I know silverlight is outdated and Microsoft it self has shutdown further development on it. However I came across one strange & security issue.
Understand the following scenario: I have my silverlight application up & running on hosted server and there are approx 500 user who are using it same time with application version around 192.3XXXX.
Later on I have developed some crucial business functionality and released application on server with version around 192.4XXXX. Next day all 500 user are working on application version 192.4XXXX. and on same day I found that I have made some serious mistake & I have to fix it as soon as possible. so I have applied the fix and released the Application on server with version around 192.5XXXX.
Now here come my Question. How can I enforce this 500 user to use 192.5XXXX at same time. I can not tell each user to reload the app and some of may misuse the application's functionality (as earlier mention, some serious mistake I made in code like showing confrontational data on some form etc. )
How to overcome such situation? Or something like that I can manage from server to force client reload app and download new version.
Thank Your All,
I came up with wonderful solution. I have created one signalR hub and I am broadcasting the message to all connected client to reload the application.
Let me know if anyone want detail description.
Related
I have a WP8.0 Silverlight app in store. It uses SterlingPhone as DB. I downloaded my app in a Windows Mobile 10 Insider Preview Version (v10.0.10536.1004) and it seems that data is removed after I exit the app.
I am using IsolatedStorageDriver:
Database = _engine.SterlingDatabase.RegisterDatabase<ItemsDatabaseInstance>(new IsolatedStorageDriver());
Has anyone faced this situation? I know Sterling is pretty old, but I think it should continue working on WM10.
In case I have to change to another Database Engine, I'd appreciate suggestions (my Data Model makes it very difficult to work with Sqlite due to nested objects).
EDIT:
Apparently Sterling is unable to find the existing database so recreates it each time the app is relauched.
Isolated storage screenshot
For anybody who found this post with the same issue, the problem lies in changed behaviour for string.GetHashCode on Windows 10 Mobile.
Sterling uses the hashcode of the database name in the path for the database. On Windows 10 Mobile the behaviour has changed and everytime the app is restarted a different hash is calculated and the path changes to the previous database is not found.
To get your app working again, get the SterlingDB code from CodePlex and change the code in the PathProvider class, in the GetDatabasePath method, then recompile your app. You can add a check to see if you are running on WM10 so users on WP8 continue to work with the old database.
The newer version of SterlingDB on GitHub doesn't appear to use the hashcode anymore so should also keep working.
We have a wpf application, which we have deployed using Microsoft's Click Once approach...manifest and application files are available in a web server.
If the application is already running on a client machine...and if I update the manifest and application files(in web server)...how do we notify the user about the changes ?
Is there anyway that we can display some kind of text to the user...that application has modified ..and he has to get latest ?
Any help will be appreciated. Thanks
ClickOnce does not provide you with an out-of-box means of alerting the end-users to an update.
In the company I worked at, it was good enough to walk around the end-users desks and making sure they weren't using the application before I updated it. Obviously, this doesn't scale too well.
If I had to implement a solution for this, I would include a message broadcast system that made sure the users were notified BEFORE the update was deployed.
If this was a client-server system, and updates to the server means that any out-of-date clients can't communicate with the server, then the end-users risk losing their work.
I am working on an in-house, iOS app that will need read-only access to a SQL Server with multiple databases. I know the stock answer here is "write some web services", but I'd like a solution that is self-contained. Is there any way to directly connect to a SQL Server database from an iOS application? I'm thinking something like a basic ODBC connection.
I've seen a lot of users asking this question, but very few answers other than "write a web service." Is that really the only way?
A web service is indeed the only way, but Red Gate's written one you can reuse:
http://www.mobilefoo.com/iSqlServerSDK.html
http://labs.red-gate.com/Tools/Details/iSqlSDK
It's not officially released yet, just in beta, so keep in mind that features & prices may change.
Actually the easiest way is to create a MVC 3 or 4 asp.net web application. call the web methods. You don't need any API to pay for.
I use SBJson to serialize domain object and then send the objects as serialized jSOn to MVC 3. It's super easy to do. I even send images with base64, so it's .net compatible.
See my blog post with sample code:
http://nickturner.wordpress.com/2012/10/09/107/
So, after much searching and trial and error, unfortunately the best (only?) way I've found is indeed using Web Services.
Fortunately, Linq to SQL makes the WCF-creation-side incredibly easy. Once I got someone at work to walk me through setting up a Windows web server and adding the web service (and buying access to an online web server), the Windows side was up and ready to go.
I'm still working through all of the syntax stuff on the SOAP interaction side, but keeping my different methods somewhat similar in structure allows me to tinker a little until it works. By this time, I think I've gotten it to work pretty well.
So, both answers I got back were (disappointingly) correct. The only way to interact is through a Web Service. Even the 3rd party solutions they mentioned were really just convenient wrappers around the same type of technology. As it turns out, I'd rather have finer control over the process.
One word of advice: Get a real, external web server. I tried doing this on a non-Server Windows VM on my iMac/MacBook Pro, and it was like pulling teeth! Once I actually got access to an external, full, stand-alone web server, the process was much more streamlined and easy. Do yourself a favor and take that headache out of the equation!
There was a SQL ISAPI extension as part of SQLXML, but I think it has been deprecated: http://msdn.microsoft.com/en-us/library/aa226559%28v=SQL.80%29.aspx
This was effectively a pre-built, and relatively open, web service - so I'm not sure this counts as a direct connection.
You could also check out http://odbcrouter.com/Main
I am interesting in hearing if others have addressed release management for Silverlight applications.
