Loading HTML or XML Content in LotusScript over HTTP
Your application needs data that are stored on a web server. If that data is available through a web service your are lucky. Since R8 web service clients are supported in LotusScript. If you want to load data from a URL you are out of luck. Typically you would resort to ActiveX and use the IE component to do the retrieval which introduces 3 evils: a Windows dependency, an IE dependency and an ActiveX dependency. The other way is to use Java, which turns a lot of LotusScript developer off. The solution is to use a ready made library that can wraps all the Java you need into a convenient LotusScript class. The use case I had was to read HTML from a remote site and return a specific table for further processing. So my class has an XPath parameter that allows to slice out some part of the returned HTML. This is how you would use it in LotusScript:
You need some libraries as dependencies:
%REM
Agent UpdateHTMLOnChange
Created May 28, 2010 by Stephan H Wissel
Description: Reads all documents that have been flagged
as changed and retrieves the update HTML
%END REM
Option Public
Option Declare
Use "HTTPUpdatesLS"
Sub Initialize
Dim updateClass As HTTPUpdates
Set updateClass = New HTTPUpdates
Call updateClass. UpdatePendingDocuments ( )
Set updateClass = nothing
End Sub
And this is the complete LotusScript class:
Agent UpdateHTMLOnChange
Created May 28, 2010 by Stephan H Wissel
Description: Reads all documents that have been flagged
as changed and retrieves the update HTML
%END REM
Option Public
Option Declare
Use "HTTPUpdatesLS"
Sub Initialize
Dim updateClass As HTTPUpdates
Set updateClass = New HTTPUpdates
Call updateClass. UpdatePendingDocuments ( )
Set updateClass = nothing
End Sub
%REM
Library HTTPUpdatesLS
Created May 29, 2010 by Stephan H Wissel
Description: Wrapper Class around the LS2J Classes
for HTTP driven updates
%END REM
Option Public
Option Declare
Use "HTTPUpdates"
UseLSX "*javacon"
Use "OpenLogFunctions"
%REM
Class HTTPUpdates
Description: LotusScript Wrapper around
Java Class for HTTPUpdates
%END REM
Public Class HTTPUpdates
'For the LS2JReader
Private jSession As JavaSession
Private httpReaderClass As JavaClass
Private httpReader As JavaObject
Private s As NotesSession
Private db As NotesDatabase
Private viewName As String
Private serverName As String
Private dbName As String
%REM
Sub new
Description: Initialize the class
%END REM
Public Sub New
Call populateDefaults ( )
End Sub
%REM
Sub Crap
Description: Comments for Sub
%END REM
Public Sub UpdatePendingDocuments
Dim fullURL As String
Dim v As NotesView
Dim doc As NotesDocument
Dim nextDoc As NotesDocument
Set db = s. Currentdatabase
Set v = db. Getview ( "pendingHTMLUpdates" )
'Now through the view
Set doc = v. Getfirstdocument ( )
Do Until doc Is Nothing
Set nextDoc = v. Getnextdocument (doc )
Call updateDocHTML (doc )
Set doc = nextDoc
Loop
'And close it down
Call httpReader. recycle ( )
End Sub
%REM
Sub updateDocHTML
Description: Here goes the update of one individual document
%END REM
Public Sub updateDocHTML (doc As NotesDocument )
'We don't let one error derail us
On Error GoTo Err_updateDocHTML
Dim unid As String
Dim result As String
Dim htmlItem As NotesItem
unid = doc. universalid
'Here all the magic happens
result = httpReader. getDocument (unid )
If result <> "" Then 'We only save if we got something
If doc. hasItem ( "FinalHTML" ) Then
Call doc. removeItem ( "FinalHTML" )
End If
Call doc. replaceItemValue ( "FinalHTML",result )
Call doc. replaceItemValue ( "HTMLStatus", "1" )
Call doc. save ( True, True )
End If
Exit_updateDocHTML:
Exit Sub
