Is there a way to connect to a MongoDB Database from Codename One, and perform "CRUD" operations?
I'm new to Codename One database implementation.
You shouldn't expose your database to the mobile tier. It would let anyone who has access to your application manipulate/corrupt your data. It would mean transactions can fail because of bad network connectivity.
The way this should work is that you would create a server (e.g in Spring Boot or any other language). Expose a web service on said server and invoke that from the Codename One app. That Web Service will perform the CRUD operations.
I go into this extensively in my courses: https://debugagent.com/series/cn1
I use MySQL but all the same principals apply regardless of the technology.
Related
I am new to web development, and have seen posts such as these . If one is using AWS and is connecting to an AWS rds instance through Node, is that still considered a direct connection as opposed to a web service?
You're probably going to get a bunch of conflicting opinions on this. My personal opinion is a web service in front of your database makes sense in some scenarios. Multiple applications connecting to the web service instead of directly to the db gives several advantages, security, caching, etc.
That being said, if this is just a single app then most of those advantages disappear and in fact just make things more complex for you. You're going to have to setup your web service for the db as well as your actual code.
If one is using AWS and is connecting to an AWS rds instance through Node, is that still considered a direct connection as opposed to a web service?
No, if Node.js is running on a server or in "serverless" containers (e.g. AWS Lambda) that is not a direct connection. That is a web service, and that's what you want.
A direct connection means the app connects to the database itself... but that requires embedding credentials in the app.
You do not want to embed anything in your app that you would not willingly hand over to an arbitrary user -- such as database credentials and API keys -- because you cannot trust that the app won't be reverse-engineered.
You should design the app in such a way that you would have no security concerns if the entire source code of the app were exposed, because knowing everything about the app's internals would give a malicious actor no valuable information. How? The code on the server side (e.g. in Node.js) should treat every request from the app as potentially suspicious, untrustworthy, etc., and validates every request to do anything.
This layer of separation is one of the strongest reasons why you never give the app direct access to the database. Code running in a trusted place -- your web server/API layer -- needs to vet every database interaction. This topology also decouples the app user from tying up resources on the database server when not actually interacting with the database, which is far less practical with a direct connection.
I have a project has two parts.
1- Windows form or WPF application that basically connects to database and write/read/update some basic text data (this part is already done).
2- On the other hand, I am currently developing an IOS app that can connect to remote database and read/write/update data.
What is the best way to connect the same SQLite or SQL database from both Windows forms app and IOS app.
Thanks in advance
The best way is creating an API/WebService which will be the interface between the database and your clients: WPF, iOS App and any other client you might want to add in the future.
Using a WebService is more secure, I guess you wouldn't want your database username and password being everywhere.
Using a WebService allows you abstract the data layer. Not using an API and using the connection to the database directly from your Apps will tightly couple your apps with the structure of your tables and any single change that happens in the database will force you to do the changes in the apps.
With WebService you decide what information will be available to the ones consuming it.
There are many others Plus on using WebServices but hope this are enough to clear your doubt.
Currently I am developing a WPF application which will handle alot on the client (non business logic that is).
Some data (the business logic) will be coming from a SQL database. To expose this data to the client I was thinking to create a WebService. Normally I would use a WCF Service (or Web Api) to fix this. But in this scenario, there is only a linux server available using a MySQL database, on this server I am unable to host a WCF Service.
I was wondering how I could implement the following:
Users opening the WPF client need to authenticate to the MySQL database.
Users logged in should retrieve some of their personal data coming from the MySQL database.
Which kind of Webservice or technology is the best to go for?
Thanks
You can build a web service in any language, so it comes down to which ones you're comfortable with, or which offer the best tools. If you or your team are already heavily invested in the Microsoft stack, you could try something like Monodevelop: http://monodevelop.com/
I am developing an mobile application which can be run on mobile devices (with OS like Android, iOS, WP7...). This application will get data from online database then store them to local database in device and I can do CRUD with data. There are three ideas:
I'll create a webservice to handle with database on host and use some cross-platform framework to building an app then connect to webservice in order to get and put data to server. Issues:
Which technology should I use to create webservice? (RESTful/SOAP...?)
Which type of return data for easy to handle? (XML/JSON...?)
How to sync between local database and database on host?
I'll make an application for loading an external URL and build a website (with all of features that I need to work with database). Issues:
iOS, Android, WP7... accept for loading external URL in applications?
How to sync data like my first idea?
Should I use single page application technology?
I'll make an application using cross-platform framework and it will work with local database. I just handle syncing between local database and host database. Issue: which is the best database and best framework to do this?
Thank you
How to sync between local database and database on host?
