Debugging agents on the Web

This piece of code traps the error messages generated by Domino and uses Javascript to popup the errors on the Web.

Before I begin this tip I would like to mention that trick was developed by Ashwin Satyamoorthi and myself. Ashwin developed the AlertForm.

The first step is to create a form and call it "AlertForm" (you can change the name of the form ... of course).

Write the following code in the OnLoad event of the form:

javascript:alert(document.forms(0).reqd_query.value)
if (document.forms(0).addl_query_redirect.value == "")
	{
	window.history.back()
	}
else
	{
	//alert (document.forms(0).addl_query_redirect.value)
	window.open("/" + document.forms(0).addl_query_redirect.value , "_self")
	}

I'll explain what this code does in sometime.

The next step is to put some fields on your form. The following fields are required on the form:

Field name:- Query_String_Decoded 
Type:- editable
Default value:-

Field name :- reqd_query
Type:- computed
value :- @Left(@RightBack(Query_String_Decoded ; "openform&") ; "redpath")

Field name :- addl_query_redirect
Type :- Computed
value :- @Trim(@RightBack(Query_String_Decoded ; "redpath"))

The next step is to include an error handler in your script that you want to debug on the Web.

On error goto errHandler
 your code goes here

errHandler:
	Print "[/" + currDoc.hdatabase_webTX(0) + "/AlertForm?openform&"+Error$ +".redpath]"
	Exit Sub

currDoc.hdatabase_webTX(0) is a field on the form from which this script was called, the field stores the value of the Web path of the database and has the following formula :- @ReplaceSubstring(@Trim(@Subset(@DbName;-1)); ""; "/")

If a calling form is not available then you can use the filepath property of the notesdatabase to generate the path in the print statement of the error handler.

explanation of the print statement:- the print statement basically opens the AlertForm and populates the value of querystring with the text of the error message. The text is got from the Error$ in the print statement. The next option in the statement is "redpath" if you include a URL after this text the alert form will take you to this URL if there is no text after redpath then after the alert message is displayed then the script will take you back to from where the script was triggered if the script was triggered from a form then the user will be taken back to the form.

You can modify the print statement to also include the line number to make debugging easier.

Explanation of the fields on the AlertForm :- Query_String_Decoded needs no explanation I guess.

reqd_query picks up the error message to be displayed from the Query_String_Decoded field

addl_query_redirect picks up the redirect path if any.

Example code

Sub Initialize
	On Error Goto errHandler
	Dim session As New NotesSession
	Dim currDB as NotesDatabase
	Dim currDoc as NotesDocument
	Dim x as integer

	' initialise variables
	
	Set currDB=session.CurrentDatabase
	Set currDoc=session.DocumentContext
	
	x=129/0
	Print cstr(x)
	Exit Sub
errHandler:
	Print "[/" + currDoc.hdatabase_webTX(0) + "/alert?openform&"+Error$ +".redpath]"
	Exit Sub
End Sub