i made a simplest application in nwjs which just takes an input of name .
now i can't store this value permanently because app is not connected with any database .
i know about mongodb but don't know how to integrate with javascript app.
i watched some tutorials how to use mongodb with apps but they in tutorials always use cmd to first start server (now a general software don't require , user to start servers manually etc).
Please help me if there is a way to store, fetch and perform other operations on data offline.
what i am missing ? Thanks
You may be looking for:
NeDB, a Mongo-like offline in-memory database
LinvoDB3, same than NeDB, but not in-memory (slower, but more scalable in terms of size)
LocalStorage a Web API
Related
I am a intermediate flutter developer and working on my first commercial app And I have almost created whole app ui but problem is when i close my app all data get lost . so how can i prevent it + how can i make my app work at background when app is close like in clock app . In clock app even if app is closed then also we get alarm at the timing we set . It is not possible to provide whole app code thats why i am explaining it in words . Hope you guys will understand the problem and provide best answer .
You can use internal data base concept to save user data like JWT key , user id, first name ,last name or app content for offline usage like blog articles ,pos system data for offline usage
Use Shared preferences to save basic data like user data, JWT but less secure
but if you need save complex data and need query or filter you can use hive and you can keep data more secure
And Alarm is totally deferent approach,
when we schedule alarm,alarm manager schedule task on system alarm services and wakeup app with intent and flutter Isolate class
We divide your question into two parts.
Question 01: How to store data locally :
You can use key-value storage like Shared preferences, Hive
If you are familiar with SQL you can use SQLite
If you are familiar with NoSQL you can use database like sembast
These are some of the popular databases that you can use with flutter. And much more available at pub.dev. But you want to use a database with your task. As an example simply store the user name or user id you can use Shared preferences
Question 02: Make Alarm Application :
For android applications, you can simply use android_alarm_manager
I suggest you take a deep look at the flutter docs about the subject:
Background processes
To run background processes continuously, take a look at this
package: https://pub.dev/packages/background_fetch
If you need to show scheduled messages, use local notifications:
I think by referring to these links you can get an idea.
To store data locally you can use local storage options like Database such as SQFlite, Hive etc or SharedPreference that will save your data locally and to run background process you need to use MethodChannel and write platform specific code or you also have the options to use Isolates. You may read more using this link
https://docs.flutter.dev/development/packages-and-plugins/background-processes
I'm developing an app that's pretty simple, and the important part of it is the content, which consists of lots of info that has been gathered over many years. I want to format it in a nice way to show to the user.
When the user downloads the app and first loads it, it goes to the server to get the whole database into the phone. Then, he can see the important items, and sort/filter through them. To avoid somebody taking my database, I'll use a SSL connection. I know if they want they could use the app to see every piece of content one by one, but there's nothing to do about that.
The thing is: I have the data in the cloud (mine). I can securely download it using an SSL connection (any other ideas to secure the transfer?). When I get it here, I'll save it in a db (Core Data is the obvious choice).
How can I secure the data in the internal database, so if the app is hacked, someone cannot access the db? I would put it in the keychain but it's a rather large db for that and it's not that important. (It's not sensible info, just info I don't want anybody to get massively.)
The other thing I could do is to never store anything in the device and have the user always making calls to the cloud, but I think this would be too time consuming. And just give him the option to save their favorite picks to the device. But that's too time consuming and there is the sync issue.
This is a reference I looked up about a similar issue, without the part I'm asking answered:
How to encrypt iPhone upload and download of info?
Basically, the only choice is to use SqlCipher. Of course, you have to port it to iPhone yourself (unless someone else has posted a port since last I looked). But it's not an insurmountable task.
Of course, even with SqlCipher you have the challenge of storing the key somehow. There's no really secure way to do this -- you have to use some form of "security by obscurity".
Why not just have some private key info stored in the code, and then when you want to download the database just have it query the server with the key? That way you wan't need to worry about SSL or encryption in the downloading part. In regards to storing it I agree with Hot Licks, SqlCipher appears to be the best and only option. However watch out for encryption, as you will have to declare it to apple and get all kinds of export permits (http://stackoverflow.com/questions/2135081/does-my-application-contain-encryption).
Hope this helps,
Jonathan
I want to have on-the-device database for my iphone app. It concerns with the data, which comes from dictionary consisting of 200.000 things and their definitions. It is only related with text-type data as appeared. My questions:
1- Does SQLite hold all of these data?
2- When the client downloaded my app, he/she will also have the db in his/her device. Does app store allow me to update my app's db and upload my new release? (i don't know these issues well by the way)
3- And can any client, who downloaded my app, hack and obtain my database? Is there any prevention methods? Is SQLite resilient enough against these?
1- Does SQLite hold all of these data?
Yes, SQLite can cope with this amount of data.
2- When the client downloaded my app,
he/she will also have the db in
his/her device. Does app store allow
me to update my app's db and upload my
new release? (i don't know these
issues well by the way)
The general approach is to store the SQLite database in your application bundle and then copy the database into the application's document directory on the device when the application is first run. On subsequent updates to your applciation, you should check if the database within the document directory is the same version and update it if necessary. See the existing Run NSBundle from the documents folder question/answer for more information on this.
3- And can any client, who downloaded
my app, hack and obtain my database?
Is there any prevention methods? Is
SQLite resilient enough against these?
