I need to call a WCF service that is behind a DMZ:
WEBDMZ .. LANDMZ
------------- ------------
ClientServer => WCF service
As there is a firewall between the two it's not possible for the Client to connect to the WCF service. So I need the WCF service to connect to the client and "listen" to connections or create a tunnel somehow.
I feel it must be a very common problem but I haven't been able to find a proper solution yet. And no it's not possible to open a port. The connection have to be initiated by the WCF.
The client is a server and can easily host any MSMQ or other service.
It seems like this problem can also be referred to as "reverse proxy" or "reverse tunnel".
Solution ideas:
MSMQ hosted by Client (but I'm afraid if it would just simply be polling all the time and creating a network overhead).
A reverse tunnel/proxy?
WCF Duplex?
I'm looking for the simplest solution, preferably in C# and without 3rd party software. Perhaps there is a WCF configuration that allows for reverse calls?
With .Net version 4, you can look at WCF Routing service at here. Or you can build a routing service by yourself following example from Michele Leroux. Here is the link.
EDIT:
You can build a routing service, put it at WEBDMZ server, it will contains list of endpoint wcf service put at DMZ server. At here it will take role as a service server as well as client connect to services at DMZ server. You also can build a discovery service to configure these endpoints automatically.
Related
I have a server physically located in the US. The OS is Windows Server 2008 R2 SP1.
I create a WCF service and host it in IIS on the server.
Now, while I'm physically in Germany, I want to write a WCF client to the WCF service. First of all, I need to create a WCF client proxy.
All the tutorials I've seen imply that the WCF service and WCF client are located on the same machine. I.e., the tutorials use "localhost" everywhere. In my case it doesn't work.
I know the IP of my server but I don't know what settings should be done to allow any programmer to use the WCF service. I guess it requires special customization of the endpoint at the WCF service and some settings at the IIS to make the WCF accessible by anybody.
Can you please give a piece of advice in this regard?
Thanks for any suggestions!
Two approaches are available :
Create a service reference using the add reference , enter your service address should be something like : http://IpAdress/service.svc , or if you have your wsdl file on your local disk , just enter your wsdl file location in the add service address bar. This will generate the proxy class.
If you have the service contract(interface) just do it programatically using ChannelFactory , you must know your binding and endpoint address as well.
If have any questions you're welcome
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 going to create a WCF service(IIS host) and it will be called from client side javascript code.
When I call a WCF from client side, is the WCF a WCF library or WCF application type?
For example:
I have the javascript below.
function AddFunds() {
var postObject = {
myID: myObject.myIDNumber,
LocationID: myObject.LocationID,
fundsToAdd: CurrencyFormatted($("#txtAddFunds").val())
};
$.post('/OrServices/myService.svc/AddFunds',
JSON.stringify(postObject)
).success(AddFundsResult);
}
In the beginning, I have to create WCF Service "myService.svc", but I am not sure if it is a library or application or doesn't matter.
this answer describes the difference:
A service application includes a website host already setup for you. A service library is a library of services that a host can reference and startup.
If you start with a service library (recommended) you can then choose
any host you wish (a windows service, IIS/ASP.NET, or even a console
application) and you'd just reference your library from your new host.
Choosing a Service Application limits your host to just IIS/ASP.NET
(though this might be ok for your purposes, but will limit the
protocols you can use).
Edit: Changes in IIS since I wrote this allow for a wider variety of
protocols on ASP.NET activated services, so choosing a service
application is much less limiting than before.
if your only going to host in IIS then I would recommend to just use a Service Application. As a lot of the work is done for you.
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