Stock Watcher

Aaron Skonnard
Developmentor

Requirements

This sample requires the following software:

Internet Explorer 5.0
Windows 98, Windows NT 4.0, or Windows 2000
Microsoft Visual C++ 6.0
IIS 4.0 or greater.

Description

This sample will demonstrate how to use XML as the communications mechanism between a WinInet client and an ISAPI extension. It consists of the following two projects:

StockWatcher.dsw - an MFC Windows application that uses WinInet
StockQuotes\StockQuotes.dsw - an ISAPI extension project

To begin using the sample, first you need to install the ISAPI extension into an IIS directory with execute permissions. Either compile the StockQuotes project or use the compiled DLL that comes in the project’s Debug directory. Then, create a new virtual directory with execute permissions using the Internet Services Manager (name the virtual directory StockQuotes and you won’t have to change the client program’s path configuration). Once you have the ISAPI extension copied into the appropriate IIS directory, you can begin testing the client application, StockWatcher.exe.

The StockWatcher client application manages a stock symbols document using the MSXML parser. All symbols and their current information are stored as XML within the main document. To refresh the document, choose "Refresh All Symbols" from the "Symbol" menu and StockWatcher will send the XML document containing the stock symbols to the ISAPI extension (StockQuotes.dll) in order to update the current quote information (the ISAPI DLL simply returns random stock data, nothing real).

StockWatcher uses WinInet to send the data to the Web server. You can configure the server name and the server path (to the ISAPI extension) using the Provider URL dialog (View | Stock Provider Settings).

Make sure the server name and path to your ISAPI extension are correct in this dialog.

Again, if you named your virtual directory StockQuotes, the default settings as shown in this dialog will work fine. Otherwise, change the path to contain the name of your virtual directory as shown here:

/<VIRTUAL DIRECTORY NAME>/StockQuotes.dll?GetQuotes

You can either enter your machine name or the standard local loopback address (127.0.0.1) for the stock quote server name.

Once StockWatcher receives the response, it updates the main document with the new XML data and refreshes its views.

The XML data that the StockWatcher client sends to the StockQuotes ISAPI extension looks like this:

<quotes>
<quote symbol="MSFT"/>
<quote symbol="INTC"/>
<quote symbol="CSCO"/>
<quote symbol="DELL"/>
</quotes>

And the corresponding XML data that the StockQuotes ISAPI extension sends back to the StockWatcher client looks like this:

<quotes>
<quote symbol="MSFT" price="83" change="-12" open="95" volume="4041" lastupdate="09/07/99 22:58:06"/>
<quote symbol="INTC" price="2" change="-48" open="50" volume="10291" lastupdate="09/07/99 22:58:06"/>
<quote symbol="CSCO" price="36" change="-38" open="74" volume="11020" lastupdate="09/07/99 22:58:06"/>
<quote symbol="DELL" price="96" change="75" open="21" volume="27348" lastupdate="09/07/99 22:58:06"/>
</quotes>