Due to deployment restrictions, we can't deploy WCF on the client-side (yet) but would like to use it on the server-side.
I am interested to know if it is possible to use WCF on the server but consume it with .NET remoting on the client side. I don't have any problems with using specific bindings, transfers or protocols on the server side to make this happen.
It is definitely possible - here is a good place to start.
Related
After developing mini project with WCF duplex (Chat Service | Sms Service), I got a Point that maybe not be correct!!
I believed Duplex theory is good and useful but there is a lot problem about using Wcf Duplex. (like reliable session, Time-out exceptions, Client address-Management on server side, proxy management on Client Side)
am I think wrong ? am I miss something?
For more Information I Used wsDualHttpBinding not tcpBinding.
If you need bidirectional communication and you want to use WCF, duplex channels are the way to go. You just need to design your application correctly and correctly handle all problems you have described. If you feel that these problems are overhead and make things even worse you can always use network programming directly (sockets) or handle bidirectional communication by yourselves exposing separate service on server and another on client (where first call from client inform server about clients address) - this scenario will suffer from the same communication problems as WsDualHttpBinding.
WsDualHttpBinding itself is special kind of duplex communication. I personally don't like it because people very often misuse it. The problem is that this binding uses two separate connections - one from client to server and second from server to client. That is big difference to net.tcp where only connection initiated from client to server is used. Obviously using WsDualHttpBinding over internet (= you don't have control over client machines) becomes much more complicated because each client must configure its firewall (in computer, on home internet gateway, etc.) to allow connection on some port. Also if you want to run more then one instance of application on the same client machine, each instance must use its own port.
In my application I need to push notifications of real time events from server to clients. The amount of data to pass is very small, mostly and Id. The number of clients listening simultaneously can be around 100 and I may have to publish one notification every 2 - 3 seconds. Both the server and client are built using .Net and WCF.
Given these requirements I have built a set of WCF services which will be run on a load balanced server cluster. The Instance context mode is Per Call and there is no need for sessions etc.
I am currently using BasicHttpBinding. Will TCP binding be better? Does it run on IIS 5 or 6? If not why?
What configuration for serialization can work best?
What are the things I need to do to make sure I get maximum performance?
Edit - Adding more information based on some of the responses -
I host a small WCF service in the client process using manual hosting. The server just calls this service on each client to push the data to all of them.
Firstly have you considered using messaging for what you are trying to achieve?
In answer to will TCP binding work better than BasicHttpBinding- almost certainly yes. If you want to use TCP, you can't use IIS- look into WAS with Windows Server 2008. If you're stuck with Windows Server 2003, then you'll have to host in a windows service instead.
You've made a good choice by choosing per call- this is the preferred instance management mode for creating scalable WCF services.
Edit:
Now you've update your question, I recommend you take a look at IDesign's Pub/Sub framework if you want to stick with WCF. I'd also look at Pub/Sub with MSMQ in WCF and also with "Vanilla" products such as Tibco RV.
If you need pushing data from service to clients you need sessions and you need duplex binding - NetTcpBinding or WSDualHttpBinding. It will not work with BasicHttpBinding because it allows only pulling data (client pools the service for changes). Push data means tha service sends data to clients when needed.
NetTcpBinding always crete session. It can't be hosted in IIS 6 or older. NetTcpBinding is allowed only in Windows Activation Service (WAS) which is extension of IIS 7.x. For older systems you need self hosting = windows service.
Edit:
Based on your description you need Publish-Subscribe message exchange pattern.
Just a technology update, now that .NET 4.0 is out.
I write an application that communicates to the server through what is basically a message bus (instead of method calls). This is based on the internal architecture of the application (which is multi threaded, passing the messages around).
There are a limited number of messages to go from the client to the server, quite a lot more from the server to the client. Most of those can be handled via a separate specialized mechanism, but at the end we talk of possibly 10-100 small messages per second going from the server to the client.
The client is supposed to operate under "internet conditions". THis means possibly home end users behind standard NAT devices (i.e. typical DSL routers) - a firewalled secure and thus "open" network can not be assumed.
I want to have as little latency and as little overhad for the communication as possible.
What is the technologally best way to handle the message bus callback? I Have no problem regularly calling to the server for message delivery if something needs to be sent...
...but what are my options to handle the messagtes from the server to the client?
WsDualHttp does work how? Especially under a NAT scenario?
