.Domino Framework

NotesURL  is a property available for the NotesSession, NotesDatabase, NotesView, NotesForm, NotesAgent, and NotesDocument classes.  It was one of those properties I had never really paid much attention to.  That was before I found myself needing to pass references to Notes objects from one application to another.  It is not the only way to pass references to these objects but it is perhaps one of the simplest to implement and is consistent across each of thes objects.

At the other end, the NotesSession class has a Resolve method.  This is basically the reverse of NotesURL, taking the URL and converting it back into an object (it also works with HTTP URLs too!).

So lets take the scenario in which a Services Oriented Architecture (SOA) is being built.  One application (Notes database) provides one or more services to other applications.  These services could operate against a database, view, document etc.  To invoke the service I need to provide a failsafe way to provide details about the database/view/document against which the service operates.   I can pass this in a number of ways:-

1. Save the NotesURLs as environment variables in the Notes.INI
2. Create a document in the other database with the NotesURL(s) placed inside a field
3. Invoke a Web service (increases the ability for Non-Notes applications ualso using the service)

The alternatives for a NotesDatabase include servername and filpath, or replicaid.  Server/filepath requires two parameters to be provided or an artificial way to combine these together.  Replicaids represent a single string but lack the ability to designate a specific server (I may have made a change to a document on one server which has not replicated to other servers and hence the serice may not operate against the latest data if it uses another replica).

Views are more difficult to define as the only other standrad way to access a view in LS is via NotesDatabase.GetView.  This requires the name or alias of the view and this is not guaranteed to be unique.  Plus I need to make sure the parent database is also known.  NotesURL and Resolve gives us a way of ensuring the exxact same view is used within the service.

NotesDocumehts have a DocumentUNID that serves us well, but again we need to provide a reference to the parent database for this to work.  The NotesURL gives us all this information in a single string.

Note: It is also possible to serialize a NotesDocumentCollection by passing an array of NotesURLs.  This is a litlle messier as more code is needed on the other side to reconstruct the NotesDocumentCollection.

I have used the above in the latest beta of the .Domino Framework to implement the new Inspector tool.  This tool will provide a "magic button" to view/edit the attributes of the current database, document collections, and document.  The code for all this to work resides in the .Domino Framework template.  To get this service to work against any database (regardless of whether it implements the framework or not) I have devised a ToolBar button that will save details about the currenty database, view, document etc. and pass them to the Inspector tool via Notes INI variables.  For applicatuions that implement the framework the ablity to pass information about the currently selected documenyts ina view is added without using Notes.INI variables.  Because this is a Notes 6.0 framework I have not (yet) developed a Web Service option.

The .Domino Framewokr has also been expanded so that the constructors for the DominoDatabase, DominoView, DominoDocumentCollection, and DominoDocument classes can take a NotesURL as a parameter for the constructor.

Notes: Because the object refered to by a NotesURL can represent any one of the supported Notes classes it is sugessted that it be resolved into variant first.  Invalid NotesURLs throw an eror so it is also necessary to set the apporpriate error trapping to handle this.

Example: The following code is the DominoDocument class to locate a document using a key that could represent a NotesURL, HTTP URL, NoteID, or DocumentUNID.

'/**
 ' *  Locates an existing document based upon the document's key
 ' * @param Key  Key that can be used to locate the existing document (NoteID, UNID, Notes URL or HTTP URL)
 ' */ 
 Sub GetByKey(Key As String)
  Dim NotesObject As Variant
  
  On Error Resume Next        ' Prevent error if key is not a a valid NotesURL
  If Ucase(Left(Key,Len(STRING_NOTES_PROTOCOL_PREFIX))) = STRING_NOTES_PROTOCOL_PREFIX Or _
  Ucase(Left(Key,Len(STRING_HTTP_PROTOCOL_PREFIX))) = STRING_HTTP_PROTOCOL_PREFIX Then
   Set NotesObject = Session.Resolve(Key$)
   If NotesObject Isa "NotesDocument" Then
    Set iDocument = NotesObject
    Exit Sub
   End If
  End If
  Select Case Len(Key)
  Case 8  ' Possible NoteID in LS format
   Set iDocument = DB.GetDocumentByID(Key$)
  Case 9  ' Possible Note ID in @Language format
   Set iDocument = DB.GetDocumentByID(Left(Key$,8) + Right(Key,8))
  Case 32 ' Possible UNID
   Set iDocument = DB.GetDocumentByUNID(Key$)
  End Select
  Exit Sub
 End Sub