3.2.09 Integrating Crowd with Acegi Security

Crowd provides centralised authentication and single sign-on connectors for the web security framework Acegi. Acegi provides a modular and highly configurable approach to authentication and authorisation for J2EE applications.

The connectors are available with Crowd 1.2 and later and have been developed and tested with Acegi 1.0.5.

Please consult the Acegi quick start guide or reference guide for a thorough insight into the Acegi framework. You might also find useful information in our Crowd-Acegi integration tutorial.

This guide assumes developer-level knowledge

This guide assumes you have Crowd 1.3 or later installed and that you want to integrate your Acegi-based web application with Crowd's security server. This guide is more for developers than administrators.

Prerequisites

Download and configure Crowd. Refer to the Crowd Installation Guide for detailed information on how to do this. We will refer to the Crowd root folder as CROWD.
Have your Acegi-based custom application ready for tweaking. We will refer to your custom application as 'AcegiApp'.

Step 1. Configuring Crowd to Talk to your Acegi Application

Crowd needs to be aware that AcegiApp will be making authentication requests to Crowd. In brief, you will need to do the following:

Add the AcegiApp application to Crowd.
Add and configure the directories visible to AcegiApp.
Add and map the groups which are allowed to authenticate with AcegiApp.

Please see 3.2 Adding an Application for a detailed guide.

Step 2. Installing the Crowd Acegi Connector

2.1 Adding the Crowd Acegi Connector to your Acegi Application

You will need to add the Crowd Acegi connector library and its associated dependencies to your Acegi application. You can do this manually by copying over the JAR files to your Acegi application or, if your Acegi application is a Maven project, you can add the Crowd Acegi connector as a project dependency.

2.1.1 Manually Adding the Crowd Acegi Connector Libraries

Follow either 2.1.1 or 2.1.2 (not both).

Copy the Crowd integration libraries and configuration files. This is described in the Client Configuration documentation. You will need to at least copy across the following file to your Acegi application:

Copy From	Copy To
CROWD/client/crowd-integration-client-X.X.X.jar	AcegiApp/WEB-INF/lib
CROWD/client/lib/*.jar	AcegiApp/WEB-INF/lib

2.1.2 Adding the Crowd Acegi Connector as a Maven Dependency

Follow either 2.1.1 or 2.1.2 (not both).

To integrate Crowd with your Maven 2 project, you will need to include the following dependency in your pom.xml:

<dependency>
	<groupId>com.atlassian.crowd</groupId>
	<artifactId>crowd-integration-client</artifactId>
	<version>X.X</version>
        <type>pom</type>
</dependency>

Because the Crowd libraries are not published to the standard Maven repository, you will need to add Atlassian's public repository:

<repositories>
	<repository>
		<id>central</id>
		<url>https://m2proxy.atlassian.com/repository/public</url>
		<snapshots>
			<enabled>true</enabled>
			<updatePolicy>always</updatePolicy>
		</snapshots>
		<releases>
			<enabled>true</enabled>
		</releases>
	</repository>
</repositories>

See more information on Maven 2 integration.

2.2 Configuring the Crowd Acegi Connector Properties

The Crowd Acegi connector needs to be configured with the details of the Crowd server.

Copy the default crowd.properties file to the classpath of your Acegi application:

Copy From

Copy To

CROWD/client/conf/crowd.properties

AcegiApp/WEB-INF/classes

Edit the crowd.properties and populate the following fields appropriately:

キー	値
application.name	Same as application name defined when adding the application to Crowd in Step 1.
application.password	Same as application password defined when adding the application to Crowd in Step 1.
crowd.server.url	http://localhost:8095/crowd/services/
session.validationinterval	This is the time interval between requests which validate whether the user is logged in or out of the Crowd SSO server. Set to 0, if you want authentication checks to occur on each request. Otherwise set to the number of minutes you wish to wait between requests. Setting this value to 1 or higher will increase the performance of Crowd's integration.

Passing crowd.properties as an environment variable

You can pass the location of a client application's crowd.properties file to the client application as an environment variable when starting the client application. This means that you can choose a suitable location for the crowd.properties file, instead of putting it in the client application's WEB-INF/classes directory.

This applies to the Crowd Administration Console's crowd.properties file too. You may find this particularly useful when integrating with a WAR deployment of an integrated application.

例:

-Dcrowd.properties={FILE-PATH}/crowd.properties

Step 3. Configuring your Acegi Application to Use the Crowd Acegi Connector

There are two ways you can integrate your application with Crowd:

Centralised user management: The user repository available to your application will be the user repository allocated to your application via Crowd. This means that your application will use the centralised user repository for retrieving user details as well as performing authentication.
Single sign-on: In addition to centralised authentication, SSO will be available to your application. If any other SSO-enabled applications (such as JIRA, Confluence, or your own custom applications) are integrated with Crowd, then SSO behaviour will be established across these applications. If you sign in to one application, you are signed in to all applications. If you sign out of one application, you are signed out of all applications.

