Web Based Architecture of an Old Windows based application - c#

We are in process of re designing an old windows client server based application to web based application.
This application is built in C# using Remoting and WCF. On client side its Windows and WPF.
My Queries
What all concepts should be taken care when we make this application web based?
What design patterns should be followed for Web Based Architecture?
In WCF part we are using Net TCP Binding which can be easily migrated to HttpBinding, but I am more concern over Remoting, will it able to Serve the purpose, means can Remoting serve the purpose when Http calls are being made?

I would probably merge "remoting" with wcf and use httpbinding endpoint. font-end you could decide to use MVC pattern which will give you a better performance.

Sorry to answer your question with a question but: From an architecture or business point of view, why would you want to do this?
Your original application uses Remoting, which does not work over the Internet, therefore I am assuming that this is an internal application.
A web application would have the following tiers:
The presentation which runs on the browser
The Web Server which sends the pages to the browser
The application server which would host your WCF services
The database server
As you see the web application in the browser does not call the services directly (unless you use REST based services)

Related

Communication between windows service and WPF with self-hosted owin web api

I need to make a WPF application running under a regular account and a windows service that will run under the admin account. The WPF application will call a service that then performs the required tasks.
What I'm dealing with is the way of communication between these two elements. Mostly I came across references to WCF and named pipes with which I do not have much experience.
So I thought I would create a self-hosting owin web api and use it instead of WCF.
I would therefore like to ask what are the disadvantages of such a solution. Is the use of a self-hosted web api suitable for such purposes, or I would rather use WCF named pipes.
Thanks for any advice :-)

WCF vs ASP.NET Web API [closed]