For synchronization, you can take a look at the open source project, OpenMobster's Sync service. You can do all types of 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. Also, when new data is created in the Cloud, it is automatically synchronized with the local database using Push notifications.
Currently only native development is supported on Android and iOS. However, the next release which is 2.2-M8 (end of March) will support end-to-end integration with PhoneGap on Android and 2.2-M9 (end of April) will add iOS.
Support for PhoneGap will give you the flexibility to build the app using web technologies like HTML5, and JavaScript along with Sync for your local data using OpenMobster.
If you want to go pure native, then you still can use the Sync service and synchronize your local database with your remote database.
Let me know if you have more questions about the framework
Here is a link to the open source project: http://openmobster.googlecode.com
Good Luck!!!
Some suggestions:
If you're planning that your mobile application exchanges data with a server, i strongly suggest you to use RESTful Services. The XML overload associated with SOAP services might get your phone and your network into trouble
The return data can be either JSON or XML. For example, in Blackberry applications i prefer XML because the support included in the SDK.
There are three kinds of mobile applications: Web applications (build with HTML/Javascript and accessed throw a Browser), Native applications (installed in the device and coded in Java/Objective-C or another language) and Hybrid applications (installed in the device but coded in HTML/Javascript and can access some features of the OS). Your URL-Loading type sounds like an Hybrid approach (not quite sure about that), so you can use PhoneGap to build that type of applications.
Hybrid and Web applications uses the capabilities of the phone browser to manage HTML/JavaScript. Now the devices come with very powefull WebKIt-based Browsers, so the single page pattern would work with no problem. Although, it's kind of a wear approach to mobile application design.
I don't see the need of a local database in your app, you can simply handle all the data in the server and access it through RESTful Services on the phone.
I am developing an mobile application which can be run on mobile
devices (with OS like Android, iOS, WP7...). This application will get
data from online database then store them to local database in device
and I can do CRUD with data
Nice!!!
Which technology should I use to create webservice? (RESTful/SOAP...?)
I Will go For REST services.
REST has advantages when:
You have a set of resources that you want to manipulate.
You want to support navigation between resources.
You need scalability.
SOAP has advantages when:
You want to publish a web service description (using WSDL).
WSDL 2 can describe RESTful web service as well. WADL is an alternative to WSDL for RESTful web services.
You want to use security etc. that relies on the use of SOAP headers or some similar mechanism in which data is added and removed from a request.
You want better tooling support.
You want tested platform interoperability.
Which type of return data for easy to handle? (XML/JSON...?)
I personally go for XML
Its not a criteria of which is easy to handle.Its about performance in Mobile applications.
JSON is generally smaller than a XML document and there for faster to work with.JSON can be parsed more efficiently because it can be parsed as JavaScript, which the built-in eval() function will do for you.
How to sync between local database and database on host?
Create a service which contains a timer and runs in background.Call the REST service at intervals to get the latest values. But Since this is a polling kind of thing,then it is not efficient and has less performance. Other Approach will be use of PUSH notifications.As soon as there is any change at the server side, send a push notification to the client(mobile) and hence perform the local database operations.
iOS, Android, WP7... accept for loading external URL in applications?
I didn't understand this point.What you want actually?
Should I use single page application technology?
Single page technology is very good.But it will depend on your business.If it is possible then use it.Else create different HTML pages.
I'll make an application using cross-platform framework and it will work with local database. I just handle syncing between local database and host database. Issue: which is the best database and best framework to do this?
Choosing of the database will depend upon choosing of the cross platform mobile framework.Phonegap is exactly what you need. And the database will be sqlite. Phonegap provide API's for storage,so you can easily access the database of the different mobile platform.
Could someone please explain to me in a simple way, what is a web service?
Please correct me if I'm wrong. I have a DB hosted somewhere in the web, and I want to perform DB transactions from a desktop application as well as a mobile application. Can this be done through a web service ? Someone mentioned it to me and I wanted to make sure this could happen.
Here's a good explanation on Wikipedia.
A middle dynamic content processing and generation level application server, for example Ruby on Rails, Java EE, ASP.NET, PHP, ColdFusion platform
The middle tier of a 3-tier application is often the web service
i want to perform DB transactions from a desktop application and a mobile application, can this be done through a web service ?
This is Exactly what a web service is for.
A web service allow you to create multiple front ends if needed, and serve your database data to all of those front ends. You can also open up the API and allow third party developers to access the web service and thereby access the data of your application in a controlled environment.
It's considered a better practice for larger applications to access a web service or a middle tier rather than directly access the database.
In your case, a web service would involve setting up your DB behind a web server that listens for incoming requests, performs the appropriate DB operations, and returns whatever data is appropriate. Then, your desktop and mobile applications could send a http request and the DB would respond appropriately. This would let all your applications access the same DB.