Develop Reference

How to protect a Web Application

I've a web application( ASP.NET WebForms). Now I need to give this application to my client for offline(Installed on Local Server and accessed via LAN) installation. I want to protect this application from being copied.
All I can think of now is:
I should maintain a online server and have a Activation Page which
runs when the Web App is run for the first time, It should connect to
the server and get a valid license against a Key(entered by me in
Web.Config during installation) and machine parameters.
Also, if I code it I need to take care of System Clock and other naive issues.
Now, I have two questions.
Are there any other options to safe guard a web app?
Does the solution I'm planning to code, already exists?
Thanks for reading and trying to help.
:)

No, no, no.. You can't tottaly protect your ASP.NET app like this..
Customer(if want to) can decompile your code and replace your activation methods, so application will allways think that it's "legally activated", or for example he can write fake activation server that will always activate your software... It's not so hard really, especially when your application is based on .NET.
This "protections" main purpose is only to make illegal copies creation little longer to do(for servial weeks or month-two..), so your selling departament can sell many-many copies to legal customers, and losses from illegall usage can be not so huge at project start time.. Or can be huge anyway even with usage of "super-super-super commercial protection product for you apps".. It's depends on luck and populariry of your app..
Only, and ONLY way protect your ASP.NET application with 100% guaranty from illegal copying is.. NOT TO give application to client for local install's at all. Use SSAS-model for selling your app. Or if it's not posible make this for some critical parts of your application.

Asp.NET Real Time Game

I want to develop a game in real time.
updated for all users on a picture every second. But I have no idea how to do, Is there something similar, i can use the sample code?
I'll use C# and Asp.NET
Note: Sorry for my bad english.

Try using SignalR, from what I can tell from your question, this would work well for doing game updates.
https://github.com/SignalR/SignalR
https://github.com/SignalR/SignalR/wiki/Getting-Started

If latency really matters then you should be looking at a WebSocket solution and not one introduces the overhead of requiring HTTP Requests. WebSockets support bi-directional communication between a client and server over a single connection which keeps latency to an absolute minimum. Other HTTP-based solutions, including EventSource, mean that data coming from the server to the client can be sent with low latency but messages from the server to the client have to be made by establishing a new HTTP request which introduces latency.
So, this means that ASP.NET is not a good choice for a truly realtime game at the moment.
What are the alternatives?
If you want to stay in the .NET world then I'd consider looking at XSockets or SuperWebSocket.
If you would consider other technology solutions then I've compiled a list of realtime web technology solutions. Again, when making a choice I'd favour solutions that have WebSocket support.
If you want to keep close to the Microsoft stack you could look at socket.io on Windows Azure. See Running Socket.io on Windows Azure Web and Worker Roles
If you would consider Node and a hosted service then the Pusher Pipe might be of interest for you.

From version 1.0 beta, the version just recently published on Nuget there is some changes regarding the XSockets Server (named XSocketsMaxiServr in prior version) , now its called XSockets.DevelopmentServer.Console.exe , and can be found in the XSockets\DevelopmentServer folder or the project where you install.
By just opening it from the "command prompt" the server starts, registers the WebSocketHandlers of yours. The examples that will be added during install, is located under XSockets\Examples.
We will update the documentation in just a few days, and i also know that Ulf , a team-member of XSockets just recently publised a new guide/video that can be found here:
http://xsockets.net/videos
The movie is called "XSockets.NET 1.0 RC1 - getting started" and im sure that i will be helpfull for you.
If you need any assistance don't hesitate to contact us, we will assist you as much as possible! You will find the correct contact information at the XSockets WebSite.
Kind regards, Magnus Thor, Team XSockets.NET

N-Tier with C#?

I am looking at writing a WinForms app and getting stumped over what seems to be simple issue.
There is a server and database (SQL Server) Open ports are HTTP, HTTPS
There is a WinForms client. It needs to connect a TCP/IP stream (possibly HTTP, SOAP, REST) to the server.
Sometimes the WinForms client goes off-line and then the WinForms client stores its data in a database.
When the WinForms client goes on-line to server, it synchronizes data to the server, gets all the latest data from the server and updates local database.
How do I do that?
Newbie question

As you've conceded, this question shows you might not know where to begin looking for how to architect this kind of application.
I'd start here: http://msdn.microsoft.com/en-us/library/ms973279.aspx
The offline architecture you've described is a little tougher for a newbie than not supporting this, consider making the application only work online first, then add offline functionality.
Also, if you have a web server you will almost always use HTTP, SOAP and REST are strategies that sit on top of HTTP. I cannot recommend that a new developer look at any server communication using direct TCP/IP.
Edit: Answer to related question - there are tons of ORMs and service builders, not a lot of them have built in support for offline workflow but ODX does, but it might be a bit out of date. NHibernate and any of the projects in the Castle Project are very popular components for what you're looking to do also.

