Hippo TechWP Understanding Hippo CMS 7 Software Architecture

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Author: Woonsan Ko

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Europe: +31 20 522 44 66

Introduction

This document describes the architecture of Hippo CMS on an abstract level. This document aims

to provide the basic understanding of the Hippo CMS software architecture to enable Architects to

define their custom requirements for their specific IT ecosystem.

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Amsterdam Boston Follow the Hippo trail: onehippo.com

Understanding Hippo CMS 7 Software Architecture

Table of Contents

1. Introduction 3

2. Use Cases Overview 4 Actors List 5

Use Cases List 5

2. Quality Attributes 5 User/Usability Considerations 5

Runtime Qualities 5

Availability 5

Interoperability 5

Manageability 5

Performance 5

Reliability 5

Scalability 5

Security 5

Design Qualities 5

Modifiability 5

Maintainability 5

Reusability 5

System Qualities 5

Supportability 5

4. Software Architectures 6 Overall Views 7

Content Production 8

Content Delivery 9

Security Concerns 10

Module View 10

Simple Enterprise SSO Enabled Architecture-Deployment View 10

View Shibboleth/SAML Enabled Architecture 11

5. Summary 12

6. References 12

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1. Introduction This document describes the software architecture of

Hippo CMS on a high level to help various stakeholders

understand Hippo CMS in general.

For enterprise architects and technology leaders,

this document will help to understand how Hippo CMS

can solve technical problems and challenges and how

Hippo CMS can be integrated with industry standard

technologies transparently and seamlessly.

For developers,

this will help understand how components are interacting

with each other and how modules are constructed and and

relate to each other.

For system administrators,

this will help understand how systems are deployed,

maintained and monitored.

For testers,

this will help understand how systems can be integrated

and tested properly.


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Actors

Web User Users accessing the websites to

search, view and edit (e.g., adding

comments to an article) the

content of the system. Can be an

anonymous or authenticated user.

Author CMS users who can create and

edit content in the system, but

normally cannot publish the

content directly by themselves.

They can request publication on

the content instead.

Editor CMS users who can create, edit,

publish and depublish content in

the system. Normally they can

approve the publication requests

from authors.

Webmaster Webmaster who manages

channels, content delivery web

application configurations and

personas.

Administrator CMS Administrator who can

manage access controls of the

system, manage content migration

tasks from the external sources

and do all other CMS related

administration tasks.

Search Engine External search engines. e.g.,

Google, Bing, etc. CMS provides

Search Engine Optimization

features for external search

engines.

Content Subscriber External users or systems,

subscribing the content through

RSS, Atom feeds, e-mails, etc.

External Content Source External content source which can

be migrated into CMS. e.g., XML

file/folders and images/assets,

external repositories, etc.

Use Cases

Search Content Web User searches content by

text, categories, tags or metadata.

View Content Web User views selected content

on the website. External Search

Engines also crawl content or

metadata on the website for

indexing purpose. The website

content includes generated

content in the markups, meta tags,

sitemap data, etc.

View Social Content Web User views opinions,

comments, etc. shared by Social

Applications (e.g., Facebook,

Twitter, Disqus, etc.) on the content.

Edit Content

Web User can create and edit

content on the website. e.g.,

comments on an article.

Syndicate Content Content Subscriber can receive

content through RSS, Atom feeds,

e-mails, etc.

Author Content Author creates and edits content

in CMS, and requests publication

on the content.

Manage Publication Editor can accept or reject the

publication requests on the

content, and schedule publication

of the content.

Manage Channel Webmaster manages channels and

their associated content delivery

web application configurations.

Manage Persona Webmaster configures collectors,

defines characteristics and

manages persona for targeting

and personalization.

Manage Access Control Administrator manages access

controls by defining users, groups

and privileges per each content

security domain.

Migrate Content Administrator configures and

monitors content migration tasks.

External Content Source External content source which can

be migrated into CMS. e.g., XML

file/folders and images/assets,

external repositories, etc.

