Entity framework in Windows Service (client-server app) - entity-framework-4

I have just developed an MVC web application with Entity Framework and Code First. This application enqueue jobs in a table.
Now I´m developing a Windows Service that reads this jobs table, and process the jobs. The perfect solution would be to use Entity Framework in this windows service.
My problem is how to implement Entity Framework in a Windows Service, and more important, how to use in the windows service (think as the client) the models of the MVC web app (think as the server).
I´ve seen that Code First is not compatible with ADO.NET Self-Tracking Entity Generator that seems the right solution for a server-client enviroment. Do I need to change the Code First EF application to STE, or are there other solutions to get the models in the windows service?
I have googled how to implement EF in a Windows Service that acts as a client, but found nothing. A how-to/tutorial would be perfect.
Thank you very much

1) Sharing the data layer:
You should separate your data layer code into a separate assembly ( project ) and reference this from both your web app and your service.
2) Self Tracking Entities:
You shouldn't use these any more. They were useful before EF 4.1, but are now obsolete. It is fine to use your POCO objects in your service.

Related

How to create Two Applications in Dotnet Domain using (MVC ,WebServices (or) Class Library)?

How can I create Two Applications in Dotnet Domain using (MVC ,WebServices (or) Class Library)?
I want to create Two application
1)which is having Database Connection(Developed One)
2)Client Application - With out Database Connection Need to get the
data from Application(1).
May I know which technologies is usefull?
A) MVC(Through Ajax Call will Connect) - WebServices(Having Database
Connection)
B) MVC(Through Ajax Call Will Connect) -Class Library(BY Sending
Class dll).
So, I need combination of technologies .
In Client Application I don't want a Database connectionstring.
Please help me.
Thanks in Advance
you need a Web Api not an mvc application to interact with db and and client application choice is upto you that can be anything mvc scf spf android
now the main thing is if you use Web Api then you can create multiple client application over multiple platforms without worrying about the code structure or platform since the webapi can return result in json format
so go for WebAPI for your application

Web Services in ASP.NET MVC 4 Application

I've a web site developed using MVC 4 ASP.net application. I'm new to .net platform & I want to add web service which would return me operating system name of users device based on certain input.
Assuming I've logic to capture OS information using inputted data, how do I go forward in building this web service?
Do I need to have a complete separate solution file which will have a web service or in existing MVC 4 asp.net application itself, should I create a new project which would be of type "WCF Service Application"? Again I don't know much about WCF service either, if I use it, how would the URL be accessible, etc?
Can anyone give me some insights?
Note: I've also a separate REST web service which is a completely separate solution with separate projects but deployed on same IIS.
Thanks in Advance!
You don't need to create a WebAPI project just for what you described (i'm assuming one or a few end points).
Simply use MVC controllers that return JSON for example, this way you deal with a single framework.
Reasons to move to Web API is if you need support for CORS, need content negotiation for results etc. From what you are describing it's completely fine to stay with MVC.

