Im using a web service to populate a tableview, but the data in my web database changes very rarely, and i don't need to always download the same data.
I need to storage the data in the device, and verify if the data on the device is different than the one on the web.
What is the best practice to do that? Parse a JSON object, containing the last version and comparing to the local version and then parsing the data if its needed ?
Is there a way to automate the last version?
If you have control over the web APIs then have a separate api that returns a timestamp for the last web data change and check this. If the date is not newer than the date of last download use the local data. imho.
I personally used local storage for the same situation on iOS and it worked great.
You just need to provide an URL which responds with the last version of the data (maybe a date) and then locally in JavaScript you first check if version online is newer than your local stored one, if it is you redownload data and place it into localstorage, otherwise you just keep old data (and don't download anything at all).
Of course everything must be done through Ajax.
Related
For our app we need the app the work offline 100% with the most recent data.
Normally the app uses a symfony api platform API to fetch data paginated server side.
But when someone is using the app in a area without Internet he still need to be able to access all data to make a new job and que it for when he is online.
So our tough is to make a json that has all the data and send it to the phone when the phone has connection.
When the phone is using the app live, it will use pagination from server and fetch data.
And when offline it will use the local downloaded data file.
Problem is the data is large, so storing it is the problem.
We are now using redux persist and we see so many people have problems with crashes and mobile ram.
We also thought of using sqlite or just async to store a json file, or download a sqlite file from the app.
How do you guys feel about this
You can use react-native-local-mongodb. This can help you store a json database on your phone.
Other option is to have react-native-sqlite-storage in case your database has to be relational and requires table.
You will have to sync this local copy with the server once this user is online. This too can be done if you have the timestamp saved of the last sync. So after that, you ll just have to sync the data created after that timestamp.
However, I had also implemented react redux persist and it didnt crash. I suppose, the reason for crash must me something else.
I was wanting to use a file sharing server to keep certain files up-to-date and constant across multiple instances of my application across multiple computers - like (for example) writing a multiplayer game, which stores all the player's positions in a text file, and uses something like Dropbox to keep the text file constant across all the applications, and each application instance can change the file with that application's player's position, and then the rest of the applications can update accordingly. This is only an example, and is not what I intend to do using this technology. What I want to do does not rely on fast sharing of data very quickly - but only periodically downloading and updating the text file.
I was wondering how I might be able to do this using the Dropbox API for Objective-C without prompting the user for any Dropbox username/password - just store a single Dropbox account's login information, log into it automatically and update/download the file stored on it?
From what I have found out from experimenting, Dropbox prompts users for their passwords via a web-broswer, and is designed to accommodate multiple accounts, whereas I only need to accommodate the 'Server' account.
So, is there anyway to do this sort of thing using the Dropbox API, or should I use something else. Or do I need to find out how to write my own server. Using some sort of file sharing API seems a lot easier to me than writing an actual server.
Thanks for any help,
Ben
You might think about using Google App Engine (GAE). I had a similar requirement recently and I'm thinking this is a good option when you want centralized data. Plus you can do the no-browser account login by using your own custom authentication, or I think it's even possible via OAuth? Depends on how sensitive the data is I guess. I just rolled my own.
From my research I found that using Dropbox as a server has some issues with scalability, since you'll be limited to maybe 5,000 calls per day. source It's built on Amazon S3, so you could also look at using that directly.
GAE lifts that limit up to 675,000, but can be increased up to 91 million for free.
https://developers.google.com/appengine/docs/quotas
I did find an open-source project for doing this with Java, alternative you could look at Python example
I've written a daemon that continuously checks for updated files and syncs them. I wrote it for my own file manager iOS app. You can find the implementation here:
https://github.com/H2CO3/MyFile/tree/master/DropboxDaemon
I'm personally not an iOS developer but I came across this question while looking for something else and thought I would offer up another potential solution to the OP's question.
Microsoft just released something called Azure Mobile Services which supports iOS development (among other platforms). It's basically a convenient way to set up a back end system complete with push notifications, authentication, etc. without rolling your own. You don't need to know anything about Azure or servers as the setup process walks you through most of it. It is new so keep that in mind, but it looks promising for situations like this.
Here's a 10 minute video explaining how to use it with an iOS developed app along with links to more documentation:
http://channel9.msdn.com/posts/iOS-Support-in-Windows-Azure-Mobile-Services/
Hope this helps.
This is my first time that I am working on a big project for a client. So I was not sure how to solve this problem. However I have come up with two different ideas but I need professionals opinion about which one is better :)
Situation :
There is an application which runs on different client's iPad. Application data is stored by using giant XML file. This XML file is shared among all client by a server. So a server has a centralised copy and each client has their own copy. Once client made changes to their XML copy they updates server copy in and other client updates their copy by updated server copy.
