Building Workflow Applications With Microsoft Exchange 2000

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Building Workflow Applications With Microsoft
Exchange 2000 Jim ReitzProgram
ManagerExchange TeamMicrosoft Corporation
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Different Kinds Of Workflow

• Ad-hoc, unstructured
• One-off document review, voting
• Team process automation
• Issue tracking, document approval
• Line-of-business, production
• Claims processing, Loan applications
• Inter-Organization
• E-commerce, supply-chain initiatives

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BackOffice Workflow Strategy

• Make it easy to add simple workflow to server
  apps
• SQL Server
• Exchange
• Make it work with unmodified Office and Web
  applications
• File.Save or Post triggers workflows
• Focus on team process automation
• Common scenarios approval, review, routing,
  tracking
• Target Office developer skillset

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Exchange 2000 Infrastructure

• Underlying platform features for robust workflow
• Single store - both documents and properties
• Synchronous store events
• Multi-object transactions
• Document-level access control
• Property-level write protection
• OLE DB and ADO data access
• Extensible CDO object model
• Native Web access

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Exchange 2000 Workflow

• Extends Exchange 2000 Web Store for simple
  workflow
• Add workflow to existing folder apps
• Works with Outlook forms, Web forms, etc.
• Declarative workflow definition
• State-machine table easy for tools to manipulate
• Condition and action scripts
• Workflow event model
• Based on Grizzly architecture

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Components

• Workflow Engine
• Applies a table of state-transition rules
  (Action Table) against a document
• Evaluates conditions
• Executes actions on transitions
• Workflow Event Sink
• Traps all changes to items in a folder
• Invokes workflow engine via Web Store events
• Uses OnSyncSave, OnSyncDelete, OnTimer store
  events

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Run-Time Architecture
Exchange Server
Event Sink Host Process
Store Process
Default Process Definition
Script Host
Workflow Engine
Workflow Event Sink
Process Instance
Client
Script
Action Table
Application Folder
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Workflow Action Table
Reject
Submit
Approve
Pending
Approved

• State transition row in recordset
• Condition and Action scripts
• WF Engine evaluates table executes matching
  row(s)

Current State
Name
EventType
Condition
Action
New State
Submit
OnCreate
---

IsValid(Session.Item)
script (notifyApprover)
Pending
Reject
OnChange
Pending
Session.Item.Approved False
script (notifySubmitter)
Pending
Approve
OnChange
Pending
Session.Ite
m.Approved True0
script (notify cleanup)
Approved
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Actions
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CDO Workflow Objects

• Included with Exchange 2000
• Design-time and run-time objects
• Extends base CDO objects
• Same DataSource interface

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Design-Time Objects

• Workflow design persisted as an item in a folder
• CDO ProcessDefinition object
• Programmatic creation of workflow process designs
• Key property is ActionTable, an ADO Recordset
• Optional URL to CommonScript file
• CommonScript file can be a separate item, or a
  stream on ProcessDefinition

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Design-Time Objects

• CDO WorkflowFolder object
• Allows for configuration of host folder
• URL specifying default ProcessDefinition
• Control whether Ad-Hoc workflow is allowed
• Ad-Hoc Workflows
• New items normally follow folders default
  ProcessDefinition
• If ad-hoc allowed, new items can contain their
  own ProcessDefinition

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Run-Time Objects

• CDO WorkflowSession intrinsic object
• Provides scripts with access to needed run-time
  data
• Item triggering the workflow is provided as ADO
  Record object
• Allows scripts to pass back errors
• Provides access to audit logging

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Run-Time Objects

• CDO ProcessInstance object
• Advanced use only, normally not required
• Wraps the workflow engine around the item
  undergoing workflow
• Uses
• Calling workflow engine directly in middle-tier
• Programatically creating ad-hoc documents that
  are workflow aware

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Workflow Engine Security

• Restricted Mode
• Actions are script only
• Script engine sandboxed for intrinsic objects
  only e.g. no CreateObject( )
• Scripts execute under guest privilege NT
  account
• What can Restricted Mode do?
• Modify properties on triggering record
• Send mail
• Write to AuditTrail

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Workflow Engine Security

• Privileged Mode
• Actions can be script or COM objects
• Script engine allows CreateObject()
• Actions execute under privileged NT account (in
  Exchange Servers group)
• What can Privileged Mode do?
• Almost anything

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Workflow Engine Security

• Who can use Privileged Mode?
• Users or Groups listed in PrivilegedWorkflowAuthor
  s role
• Workflow Event Sink is implemented as COM
  application package
• The COM application contains this role
• Managing role membership
• Administrative Tools-gtComponent Services in
  Windows 2000
• Role membership is per-machine

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Creating A Workflow Steps

• Create ActionTable recordset
• Create CommonScript
• Create ProcessDefinition
• Attach ActionTable, CommonScript
• Configure WorkflowFolder properties
• DefaultProcessDefinition
• Register Workflow Event Sink in folder
• OnSyncSave, OnSyncDelete, OnTimer

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Exchange Workflow Designer
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Exchange 2000 Workflow Designer

• Visual editor for Exchange 2000 workflows
• Joint project with Microsoft Office Developer
  (Grizzly) team
• Same UI and architecture as Grizzly designer
  for Access/SQL Server
• Beta of designer in Exchange 2000 RC1 timeframe
• Final packaging/naming TBD

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Resources

• Exchange 2000 Beta 3
• Workflow engine, event sink, and CDO Workflow
  objects installed by default
• Preliminary SDK documentation
• EXCHSERV2K.CHM, in \support\CDO directory
• See release notes for COM and NT account
  configuration

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