ASP.NET MVC Enterprise DDD Architecture and WCF layer

I've desgined my ASP.NET MVC application using the Domain Driven Design, and I got the following projects:
MyApp.Core - the app core, contains the domain models etc.
MyApp.Infrastructure - the app main infrastrucutre, contains implementation for the domain model storing (repos etc.) using EF.
MyApp.Web.Core - domain models, services declaration (interfaces) and such only for web (e.g. IFormAuthenticationTicketSupplier, IOAuthAuthenticationProvider etc.)
MyApp.Web.Infrastructure - web implementation
MyApp.Web.UI - ASP.NET MVC standard application.
This application should be used by enterprise with multiple servers, etc. Currently, the application calls a service in the infrastructure layer at the controllers, which uses Repositories and EF. I can connect to the DB server using the connection string.
When digging about this topic at Google, I've read that some approches taken when creating an enterprise application are create an Application server and Web server. In the application server - storing a WCF service, and in the web server just calling it.
I'd like to know if I should do so (if creating a WCF service is the right and required approch when dealing with enterprises):
- Why should someone not just use the Services in the controllers and instead use an API?
- In case I'm using an API, it won't slow down the response? since even if the computers are on the same network, I still open an HTTP request.
- If I should use WCF, or ASP.NET WebAPI?
Thanks for any feedback and help!
First, regarding your projects, is there a need to split up MyApp.Web.Core, MyApp.Web.Infrastructure and MyApp.Web.UI? Sure they may be separate responsibilities, but sometimes dependency hygiene trumps encapsulation. You can always leave them in separate folders and namespaces. I wouldn't extract something into a separate project unless I needed to reference that as a library from elsewhere.
As far as the application service, that also depends on your needs. If the only place that would call that application service is the ASP.NET MVC app, then there isn't much of a need to extract an application service. There are some benefits however. One is that you don't have to worry about all of the dependencies required for a service - you just references it via Url. And of course you have the ability to call the service from places other than the controller, although the MVC controller can act as a pure HTTP service as well. You also have the ability to deploy updates to a specific service without releasing the MVC app. But you do have the burden of maintaining a separate service. If you do go that route, go with the WebAPI, WCF is just too much abstraction.

Sessions when one has an ASP.NET MVC 4 + Node.JS Hybrid application

I have already done a proof where I can include Node.JS within an ASP.NET MVC application.
Assume that I am going to use an external session provider like windows server appfabric Cache or memcache.
I have an application where there is a quite sophisticated assembly that we use to build middle tier objects that we then store in the session. The assembly and the objects it produces is our most valuable piece and I cannot justify rewriting this C# project into something this is more Node.JS friendly.
This data is stored in an external cache, and now the node.JS developers need access to that.
What techniques have you guys used in situations like this? I am pretty sure that I am going to have to have some sort of service interface provide by the asp.net side as it is the one that owns this system of record.
I am also looking for a green field option for new projects that allow both ASP.NET MVC and Node.Js work together well in a hybrid fashion anyway, so perhaps this could be solved by data being stored in a convention that works for both.
Thanks.
I wouldn't use ASP.NET session at all. Maybe a database would be a more interoperable approach. SQL Server or even NoSQL solution such as RavenDB might be a good choice.
The problem with ASP.NET out-of-proc session state providers is that they use non-interoperable serializers (such as BinaryFormatter or NetDataContractSerializer) so you cannot read the data back from NodeJs. There might even be differences in the serialization mechanism between the different versions of the .NET framework so even with 2 ASP.NET applications running on different versions of the framework it might be a challenge to share session data.

Entity framework along with plain old ADO.Net

I am building a new applications architecture and I need your advice. We have a central MSSQL server database hosted as SQL Azure. This database needs to be accessed from many different applications, most of them are web applications hosted in windows azure and couple of them are winforms apps.
Accessing database for web application is straight forward with ADO.Net. For winforms applications, the wcf data services technology seems impressive along with client authentication services for security.
I need to know whether this mixed mode of database access will work? In other words, will database integrity will be maintained if it is being hit by applications using a mix of ADO.Net and Entity framework.
Thanks in advance.
If you query the database using EntityFramework it will cache the data until you call SaveChanges(). If the database is modified (e.g. using plain old ADO.NET) in the meantime there is a risk of the data from the database being overriden by the application that is using Entity Framework. To prevent from this you need to use Concurrency Token. You can find some details here: http://social.technet.microsoft.com/wiki/contents/articles/3866.aspx
Note that when you start using concurrency tokens you need to be aware of possible concurrency exceptions which you need to handle. You can take a look at this blog post http://blogs.msdn.com/b/rickandy/archive/2011/02/17/handling-optimistic-concurrency-exception-with-ef-and-mvc-3.aspx for some ideas. WCF Data Services uses ETags for concurrency (http://blogs.msdn.com/b/astoriateam/archive/2008/04/22/optimistic-concurrency-data-services.aspx) but you may not need to do anything here if you setup concurrency in the EF model for the database that is exposed via WCF Data Services.
We are going with WCF RIA services. They seem to work well with multiple client types providing out of the box data access layer.

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