Site

CMS

Search Engine

Editor

Author

Web User

Social Application

Webmaster

Content Subscriber

Administrator

External Content Source

Key Roles and their Use Cases

Search Content

View Content

View Social Content

Edit Content

Author Content

Syndicate Content

Manage Channel

Manage Persona

Manage Publication

Manage Access Control

Migrate Content

>


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2. Use Cases Overview

The use cases overview diagram on the previous page

shows higher level use cases. Please note that the actors

and use cases will vary in specific systems and the

overview shows a simplified generic model only.

3. Quality Attributes

Hippo follows a number of core architectural principles

when designing features and functionalities for Hippo

CMS, which are described in more detail below.

User/Usability Considerations

Intuitive and customizable user experiences for easy

creation and management of web content without IT

assistance.

Enables authors to manage multi lingual have content

and deliver the right content based on user locale.

Enables to publish content to multiple, disparate

channels such as mobile, email, website, landing page,

social network, print, and campaign management

system.

Enables to target and personalize to any visitor based

on context, behavior, geography and profile data.

Easy management of rich media files such as images

and asset files, and seamless integration for streaming

audio and videos.

Provides social and community features that can be

incorporated into existing sites for sharing of opinions,

articles and reviews.

Runtime Qualities

Availability

Websites are mission critical systems for online

businesses. The website and CMS system have to be

functional and working without being affected by any

critical system errors, infrastructure problems, malicious

attacks and system loads.

Interoperability

Conforms web standards (e.g., W3C XHTML, CSS, etc.).

Supports search engine optimizations for website.

Supports enterprise search engine integration.

Enables industry standards based communications

(e.g., Servlet/JSP/JSTL, JSR-283, etc.) and supports

easy JEE standard based integrations.

Allows standards based information exchanges. e.g.,

XML, RSS, Atom feeds, RESTful APIs.

Enables to use external authoring tools such as Office

documents.

Content migration support from external sources in

various formats such as XML and image files.

Application Integration support. Enables seamless

integration with various enterprise systems such as

eCommerce, CRM, BPM, etc.

Manageability

Supports easy management with useful tools for

monitoring and tuning.

Performance

Meets performance needs for online business. System

have to be responsive to execute any action within a given

time interval. Reliability

Remains operational over time. System will not fail to

perform its intended functions over a specified time

interval.

Scalability

Meets massive scalability for online business. System

should handle increases in load without impact on the

performance of the system and should be readily enlarged.

Security

Provides safe and secure access, and supports access

control with user groups on domain rules.

Supports integration with industry security standards

based solutions, e.g., JAAS, LDAP, Single sign-on using

popular Central Authentication Services (e.g. OpenID,

SAML, Shibboleth, SiteMinder etc.)

Supports customization and plugging in custom

authentication implementations, Remember-me,

CAPTCHA, concurrent sessions etc.

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6Design Qualities Modifiability

Support templates to be applied to new and existing

content, allowing the appearance of all content to be

changed from one central place.

Support plugin architecture. Developers should be able

to add functionalities with plugins easily.

Maintainability

Should be easy to undergo changes on components,

services, features and interfaces when adding or

changing functionalities, fixing errors, and meeting new

business requirements.

Reusability

Components and subsystems should be designed to

be suitable for use in other applications and in other

scenarios as much as possible in order to minimize the

duplication of components and implementation time.

System Qualities

Supportability

Should provide information helpful for identifying and

resolving issues when it fails to work correctly.

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Browser Clients can visit websites through HTTP/S connections.

Search Engines can crawl websites and metadata through HTTP/S connections.

Content Subscribers (e.g., RSS/Atom feed clients) can retrieve contents through content syndication protocols.

JCR Clients can communicate with the repository, which can be deployed onto the same Application Server node as shown above or a

separate Application Server node, through the JCR API. The underlying

connection for JCR API for remote clients can be either WebDAV or

RMI. By the standard of JCR API, JCR Clients can communicate with

the repository in either client-server invocation style or asynchronous

event subscription style.

The content delivery web application, SITE, can be deployed onto any JEE compliant servlet containers such as Tomcat 6, JBoss, Glassfish,

WebSphere, etc.