No idea how actively this is still being supported by Microsoft, but you might check out the Smart Client Software Factory, it seems to support offline mode and smart reconnecting like you need.
http://msdn.microsoft.com/en-us/library/ff709809.aspx

You could approach this with a 'Service' mindset - Write a WebService (preferably a WCF service) - that forms the synchronization tier between your Winforms app. and remote database.
So, you would have your
1. Local WinformsApp. with a local database (as functional/lightweight as you want it to be)
2. WebService
3. Remote app./DB

Here are some links to tutorials/resources:
http://www.codeproject.com/KB/architecture/three_tier_architecture.aspx
http://services.community.microsoft.com/feeds/feed/query/tag/n-tier/eq/tag/visual%20basic/eq/and/locale/en-us/eq/and
http://msdn.microsoft.com/en-us/library/bb384570.aspx
http://msdn.microsoft.com/en-us/library/bb384398.aspx

IMHO this isn't usually as simple as it may sound
If you were able to go DB to DB, then SQL replication could be the simplest mechanism for synchronisation.
However, since it sounds like you are using a SOA approach, you might need to look at frameworks which have offline support built in, such as the Ent Lib Composite Application Block and Smart Client Software Factory
You might also look at using Queues (e.g. MSMQ) to accomodate network connectivity problems.

Microsoft Sync Framework (http://code.msdn.microsoft.com/sync) + WCF solution here:
http://code.msdn.microsoft.com/sync/Release/ProjectReleases.aspx?ReleaseId=3762
Database synchronisation is not an easy task to get started with, by any means. Good luck.

Generally, you need a local database, or at least a local cache.

What are the challenges in porting your existing applications to Microsoft Azure?

What are the challenges in porting your existing applications to Azure?
Here are few points I'm already aware about.
1) No Support for Session Affinity (Azure is Stateless) - I'm aware that Azure load balancing doesn't support Session Affinity - hence if the existing web application should be changed if it has session affinity.
2) Interfacing with COM - Presently I think there is no support for deploying COM components to the cloud to interface with them - if my current applications need to access some legacy components.
3) Interfacing with other systems from the cloud using non-http protocols
Other than the above mentioned points, what are other significant limitations/considerations that you are aware off?
Also, how these pain points are addressed in the latest release?

our biggest challenge is the stateless nature of the cloud. though we've tried really really hard, some bits of state have crept through to the core and this is what is being addressed.
the next challenge is the support of stale data and caching as data can be offline for weeks at a time. this is hard regardless.

Be prepared for a lengthy deployment process. At this time (pre-PDC 2009), uploading a deployment package and spinning up host services sometimes has taken me more than 30 minutes (depends on time of day, size of package, # of roles, etc).
One side effect of this is that making configuration changes in web.config files is expensive because it requires the entire app package to be re-packaged and re-deployed. Utilize the Azure configuration files instead for config settings - as they do not require a host suspend/restart.

My biggest problem with Azure today is operability with other OS’es. Here I am comparing Azure to EC2/Rackspace instances (Even though Azure as PAAS offers a lot more than them e.g. load balancing, storage replication, geographical deployment etc in a single cheap package).
Even if you consider me as a BizSpark startup guy, I am not inclined to run my database on SqlAzure (Sql2005 equivalent) since I can’t accept their pricing policy, which I’ll have to bear three years after of the BizSpark program. Now they don’t have an option for MySql or any other database. This to me is ridiculous for an SME. With EC2 I can run my MySql instance on another Linux VM (obviously in the same network. Azure gives you the capability to connect to network outside theirs, but that is not really an option)
2nd. This is again is related to using *nix machines. I want all my caching to be maintained by Memcached. With asp.net 4 they have even given us out of the box memcached support through extensible output caching. The reason why I am adamant about memcached is the eco system it provides. E.g.: Today I can get memcached with persistent caching as an add-on. This will even give me the opportunity to store session data with memcached. Additionally I can run map reduce jobs on the IIS logs. This is done using cloudera images on EC2. I don’t see how I can do these with Azure.
You see, in the case of Amazon/Rackspace I can run my asp.net web app on a single instance of Windows Server 2008 and the rest on *nix machines.
I am contemplating running my non hierarchical data (web app menu items) on CouchDb. With Azure I get the Azure table. But I am not very comfortable with that ATM. With EC2 I can run it on the same MySql box(don't catch me on this one :-)).
If you are ready to forget these problems, Azure gives you an environment with a lot of grunt work abstracted. And that’s a nice thing. Scaling, loading balancing, a lot of very cheap storage, CDN, storage replication, out of the box monitoring for services through Fabric Controller etc among these. With EC2/Rackspace you’ll have to hire a sysadmin shelling $150k PA to do these things (AFAIK Amazon provides some of these feature at additional cost).
My comparisons are between azure and Amazon/Rackspace instances (and not cloud). For some this might seem like apples and orange. But azure does not provide you with instances. Just the cloud with their customized offerings…

My biggest problem is/was just signing up and creating a project. And that's how far it got over the last month.
Either I am doing something very wrong, or that site is broken most of the time.

One important challenge is the learning curve, lack of experienced developers, the time it takes to become productive .
This happens with all technologies, but with the cloud there is a fundamental change in how somethings are done.

If your application needs a database, I'm not sure that Windows Azure has a relational database (right now)
Also, there are other cloud computing providers that can offer you more options in configuring your virtual machine for example, it really depends on what you actually need and want.

