Current scenario :
There is a webservice (build in php/mysql). User filled data is stored on a remote server.
Issue is user has extremely bad internet connection, webservice is down most of the time. Is there a way to store data locally and sync it when internet is available?
Please note, user might not have database installed on his machine also there is no localserver to work with.
Even if user had some type of RDBMS installed on the box, you probably wouldn't have any way to communicate with it. You can use the HTML 5 Storage API, but it will not solve the connection issues.
And since localStorage (which you probably would use) is available directly only from JavaScript, you would have to make a complicated and fully functional JS application to utilize it.
Note: based on your profile, I would estimate that your JavaScript skills would not be adequate for such task.
If your target audience is mobile users, then you have another alternative: create a native application.
You would still be able to use HTML for the interface (using built in web browser components). But it also would let you have SQLite DB and file storage available on the mobile device, where you can cache the necessary data.
look at the features in HTML 5 for local storage
Typically I would go with IndexDB and then push the local data to the server once the connection is back
http://diveintohtml5.info/storage.html - Should give you a brief about the features and implementation.
Related
I'm looking to build a dummy CardDav server that allows me to do the following:
- add a CardDav source on an iOS device
- the source will show up as a group on the native Contacts app
- no syncing actually takes takes place with the server (no contacts should be stored on the server or deleted from the device)
The purpose for all of this is that I'm looking to manage the source from an iOS app.
I deployed a Baikal CardDav server successfully and I tried to sniff out the requests that take place when registering a new source, unfortunately I'm quite stuck.
At the moment I have a php file that responds to a PROPFIND request and allow for the source to be validated, but it doesn't show up in the Contacts application.
Any tips would be appreciated in either writing a dummy CardDav server or crippling a functioning one in order to only provide the auth functionalities?
Not sure if i understood your question.
You may try Calendarserver at http://trac.calendarserver.org/wiki/docs-trunk . It is simple to install and setup and works without any quirks.
If you need the server to behave a certain way might be best to use a Carddav framework like SabreDav (for PHP) or milton.io (for java, my project). Then you can do all sorts of weird backend stuff
Milton actually comes with really simple example projects with in-memory data thats perfect for mucking about with
I've successfully managed to use POST to run a PHP script on my website, which allows the phone application to add a new entry to the database (MySQL), and delete an entry.
The next step is the one I have been struggling with for the last few hours now, and that is getting the information FROM the DB onto the phone!
I would like a method that initially just connects to the DB upon starting the activity and populating listview or something will all entries, and later down the line I plan on copying the information to a SQLite DB within the phone.
What is the easiest method I can look into for achieving this?
I can be resourceful but I just need to know what I'm looking for!
you have many options.
higher level abstraction over HTTP (REST/SOAP/etc) like already mentioned
HTTP as a proxy for plaintext/CSV data (without abstraction)
a direct JDBC connection from android device to the MySQL
database data export/import
I guess you're looking for option 3. That is syncing a remote database to local (SQlite on android) and then working with local data? In this case you just get a mysql-client jar (JDBC drivers) into your app and you can start. There're some restrictions though, like Sébastien Renauld already mentioned in the comment. Yet, those issues can be worked around, i.e. with custom configuration of MySQL or with option (2) which can be implemented in generic way (write once)
In general you need to create server API: choose some format to talk to between your web service and android application.
Then you'll always be need to request some data from server, that will be returned to you in format described above in a body of network response of some sort.
Next all you need is parse this data and populate to your adapters or whatever.
Note that networking operation might take quite some time depending on your connection, so you can't wait while it ends to show your UI - you need to do this in async manner, and give user a feedback that data is retrieving.
Nowadays json format passed in body of http post requests are quite popular. Take a look at this tutorial on how to parse json on android and this video about how to create json api in php.
Of course you can try to connect to remote MySQL server directly.. It really is more simple solution in some cases (you don't need to code server-side api), but might be not so accessible because standard MySQL ports aren't opened in all networks. Also your API server might hide some implementation details on how is data stored in reality, thus allowing you to migrate for example from MySQL to PostgreSQL without pain for android application.
Don't forget to secure your data from unauthorized access!
EDIT
It's 2017 and what would be the easiest option now is to use opensource project which will provide rest api for your database, for instance ArrestDB or postgrest
I personaly had to develop this following REST API Service (based on Laravel framework, which I call it lRapi) for an iOS and Android devices, and works great (the version in use for the apps, is much more complex).
https://github.com/w0rldart/lRapi
There are plenty Models and Controllers there that you may use to get started. Responses are JSON formatted, with proper headers.
I still have to add some more documentation to it, but there is some on the main example view, which you may access by just setting the virtual host and opening the root page in browser.
Laravel is a MVC PHP Framework, and it's really easy to get used to it.
This a good way to avoid to do most of the work, and just focus on implementing what else you need.
I have an application that retrieves some info and give them to user from a certain public website. However, i am not sure whether i should let my app immediately connect to the target website or it should get the info through my web server using a simple PHP script (JSON).