The content production web application, CMS, can be deployed onto any JEE compliant servlet containers such as Tomcat 6, JBoss,

Glassfish, WebSphere, etc.

The repository server module, Repository, can be deployed onto an application server together with the CMS web application, but also can

be deployed onto a separate application server or as a separate web

application.

Each repository instance has its own Lucene index, while all the cluster repository nodes should share the same DBMS.

Hippo CMS can leverage CouchBase as separate server installation for storing visitor data used for targeting and analytics.

Hippo repository supports various DBMS such as MySQL, PostgreSQL, Oracle, MS SQL, Amazon RDS and IBM DB2.

System Admin Tools are mostly web-based applications and can be deployed onto any JEE compliant servlet containers. System

administrators can also use JMX tools to monitor JVMs and Content

Delivery web applications, by connecting through JMX protocol (either

local, RMI, or HTTP based).

Content Import Tool application, which imports XML files and binary files into the repository, can be deployed onto any JEE compliant

servlet containers, too.


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7System Overview

An explanation of core nodes:

JCR

(ove

r W

ebDA

V o

r R

M)

RSS/

Atom

< < artifact > > < < war > >

CMS

< < artifact > > < < war > >

System Admin Tools

l

< < artifact > > < < war > >

http

http

Load Balancer

HTTPd DBMS

Lucene Index (1)

Lucene Index (n)

< < artifact > > < < jar > >

Repository

< < artifact > > < < war > >

SITE

Application Server (1)

Browser Client

Content Subscriber

JCR Client

Search Engine

CouchBase Server

Application Server (n)

Import Tool

4. Software Architecture

Overall Views

Deployment View

The following deployment view shows a simplified deployment with core systems. For simplicity, it just shows a typical

simple deployment, without considering specific concerns such as security, caching options,

etc. in detail.


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The Content production CMS web application is based on the Apache Wicket framework, providing a very flexible Hippo plugins architecture

and extensions points.

Like normal Apache Wicket applications, a page component consists of descendant components. In addition, the CMS Frontend Plugin

Architecture allows dynamic plugin components aggregation, at

runtime, which can be configured in the repository, without having to

know all the descendant components at design time.

With rich component set of Wicket based plugins, native Wicket AJAX support and extensions of ExtJS and jQuery by Hippo, usability can be

maximized.

WicketApplication is just a standard Apache Wicket filter, and Main is the entry point Wicket application which shows homepages such

as PluginPage, LoginPage, etc. and has the UserSession which is

associated with a JCR Session.

PluginPage consists of multi ple Perspective plugin components and each Perspective plugin component consists of multiple child plugin components.

For example, Dashboard Perspective plugin component consists of Document Wizard, Document History, Todo List, Folder Tree, Document

List plugin components, etc.

A plugin component can contain multiple child plugin components by defining configurations in the repository, which increases

customizability, maintainability and reusability.

All component may use the JCR Session in the UserSession to retrieve/update content in the repository through JCR API. Also they may use

Hippo Repository API to handle virtual nodes and workflows.

Because it has to communicate with SITE web application at runtime when composing page layouts or assembling components in pages,

ChannelManager Perspective can connect to the ChannelManager

through RESTful APIs.

< < http/ rest > >

< < Servlet Filter > > Wicket Application

User Session Hippo JCR Repository

Plugin Config Service

Plugin Page

Login Page

Browse Perspective

Admin Perspective

Reports Perspective

Targeting Perspective

JCR Session

Plugin Config

Main

Document Wizard Plugin

Document History Plugin

Folder Tree Plugin

Document List Plugin

Dashboard Perspective

Todo List Plugin

Experience Optimizer Plugin

Google Analytics Plugin

Channel Manager

Channel Manager

Perspective

Content Management System Application Components and Connectors View

An explanation of core components and connectors:

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HST Core is the core module of the Hippo Delivery Tier, including component manager, pipeline, valves, component invoker, etc.

HST Client is the base module for Content Delivery applications such as custom HSTComponents, containing base component classes,

utilities, etc.