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I've spent a few months trying to grasp the concepts behind WCF and recently I've developed my first WCF service application.
I've struggled quite a bit to understand all the settings in the config file.
I am not convinced about the environment but it seems that you can do amazing stuff with it.
The other day I've found out that Microsoft has come out with a new thing called ASP.NET Web API.
For what I can read it's a RESTful framework, very easy to use and implement.
Now, I am trying to figure out what are the main differences between the 2 frameworks and if I should try and convert my old WCF service application with the new API.
Could someone, please, help me to understand the differences and usage of each?
For us, WCF is used for SOAP and Web API for REST. I wish Web API supported SOAP too. We are not using advanced features of WCF. Here is comparison from MSDN:
The new ASP.NET Web API is a continuation of the previous WCF Web API project (although some of the concepts have changed).
WCF was originally created to enable SOAP-based services. For simpler RESTful or RPCish services (think clients like jQuery) ASP.NET Web API should be good choice.
ASP.net Web API is all about HTTP and REST based GET,POST,PUT,DELETE with well know ASP.net MVC style of programming and JSON returnable; web API is for all the light weight process and pure HTTP based components. For one to go ahead with WCF even for simple or simplest single web service it will bring all the extra baggage. For light weight simple service for ajax or dynamic calls always WebApi just solves the need. This neatly complements or helps in parallel to the ASP.net MVC.
Check out the podcast : Hanselminutes Podcast 264 - This is not your father's WCF - All about the WebAPI with Glenn Block by Scott Hanselman for more information.
In the scenarios listed below you should go for WCF:
If you need to send data on protocols like TCP, MSMQ or MIME
If the consuming client just knows how to consume SOAP messages
WEB API is a framework for developing RESTful/HTTP services.
There are so many clients that do not understand SOAP like Browsers, HTML5, in those cases WEB APIs are a good choice.
HTTP services header specifies how to secure service, how to cache the information, type of the message body and HTTP body can specify any type of content like HTML not just XML as SOAP services.
Since using both till now, I have found many differences between WCF and Web API. Both technology stacks are suited well to different scenarios, so it is not possible to say which is better, this depends on configuration and scenario.
Properties ASP.Net Web API WCF
--------------------------------------------------------------------------------------------------
End point (mainly) Http based SOAP based
Service Type Front End Back-end
Support caching, compression, versioning No
Framework ASP.net WCF
Orientation Resource Oriented Service Oriented
Transports http http, tcp, MSMQ, Named pipe
Message pattern Request reply request Reply, one way, duplex
Configuration overhead Less Much
Security lesser than WCF (web standard security) Very high (WS-I standard)
Hosting IIS IIS, Windows Service, Self hosting
Performance Fast A bit slower than Web API
In use from .NET 4.0 .NET 3.5
Note: The data is not only my view, it is also collected from other official websites.
WCF will give you so much of out the box, it's not even comparable to anything. Unless you want to do on your own implementation of (to name a few) authentication, authorization, encryption, queuing, throttling, reliable messaging, logging, sessions and so on. WCF is not [only] web services; WCF is a development platform for SOA.
Why I'm answering:
I took huge amount of time to understand the difference between these two technologies. I'll put all those points here that I think "If I had these points at the time when I was wondering around in search of this answer, then I have decided very earlier in selecting my required technology."
Source of Information:
Microsoft® Visual Studio® 2015 Unleashed
ISBN-13: 978-0-672-33736-9 ISBN-10: 0-672-33736-3
Why ASP.NET Web API and WCF:
Before comparing the technologies of ASP.NET Web API and WCF, it is important to understand there are actually two styles/standards for creating web services: REST (Representational State Transfer) and SOAP/WSDL. The SOAP/WSDL was the original standard on which web services were built. However, it was difficult to use and had bulky message formats (like XML) that degraded performance. REST-based services quickly became the alternative. They are easier to write because they leverage the basic constructs of HTTP (GET, POST, PUT, DELETE) and typically use smaller message formats (like JSON). As a result, REST-based HTTP services are now the standard for writing services that strictly target the Web.
Let's define purpose of ASP.NET Web API
ASP.NET Web API is Microsoft’s technology for developing REST-based HTTP web services. (It long ago replaced Microsoft’s ASMX, which was based on SOAP/WSDL.) The Web API makes it easy to write robust services based on HTTP protocols that all browsers and native devices understand. This enables you to create services to support your application and call them from other web applications, tablets, mobile phones, PCs, and gaming consoles. The majority of applications written today to leverage the ever present Web connection use HTTP services in some way.
Let's now define purpose of WCF:
Communicating across the Internet is not always the most efficient means. For example, if both the client and the service exist on the same technology (or even the same machine), they can often negotiate a more efficient means to communicate (such as TCP/IP). Service developers found themselves making the same choices they were trying to avoid. They now would have to choose between creating efficient internal services and being able to have the broad access found over the Internet. And, if they had to support both, they might have to create multiple versions of their service or at least separate proxies for accessing their service. This is the problem Microsoft solved with WCF.
With WCF, you can create your service without concern for boundaries. You can then let WCF worry about running your service in the most efficient way, depending on the calling client. To manage this task, WCF uses the concept of endpoints. Your service might have multiple endpoints (configured at design time or after deployment). Each endpoint indicates how the service might support a calling client: over the Web, via remoting, through Microsoft Message Queuing (MSMQ), and more. WCF enables you to focus on creating your service functionality. It worries about how to most efficiently speak with calling clients. In this way, a single WCF service can efficiently support many different client types.
Example of WCF:
Consider the example:
The customer data is shared among the applications. Each application might be written on a different platform, and it might exist in a different location. You can extract the customer interface into a WCF service that provides common access to shared customer data. This centralizes the data, reduces duplication, eliminates synchronization, and simplifies management. In addition, by using WCF, you can configure the service endpoints to work in the way that makes sense to the calling client. Figure shows the example from before with centralized access of customer data in a WCF service.
Conclusion:
i) When to choose Web API:
There is no denying that REST-based HTTP services like those created using ASP.NET Web API have become the standard for building web services. These services offer an easy, straightforward approach for web developers building services. Web developers understand HTTP GET and POST and thus adapt well to these types of services. Therefore, if you are writing services strictly targeted to HTTP, ASP.NET Web API is the logical choice.
ii) When to choose WCF:
The WCF technology is useful when you need to support multiple service endpoints based on different protocols and message formats. Products like Microsoft BizTalk leverage WCF for creating robust services that can be used over the Web as well via different machine-to-machine configurations.If, however, you do need to write an application that communicates over TCP/IP when connected to the local network and works over HTTP when outside the network, WCF is your answer.
Be Warned:
Web developers often view WCF as more difficult and complex to develop against. Therefore, if you do not foresee the need for multiprotocol services, you would likely stick with ASP.NET Web API.
There is a comparison on MSDN about this
WCF and ASP.NET Web API
For me, the choice was about Who the clients are, and where are they located?
Within the company Network and .NET based clients : Use WCF with TCP binding (Fast communication than HTTP)
Outside the company Network, and use diverse technologies like PHP, Python etc: Use Web API with REST
Business speaking, WebApi lacks of a WSDL, so the developers should document all manually. And if, for example, the WebApi operation returns a list of objects then, the client should creates the objects manually, i.e. WebAPI is really prone to errors of definitions.
The pro of Webapi is its more lightweight than WCF.
Regarding the statement "WebApi lacks of WSDL" there are several ways to generate Rest client. One popular approach is Swagger UI / (Swashbukkle Nuget). This gives a rich interface to understand the REST end point's input and output schema and online tool to test the end points.
JSON LD (Json Linked Documents) is another emerging standard which will further improve the JSON based REST developer experience by exposing the JSON schema with better semantics.
With wcf we can configure and expose the same service support for multiple endpoints like tcp, http.if you want your service to be only http based then it will be better to go with web API. Web API has very less configuration when compared to wcf and is bit faster than wcf. Wcf also supports restful services. If you have limitation of .Net framework 3.5 then your option is wcf.