Just as a note: polling is most likely out - the main problem here is that I would have a significant overhead OR a significant delay, both aren ot really wanted. Technically I would love some sort of streaming appraoch, where the server can write messags to a stream while he generates them and they get sent to the client as they come. Not esure this is doable with WCF, though (if not, I may acutally decide to handle the whole message part outside of WCF and just do control / login / setup / destruction via WCF).
For bidirectional communications, your best bet is NetTcpBinding, rather than the http bindings, if they're available.
This has the advantage of only requiring that the client can initiate a connection with the server.
I would go with Windows Azure Service Bus. See my answer in the following question:
WCF, 4.0, Bidirectional
Take a look at Windows AppFabric, good place to start is Here. It fundamentally wraps up WCF and WF into an application server, with WCF activation supported through WAS. Its where I would host this type of app. It offerd full duplex connection orientated, p2p or sessions between client and server. Don't confuse the Windows appfabric with Azure appfabric, (formely called Azure Service Bus).
As regards bindings above, both NetTcpBinding and WsDualHttp offer callbacks, but the ws binding you get a lot for your cash, especially if it's a mixed programming environment and you have to flatten the wsdl to make interop work. I also think that WsDual is easier on routers traversal, although I understand talking to friends, that Windows AppFabric mitigates this, with new Relay Services, (which i've not seen, and I think have now been renamed).
Hope that helps.
I understand to an extent that it helps applications communicate regardless of their location. Why is it important and what is an example of a real-world use of WCF?
WCF is a generic communication mechanism that allows you to setup generic client/host communication between two parties. The neat thing about WCF is that is allows you to configure service properties such as transport (http/pipes/tcp/Tibco EMS), security models (any of the W3C standards), compression, encoding, timeouts, etc, without changing ANY code. That is powerful. Best of all, you can configure it so that you can have a service in C# and a client in Java (or any other language or the other way around), as long as they both talk using the same mechanisms.
You can create a standard HTTP SOAP web service using WCF and one day decide to switch it to use the faster named pipes for local communication. You can create web services that talk over TibcoEMS and have easy failover on the queue level. You can create a file streaming web service that distributes all kinds of images/videos to your application.
Here Are some brain dump i think might be useful to understand the whole scenario.
Reason of Creating WCF : Background
Modern Application[Distributed Application] development we use different architechtures and technologies for communication
i.e:
COM+
.NET Enterprise Services
MSMQ
.NET Remoting
Web Services
As there are various technologies. they all have different architechtures. so learning all them are tricky and tedious.
one need to focus on each technologies to develop rather than the application business logic
so microsoft unifies the capabilities into single, common, general service oriented programming model for Communication. WCF provides a common approach using a common API which developers can focus on their application rather than on communication protocol.
Now-a-days we call it WCF.
N.B: image collected from - http://www.codeproject.com/Articles/255114/Windows-Communication-Foundation-Basics
What Exactly WCF Service Stands For?
WCF lets you asynchronus messages transform one service endpoint to another.
The Message Can be simple as
A Single Character
A word
sent as XML
complex data structure as a stream of binary data
Windows Communication Foundation(WCF) supports multiple language & platforms.
WCF Provides you a runtime environment for your services enabling you to expose CLR types as Services and to consume other Services as CLR Types.
A few sample scenarios include:
A secure service to process business transactions.
A service that supplies current data to others, such as a traffic report or other monitoring service.
A chat service that allows two people to communicate or exchange data in real time.
A dashboard application that polls one or more services for data and presents it in a logical presentation.
Exposing a workflow implemented using Windows Workflow Foundation as a WCF service.
A Silverlight application to poll a service for the latest data feeds.
Why on Earth We Should Use WCF?
from a Code Project Article, thanks to #Mehta Priya I found the following Scenarios to illustrate the concept. Let us consider two Scenario:
The first client is using java App to interact with our Service. So for interoperability this client wants the messages in XML format and the Protocol to be HTTP.
The Second client uses .NET so far better performance this clients wants messages in binary format and the protocol to be TCP.
Without WCF Services
now for the stated scenarios if we don't use WCF then what will happen let's see with the following images:
Scenario 1 :
Scenario 2:
These are two different technologies and have completely differently programming models. So the developers have to learn different technologies
so to unify & bring all technologies under one roof. Microsoft has come with a new programming model called WCF.
How WCF Make things easy ?
one implement a service and he/she can configure as many end points as it required to support all the client needs .