HST JAXRS contains RESTful API support components based on JAX-RS standard. Custom JAXRS Resource Beans can be implemented

based on the JAX-RS standard and configured with this module in the

Spring Framework configurations.

HST Security contains authentication/authorization support for websites, including JAAS and form based authentication support.

Spring Security Framework can be configured with this, too, in order to

support various security requirements such as SiteMinder integration,

Enterprise SSO integrations, etc.

HST Session Pool has JCR Session pool support, with sophisticated resource management and JMX management features.

HST Content Beans has Object-Content mapping support, which allows to map JCR content nodes to POJOs and vice versa.

HST Rewriter has HTML content rewriting support with link and image rewriting features.

HST Commons has default implementations of standard interfaces and common utilities.

HST API provides all the standard APIs of the Hippo Delivery Tier.

HST Mock contains some necessary mocking classes for easy unit testing, which increases testability.

The Content Delivery Framework depends on Hippo Repository API and JCR API.

Hippo Delivery Tier Modules view

HST Core

HST Security HST Content Beans HST Rewriter

HST Commons HST API HST Mock

JCR API

HST Client

HST Session Pool

Hippo Repository API

HST JAXRS

The figure above shows module dependencies of the Hippo Delivery Tier:

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httpd authenticates the secured resources by mod_shib2 module, which invokes Shibboleth Daemon. Shibboleth Daemon may communicate with Enterprise Shibboleth Identity Provider via SAML/HTTPS.

If the user is successfully authenticated by the handshakes between Client Browser and Shibboleth Identity Provider, then httpd will do reverse proxy to Tomcat.

If the user is authenticated in the httpd level by mod_shib2 module and Shibboleth Daemon, then it is regarded as pre-authenticated state from the viewpoint of Java Web Applications on Tomcat.

Spring Security Framework Filter initializes proper user principal based on the pre-authenticated user information, which should be provided by HTTP Header. [8] The components initializing the pre-authenticated user detail can be easily customized. See [9] for an example.

Now, HST-2 Container can use the initialized user principal on serving secured page resources.

Also, CMS Frontend Application can create a user JCR session based on the initialized user principal.

In most cases, HTTPS connection for browser clients is configured and enabled on the HTTPd (Apache2) layer.

In many cases, HTTPd or other reverse proxy layer node can redirect to the Enterprise SSO Server for authentication required clients and the

request can be redirected back with a valid security token.

Enterprise SSO Server such as SiteMinder can be accessed by applications on the Application Server to validate the security tokens if

needed.

CMS and site applications on Application Server can also authenticate users against LDAP Server if configured.

CMS and site applications on Application Server can also authenticate users by either Form Authentication or JAAS or Spring Security

Integration. If Enterprise SSO Server is used, Spring Security

Integration is capable of integrating with it seamlessly.

Security Aspects An Enterprise SSO Enabled Architecture-Deployment View

< < artifact > > SSL

Configuration

< < artifact > > < < war > >

CMS

< < artifact > > < < war > >

Site

http/sBrowser Client

HTTPd Application Server

SSO Server

DBMS

LDAP Server

< < artifact > > Form

Authentication Configuration

< < artifact > > JAAS

Configuration

< < artifact > > Spring Security

Integration Configuration

An explanation of core nodes:

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11Deep Dive Example for SSO Shibboleth/SAML Deployment

Browser Client attempts to access WCMS system through the web URLs served by the frontend Apache HTTPd Server.

The Apache HTTPd Server has authentication configuration for secured resources (e.g., /cms, /SITE/secured/articles/, etc.) with

Shibboleth authentication option. For the Shibboleth authentication

option, the Apache HTTPd Server invokes mod_shib2 module which is

deployed onto the server.

The mod_shib2 module communicates with Shibboleth Daemon to request authentication through either Unix socket or TCP socket based

on configuration.

