Spring Module - Mule 4

The Spring module allows Mule apps to make use of the Spring Framework.

To Configure the Spring Module

Add the following configuration:

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:spring="http://www.mulesoft.org/schema/mule/spring"
      xmlns="http://www.mulesoft.org/schema/mule/core"
      xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core
        http://www.mulesoft.org/schema/mule/core/current/mule.xsd
        http://www.mulesoft.org/schema/mule/spring
        http://www.mulesoft.org/schema/mule/spring/current/mule-spring.xsd">

    <spring:config name="springConfig" files="beans.xml" />

</mule>

Put the beans.xml file in src/main/resources.

Note that the Spring configuration must be valid. Here is an example:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"

    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
        http://www.springframework.org/schema/jdbc
        http://www.springframework.org/schema/jdbc/spring-jdbc-4.1.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.1.xsd">

    <jdbc:embedded-database id="dataSource" type="DERBY">
        <jdbc:script location="classpath:db/sql/create-db.sql" />
        <jdbc:script location="classpath:db/sql/insert-data.sql" />
    </jdbc:embedded-database>

</beans>

IMPORTANT: The beans files used with the Spring Module must be exported, if not the application won't start. See How to Export Resources.

To Use Spring Objects in Mule Components

You can use Spring objects in Mule configuration components, for instance, to point to the Derby data source created with Spring beans:

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:db="http://www.mulesoft.org/schema/mule/db"
      xmlns:spring="http://www.mulesoft.org/schema/mule/spring"
      xmlns="http://www.mulesoft.org/schema/mule/core"
      xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core
        http://www.mulesoft.org/schema/mule/core/current/mule.xsd
        http://www.mulesoft.org/schema/mule/spring
        http://www.mulesoft.org/schema/mule/spring/current/mule-spring.xsd
        http://www.mulesoft.org/schema/mule/db
        http://www.mulesoft.org/schema/mule/db/current/mule-db.xsd">

    <spring:config name="springConfig" files="beans.xml" />

    <db:config name="derbyConfig" doc:name="Database Config"  >
        <db:derby-connection database="datasource" create="true" />
    </db:config>
</mule>

To Use Spring Properties Placeholders

Properties defined by Spring properties placeholders cannot be used within the Mule app configuration, only in Spring configuration files. However, properties defined in Mule through <configuration-properties/> can be used within Spring configuration files.

Limitations Over Spring Objects

• Spring objects cannot implement Mule API lifecycle methods.
• Spring objects cannot be injected with Mule API services. The only service that can be used is the org.mule.runtime.api.artifact.Registry, which can be used to access any other service within the Mule API. This can be accomplished by using @PostConstruct over a method to initialize the object and retrieve the Mule API service.

To Use Spring Security as a Security Manager

The Spring module supports the use of Spring security as a Security Manager in Mule apps.

In the Spring configuration file, an Authentication Manager must be defined, for example:

<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:context="http://www.springframework.org/schema/context"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:jdbc="http://www.springframework.org/schema/jdbc"
  xmlns:ss="http://www.springframework.org/schema/security"

  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
    http://www.springframework.org/schema/jdbc
    http://www.springframework.org/schema/jdbc/spring-jdbc-4.1.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-4.1.xsd
    http://www.springframework.org/schema/security
    http://www.springframework.org/schema/security/spring-security-4.1.xsd">

  <ss:authentication-manager alias="authenticationManager">
    <ss:authentication-provider>
      <ss:user-service id="userService">
        <ss:user name="admin" password="admin" authorities="ROLE_ADMIN" />
        <ss:user name="joe" password="secret" authorities="ROLE_ADMIN" />
        <ss:user name="anon" password="anon" authorities="ROLE_ANON" />
        <ss:user name="user" password="password" authorities="ROLE_ANON" />
        <ss:user name="ross" password="ross" authorities="ROLE_ANON" />
        <ss:user name="marie" password="marie" authorities="ROLE_ANON" />
      </ss:user-service>
    </ss:authentication-provider>
  </ss:authentication-manager>

</beans>

You can define a Security Manager within a Mule app that makes use of the Spring Authentication Manager like this:

<?xml version="1.0" encoding="UTF-8"?>
<mule
  xmlns:spring="http://www.mulesoft.org/schema/mule/spring"
  xmlns="http://www.mulesoft.org/schema/mule/core"
  xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-current.xsd
    http://www.mulesoft.org/schema/mule/core
    http://www.mulesoft.org/schema/mule/core/current/mule.xsd
    http://www.mulesoft.org/schema/mule/spring
    http://www.mulesoft.org/schema/mule/spring/current/mule-spring.xsd">

  <spring:config name="springConfig" files="beans.xml" />

  <spring:security-manager>
    <spring:delegate-security-provider name="memory-provider" delegate-ref="authenticationManager" />
  </spring:security-manager>

</mule>

To Validate Authentication Using the Spring Authorization Filter

The Spring module adds support for a filter that fails if the authentication cannot be validated using the Mule Security Manager, for example:

<?xml version="1.0" encoding="UTF-8"?>
<mule
  xmlns:http="http://www.mulesoft.org/schema/mule/http"
  xmlns:db="http://www.mulesoft.org/schema/mule/db"
  xmlns:spring="http://www.mulesoft.org/schema/mule/spring"
  xmlns="http://www.mulesoft.org/schema/mule/core"
  xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-current.xsd
    http://www.mulesoft.org/schema/mule/core
    http://www.mulesoft.org/schema/mule/core/current/mule.xsd
    http://www.mulesoft.org/schema/mule/spring
    http://www.mulesoft.org/schema/mule/spring/current/mule-spring.xsd
    http://www.mulesoft.org/schema/mule/db      http://www.mulesoft.org/schema/mule/db/current/mule-db.xsd
    http://www.mulesoft.org/schema/mule/http
    http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd">

  <spring:config name="springConfig" files="beans.xml" />

  <spring:security-manager>
    <spring:delegate-security-provider name="memory-provider" delegate-ref="authenticationManager" />
  </spring:security-manager>

  <http:listener-config name="HTTP_Listener_config" doc:name="HTTP Listener config"  >
      <http:listener-connection host="0.0.0.0" port="9090" />
  </http:listener-config>

  <flow name="spring-exampleFlow" >
    <http:listener config-ref="HTTP_Listener_config" path="/" doc:name="Listener"  />
    <http:basic-security-filter realm="mule" />
      <spring:authorization-filter requiredAuthorities="ROLE_ADMIN" />
  </flow>
</mule>

The http:basic-security-filter tries to authenticate the user using basic authentication. If the request is authenticated successfully, Mule will retrieve the username and use it in the Spring authorization-filter to search for that user and try to authorize the request against the authority ROLE_ADMIN.