Read Part 1
In Part 1 we looked at the two new methods of the
Server object: Execute and Transfer. Also new to
ASP 3.0 is a brand new intrinsic object, the ASPError object.
ASPError Object
(view the technical
docs) - This new, intrinsic object provides a graceful error handling not available in
earlier versions of the ASP engine. Previously, handling ASP errors was impossible. You
could catch scripting errors using VBScript's On Error Resume Next, or using
JScript's try ... catch blocks, but you could not trap errors that occurred
in COM objects, or intrinsic ASP errors. That has all changed with the advent of the
ASPError object.
To utilize this object, first you need to customize the custom HTTP errors within IIS.
When an ASP-related error occurs, the HTTP error 500;100 is triggered. In
IIS 4.0 you can trap HTTP errors, and, when they occur, you can have an ASP script execute.
(See Creating a Custom 404 Error Page for information
on how to trap the HTTP 404 Error using IIS 4.0.) With IIS 5.0, you can trap the 500;100
HTTP error, and, when it occurs, have the user redirected to an ASP script.
This ASP script can access the ASPError object to determine the specifics of
the error that just occurred. The ASPError object has a number of
read-only properties that reveal detailed information on the last error. The Server
object contains a new method, GetLastError, which must be used to obtain the
information on the latest ASP error. The GetLastError method returns an instance
of the ASPError object.
So, imagine that you created a default error handling script titled CatchError.asp.
You would need to setup your IIS web server such that when an HTTP 500;100 error
occurred, the user was redirected to CatchError.asp. Then, to display the
detailed information of the error that just occurred, CatchError.asp could
contain the following code:
<%
Dim objLastASPError
'Obtain an instance of the latest error
Set objLastASPError = Server.GetLastError
'Output some of the properties
%>
An error occurred:<BR>
Description: <%=objLastASPError.Description%><BR>
Category: <%=objLastASPError.Category%><BR>
File: <%=objLastASPError.File%><BR>
Number: <%=objLastASPError.Number%><BR>
|
You can read the technical
docs for a full listing of the ASPError object's properties.
The ASPError object, along with the Server.Transfer and
Server.Execute methods are the big additions to ASP 3.0. There are some
minor changes. For example, in ASP 2.0, by default, Response.Buffer was set
to False. In ASP 3.0, Response.Buffer is set to True.
(Buffering output yields better performance.) Also, the ASP engine is more streamlined,
and more efficient.
That about wraps up the major changes. Of course, with ASP 3.0 comes the latest
scripting engine versions for both VBScript and JScript. You can read about these at
Microsoft's Scripting Site.
Happy Programming!
Read Part 1
