Alfresco Repository ArchitectureOverview

12 March 2008

Presented by:

Sumer Jabri

Rivet Logic Corporation

1800 Alexander Bell Drive

Suite 400

Reston, VA 20191

Ph: 703.234.7761 Fax: 703.234.7711

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Presentation Overview

! Motivation

– Get a high-level architectural overview of Alfresco’s

content repository

! Scope

– Positioning

– Technology Overview

– Services and Components

– Programmatic APIs

– Repository Protocols

– Alfresco-based Content Rich Application

Considerations

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Technology Overview

! Alfresco

– Built using best of breed OSS projects

– Provides complete set of content management

solutions

– Not tied to a specific operating system, web browser,

application server, nor database

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The Four Big Areas of Content Management

Records ManagementContent

Repository

Document ManagementWeb Content Management

ImageManagement

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Alfresco as an ECM Solution

Full-text Indexes& Categories

Storage

MetadataDBMS

App Server

Message

System

Integration

Virtual File

System

WebDAV

CIFS

FTP

Content

Repository

Business

Process

Engine

CRM

Web Services

Portal Server

Knowledge

Portals

High

Availability

Hot

Standby

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Out of the Box

! Out of the box, Alfresco

– Deploys as a complete working content management

application

– Runs like a typical web application

~ Application server

! User interface

! Repository

~ Persistent back-end

! Database

! File system

~ Any number of web browsers

! No client installation costs

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Out of the Box Installation

! App server houses– Alfresco application

– Alfresco repository

! Alfresco repository– Reusable, cross-cutting, content

management services~ Content storage

~ Query

~ Versioning

~ Transformation

! Architecture is– Open

– Modular~ Components can be used in isolation or

together

! Support for– DM - Document Management

– RM - Records Management

– WCM - Web Content Management~ Currently only uses subset of repository

services

~ Adds complex layering and versioningsupport for sophisticated web production

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Services and Components

! Alfresco Repository is composed of

– Services

~ Interface entry point for a client to bind to and use

– Components

~ Implementation black box

~ Provides specific capabilities

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Architecture Advantages

! Existing components can be replaced

– Better implementation

– Better integration with existing environment

– No impact to clients

! Remove unnecessary features

– Lighter, possibly faster Alfresco

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Spring Framework

! Simplifies architecture implementation

! Core foundation of Alfresco architecture

! Components are

– Declaratively configured and bound together

! Spring AOP allows for

– Adding transactions and security to components

declaratively

– No implementation pollution

! Resources are abstracted (e.g. Database)

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Programmatic APIs

! Alfresco provides three primary APIs

– Repository Foundation Services

~ Local Java interfaces covering all capabilities

~ Ideal for embedding the repository

– JCR

~ Standard Java API (JSR-170)

– Web Services

~ Remote access and binding to any client environment (Java,

.NET, PHP, Ruby)

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Repository Foundation Services [1/3]

! Repository Foundation Services

– Public interface point

– Services are Java interfaces

– Client isn't aware ofimplementation

– Services registry lists availableservices

! Components

– Provide implementation

– Configured using Spring~ XML Context files

~ Foundation services areconfigured and bound in“public-services-context.xml”

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Repository Foundation Services [2/3]

! Repository foundation services

– Lowest level public interface

– Provide access to all repository capabilities

– Client binds to services using

~ Service registry

~ Spring dependency injection (if Spring aware)

– Client must be running within same JVM (embed

Alfresco)

– Enforce transactions and security policies

~ Declaratively specified and enforced using Spring AOP

~ Every service in Alfresco is transactional and secure

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Repository Foundation Services [3/3]

! Repository foundation services (cont'd)

– All public entry points go through this layer

~ Web services

~ JCR

– Common scheme for extending the repository

~ Component configuration

~ Additional components and services

~ Externalized extensions

! Automatically plugged-in

! Core repository can be upgraded independently

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Key Foundation Services [1/4]

! Repository is about storage and retrieval of

content

! In Alfresco, this is accomplished using

– Node

– Content

– Index/Search

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Key Foundation Services [2/4]

! Node

– Provides meta-data

~ Name, date, author, etc.

! Not the same as meta-data supplied via WCM’s web-forms

– Provides structure

~ Relationship to other nodes (file/folder model)

! Content

– Actual stored information

~ Word document, JPG image, etc.

! Index/Search

– Indexing information allows retrieval of meta-data

and content

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Key Foundation Services [3/4]

! Repository storage and retrieval is provided by

– Node Service

– Content Service

– Search Service

! These three services form the core

– Nearly all foundation services and clients go through

these

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Key Foundation Services [4/4]

! Meta-data is stored in thedatabase

– Transaction support

– Scalability

– Administration capabilities

! Content is stored in the filesystem

– Allows for very large content

– Random access

– Streaming

– Options for different storagedevices

! Built upon strong OSS projects– Hibernate

– Lucene

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Content Domain Foundation Services

! All services are implemented using the same

component architecture

– Transactional

– Secure

– Configured using Spring

! Services include

– WCM’s AVM services, Meta-data extraction, Content

Transformation, Templating, Classification,

Versioning, Locking, Content Modeling, Image

Manipulation, Work-flow, Import and Export,

Permissions, …

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Repository Protocols [1/2]

! Alfresco repository supports

– CIFS (Common Internet File System)

– WebDAV (Web Distributed Authoring and Versioning)

– FTP

! These protocols are exposed for content

management

– Limited to files and folders

– Described by the default content model and

derivatives

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Repository Protocols [2/2]

! Protocol components are Spring configured

! Protocol components are built on top of the repository

foundation services

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Triggers and Stored Procedures

! Rules

– Get initiated based on a trigger, and conditions

~ Trigger examples: Inbound, outbound

~ Condition examples: Item matches a MIME type

! Actions

– Examples: Move, copy, apply aspect

– Compound actions are a series of actions wrapped

together into one action

! Policies

– Are similar to events

– Allow model specific behavior to be injected

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Content Rich Application Considerations [1/2]

! Content Model

– Custom meta-data

~ Properties, indexing, multi-valued

~ Compound documents

– Associations and structure

– Meta-data constraints

– Model specific automatic behaviors

– Custom meta-data extractors, content transformers,

actions, and conditions

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Content Rich Application Considerations [2/2]

! Repository Structure

– Space (folder) hierarchy

~ Spaces as content packages

– Space rules to automate:

~ Meta-data extraction

~ Content arrangement

~ Naming-convention enforcement

~ Content type specialization

~ Content MIME-type transformation

~ Etc.

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Real-World Examples

! Content Model– Custom spaces with meta-data as content packages

– Custom content items with multi-valued content property

~ Multi-page scanned document

– Associations between documents and various renditions ofthose documents (e.g. XML <-> PDF)

! Repository Structure– Space (folder) hierarchy

~ …/YYYY/MM/DD/Package/…

! Custom meta-data for a package includes a Package Id derived fromcontent

! Facilitates rapid package search and retrieval

~ …/Package/Sub-Package/item

! Naming convention enforced for certain types/spaces

~ …/DropZone/ (CIFS mapped)

! Automatic meta-data extraction, content type specialization, andcontent arrangement (into packages)

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Questions?

! Questions?