I have developed a .NET UI and windows service which communicate with each other using WCF through the NetNamedPipeBinding protocol. I chose NetNamedPipe because it is the best and efficient choice for interprocess communication on the same machine.
However, one of the key requirements of the application is that the UI should be able to send actions to the windows service and vice versa asynchronously. This means that the windows service should be able to call back the .NET UI application without the need for the .NET UI application to connect to the windows service first.
Keeping this in mind, I have hosted a WCF service in the windows service and a separate WCF service in the .NET UI application so that they can communicate asynchronously without the need to keep the communication channel always alive.
I would like to know if this makes good design sense.
I would appreciate your comments on the same.
Thanks in advance.
Subbu
Hosting another WCF service in the client to receive calls from the main WCF service is not a good idea. You need to use WCF duplex communication (as Subbu posted) aka WCF callback.
WCF: Duplex Operations and UI Threads
The problem with this approach is that your service needs to connect to the client as a host.
A better option would probably be to setup a WCF Callback when you first startup the client. The service can then use the callback for service to client notifications. For details, see this MSDN article which shows using WCF callbacks.
WCF Callback allows server to drive events to the client. See a short and simple example here: A simple WCF Callback example
Related
I have an application in WPF c# which will run on client machine. Another application (maybe some kind of service) on a particular server will be running all the time and will wait for any incoming message from the client app. As soon as the server receives a request from any of the client application, it triggers a command line process and also responds to the client about the staring info(whether it was successful or not) and as well as when the command line process is finished it again responds to the calling client application that it got finished.
I am new to in this area.
So my question is should I use normal windows service or Web service or WCF?(Some kind of link to a demo project will really help). Any other suggestion are also welcomed.
You did not mention if your clients will be outside of your firewall or with in the same intranet. We have intranet scenario, and we use WCF service that communicates with WPF based applications over the internal network. WCF provides Duplex feature which enables two-way client server communication using an easy to implement programming model. I recently wrote an article on this and it can give you a head start for the WCF way.
However, WCF does not have the best support for callbacks over the internet and you may have to look in to effectively using it in your case. But if it is intranet, then my suggestion is surely to go for the WCF way. Hope it helps.
I am a newbie developer to WCF and Windows services. I do know c#. The scenario requires various custom applications running on Windows 7 to call methods in another application. It is a client/server relationship, all running on the same computer. The server must be able to notify each client (one at a time) when a specified condition occurs.
I need to develop the server code only.
Would the following be an acceptable solution:
Make the server a windows service that uses WCF. The server could notify the clients by using a different named pipe for each client ?
Thank you...any suggestions would be appreciated.
Just use duplex communication over tcp/named pipes/msmq/http (WSDualHttpBinding) channel.
AFAIK you need two ports (in/out) for duplex over http
I would ditch wcf altogether. Although as Brian says, you can use the duplex bindings, these are complicated at best.
If it's all going to run on the same computer, why do you even need client/server? Just build a single client which does everything you need.
That is a acceptable solution and should work fine.
Other option for consideration (in the spirit of learning) is creating a Routing Service as an intermediary service which spawns the calls to multiple services. So in your scenario, your client would call the routing service and the routing service will in turn call each of your service
The following link should provide more information on routing service...
[Routing Service][1]
http://msdn.microsoft.com/en-us/library/ee517423.aspx
I need multiple clients that talk to a WCF service. The WCF service also must be able to connect to any one of the clients also.
So - it sounds like the server and the clients need to have both a WCF server and client built into each one.
Is this correct or is there some way to do this?
I was looking at NetPeerTcpBinding, but that is obsolete. To be fair I'm not sure if that is a valid solution either.
Background:
I plan to have a Windows service installed on hundreds of machines in our network with a WCF service and a WCF client built in.
I will have one Windows service installed on a server with a WCF service and a client built in.
I will have a Windows Forms application
I will have a database
The clients on the network will connect to the service running on the server in order to insert some information on the database.
The user will use the Windows Forms application to connect to the Windows service on the server and this Windows service will connect to the relevant client on the factory floor (to allow remote browsing of files and folders).
Hence I believe the machines on the floor and the server both require a WCF cleint and service built in.
The reason people are recommending wsHttpDualBinding is because it is in itself a secure and interoperable binding that is designed for use with duplex service contracts that allows both services and clients to send and receive messages.
The type of communication mentioned 'duplex' has several variations. Half and Full are the simplest.
Half Duplex: Works like a walkie-talkie, one person may speak at any given time.
Full Duplex: Like a phone, any person may speak at any given time.
Each will introduce a benefit and a problem, they also provide ways to build this communication more effectively based upon your needs.
I'm slightly confused, but I'll attempt to clarify.
You have an assortment of approaches that may occur here, a Windows Communication Foundation (WCF) Service requires the following:
Address
Binding
Contract
Those are essentially the "ABC's" for WCF. The creation of those depicts a picture like this:
As you can see the Service will contain:
Host
Service
Client
The host houses the service which the client will consume so those service methods perform a desired task. An example representation:
As you see Client-1 is going through the Internet (HTTP, HTTPS, etc.) then will hit the Host, which will have the service perform those tasks.
