This guide walks you through the process creating an application and securing it with the Spring Security LDAP module.
You will build a simple web application that is secured by Spring Security’s embedded Java-based LDAP server. You will load the LDAP server with a data file that contains a set of users.
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Note
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Because the point of this guide is to secure an unsecured web application, you will first build an unsecured web application and, later in the guide, add more dependencies for the Spring Security and LDAP features. |
If you use Maven, visit the Spring Initializr to generate a new project with the required dependency (Spring Web).
The following listing shows the pom.xml file created when you choose Maven:
link:initial/pom.xml[role=include]
If you use Gradle, visit the Spring Initializr to generate a new project with the required dependency (Spring Web).
The following listing shows the build.gradle file created when you choose Gradle:
link:initial/build.gradle[role=include]
If you want to initialize the project manually rather than use the links shown earlier, follow the steps given below:
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Navigate to https://start.spring.io. This service pulls in all the dependencies you need for an application and does most of the setup for you.
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Choose either Gradle or Maven and the language you want to use. This guide assumes that you chose Java.
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Click Dependencies and select Spring Web.
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Click Generate.
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Download the resulting ZIP file, which is an archive of a web application that is configured with your choices.
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Note
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If your IDE has the Spring Initializr integration, you can complete this process from your IDE. |
In Spring, REST endpoints are Spring MVC controllers. The following Spring MVC controller
(from src/main/java/com/example/authenticatingldap/HomeController.java) handles a
GET / request by returning a simple message:
link:initial/src/main/java/com/example/authenticatingldap/HomeController.java[role=include]The entire class is marked up with @RestController so that Spring MVC can autodetect the
controller (by using its built-in scanning features) and automatically configure the
necessary web routes.
@RestController also tells Spring MVC to write the text directly into the HTTP response
body, because there are no views. Instead, when you visit the page, you get a simple
message in the browser (because the focus of this guide is securing the page with LDAP).
Before you secure the web application, you should verify that it works. To do that, you
need to define some key beans, which you can do by creating an Application class. The
following listing (from
src/main/java/com/example/authenticatingldap/AuthenticatingLdapApplication.java) shows
that class:
link:complete/src/main/java/com/example/authenticatingldap/AuthenticatingLdapApplication.java[role=include]https://raw.githubusercontent.com/spring-guides/getting-started-macros/main/build_an_executable_jar_subhead.adoc https://raw.githubusercontent.com/spring-guides/getting-started-macros/main/build_an_executable_jar_with_both.adoc
If you open your browser and visit http://localhost:8080, you should see the following plain text:
Welcome to the home page!To configure Spring Security, you first need to add some extra dependencies to your build.
For a Gradle-based build, add the following dependencies to the build.gradle file:
link:complete/build.gradle[role=include]|
Note
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Due to an artifact resolution issue with Gradle, spring-tx must be pulled in. Otherwise, Gradle fetches an older one that doesn’t work. |
For a Maven-based build, add the following dependencies to the pom.xml file:
link:complete/pom.xml[role=include]These dependencies add Spring Security and UnboundId, an open source LDAP server. With
those dependencies in place, you can then use pure Java to configure your security policy,
as the following example (from
src/main/java/com/example/authenticatingldap/WebSecurityConfig.java) shows:
link:complete/src/main/java/com/example/authenticatingldap/WebSecurityConfig.java[role=include]To customize the security settings you use a WebSecurityConfigurer. In the above example this is
done by overriding the methods of WebSecurityConfigurerAdapter which implements the WebSecurityConfigurer interface.
You also need an LDAP server. Spring Boot provides auto-configuration for an embedded
server written in pure Java, which is being used for this guide. The
ldapAuthentication() method configures things so that the user name at the login form is
plugged into {0} such that it searches uid={0},ou=people,dc=springframework,dc=org in
the LDAP server. Also, the passwordCompare() method configures the encoder and the name
of the password’s attribute.
LDAP servers can use LDIF (LDAP Data Interchange Format) files to exchange user data. The
spring.ldap.embedded.ldif property inside application.properties lets Spring Boot pull
in an LDIF data file. This makes it easy to pre-load demonstration data. The following
listing (from src/main/resources/test-server.ldif) shows an LDIF file that works with this example:
link:complete/src/main/resources/test-server.ldif[role=include]|
Note
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Using an LDIF file is not standard configuration for a production system. However, it is useful for testing purposes or guides. |
If you visit the site at http://localhost:8080, you should be redirected to a login page provided by Spring Security.
Enter a user name of ben and a password of benspassword. You should see the following
message in your browser:
Welcome to the home page!Congratulations! You have written a web application and secured it with Spring Security. In this case, you used an LDAP-based user store.
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