Actually I am using Jsoup to get the information and I tried both and they worked perfectly ( immediate and PHP) using Jsoup. However, I have not published my app yet due to the confusion aforementioned.
Use the web service. If your client has logic to parse the HTML, it can break when the web page changes. The web service can absorb this change and make corrections, but your client cannot. Not unless you release another version of your app, and that can be a pain.
I'm writing a web application in PHP which needs to store images and image meta data. In future, the application may need to work offline on the client. A user might need to download all the images and data to his laptop before going to a remote area without internet access. Whilst at the remote location the user could add new images to the system and be able to compare them with his local copy of the image database. When returning to an area with internet access, the user would run a sync operation which would copy his new images to the server and retrieve any new ones.
I've looked at the new web storage / localstorage options in HTML5 (web sql database seems to have been dropped) and I think this is going to be too limited as there is only 5MB space and one or two images could easily exceed that.
Is what I want to do actually possible / practical with a browser-based web application? Or should I be looking at writing a desktop/tablet application with local file storage capabilities for users without net access. Initially, it does need to be a web application, I'm just trying to think ahead. Will I give myself more options in future by using something like couchDB for the backend from the start? As I understand it, this comes with good syncing functionality.
Thanks,
I decided to use Titanium Desktop.
http://www.appcelerator.com/products/titanium-desktop-application-development/
I am currently working on 2 web servers, One Coldfusion and the other PHP.
Right now, the Coldfusion server is my main server where users log in to access restricted data.
However, I have also begun using a PHP server and want to make it transparent for users to access a specific page on that server - that server requires log in information as well.
I do not want the users to log in twice.
Is there a way to accomplish this ?
Thx
UPDATE: Working in an Intranet environment, so I can't use any public solution.
UPDATE: Reason I am asking for this is because we are moving from a MSQL / Coldfusion environment (Initial server) to a PHP / ORACLE (new server). So I have 2 user tables as well (although they contain mostly the same information).
I am trying to faze out the use of our initial server in favor of our new server transparently to the user and thus I have to work in parallel for the time being.
Most single-sign-on solutions work a bit like this...
Main system authenticates use
User opts initiates a need to move to system 2
Main system authenticates the user with system 2 in the background
System 2 supplies a random, long and disposable token to Main system
Main system redirects the user, with the token, to system 2
System 2 checks the token (and other factors such as IP address) to validate the session
System 2 disposes of the token to ensure it can't be replayed
You would want to ensure that the transmission channels had some security on, especially where Main system and system 2 are talking to each other. You would want that to be a secure transport.
Store sessions in a database, and share them between the two apps.
You could use xml-rpc to get user data and log the user into the other site when they have a login cookie for the first one and vice versa.
Php manual page for XML-rpc
Here is what I have done, in running my own game server, had users on sql server, and on mysql, and wanted to integrate them both.
I made sure that if a user was created on 1 system, was also created on the other.
So you can modify code in both applications, to automatically create a user in other system if it is created on here.
Depending if both servers share a domain, can you do cross-domain sessions or cookies...But my best guess is to store and retreive data...
Or..
as a person logins/registers record their current ip address, on both servers, then check if this person was on the other server within 2-5 minutes, if so, use the ip address to identify them....
This system is tricky because timing is important, so your not leaving a huge hole in your security....But for short term, going between servers, this is simplest solution, in my own opinion.
Good Luck.
If you are on an intranet, you can actually sniff out the network username of the user from the PC they are logged into the network on using PHP. This assumes that:
You are using IIS to host your PHP application.
Your users are using Windows.
Check the section "2.2 Enabling Support for Detecting Usernames" here.
After that, all you need to do is investigate if the same is possible from Coldfusion, and you have the basis of an SSO solution based on the network usernames.
How about implementing an OpenID solution, much like the one apparent on StackOverflow?
You may benefit from dropping a shared object on the client machine via Flash or Flex. This object could then be read from ColdFusion/PHP/Python on servers that otherwise had no connection to each other or access to a common database.
Here is a simple example from the Adobe Docs
Maintain local persistence. This is
the simplest way to use a shared
object, and does not require Flash
Media Server. For example, you can
call SharedObject.getLocal() to create
a shared object in an application,
such as a calculator with memory. When
the user closes the calculator, Flash
Player saves the last value in a
shared object on the user's computer.
The next time the calculator is run,
it contains the values it had
previously. Alternatively, if you set
the shared object's properties to null
before the calculator application is
closed, the next time the application
runs, it opens without any values.
Another example of maintaining local
persistence is tracking user
preferences or other data for a
complex website, such as a record of
which articles a user read on a news
site. Tracking this information allows
you to display articles that have
already been read differently from
new, unread articles. Storing this
information on the user's computer
reduces server load.
Full Information: http://livedocs.adobe.com/flex/3/langref/flash/net/SharedObject.html