[[servlet-hello]]
= Hello Spring Security

This section covers the minimum setup for how to use Spring Security with Spring Boot.

[NOTE]
====
The completed application can be found {gh-samples-url}/servlet/spring-boot/java/hello-security[in our samples repository].
For your convenience, you can download a minimal Spring Boot + Spring Security application by https://start.spring.io/starter.zip?type=maven-project&language=java&packaging=jar&jvmVersion=1.8&groupId=example&artifactId=hello-security&name=hello-security&description=Hello%20Security&packageName=example.hello-security&dependencies=web,security[clicking here].
====

[[servlet-hello-dependencies]]
== Updating Dependencies

The only step you need to do is update the dependencies by using xref:getting-spring-security.adoc#getting-maven-boot[Maven] or xref:getting-spring-security.adoc#getting-gradle-boot[Gradle].

[[servlet-hello-starting]]
== Starting Hello Spring Security Boot

You can now https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#using-boot-running-with-the-maven-plugin[run the Spring Boot application] by using the Maven Plugin's `run` goal.
The following example shows how to do so (and the beginning of the output from doing so):

.Running Spring Boot Application
====
[source,bash]
----
$ ./mvn spring-boot:run
...
INFO 23689 --- [  restartedMain] .s.s.UserDetailsServiceAutoConfiguration :

Using generated security password: 8e557245-73e2-4286-969a-ff57fe326336

...
----
====


[[servlet-hello-auto-configuration]]
== Spring Boot Auto Configuration

// FIXME: Link to relevant portions of documentation
// FIXME: Link to Spring Boot's Security Auto configuration classes
// FIXME: Add a links for what user's should do next

Spring Boot automatically:

* Enables Spring Security's default configuration, which creates a servlet `Filter` as a bean named `springSecurityFilterChain`.
  This bean is responsible for all the security (protecting the application URLs, validating submitted username and passwords, redirecting to the log in form, and so on) within your application.
* Creates a `UserDetailsService` bean with a username of `user` and a randomly generated password that is logged to the console.
* Registers the `Filter` with a bean named `springSecurityFilterChain` with the Servlet container for every request.

Spring Boot is not configuring much, but it does a lot.
A summary of the features follows:

* Require an authenticated user for any interaction with the application
* Generate a default login form for you
* Let the user with a username of `user` and a password that is logged to the console to authenticate with form-based authentication (in the preceding example, the password is `8e557245-73e2-4286-969a-ff57fe326336`)
* Protects the password storage with BCrypt
* Lets the user log out
* https://en.wikipedia.org/wiki/Cross-site_request_forgery[CSRF attack] prevention
* https://en.wikipedia.org/wiki/Session_fixation[Session Fixation] protection
* Security Header integration
  ** https://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security[HTTP Strict Transport Security] for secure requests
  ** https://msdn.microsoft.com/en-us/library/ie/gg622941(v=vs.85).aspx[X-Content-Type-Options] integration
  ** Cache Control (can be overridden later by your application to allow caching of your static resources)
  ** https://msdn.microsoft.com/en-us/library/dd565647(v=vs.85).aspx[X-XSS-Protection] integration
  ** X-Frame-Options integration to help prevent https://en.wikipedia.org/wiki/Clickjacking[Clickjacking]
* Integrate with the following Servlet API methods:
  ** https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#getRemoteUser()[`HttpServletRequest#getRemoteUser()`]
** https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#getUserPrincipal()[`HttpServletRequest.html#getUserPrincipal()`]
** https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#isUserInRole(java.lang.String)[`HttpServletRequest.html#isUserInRole(java.lang.String)`]
** https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#login(java.lang.String,%20java.lang.String)[`HttpServletRequest.html#login(java.lang.String, java.lang.String)`]
  ** https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#logout()[`HttpServletRequest.html#logout()`]