WAR Overlay Installation

CAS installation is a fundamentally source-oriented process, and we recommend a WAR overlay project to organize customizations such as component configuration and UI design. The output of a WAR overlay build is a cas.war file that can be deployed on a Java servlet container like Tomcat.

WAR overlay projects are provided for reference and study.

Gradle

Maven

CAS uses Spring Webflow to drive the login process in a modular and configurable fashion; the login-webflow.xml file contains a straightforward description of states and transitions in the flow. Customizing this file is probably the most common configuration concern beyond component configuration in the Spring XML configuration files. See the Spring Webflow Customization Guide for a thorough description of the various CAS flows and discussion of common configuration points.

Spring Configuration

CAS server depends heavily on the Spring framework. There are exact and specific XML configuration files under spring-configuration directory that control various properties of CAS as well as cas-servlet.xml and deployerConfigContext.xml the latter of which is mostly expected by CAS adopters to be included in the overlay for environment-specific CAS settings.

Spring beans in the XML configuration files can be overwritten to change behavior if need be via the Maven overlay process. There are two approaches to this:

  1. The XML file can be obtained from source for the CAS version and placed at the same exact path by the same exact name in the Maven overlay build. If configured correctly, the build will use the locally-provided XML file rather than the default.
  2. CAS server is able to load patterns of XML configuration files to overwrite what is provided by default. These configuration files that intend to overrule CAS default behavior can be placed at /WEB-INF/ and must be named by the following pattern: cas-servlet-*.xml. Beans placed in this file will overwrite others.

Custom and Third-Party Source

It is common to customize or extend the functionality of CAS by developing Java components that implement CAS APIs or to include third-party source by Maven dependency references. Including third-party source is trivial; simply include the relevant dependency in the overlay pom.xml file. In order to include custom Java source, it should be included under a src/java/main directory in the overlay project source tree.

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├── src
│   ├── main
│   │   ├── java
│   │   │   └── edu
│   │   │       └── vt
│   │   │           └── middleware
│   │   │               └── cas
│   │   │                   ├── audit
│   │   │                   │   ├── CompactSlf4jAuditTrailManager.java
│   │   │                   │   ├── CredentialsResourceResolver.java
│   │   │                   │   ├── ServiceResourceResolver.java
│   │   │                   │   └── TicketOrCredentialPrincipalResolver.java
│   │   │                   ├── authentication
│   │   │                   │   └── principal
│   │   │                   │       ├── AbstractCredentialsToPrincipalResolver.java
│   │   │                   │       ├── PDCCredentialsToPrincipalResolver.java
│   │   │                   │       └── UsernamePasswordCredentialsToPrincipalResolver.java
│   │   │                   ├── services
│   │   │                   │   └── JsonServiceRegistryDao.java
│   │   │                   ├── util
│   │   │                   │   └── X509Helper.java
│   │   │                   └── web
│   │   │                       ├── HelpController.java
│   │   │                       ├── RegisteredServiceController.java
│   │   │                       ├── StatsController.java
│   │   │                       ├── WarnController.java
│   │   │                       ├── flow
│   │   │                       │   ├── AbstractForgottenCredentialAction.java
│   │   │                       │   ├── AbstractLdapQueryAction.java
│   │   │                       │   ├── AffiliationHandlerAction.java
│   │   │                       │   ├── CheckAccountRecoveryMaintenanceAction.java
│   │   │                       │   ├── CheckPasswordExpirationAction.java
│   │   │                       │   ├── ForgottenCredentialTypeAction.java
│   │   │                       │   ├── LookupRegisteredServiceAction.java
│   │   │                       │   ├── NoSuchFlowHandler.java
│   │   │                       │   ├── User.java
│   │   │                       │   ├── UserLookupAction.java
│   │   │                       │   └── WarnCookieHandlerAction.java
│   │   │                       └── util
│   │   │                           ├── ProtocolParameterAuthority.java
│   │   │                           ├── UriEncoder.java
│   │   │                           └── UrlBuilder.java

Also, note that for any custom Java component to compile and be included in the final cas.war file, the pom.xml in the Maven overlay must include a reference to the Maven Java compiler so classes can compile.

Here is a sample Maven build configuration:

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...

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.3</version>
            <configuration>
                <warName>cas</warName>
                <overlays>
                    <overlay>
                        <groupId>org.jasig.cas</groupId>
                        <artifactId>cas-server-webapp</artifactId>
                        <excludes>
                <exclude>WEB-INF/cas.properties</exclude>
                            <exclude>WEB-INF/classes/log4j.xml</exclude>
                            <exclude>...</exclude>
                        </excludes>
                    </overlay>
                </overlays>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>${java.source.version}</source>
                <target>${java.target.version}</target>
            </configuration>
        </plugin>

    </plugins>
    <finalName>cas</finalName>
</build>

...

(1) The filesystem hierarchy visualization is generated by the tree program.