Shibboleth Deamon may initiate user sessions, manage the sessions for the specified time duration, let Browser Client be redirected to the

Shibboleth Identity Provider, and provide authentication information

environment variables or http headers. Shibboleth Identity Provider

is normally deployed centrally in the enterprise, and so WCMS system

should normally be configured to access remote Shibboleth Identity

Provider through Shibboleth Damon.

Shibboleth Deamon is configured by shibboleth2.xml. Because the authentication information should be used in Java Applications

connected through either mod_proxy or mod_jk2, Shibboleth Daemon

should be configured to leave the authentication information as HTTP

Headers.

For authenticated user session, Apache HTTPd Server will serve Java Web Applications (e.g., Content Production Application and Content

Delivery Application) hosted by Tomcat, which is connected by either

mod_proxy or mod_jk2.

CMS (Content Production) Application and SITE (Content Delivery) Application can be configured with Spring Security Framework

enabled. Spring Security Framework can read the pre-authenticated

HTTP Header [8], which is provided by Shibboleth Daemon, and it can

build a user principal based on the pre-authenticated HTTP Header.

CMS (Content Production) Application and SITE (Content Delivery)

Application should be configured to use the user principal provided

by the Spring Security, instead of trying to authenticate the user by

themselves.

CMS (Content Production) Application should be configured to synchronize the user data from the LDAP Server.


An explanation on core nodes:

< < http/s > >

< < http/s > >

< < SAM

L/https > >

Browser Client

Apache2 HTTPd

Shibboleth Deamon

Shibboleth Identity Provider

< < artifact > > Spring Security

Integration Configuration

< < artifact > > mod_shib2

< < artifact > > < < war > >

CMS

< < artifact > > < < war > >

SITE

< < artifact > > shibboleth2.xml

WCMS

Enterprise Federated

Security Resources

LDAP Server

Tomcat

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Shibboleth/SAML Enabled Architecture

Shibboleth is a single-sign in, or logging-in system for computer networks and the internet. It allows people to sign in,

using just one identity, to various systems run by federations of different organizations or institutions. The federations

are often universities or public service organizations. [5] This section describes how Hippo CMS 7 can be deployed,

integrating with Enterprise Shibboleth SSO Solution, and how internal components interact with each other. For detail of

About Hippo


Whitepaper

At Hippo, we believe, digital is here to make our lives a

little bit better.

Hippo sets the standard for how organizations can bring

real-time relevance to their audience and is the foundation

for personalized communication across all channels:

mobile, social and web. Our purpose is to facilitate

innovation so our customers can create digital miracles.

We serve our customers, by creating a platform that is fun

to use, easy to implement and open for innovation.

Hippo CMS is a powerful, enterprise-class foundation

to deliver outstanding Customer Experiences based on

Enterprise Agility and Innovation Power.

Hippo CMS is open source, 100% Java and convinces

with its lean product architecture that is built for uptime,

security and performance.

Our dedicated, Certified Partner Network delivers Hippo

Awesomeness around the globe to our valued customers.

Hippo is proud to serve organizations such as Disney,

British Telecom, Dolce & Gabbana, Max Bahr, the Dutch

Police, Thomson Reuters and Crdit Agricole.

Hippo is headquartered in Amsterdam, The Netherlands

and Boston, USA.

Curious for more? Visit www.onehippo.com

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1. Hippo Campus Community

http://www.onehippo.org

2. Spring Framework

http://www.springsource.org/spring-framework

3. Spring Security Framework

http://static.springsource.org/spring-security/

site/

4. Apache Wicket

http://wicket.apache.org

5. Shibboleth (Internet2)

http://en.wikipedia.org/wiki/

Shibboleth_%28Internet2%29

6. Shibboleth Documentation

https://wiki.shibboleth.net/confluence/

dashboard.action

7. Deployment of Shibboleth Service Provider (SP)

2.0 on Debian GNU/Linux 4.0

https://www.switch.ch/aai/docs/shibboleth/

SWITCH/2.0/sp/deployment-sp-2.0-debian-

4.0.html

8. Spring Security Framework-Pre-Authentication

Scenario

http://static.springsource.org/spring-security/

site/docs/3.1.x/reference/preauth.html

Resources

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