Err_updateDocHTML:
Call logErrorEx ( Error$,SEVERITY_HIGH,doc )
Resume Exit_updateDocHTML
End Sub
%REM
Sub updateDocHTML
Description: get arbitrary HTML
%END REM
Public Function getRemoteHTML (url As String ) As String
'We don't let one error derail us
On Error GoTo Err_getRemoteHTML
getRemoteHTML = httpReader. getURL (url )
Exit_getRemoteHTML:
Exit Function
Err_getRemoteHTML:
Call logErrorEx ( Error$,SEVERITY_HIGH, nothing )
getRemoteHTML = "<h3>Error:"+ Error$+ "</h3>"
Resume Exit_getRemoteHTML
End Function
%REM
Sub populateDefaults
Description: Populate default setting
presuming the Notes server is known with
its Common name in the DNS
%END REM
Private Sub populateDefaults
Set s = New NotesSession
Set db = s. Currentdatabase
If db. Server = "" Then ' it runs local
servername = "http://localhost"
Else
servername = me. GetServerURL (db. Server )
End If
'We use the replicaid to be save from
'moving of databases and the peril of local nsf names
dbName = "__"+db. Replicaid+ ".nsf"
viewname = "0"
'Create an HTTPReader Instance
Set jSession = New Javasession
Set httpReaderClass = jSession. getClass ( "org.lotususers.tools.HTTPReader" )
Set httpReader = httpReaderClass. CreateObject ( )
Call httpReader. setServerURL (servername )
Call httpReader. setDatabaseURL (dbName )
Call httpReader. setViewName (viewname )
Call httpReader. setXPath ( "//body/*" )
Call httpReader. setUseSSO ( False )
'ToDo: Username & Password from a profile - don't hardcode here!
If Not db. Server = "" then
'Call httpReader.setUserName("user")
'Call httpReader.setPassWord("password")
End if
End Sub
' Cleanup
Public Sub Delete
On Error Resume next
If Not me. httpReader Is Nothing Then
Call httpReader. recycle ( )
End If
End Sub
%REM
Function GetServerURL
Description: Gets the server name from the NAB
%END REM
Private Function GetServerURL (serverName As String ) As String
Dim domDir As NotesDatabase
Dim sView As NotesView
Dim doc As NotesDocument
Dim n As NotesName
Set domDir = New NotesDatabase (serverName, "names.nsf" )
If Not domDir. Isopen Then
Call domDir. Open ( "", "" )
End If
If Not domDir. isOpen Then
Set n = s. Createname (serverName )
GetServerURL = "http://"+n. Common
Exit function
End If
Set sView = domDir. Getview ( "($Servers)" )
Set doc = sView. Getdocumentbykey (serverName, true )
If Doc Is Nothing Then
Set n = s. Createname (serverName )
GetServerURL = "http://"+n. Common
End If
GetServerURL = "http://"+ doc. Getitemvalue ( "NetAddresses" ) ( 0 )
End Function
End Class
Of course that class is useless without the Java class. Here you go: HTTPReader.java
Library HTTPUpdatesLS
Created May 29, 2010 by Stephan H Wissel
Description: Wrapper Class around the LS2J Classes
for HTTP driven updates
%END REM
Option Public
Option Declare
Use "HTTPUpdates"
UseLSX "*javacon"
Use "OpenLogFunctions"
%REM
Class HTTPUpdates
Description: LotusScript Wrapper around
Java Class for HTTPUpdates
%END REM
Public Class HTTPUpdates
'For the LS2JReader
Private jSession As JavaSession
Private httpReaderClass As JavaClass
Private httpReader As JavaObject
Private s As NotesSession
Private db As NotesDatabase
Private viewName As String
Private serverName As String
Private dbName As String
%REM
Sub new
Description: Initialize the class
%END REM
Public Sub New
Call populateDefaults ( )
End Sub
%REM
Sub Crap
Description: Comments for Sub
%END REM
Public Sub UpdatePendingDocuments
Dim fullURL As String
Dim v As NotesView
Dim doc As NotesDocument
Dim nextDoc As NotesDocument
Set db = s. Currentdatabase
Set v = db. Getview ( "pendingHTMLUpdates" )
'Now through the view
Set doc = v. Getfirstdocument ( )
Do Until doc Is Nothing
