Client-side DLLs

The Siebel 7 thin-client is marvellous for many reasons, but sometimes it’s necessary to integrate with an old-fashioned, locally installed thick-client application. In Server Script it’s possible to access any DLL by using the eScript SElib.dynamicLink() function, but browser script doesn’t give us the same flexibility.

What we have in the browser is JScript’s ActiveXObject function, which creates an instance of an ActiveX component. For instance, to get the installed version of Microsoft Word, we do:

var wdApp = new ActiveXObject("Word.Application");
alert(wdApp.Version);

No problemo. (Although note that for the function to work, the ActiveX component must be successfully registered).

The big limitation of this function is in the name: it will only talk to OLE Automation (i.e. ActiveX/COM) components. If your client-side object is an old C library then you’ll have no luck. There is a solution, however: open up any installation of Visual Studio (or similar) and whip up a COM wrapper for your old school object. Performance will take a hit, but it saves rewriting applications from scratch.

Siebel’s explanation of ActiveXObject is buried in the upgrade guide – and is missing from some versions of Bookshelf. Find it here. They’ve also got a good technote on creating a COM wrapper, but note that they’re linking the DLL from eScript using COMCreateObject: for browser script use ActiveXObject as above.