I have a business application that is to be released shortly andam concerned about how to "release" updates to this application. Typically this application's users will leave the application open all day (and potentially all night) without reloading it.
What if there is is need to release an change that includes an web service interface change? How can this be deployed w/o causing errors on the client side?
We have grown so used to deploying ASP.Net apps by just dropping the latest code on the server. My only idea currently involves a client version number and a periodic timer on to check for updates.
I would love to know what others have done before implementing this.
Thanks,
Mike
I just answered a question on how to make sure that .xap files are not cached by the browser, which might be of some help:
Prevent Silverlight xap from being cached by proxy server
But that's no use if the users never reload your application. In my own application this is not a problem since users will be automatically thrown out whenever we deploy an update to the web service. But I like your idea with the timer, I would go with that.
Stating the obvious but don't do anything to annoy your users. E.g. could they spend twenty minutes entering data, nip off to the coffee machine and return to click Submit to find the timer has expired, noticed an update and their work is lost due to a forced restart?
If so, and I admit this hasn't had a lot of thought, if e.g. you have to make changes to the web service that break the current release, could you have the new web service version side-by-side such that users don't get thrown out until the timer has expired and the unit of work is complete? Or is this also stating the obvious?
For server code, i.e. endpoints just do as per normal. for the xap's I think you have a few options depending upon how you handle communications. You could have request contain a version number and if the server has been updated then force some code to reload the client, bit lame, messy but do-able. Perhaps a cleaner solution would be to control the clients session, which presumably is part and parcel with requests to the backedn. When you deploy a new version you could invalidate the client session, perhaps forcing a page refresh with custom logic. If your protocol is push base you could send a command to the client to do what ever you want, for many systems that are on all day its likely that this infrastructure would exist (if u've build it nicely :)). For instance our service layer is abstracted away from the repositories models and view models, in our case we'd could send a logout or perhaps a specific command to kick in some custom logic on the client informing the application is being updated and to refresh your browser when done. Our shell is light weight so our modules (basically other xap's) can be updated in time for the refresh.
I would recommend you to use a solution like mentioned in App Arch Guide:
The Guide Chapter I mean see Deployment considerations.
Divide the application into logical
modules that can be cached
separately, and that can be replaced
easily without requiring the user to
download the entire application
again.
Version your components.
Have you considered keeping a WCF polling duplex channel going that alerts the app when it needs to reload? In addition, you can have your WCF calls direct to a virtual directory that contains 'interfaced' calls. For example:
Silverlight app hosted at "x.x.x.x\Default.aspx"
Silverlight talks to WCF at "x.x.x.x\Version2\DataPortal.svc"
DataPortal.svc talks to a GAC (or otherwise base) assembly that can identify what version can handle what calls.
This way, if you upgrade to "x.x.x.x\Version3\DataPortal.svc", you can still make calls against Version2, assuming those calls have code to convert them to a Version3 concept.
This helps in cases where your line of business app has dynamic xap downloading ('main', 'customer', 'inventory', etc.) and you want to release them independently.
When creating an auto updating feature for a .NET WinForms application, how does it update the DLLs and not affect the currently running application?
Since the application is running during the update process, won't there be a lock on the DLLs (because those DLLs will have to be overwritten during the update).
Usually you would download the new files into a separate area. Then shutdown and restart and at startup you look for and use the new files if found. Always keeping a last known working version on the side so that the user can revert to something that definitely works if the download causes problems.
ClickOnce is a good technology from Microsoft that does this for you and you can use it directly from Visual Studio 2008.
You'll have to shutdown your application and restart it, as other people have already commented.
I wrote an open-source code to do just that in a transparent mode - including an external update application to do the actual cold update. See http://www.code972.com/blog/2010/08/nappupdate-application-auto-update-framework-for-dotnet/
The code is at http://github.com/synhershko/NAppUpdate (Licensed under the Apache 2.0 license)
I have a seperate 'launcher' application that checks for updates via a web service. If there are updates, it downloads them and then executes my application, which is in a seperate assembly.
The other alternatives are using things like ClickOnce, or downloading the files to a seperate area and restarting the app, as someone else mentioned.
Be warned about ClickOnce, though - it's not as flexible as it sounds. And if you deploy to a system that requires elevating your program to a higer security level to run, you might run into problems if you don't have a certificate for your app installed. I found it very difficult to get straight answers on the Internet to things like certificate management when it comes to ClickOnce. If you have a complex app, you may want to just roll your own updater, which is what I ended up having to do.
If you publish via ClickOnce, all of that tends to be handled for you. It has it's own pro's and con's but usually easier than trying to code it all yourself.
Both Wikipedia and 15seconds have decent info on using ClickOnce, how it works, etc.
As others have stated, ClickOnce isn't as flexible as rolling your own solution but it is a LOT less complicated. It has a small learning curve at first, but with pretty much everything bundled into Visual Studio and the use of Wizards, it usually doesn't take long to stumble onto a working solution.
As deployments get more complex (i.e. beyond than just having prerequisites or application code that needs updating) and you need to do a lot of post-install or pre-install tasks, there are things like WiX which give you somewhat of a hybrid solution between Windows Installer and ClickOnce, with the cost of flexibility being a much steeper learning curve.
The only reason I try to avoid custom installers is that you end up spending way too much time trying to get it just right to handle a bunch of different "What If" scenarios...
These days Windows can do such updates automatically for you with AppInstaller if your app is packaged in the MSIX package.
It downloads the new version of the app in another folder inside ProgramFiles\WindowsApps, then when a user runs the app via the start menu, the system knows what folder it should use. The previous version gets deleted when not in use.
If you want to know how to package your app this way I collected my findings in this answer.