Now only one client can make changes at one time, To fix this I have logic by which before client starts editing XML they need to get ownership from server and server will only allow one client to edit at one time.
Visual Representation :
Now on client side I have to think of a logic by which I will update my client copy and upload it to server. There are two options,
Option 1 :
In option 1, I can directly manipulate XML file by using GDataXML parser and upload that copy to server. For persistence I can save client copy on my iPad in document directory.
Option 2 :
In option 2, I can read XML file create a CoreData representation for local storage. When ever I update data inside core data it will I will change XML file too and than upload that file on server. Double work but I guess better persistence.
Now which one more robust and advisable? Personally I was planning to do option 2 because it seems more robust as I am persisting application data in core data. But option 1 seems more easy work but I don't know how good persistency will remain.
Sorry for lengthy question,
Thanks for any input given.
There are a number of factors which would influence selecting the second option over the first.
How big is the XML file? If you need to work with very large documents, you may need to incrementally parse the XML (SAX) into core data. This will allow you to access the document's contents without loading it all into memory at once.
Do you need to run complex queries in the data? If so, you may be better off using core data fetch predicates, rather than xpath or XSL.
Are you already using core data? Depending on how the XML data is structured, it might be simpler overall to import the data into your existing persistent store.
Otherwise, you can probably make due with parsing the entire document and either traversing the resulting tree or querying with xpath.
If you need to create an object graph based on what you get from server and show it to user (which you most probably need to do), you should stick up to second option, since it allows easy and robust data persistence.
If you do not need to present user with any data from the XML file you can, of course, store it in the Documents directory.
So, if this is a client application and it has at least some visual representation of the data from an XML file you should use CoreData.
If you want a regular update of data , then use CoreData
It would be useful for many people to know how to completely remove an application from your device when testing.
I have downloaded my app many times now, and likewise have deleted it many times. The problem is when deleting the app, it does not remove things like the persistent object related to my app, or the images downloaded through the app. So, when I download the next build, I have no idea if something broke that is related to building the persistent object or fetching the images since those elements already exist from the last build.
I don't know if this is a cache thing. I don't know if this is expected and I have to use some utility to wipe this data after deleting the app. I can't really find much info through basic web searches.
Any information would be appreciated.
Blackberry Bold 9000. 4.6 OS. tested with both SD card and no SD card.
Objects stored in the PersistentStore are automatically deleted on uninstall if their interfaces were defined in your project. If they are from the standard BlackBerry API then they will stick around until they're deleted. E.G if you save a String in the PersistentStore it will stay in the PersistentStore but if you save a class you created it will be deleted on an uninstall. So if you want to have those objects be deleted automatically just create a wrapper class and save that.
Images stored on the filesystem will not be deleted until you or some application deletes them. However, it should be easy for you to write an app that clears everything out.
Another solution you could implement is making your app somewhat self-aware of its data.
Create a simple String value that you persist (or optionally, persist it in a Hashtable so you can store many properties this way) that includes "Version".
At startup of the GUI app, compare the stored "Version" against the application's current version. If the stored version doesn't exist, or if it exists and matches, take no action.
If it exists and does not match, automatically clean up old persisted data; or alternatively prompt the user to see if they want that data to be deleted (which one is better will depend on your implementation)
You can also use CodeModuleListener to listen for an uninstall event -- when that happens, you can clean up at that time as well or instead.
(As an aside and a bit of shameless self promotion, I am actually currently working on a shareable library for Blackberry that makes managing persistence much easier, as well as desktop data backup/restore. I'm doing this as part of the BBSSH project, but I'll be splitting it off into a separate library of core components and publishing it under a dual GPL/optional commercial license. It will contain hooks for data cleanup and data versioning. )
I wrote a few iPhone apps using Core Data for persistent storage. Everything is working great but I would like to add the ability for users to back up their data to a PC (via WiFi to a PC app) or to a web server.
This is new to me and I can't seem to figure out where to begin researching the problem. I don't want to overcomplicate the issue if there is an easy way to implement this.
Is anyone familiar enough with what I am looking to do to point me in the right direction or give me a high level overview of what I should be considering?
The data is all text and would be perfectly stored in .csv files if that matters.
Unfortunately, I don't think there's a good all-purpose solution under the current SDK. Here are some ideas:
If you only want backup, you could just back up the whole sqlite file to the server or over wifi, but you then can't really use it with anything other than Core Data (and you might even run into trouble with iPhone-Mac compatibility, e.g. between 32-bit and 64-bit types).
A very robust solution would be to implement cloud storage with a REST API and sync the iPhone and desktop app to the server (this is what the Evernote app does, for instance), but that is obviously much more work.
You could also manually convert your data to a .csv and send that to the server or desktop, but parsing it could be problematic (and you'd have to worry about the data getting corrupted). If you did want to go that route, here is a tutorial.