xpages validate database exist - xpages

Question

I'm new to javascript and xpages here. I'm upgrading an old notes application to xpages. In my xpage I have a field, a save button, and an error messages control. The field is used to save the value of a nsf path/name that the user typed in to be used later on (e.g: //SAS/address.nsf). How do I validate if that path/database exist? The previous lotusscript is like this(it uses 2 field, one to get the server path, the other to get the db path. but for current xpage, the requirement is to use one field only):
svr$= source.FieldGetText("ServerPath")
dbsvr$= source.FieldGetText("DBPath")
Dim db1 As New NotesDatabase(svr$ , dbsvr$)
If Not db1.IsOpen Then
Messagebox "Cannot find the database."
Call source.GotoField("DBPath")
continue = False
Exit Sub
End If
In the field in the xpage, I've added a validateExpression validator. In the expression property, I compute the following SSJS:
var dbdir:NotesDbDirectory = session.getDbDirectory(null);
var db:NotesDatabase = dbdir.openDatabase(document1.getItemValue("dbpath"));
return db.isOpen();
In the validator's message property, I put "Cannot find database".
The error I'm keep getting is:
Expression is invalid.
Expression did not return a boolean value.
Any way to fix this? Is it the wrong use of validator? I've already test with local database and database on other server. None seems to work. All those database I tried I had access rights to them.

Answer 1

You should probably use sessionAsSigner in order to open the database as the signer of the XPage - instead of as anonymous (if you are not logged in). Also, consider adding try/catch around your dbdir.OpenDatabase() in order to catch errors opening a database with an invalid path.
Also, notice that the validateExpression validator must return a boolean true or false. In your case dbdir.openDatabase() will return null if the database can not be opened - which means that db.isOpen() will fail to work since it can not operate on a null object.
You could consider using the customValidator validator which must return an error message (and not a boolean true or false).
I hope this can help you complete the validation.

Answer 2

Use try/catch block for attempt to open database. If everything is OK, just return true in try block. Catch block will return false, what will handle most of the possible fails: wrong server, broken connection, invalid path, no access, and so on.
try {
// open database here and touch some property, doc count, for example
return true;
} catch (e) {
return false; // failed to open database
}