HelloService sample

This document contains the release information for the NGWS Hello Serveice sample. You will find the following sections below:

• Sample Overview
• Location of the sample
• Building the sample
• Running the sample

Sample Overview

This example shows how to write a typical “Hello World" application using the remoting services provided by the NGWS runtime. Despite being a very simple example, it serves a useful purpose for testing the remoting services installation when things go wrong, and illustrates a number of vital concepts used when writing remoting applications. HelloService is the server side object called by the MyHello client example.

Location of the Sample

This sample is located in the Remoting directory of the NGWS SDK sample directories.

For Example, the server object is located at:

C:\Program Files\NGWSSDK\Samples\Remoting\HelloService

And the client object at:

C:\Program Files\NGWSSDK\Samples\Remoting\MyHello

Building the Sample

All remoting examples can be build at once by invoking NMAKE from the Remoting directory as follows prior to running the samples…

· Change to the Remoting directory and type NMAKE ALL

For Example:

C:\Program Files\NGWSSDK\Samples\Remoting\:>NMAKE All

· Alternatively, go to the individual client and server directories, and build them individually.

For Example:

C:\Program Files\NGWSSDK\Samples\Remoting\HelloService:>NMAKE All

C:\Program Files\NGWSSDK\Samples\Remoting\MyHello:>NMAKE All

Running the Sample

Open two command windows. Start the server in one window by entering the following at the command line

MyHost -cfg HelloService.cfg

You should get the following output

C:\NGWSSDK\Samples\Remoting\HelloService>MyHost -cfg HelloService.cfg

MyHost is ready to process remote messages.

Press a key and ENTER: G=GC.Collect, 0=Exit

Start the client in another command window and enter the following

MyHello -cfg MyHello.DirectHTTP.cfg

You should get the following output

C:\NGWSSDK\Samples\Remoting\MyHello>MyHello -cfg MyHello.DirectHTTP.cfg

MyHello Sample

Enter your name:

Type your name and press enter. Here's the output.

Enter your name: Dracula

Calling Hello.HelloMethod with: Dracula

Hello.HelloMethod returned: Hi there Dracula

End

The server process should echo the following to the command line

Hello.HelloMethod : Dracula

If this does not happen, the application is not working properly. It is therefore important to check if the server echoed the text passed to it. What does this mean? It is possible for the application to fail and still appear to work. When you call a method on a remote object, the COM runtime attempts to find remote object and call the required method on it. If it does not find the remote object, it searches the current path and if found, instantiates the object from there. All these examples are linked to the server dll when the client is built, therefore the server DLL is in the same directory as the client. When you run the client and the server is found on the network, a local copy is executed. When this happens, you don't see the output the server echoes to the console.

It is also possible to access the server object through Internet Information Server using HTTP. First we have to tell IIS about our object by setting up a Virtual Root as follows:

• Under Control Panel open Administrative Tools. (Start Menu, Settings, Control Panel).
• Select Internet Services Manager from the available options.
• Right click on the "Default Web Site", listed under your web server, and select new Virtual Directory.
• In the Virtual Directory Creation Wizard, click next.
• In the Alias field, enter HelloServices and press next.
• In the Directory field, enter the location of the HelloServices directory, and press next.
• Press next on the next tab.
• Now press finish.

Since the object will automatically be instantiated via the ASP framework, we don't have to start the server app when using normal HTTP.

Run the client by entering the following

MyHello -cfg MyHello.cfg

The client examples should produce exactly the same output we obtained above. The only difference between this and the previous example is that we are using a WEB server to publish the server object and the client gains access to the server object via the WEB server.

We can also run the client from a WEB browser using ASP+. Start Internet Explorer and enter the following Address

http://localhost/MyHello/MyHello.aspx

The specified ASP+ page will be loaded that prompts you for a name. The output is similar to the previous examples, except that the output is displayed in the browser rather than the command line. This example assumes you have already set up the Virtual Root described above.