Distributed application (WCF/Remoting/web servervices) Vs Web application

I am making a medium sized standard LOB application. Currently its a web application but I am formulating a proposal to revamp it into a Desktop remote application. By this I mean that the database and the application server will be hosted in a remote location. The client application will communicate with the server via the internet through (either WCF / Webservices / Remoting).
My question is this: The only reason I am shifting this from a web platform is due to the constraints of the web (I dont want to do AJAX or Java scripting to minimize those constraints, so please no JS/AJAX recommendations). I have made traditional desktop applications and they are considerably fast but i have never made a remote or a distributed application. I am not sure weather the speed of the application will be faster then the web or not.
As I understand it, the remote desktop application would be much faster. For one, there wont be any post backs involved, (I hate them so much). The data will obviously come via internet, so in that respect, is it better to shift to the remote desktop just for sheer speed and power?
Any help in the right direction would be greatfull. Many thanks.
Zeeshan

I think biggest advantage of desktop clients over web applications is freedom in UI design, and you don't have to worry about any inconsistencies in the client environment, although those are not an issue if you are using a client that runs on silverlight.
Personally I don't like web applications that requires a lot of user interaction, there are some of them that is a pleasure to use but I think it is very easy to do it the wrong way and end up having a buggy or not so responsive application (probably because of the incompatibilities in browsers, I have IE, Firefox and Chrome installed on my computer and I use one for some websites because they run faster on it, and others for other sites because web pages show up correctly only on them). Though this might not be an issue for a silverlight client.
In case of network speed, depending on the things that goes on the wire even with binary serialization remoting might have quite a bit of overhead. For example along with the data it writes full class names, library names and their versions so it can get pretty big and slow even for small amounts of data (although it should still be smaller then HTTP). It also has the same problems that HTTP has over unreliable connections because it uses a similar protocol. For one project we had to write a custom serializer for some objects because binary serialization alone was generating 200K, but our custom serializer for those objects were generating 50K. Then we ended up writing our own network protocol because the one that comes with the runtime was frequently stalling over unreliable wireless networks, and remoting doesn't give any control on the socket created by it (which makes sense in terms of encapsulation but you can't close it and force it to open a new one).
(I am assuming that you are asking about remoting vs web app. not remote desktop vs. web apps, because of your note about post back, you can't avoid it with a remote desktop session)
Rewriting an application just for sheer speed? No, because probably user won't see much difference in response time.

You are somewhat ambiguous with your terminology - do you want a client app that runs on the user's machine, or do you want an app that runs on the server and the user connects via remote desktop (RDP)?
If you are talking about a client app that communicates to the server via WCF etc., then yes it will be faster than a standard web app, although it will still be slower than a native desktop app. It will be faster than the web app not just because of the lack of postbacks, but also because you will be sending pure data through the wire, not a massive amount of HTML/Javascript combined with your data. With a client app, you have several options so consider them carefully - do you want Silverlight, WPF, or a native WinForms app? Each have their positives and negatives.
If you were talking about having a client app running on the server which the user then access via RDP, then you have other considerations to think of. For any more than two concurrent users you will need to consider buying CALs so the users can connect to the server. At this point you should also be considering whether you should be running a terminal server or Citrix type setup instead of using remote desktop.
Edit
When using WCF over a WAN (internet) you will certainly have to consider how you will secure it. WCF makes it trivial to secure the channel, but you need to consider how you will do authentication - there are a couple of different ways, but you can easily google that stuff yourself. The method you choose will be important due to the limited resources or skill-sets of the users.
As for what you write it in, you can't argue with Winforms if that is where your experience is. Personally, i would never again use ASP.NET/Ajax/etc for a web type application, it would be WPF or Silverlight all the way (i would only use ASP.NET for simple web sites). You can use the express (free) versions of Visual Studio to write it in, you don't need Expression (it's just a nice to have, and is more aimed at the design side than the actual coding side). Deploying the app need not be difficult - Silverlight or WPF xbap are delivered via the web, the user has to do nothing (except for the simple install of the Silverlight plugin or installing the right .Net framework for WPF - check this link). Winforms or stand-alone WPF require slightly more work, but you can avoid most issues by writing a good installer.
Whichever you choose, make sure you don't under estimate the time for development (because you will have a bit of a learning curve), and also make sure you budget enough time for testing it - especially the security side of it :)

I have been in a similar situation, although started with a Winforms LOB application.
Heres what we found with WinForms...
It's going to be harder to deploy in your release cycle, to all client machines.
WinForms can't be run on other operating systems easily. (with the exception on mono)
WCF endpoints can get complicated, and you need to manage an endpoint for release/version of your application.
Authentication, Authorization and Security can be tricky to get right!
Heres why you should stick to a html web application.
it's going to be easier to deploy, as you just need to copy one set of DLL's into the bin folder. Can be scripted from a continuous integration or staging server.
Security is going to be easy, by using a SSL certificate.
Silverlight/Flash should fill in the gaps that HTML leaves out.
Microsoft has also combined the connected systems in .net 3.5, they now call it WCF (ASMX/Remoting/etc...). It's got quite a learning curve 4-5 weeks.