It's fairly trivial to open up an app (the deployment package is just a zip file after all), so yes, it will be possible to obtain access to your database data. Unfortunately there's no easy way around this that I'm aware of. (You could I suppose download the data from a server when you first run you app, but it'll still be accessible on a jailbroken device.)
Sometimes, you just have to bite the bullet and accept the fact that your data is going to be ripped off.
1) sqllite can definitely hold that amount of data.
2) You can put up an option of refreshing the database in your app. That can be used to sync the local db with the server copy. Updated db can also be added with the new version of the app.
3) You can encrypt your local db using SQLCipher for protecting your application db against hacks.
I want to develop a CRM iphone app. I think there are 2 methods to deal with the data store, one is using the Sqlite(but it can not share datas with others ?), the other method is using the webservice(let the app CURD data by one web application), I want to know which is better?
I think the question is not about having one or the other, you could have both: Webservices to expose a central server somewhere where common data is stored and your local SQLite database where a copy of this data is stored. This allows you for fast search etc. instead of contacting some remote server that may or may not be on-line.
If you want to share your data then you have to store your data in webdatabase otherwise store in sqlite
you can store your data in sqlite for fast access and when you want to share that time you can send it to webservice and retrive when you need to see more data
I'm looking into building an application which works just as well offline as it does online. Since the application cannot communicate with the server while in offline, there is some level of synchronization which needs to take place.
What are some good tools to read about and start thinking about when planning offline operations with synchronization for your iPhone?
What tools would I have to create on my own, versus tools that apple already provides to help with this particular issue?
I've been working on an app that handles this exact behavior for the last 2 months or so. It has a small subset of functions which are online only and a large set of functionality that is offline/online.
I'm using sqlite for local storage as suggested here with a modified version of the sqlitepersistentobjects library. The base version of sqlitepersistentobjects is not thread safe so watch out if you are using it. (check out objectiverecord in: objectivesync for a thread safe alternative but be prepared to dig into the code). If you are willing to develop for the 3.0 sdk then core data is another possibility for a sqlite library.
The overall architecture is simple enough I have modeled local storage using sqlite and remote interaction using objective resource against a rails app and REST api. It can use either xml or json for data serialization.
When an object is modified locally the change is first saved to the sqlite database record for that object and then added to a queue which is serialized and stored in the local sqlite db as well. (The queue can then be processed at any time)
If there is a connection available any queued local changes are deserialized and added to an NSOperationQueue which then processes them in the background.
In order to make this all work I've subclassed NSOperation so that it can support several types of remote queue operations - create, update, delete essentially using objective resource to make the remote requests.
The nice thing about using NSOperationQueue and NSOperation is that they handle the background threading for you so I'd highly recommend having a look at the apple docs for those classes and also at the apple threading guide.
When the application loads there is a bit of remote checking done and processed in the background to pull down the latest data - although to be honest I am still changing the way this behaves a bit.
That's a quick overview of what I've had to deal with so far...hope it helps a little.
there are plenty of application on the app store which rely on both online as well as offline data
what you should really be doing is on start of your app, run a background thread (which runs silently so your user never sees any delay). this thread downloads the latest data from your server and pushes it into your local database (sqlite is the best choice)
make sure you implement some kind of data versioning so that your app only downloads data which is actually changed since last download - else you would unnecessarily be downloading the entire dataset which can be quite huge (depending upon your app requirements)
also make sure to test for internet connectivity when doing this. if no internet is available, alert the user for sure
this way you get the best of both worlds. users when away from internet can still use your app with their local sqlite data
in iphone os 3.0 apple has introduced push services - where you can simply "PUSH" your data instead of doing a "PULL" however this is not available in the current iPhone OS (2.x.x)
Push is probably not a viable option here, since the amount of data you can push is miniscule, and basically comes back to "tell my app to make a server call". We use an online/offline model in Satchel. Whenever we have to communicate with the server, we bundle that communication (a URL and possibly some POST data) and store it to a database. If we're online, we pull it right back out, send it, and when we get a valid response back, we remove the record from the database. If we're offline, those rows build up, and the next time we ARE online, they get sent out. This is not a workable model in all situations, but can be adapted to most.
In 3.0, you've got access to CoreData, which is a great data management tool. Other than that, the NSURLXXX family is your friend.
I would store all the information I gather while offline in a SQLite database. Then, on user 's request, you can SYNC all the stored information with a server using HTTP or a custom TCP/IP protocol you can come up with.
I have been using this approach on Palm OS applications for almost 10 years now, and they do work very effectively.
As far as I know, the only "tool" you will have to accomplish this is plain old OBJECTIVE-C with Cocoa Touch. Although you could use some TCP/IP C++ libraries that will make your life easier if you decide to implement your own protocol.
Wonder if you have considered using a Sync Framework to manage the synchronization. If that interests you can take a look at the open source project, OpenMobster's Sync service. You can do the following sync operations
two-way
one-way client
one-way device
bootup
Besides that, all modifications are automatically tracked and synced with the Cloud. You can have your app offline when network connection is down. It will track any changes and automatically in the background synchronize it with the cloud when the connection returns. It also provides synchronization like iCloud across multiple devices
Also, modifications in the Cloud are synched using Push notifications, so the data is always current even if it is stored locally.
Here is a link to the open source project: http://openmobster.googlecode.com
Here is a link to iPhone App Sync: http://code.google.com/p/openmobster/wiki/iPhoneSyncApp