WCF Service Tutorial question

[Mike Pliam]

Trying to enhance my skills, I tried to build a WCF Service following the steps of the tutorial provided by M$:

http://msdn.microsoft.com/en-us/library/ms733133.aspx

All seemed to go well up until the time that I was supposed to use svcutil.exe tool. Using the command prompt that M$ provided

svcutil.exe /language:cs /out:generatedProxy.cs /config:app.config http://localhost:8000/ServiceModelSamples/service

which is supposed to generate the proxy code for the client, I instead received one of my old favorites:

'svcutil.exe' is not recognized as an internal or external command,
operable program or batch file.

A search of my VS 2008 directories failed to find svcutil.exe. Little wonder it didnt work. But it should be there somewhere, shouldnt it?

Any clues would be helpful.

Edit: Well, I found it. It was right where M$ said it would be.
http://msdn.microsoft.com/en-us/library/aa347733.aspx

Question now is (and it's an old one for me): How do I set the path so that from a command prompt anywhere in the directory system, the OS will know how to find svcutil.exe ? (Or any other thing I wish to 'add to the path' for that matter. I'm ashamed to admit it, but I've always wondered how to do that.)

Edit: OK. I found out how to access Environment Variables in VISTA. There are two ways to do this.

The easy way:

1.Click Start and choose Control Panel
2.In the Search box on the top right of the window type “system path” (no quotes)
3.Click “Edit the system environment variables”
4.Begin at step 4 below.

The hard way:

1.Click Start and choose Control Panel
2.Click System, on the right you’ll see “View basic information about your computer”
3.On the left is a list of tasks, the last of which is “Advanced system settings.” Click that.
4.The Advanced tab of the System Properties dialog box is shown. Click the Environment Variables button on the bottom right.
5.In the lower box titled “System Variables” scroll down to Path and click the Edit button.
6.Change your path as need be.
7.Restart your system. Vista didn’t pick up the system path environment variable change until I restarted.

THEN WHAT ? How do you actually add a target directory or app? I need an example.

[cilu]

I saw you found it by yourself. The idea is that svcutil.exe is distributed with the Windows SDK. To be able to run it from everywhere, add the folder where it's located to the PATH environment variables.

THEN WHAT ? How do you actually add a target directory or app? I need an example

Add to what?

[Mike Pliam]

OK. Just pasted the path in a new User Environment variable. But still have a problem with VISTA.

Ran the Microsoft Visual Studio 2008 tool Command Prompt as 'Administrator' (with Administrator privileges). But something is amiss.

C:\Users\mbpliam\Documents\Visual Studio 2008\Projects\SERVICES\Service\Client>s
vcutil.exe /language:cs /out:generatedProxy.cs /config:app.config http://localho
st:8000/ServiceModelSamples/service
Microsoft (R) Service Model Metadata Tool
[Microsoft (R) Windows (R) Communication Foundation, Version 3.0.4506.648]
Copyright (c) Microsoft Corporation.  All rights reserved.

Attempting to download metadata from 'http://localhost:8000/ServiceModelSamples/
service' using WS-Metadata Exchange or DISCO.
Microsoft (R) Service Model Metadata Tool
[Microsoft (R) Windows (R) Communication Foundation, Version 3.0.4506.648]
Copyright (c) Microsoft Corporation.  All rights reserved.

Error: Cannot obtain Metadata from http://localhost:8000/ServiceModelSamples/ser
vice

If this is a Windows (R) Communication Foundation service to which you have acce
ss, please check that you have enabled metadata publishing at the specified addr
ess.  For help enabling metadata publishing, please refer to the MSDN documentat
ion at http://go.microsoft.com/fwlink/?LinkId=65455.


WS-Metadata Exchange Error
    URI: http://localhost:8000/ServiceModelSamples/service

    Metadata contains a reference that cannot be resolved: 'http://localhost:800
0/ServiceModelSamples/service'.

    Could not connect to http://localhost:8000/ServiceModelSamples/service. TCP
error code 10061: No connection could be made because the target machine activel
y refused it 127.0.0.1:8000.

    Unable to connect to the remote server

    No connection could be made because the target machine actively refused it 1
27.0.0.1:8000


HTTP GET Error
    URI: http://localhost:8000/ServiceModelSamples/service

    There was an error downloading 'http://localhost:8000/ServiceModelSamples/se
rvice'.