To support the above 2 client requirements
-we would configure 2 end points
-we can specify the protocols and message formats that we want to use in the end point of configuration
References:
WCF : What , Why and When https://vishalnayan.wordpress.com/2010/12/31/wcf-what-why-when/
Why we use WCF Service? http://www.codeproject.com/Tips/815742/Why-We-Use-WCF-Service-and-Sample-of-WCF-Service
What Is Windows Communication Foundation https://msdn.microsoft.com/en-us/library/ms731082(v=vs.110).aspx
Windows Communication Foundation Basics http://www.codeproject.com/Articles/255114/Windows-Communication-Foundation-Basics
There's little to add to the responses so far, especially the one from "siz".
One thing to add is that WCF is the current way to do web services on the .NET platform. It's not the "new" way, it's the current way. ASMX web services are the old and just barely maintained way. One Microsoft employee has publicly stated that only critical security fixes will be made to the ASMX platform, so if you intend for your services to be useful more than a year from now, don't use ASMX.
In addition to the typical "web service" use cases, WCF handles atypical cases, like binary communication over named pipes, message queues, etc. To a very large extent, the service you write to support something simple like SOAP over SSL can also support these other protocols, with no changes to the code.
To answer the "real world" bit, I'm just finishing up a dispatch system by which a Visual Basic 6.0/access alarm receiver, a WPF/SQL ERP system and an iPhone application all share information to schedule and execute jobs.
Essentially the use case is where you want two separate applications to talk to each other somehow and their locations are unknown (could be same machine (but different application domain), same network or on the other side of the internets)
You can easily embed it into a Windows Forms application. That was a nice thing to discover. It is so much easier than .NET Remoting too.
There are a number of reasons why it is advantageous over classic ASP.NET web services (.asmx).
A couple of these off the top of my head are:
The ability to have multiple bindings for the same service call means the message doesn't have to serialise into XML and back if you simply want to communicate inside a web farm.
The way contracts are defined is much more forgiving when it comes to multiple versions of the same contract.
I am looking at using MSMQ as a solution to do asynchronous execution in my upcoming project. I want to know the differences between using WCF and frameworks like MassTransit or even hand written MSMQ client to place/read task off MSMQ.
Basically the application will be several websites (internal through LAN or external through the Internet) reading/writing data through a service layer (be it WCF or normal web service). Then this service layer will do one of two things: 1. write data to database 2. and/or trigger the background process by placing a message in the queue. 3. obviously it can also retrieve data from database. The little agent (a windows service) on the other side of the queue will monitor the queue and execute based on the task command.
This architecture will be quite easy to scale (add more queues and agents) and easy to implement compared to RPC or distributed execution or whatever. And the agent processing doesn’t need to be real time. And the agent and service layer are separate applications except they share the common domain objects and Repositories etc.
What do you think? Architecture suggestions for the above requirements are welcomed. Thank you!
WCF adds an abstraction over MSMQ. In fact, once you define compatible contracts (operations must be OneWay), you can switch out MSMQ in the config, transparently. (For instance, you could switch to normal HttpWS or a NetTcp binding.)
You should evaluate the other WCF benefits, like security and so on, to see how those fit in with your needs. Again, they should be reasonably transparent of the fact you're using MSMQ underneath. For instance, adding SOAP security and so on should "just work", independent of using MSMQ.
(Although, IIRC, you still need to login to the desktop on each machine that uses MSMQ, with the service account that will use MSMQ, to generate the certificate in the machines local profile. And then, it doesn't work very well from IIS6, since user profiles aren't loaded. A real pain in general, but nothing to do with WCF specifically.)
Apart from that:
Have you looked at SQL Server Service Broker? After using MSMQ + WCF and SSSB, I think that SSSB is vastly easier to configure and manage. SSSB works with T-SQL commands over any SQL client (I use it from Mono, on Linux, with transactions). It'll also give you transactional send/receive, even remotely (I think MSMQ 4 now allows this). It really takes a lot of the pain away from message queuing, and if you're using SQL Server already...
SSSB is often overlooked since the SQL Management Studio doesn't have GUI designers for it all, but it isn't hard and is a great option. The one downside is that if you want local send capability (i.e., queue message when network is down), you'll need to run a local SQL Express instance.
Your architecture seems sound and reasonable. However you should consider using the WCF net MSMQ transport over hand coded MSMQ classes. WCF wraps this common functionality into a nice programming model. Also I believe there is some improvements in the protocol used by wcf compared to basic System.Messaging
Have a look at the value-add over plain MSMQ:
http://readthedocs.org/docs/masstransit/en/latest/overview/valueadd.html
In summary, you get a lot of messaging concepts clearly presented in the API with MassTransit; to an extent you wouldn't have if you hand-coded it or used WCF.