Good way of communicating between web and desktop app

I want my web app (running in a browser) to, at some point, communicate (bidirectionally) with a desktop app (in Windows), the client has installed in its computer.
What's an elegant and modular and simple way of doing this (with Java and C#)?
Not much information will be passed between the web app and the desktop app. Just something like "I was here", "Pick this from this point", etc.
I solved that problem by using a database on the network.
All communications where made trough the database.
Website -> DB -> User logged in <- DB <- Desktop
However, if no trusted information needs to be shared, you could consider just posting and reading some http headers to a common website, or a simple log file.
Greetings
I suggest you to use the backend part of your webapp, assuming that your app is based on some backend services.
You have two options:
Your desktop apps use the same services of your web app. You must use a class that mimic a web-browser to give the data (curl, ie). If your web app is based on AJAX push ( APE Server i.e ) use library that is able to run some javascript
Use a REST protocol, with a JSON format in your backend services. It's easy to manage and is supported by many client-side languages (java/c#/python....)
Use a specialized endpoint only for your desktop app,for C#, you can use WCF, that allow you, in one of his forms bidirectional communications. For JAVA, there are WSDL, DWR
My preferred solution is to decouple the web app in a front-end side and a backend side, that expose the services as REST that are used by the web app via AJAX.
If I need true bidirectional communication with other desktop app, I'll create a separate service / endpoint for it. (APE , WCF, ..)
I see several options to achieve part of what you are asking:
Besically you expose the relevant parts of your apps (web and desktop) via some sort of API and use that for the communication - for example DB and/or WCF (SOAP/REST/whatever).
BEWARE:
If you are after some sort of direct/interactive communication between both apps on the same computer then this won't be possible - at least not without some security related issues.
The browser executes your web app in a sandbox which doesn't allow for direct communication between the web app and the desktop... there are technologies which can help circumvent that (ActiveX, signed Java applets, some Flash technology called AIR etc.)... or you could host some webbrowser/control in your desktop app which in turn runs the web app... BUT basically I would recommend against using any such measures...
IF you really want to go this route then please describe your environment and goal with much more detail.

securing wcf services from specific sources

I am using wcf services for interaction between my javascript files and server side.
I am concerened about security around this as anyone can call these services via an application, firebug etc.
So I want to secure my web services to only be accessible from specified sources, for example the javascript files on my site - ie. the main function why I have wcf services.
I am running on the .net 3.5 framework in a c# web application.
Could anyone assist my securing my wcf services as outlined above?
If this is a combination of javascript and server side , you can probably generate a Key from the server side and store it in the javascript variable and pass again to the WCF webservices.
Kobe's answer of generated request keys is definitely one possible way. Given that your services are running on the same machine as your UI code, another way to limit access would be to set them up as regular services and not Web Services. That is of course assuming you don't need them to be Web Services.
Check out the cool work that the WCF team has done/ is doing with jQuery and WCF.

.net web service hosted within my application

I'm migrating an old Delphi application that I wrote into C#. The application is a datalogger that exposes logged data requests via a SOAP web service interface.
The web service is contained with the delphi graphical windows application, i.e. no need to run a web server like IIS, etc I just run the application and it's up and running under the hood.
I'm looking to do the same in my c# Windows form application, I can find loads of resources on writing web services that are ultimately hosted within IIS but am struggling to find a solution for a self contained web service within my application.
Does anyone have any suggestions or can point me towards any resources on this?
The web service does not neceserily have to be SOAP, REST is fine (in fact probably prefered).
Look into WCF Services.
Hosting and Consuming WCF Services
Hosting WCF services in a Windows Forms Application
The System.Web.Hosting namespace allows you to host ASP.Net pages without using IIS within your applications. I have never used it to host web services but I found a tutorial that seems to provide a guide on doing this-
http://msdn.microsoft.com/en-us/magazine/cc163879.aspx
If you're wanting to host a service inside your application, it's possible with the System.ServiceModel.ServiceHost class. You need to learn WCF first, but that at least answers your question to get you started. If you have any further questions, leave me a comment or two and I'll update my answer to accommodate your inquiries.

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