    Unable to connect to the remote server

    No connection could be made because the target machine actively refused it 1
27.0.0.1:8000

If you would like more help, type "svcutil /?"

C:\Users\mbpliam\Documents\Visual Studio 2008\Projects\SERVICES\Service\Client>

Any idea what I have done wrong?

Edit: Sorry! I forgot that I had to run the service before attempting to use svcutil.exe. Of course, everything has to be Run as Administrator on VISTA. Then it worked just as M$ said it would. Looks like this whent it works, and generates an app.config and generatedProxy.cs files

C:\Users\mbpliam\Documents\Visual Studio 2008\Projects\SERVICES\Service\Client>s
vcutil.exe /language:cs /out:generatedProxy.cs /config:app.config http://localho
st:8000/ServiceModelSamples/service
Microsoft (R) Service Model Metadata Tool
[Microsoft (R) Windows (R) Communication Foundation, Version 3.0.4506.648]
Copyright (c) Microsoft Corporation.  All rights reserved.

Attempting to download metadata from 'http://localhost:8000/ServiceModelSamples/
service' using WS-Metadata Exchange or DISCO.
Generating files...
C:\Users\mbpliam\Documents\Visual Studio 2008\Projects\SERVICES\Service\Client\g
eneratedProxy.cs
C:\Users\mbpliam\Documents\Visual Studio 2008\Projects\SERVICES\Service\Client\a
pp.config

I only post all this here in case it might help some others because there are alot of negative Community Responses on this tutorial (which is actually quite good provided one reads it carefully and follows the instructions).

[Arjay]

This article is a bit out of date because there really isn't any need to generate a proxy from the command line. The way to generate the proxy in VS2008, is to right click on the project in the solution explorer and choose "Add Service Reference...". You'll need to run VS as an admin as well.

On Win 7, you need to adjust permissions to get the service to run.

// HTTP could not register URL http://+:<port>/<servicename>/.
// Your process does not have access rights to this namespace
// (see http://go.microsoft.com/fwlink/?LinkId=70353 for details).


Welcome to the world of WCF - 'M$' has done a great job of it.


Tip: If you control both the service code and the client code, then you may not want to use a proxy anyway.

[Mike Pliam]

Thanks for the advice, Arjay. I agree, this is really great technology. There is a note in the tutorial suggesting an alternative to running a proxy from the command line. I just havnt tried it yet.

BTW, my interest in this was stimulated by a comment that you had made some time ago about using a service to monitor a network share application in the event of an appcrash. I presume that this type of application is what is needed. The next question is how to code such a service? Does the target app (to be monitored) have to be a client of the service, or is there some other model?

[Arjay]

Thanks for the advice, Arjay. I agree, this is really great technology. There is a note in the tutorial suggesting an alternative to running a proxy from the command line. I just havnt tried it yet.

Essentially in the 'proxy-less' approach, you pull out the interface and contracts out of the WCF service project and put them into a separate class library. Then you include references of the library in the service and client projects. On the client you use the ChannelFactory (or DuplexChannelFactory) class to connect to the client.

I have a little templated class that wraps these classes to allow the following:

var client = ChannelProxy<IMyService>.Open( Constants.Configs.MyServiceConfig );

The advantage of the proxyless approach is that the client doesn't need to do any 'conversions' that you need to sometimes have to do when the proxy generates a different namespace than other shared objects. It greatly simplifies the code if you can do without the proxy (of course, if you don't own both the server and client code, you can't do this).

BTW, my interest in this was stimulated by a comment that you had made some time ago about using a service to monitor a network share application in the event of an appcrash. I presume that this type of application is what is needed. The next question is how to code such a service? Does the target app (to be monitored) have to be a client of the service, or is there some other model?

There are several approaches. One approach is to have the application to be monitored send 'ping alive' notifications to the WCF service. Inside the service, you'll check for a last received alive ping and if it's been longer than your specified timeout, you know something has happened to the app. If you can't modify the client application, you can use another approach where a service on the client machine monitors the status of the application (using the process class). It then sends status info back to the main service using WCF. I'm sure there are plenty of other approaches as well - it really depends on what you need.

[Mike Pliam]

I have a little templated class that wraps these classes to allow the following

Would you be willing to post or send me an service and client example of your approach ? mbpliam@pliatech.com

[Arjay]

I'm currently writing an article about using WCF to communicate between a Windows Service and Taskbar client app.

The ChannelProxy class (and other utility classes) will be included in the article source.

Stay tuned.