the application’s sandbox and the application cannot create or modify files or directories outside of these directories. Check this
The general answer to the first part of this question is: "No". Apps are inherently sandboxed and thus can not communicate between each other. There are a number of exceptions to this:
If you have access to a custom URL scheme for the particular app (Facebook Single Sign On makes use of this).
Opening a document type that is handled by multiple apps on the system (like when opening an attachment in Mail)
If both apps are developed by the same publisher, there are options to use UIPasteboard, iCloud shared Key/Value Dictionaries (only small datasets though), or accessing a shared Keychain Store.
UIPasteboard has some odd behavior as you can have system-wide pasteboards or application specific pasteboards, and there's no guarantee when its going to be cleared or not.
The second question - folder structure - is variable dependent on OS version but generally all applications are stored under the /var directory, followed by a subdirectory structure that utilizes UUIDs to denote the application and then the main app bundle, with the standard app bundle structure (including the Documents directory).
As for modifying data and storage, once again, generally "No". Some apps will utilize UIPasteboard for temporary data storage, but generally you won't know about that inside another application unless you've written the original app.
Generally speaking every app has only access to its own working directory and saves all it's data there. So no app does have access to the data of another.
Except a few of Apple's apps like Photos, Address Book, Calendar and so on. App's can use a well defined API to get access to them and do some (controlled) changes. In future iOS versions (beginning with iOS 6) the user will then be asked if a third party application should have access to the data of these few Apple apps.
There's no file-based solution from Apple directly to share data between apps yet (except the clipboard, which is a one-file exception).
I need to make my app such that
the first screen will have the option : NEW and SEARCH.
2.Clicking NEW should allow the user to create a new profile,
3.but clicking search should allow to access one of the stored profiles by searching for the user number.
These profiles will actually be some data about the person, his name etc. and then yes/no answers to some questions.
At the moment my app works such that I can type in my name, and do the yes/no checks and I am using plists to save the info. this means that when the I start the app the next time the app loads with the saved info. So I have got half the task done.
Now how do I make it multi-user capable so that it has the option of creating a new file or providing a search option to access existing data?
also, I am creating the plist in application directory, using the code on apple's website, but I have no clue how to access these files directly..is it possible to access these files, if I want to show the information on a desktop? Thanks.
The key phrase you want for searching Apple's docs is: Data Management.
Specifically, I would recommend the Data Management Starting Point.
Handling data can be as simple as writing a string or array to disk or as complex as a big Core Data data model. If you plan on writing and maintaining several Apple API apps, I strongly recommend eventually learning Core Data.
I'm setting out to create an app where it will use 7-10 instances of a custom class, lets call them "books" each class will consist of a number of pages, a title, a int of how many pages a book contains and possibly some notes of the author associated with a specific page.
My question is what is the best way of creating these objects. it seems weak to just hard-code all the books together programatically, and if there are more added after the initial release I'd almost like to have the author be able to construct them with a simple desktop app.
So I guess what I'm looking for is a way to a create a small app to create instances of a custom class on a desktop, then bring those instances into the iphone app.
I only have an iphone dev license as far as I know. Obviously you don't have to be super specific but I'm looking for ways to accomplish this type of task. Maybe if there is a good way to go about hard coding them I would like to hear about that as well.
I guess an equivalent would be a game developer making like a level editor for his game so he doesn't have to create the boards programatically.
Provide your data in XML or JSON
format (or whatever flavour of file
format you prefer), this is to transfer data to/from application.
Parse your data file (xml/json) and store in permanent storage (file,sqlite,core data) on phone. This is the data that your application will regularly use from now on.
Offer user the option to get updates over network
If user selects to get updates, download updated xml/jason file over network, parse and update your permanent store
Use SQLite. You could easily create a sqlite database editor, or use some of the free ones out there. The iPhone can read a sqlite database natively, just include the library.