First, you will need to add the Crowd client application context to wire up the Crowd beans that manage the communication to Crowd. You can do this by including the applicationContext-CrowdClient.xml Spring configuration file, found in crowd-integration-client.jar. For example, if you are configuring Spring using a context listener, you can add the following parameter in your WEB-INF/web.xml:

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            ...
            classpath:/applicationContext-CrowdClient.xml
            ...
        </param-value>
    </context-param>

Next, open the applicationContext.xml file relevant to your application, which contains the Acegi configuration. You are likely to have a bean configuration similar to this snippet:

<bean id="filterChainProxy" class="org.acegisecurity.util.FilterChainProxy">
  <property name="filterInvocationDefinitionSource">
    <value>
      CONVERT_URL_TO_LOWERCASE_BEFORE_COMPARISON
      PATTERN_TYPE_APACHE_ANT
      /images/**=#NONE#
      /scripts/**=#NONE#
      /styles/**=#NONE#
/**=httpSessionContextIntegrationFilter,logoutFilter,authenticationProcessingFilter,securityContextHolderAwareRequestFilter,rememberMeProcessingFilter,anonymousProcessingFilter,exceptionTranslationFilter,filterInvocationInterceptor
    </value>
  </property>
</bean>

3.1 Configuring Centralised User Management

Perform the following updates to your Acegi Spring configuration:

Add the definition of the CrowdUserDetailsService:

    <bean id="crowdUserDetailsService" class="com.atlassian.crowd.integration.acegi.CrowdUserDetailsService">
        <property name="securityServerClient" ref="securityServerClient"/>
    </bean>

Add the definition of the CrowdAuthenticationProvider:

    <bean id="crowdAuthenticationProvider" class="com.atlassian.crowd.integration.acegi.CrowdAuthenticationProvider">
        <property name="userDetailsService" ref="crowdUserDetailsService"/>
        <property name="httpAuthenticator" ref="httpAuthenticator"/>
        <property name="securityServerClient" ref="securityServerClient"/>
    </bean>

Update the definition of your AuthenticationManager / ProviderManager to use the CrowdAuthenticationProvider. If you need multiple authentication providers, you can append the CrowdAuthenticationProvider to your list.

<bean id="authenticationManager" class="org.acegisecurity.providers.ProviderManager">
  <property name="providers">
    <list>
      <ref local="crowdAuthenticationProvider"/>
      ...
    </list>
  </property>
</bean>

Further extensions

If you have an existing user data model, then you can extend or wrap the CrowdDetailsService to cater for user objects within your application domain.
If you require users within Crowd to be created in your application's persistence model so that you can store application-specific user data, you can extend the CrowdAuthenticationProvider to create records for successfully authenticated Crowd users.

Crowd's remote API

We recommend that applications do not store the Crowd users locally. Rather, applications should query users via Crowd's remote API.

3.2 Configuring Single Sign-On (SSO)

SSO is optional and requires centralised user management

Single sign-on is optional. If you wish to configure SSO you must first configure centralised user management as described in step 3.1 above.

Perform the following additional updates to your Acegi Spring configuration:

Update the definition of the AuthenticationProcessingFilter to use the CrowdAuthenticationProcessingFilter:

    <bean id="authenticationProcessingFilter" class="com.atlassian.crowd.integration.acegi.CrowdAuthenticationProcessingFilter">
        <property name="httpAuthenticator" ref="httpAuthenticator"/>
        <property name="authenticationManager" ref="authenticationManager"/>
        <property name="authenticationFailureUrl" value="/login.jsp?error=true"/>
        <property name="defaultTargetUrl" value="/"/>
        <property name="filterProcessesUrl" value="/j_security_check"/>
        ...
    </bean>

Add the definition of the CrowdLogoutHandler:
<bean id="crowdLogoutHandler" class="com.atlassian.crowd.integration.acegi.CrowdLogoutHandler">
<property name="httpAuthenticator" ref="httpAuthenticator"/>
</bean>

Update the definition of the LogoutFilter to use the CrowdLogoutHandler:

   <bean id="logoutFilter" class="org.acegisecurity.ui.logout.LogoutFilter">
        <constructor-arg value="/index.jsp"/>
        <constructor-arg>
            <list>
                ...
                <ref bean="crowdLogoutHandler"/>
                <bean class="org.acegisecurity.ui.logout.SecurityContextLogoutHandler"/>
            </list>
        </constructor-arg>
        <property name="filterProcessesUrl" value="/logout.jsp"/>
    </bean>

Step 4. Restarting your Acegi Application

Bounce your application. You should now have centralised authentication and single sign-on with Crowd.

Authorisation

For the purposes of Crowd integration with Acegi, you should map Acegi's roles to Crowd's groups. To put it another way: in order to use Acegi's authorisation features, users in Crowd will have their Acegi roles specified by their group names.

For example if user 'admin' is in the 'crowd-admin' group, then the user 'admin' will be authorised to view pages restricted to the 'crowd-admin' role in Acegi.

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