Set nextDoc = v. Getnextdocument (doc )
Call updateDocHTML (doc )
Set doc = nextDoc
Loop
'And close it down
Call httpReader. recycle ( )
End Sub
%REM
Sub updateDocHTML
Description: Here goes the update of one individual document
%END REM
Public Sub updateDocHTML (doc As NotesDocument )
'We don't let one error derail us
On Error GoTo Err_updateDocHTML
Dim unid As String
Dim result As String
Dim htmlItem As NotesItem
unid = doc. universalid
'Here all the magic happens
result = httpReader. getDocument (unid )
If result <> "" Then 'We only save if we got something
If doc. hasItem ( "FinalHTML" ) Then
Call doc. removeItem ( "FinalHTML" )
End If
Call doc. replaceItemValue ( "FinalHTML",result )
Call doc. replaceItemValue ( "HTMLStatus", "1" )
Call doc. save ( True, True )
End If
Exit_updateDocHTML:
Exit Sub
Err_updateDocHTML:
Call logErrorEx ( Error$,SEVERITY_HIGH,doc )
Resume Exit_updateDocHTML
End Sub
%REM
Sub updateDocHTML
Description: get arbitrary HTML
%END REM
Public Function getRemoteHTML (url As String ) As String
'We don't let one error derail us
On Error GoTo Err_getRemoteHTML
getRemoteHTML = httpReader. getURL (url )
Exit_getRemoteHTML:
Exit Function
Err_getRemoteHTML:
Call logErrorEx ( Error$,SEVERITY_HIGH, nothing )
getRemoteHTML = "<h3>Error:"+ Error$+ "</h3>"
Resume Exit_getRemoteHTML
End Function
%REM
Sub populateDefaults
Description: Populate default setting
presuming the Notes server is known with
its Common name in the DNS
%END REM
Private Sub populateDefaults
Set s = New NotesSession
Set db = s. Currentdatabase
If db. Server = "" Then ' it runs local
servername = "http://localhost"
Else
servername = me. GetServerURL (db. Server )
End If
'We use the replicaid to be save from
'moving of databases and the peril of local nsf names
dbName = "__"+db. Replicaid+ ".nsf"
viewname = "0"
'Create an HTTPReader Instance
Set jSession = New Javasession
Set httpReaderClass = jSession. getClass ( "org.lotususers.tools.HTTPReader" )
Set httpReader = httpReaderClass. CreateObject ( )
Call httpReader. setServerURL (servername )
Call httpReader. setDatabaseURL (dbName )
Call httpReader. setViewName (viewname )
Call httpReader. setXPath ( "//body/*" )
Call httpReader. setUseSSO ( False )
'ToDo: Username & Password from a profile - don't hardcode here!
If Not db. Server = "" then
'Call httpReader.setUserName("user")
'Call httpReader.setPassWord("password")
End if
End Sub
' Cleanup
Public Sub Delete
On Error Resume next
If Not me. httpReader Is Nothing Then
Call httpReader. recycle ( )
End If
End Sub
%REM
Function GetServerURL
Description: Gets the server name from the NAB
%END REM
Private Function GetServerURL (serverName As String ) As String
Dim domDir As NotesDatabase
Dim sView As NotesView
Dim doc As NotesDocument
Dim n As NotesName
Set domDir = New NotesDatabase (serverName, "names.nsf" )
If Not domDir. Isopen Then
Call domDir. Open ( "", "" )
End If
If Not domDir. isOpen Then
Set n = s. Createname (serverName )
GetServerURL = "http://"+n. Common
Exit function
End If
Set sView = domDir. Getview ( "($Servers)" )
Set doc = sView. Getdocumentbykey (serverName, true )
If Doc Is Nothing Then
Set n = s. Createname (serverName )
GetServerURL = "http://"+n. Common
End If
GetServerURL = "http://"+ doc. Getitemvalue ( "NetAddresses" ) ( 0 )
End Function
End Class
You need some libraries as dependencies:
- Apache HTTP Client
- Apache Commons logging (a HTTP client dependency)
- HTML Cleaner which ensures that HTML you read is transformed into valid HTML so it can be parsed
Posted by Stephan H Wissel on 01 December 2010 | Comments (6) | categories: Show-N-Tell Thursday