Now Client-n is consuming the service locally, so it is talking over (TCP, etc.) as an example.
The easiest way to remember: One service can be consumed by however many clients require those methods to perform a task. You can create very complex models using a service-oriented architecture (SOA).
All WCF is, is a mean to connect your application to a host or
centralized location you may not have access to.
As you can see in the above image, the Client communicates through a Service to the Host. Which performs a series of task. WCF will talk over an array of protocols. Hopefully this will provide a better understanding of how WCF is structured.
There are a lot of tutorials and even post to get you started. Some excellent books such as "WCF Step by Step".
Essentially your looking for an asynchronous full duplex connection, or a synchronous full duplex service. As mentioned above, your task in essence is the point of a Service.
The question: How does this work best?
It will boil down to your design. There are limitations and structures that you will need to adhere to to truly optimize it for your goal.
Such obstacles may be:
Server Load
Communication Path
Security
Multiple Clients Altering UI / Same Data
Etc.
The list continues and continues. I'd really look up tutorials or a few books on WCF. Here are a few:
WCF Step by Step
WCF Multi-Tier Development
WCF Service Development
They will help you work with the service structure to adhere to your desired goal.
Remember the "ABCs" for the most success with WCF.
Use wsDualHttpBinding if you want your service communicate with your clients.
Read WS Dual HTTP.
You might want to try out creating a WCF service using netTcpBinding. It will work for your requirements. You can use the article How to: Use netTcpBinding with Windows Authentication and Transport Security in WCF Calling from Windows Forms as a start:
Also, there are many examples included within the WCF Samples package which you can use.
I am new to WCF (Just a day or 2). I am planning to make an application having Client/Server
WCF Service (On Server hosted as windows service):
Will invoke some commands using (Process.Start())
Will send some information from my database
Questions:
What WCF binding should I use? WsDualhttp or netTCP (Please elaborate if you can)
Does WCF works with SqlServer + EF 4.1
Server UI:
This will primarily will be used to
Start ot stop the above service
Change Address (localhost to [My Ip address]) and Port
Show status of service (Running or dead)
Questions:
How can I Change the address and port of my WCF service from this UI (it will be a different project and hence different config file).
Client App:
Used to issue commands to WCF service.
Get to know if the service is running or dead.
Receive status messages for task completion or faults.
Also, can the windows installer be combined to install ServerUI + WCF Service + Windows service?
WCF Service
Here are a couple links on choosing the right binding. Based on the scenario you're describing, I'd go with the netTCP.
C# - WCF - inter-process communication
Choosing the right WCF binding
WCF and SQL Server are independent of each other, so I wouldn't expect any problems using the Windows service to interact with your database.
I'd suggest reading up on how to start a process from a Windows service.
Server UI
I would suggest hosting another WCF service in your Windows service for interacting with your Server UI. You can use the netNamedPipeBinding since this communication channel will always be local, i.e., on the same box. So your Windows service will host two WCF services - one for the external communication with the client and one for the local communication with the configuration UI.
Installer
Yes, the Windows installer can be used, but that might be overkill for what you're describing. Of the Server UI, WCF Service, and Windows service, the only one that absolutely requires installation is the Windows service. The others could theoretically run simply by copying the assemblies to the target system. You might consider having the Windows service install itself via command line. That way you could get away with a self-extracting executable using software like WinZip. This might be less heavyweight than a formal install. If you go this route, have a look at the step-by-step here.
Ha a look at WCF duplex services:
http://msdn.microsoft.com/en-us/library/ms731064.aspx
Why do you want to have a interface to an windows service? And if you have access to IIS7 and WAS, I would recommend to use it instead of self-hosting in windows service.
Here is a good starting point for WCF Configuration Management:
http://msdn.microsoft.com/en-us/library/ff650534.aspx
Yes, you can use windows installer.
Cheers
--Jocke
We have a number of Windows services running in our system (built in C#). We use WCF to communicate with them and control them, since WCF offers very convenient communication with these processes.
Right now in our Windows GUI for managing, monitoring and troubleshooting the services, we simply register callbacks and receive notifications when a message is available from the service. Obviously this application is stateful and WCF provides the ability for the local delegate to be called when the maintained connection to the service indicates.
In our web application which users actually use, we'd like to use long-polling to have a status area on the web page (iframe, AJAX, whatever) which shows any issues which the services are reporting. We'd like to use a long-polling or other technique which minimizes actual polling on the network.
The problem we are running up against is that we need something to make the long-polling HTTP request against which will somehow always be running in IIS and which itself can be WCF-connected to our services and which can convert the event/delegate-based WCF response into a blocking-style long-poll response. It feels like a chicken-and-egg situation that some component in our system is always going to be in a loop, polling - and that's exactly what we are trying to avoid.
Does anyone have an example of doing this?
Well, if your services present with WCF, why not simply consume the WCF services with javsacript? Then you remove your IIS servers from the equation completely. if a user wants to see what the services are doing then they can retrieve the information directly from the service.
Here's a blog with someone showing how to do this:Call wcf service from Json