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@@ -8,12 +8,12 @@
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<title>Introduction</title>
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</info>
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<para>
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- Namespace configuration has been available since version 2.0 of the Spring framework. It allows you to
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- supplement the traditional Spring beans application context syntax with elements from additional XML schema.
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- You can find more information in the Spring
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+ Namespace configuration has been available since version 2.0 of the Spring framework. It
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+ allows you to supplement the traditional Spring beans application context syntax with elements
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+ from additional XML schema. You can find more information in the Spring
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<link xlink:href="http://static.springframework.org/spring/docs/2.5.x/reference/xsd-config.html">
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- Reference Documentation</link>. A namespace element can be used simply to allow a more concise
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- way of configuring an individual bean or, more powerfully, to define an alternative
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+ Reference Documentation</link>. A namespace element can be used simply to allow a more
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+ concise way of configuring an individual bean or, more powerfully, to define an alternative
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configuration syntax which more closely matches the problem domain and hides the underlying
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complexity from the user. A simple element may conceal the fact that multiple beans and
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processing steps are being added to the application context. For example, adding the following
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@@ -24,23 +24,24 @@
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]]></programlisting>
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This is much simpler than wiring up the equivalent Apache Directory Server beans. The most
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common alterative configuration requirements are supported by attributes on the
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- <literal>ldap-server</literal> element and the user is isolated from worrying about which
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- beans they need to be set on and what the bean property names are.
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+ <literal>ldap-server</literal>
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+ element and the user is isolated from worrying about which beans they need to be set on and
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+ what the bean property names are.
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<footnote>
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<para>You can find out more about the use of the
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<literal>ldap-server</literal>
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element in the chapter on
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<link xlink:href="ldap">LDAP</link>.</para>
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- </footnote>. Use of a good XML editor while editing the application context
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- file should provide information on the attributes and elements that are
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- available. We would recommend that you try out the
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+ </footnote>. Use of a good XML editor while editing the application context file should
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+ provide information on the attributes and elements that are available. We would recommend that
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+ you try out the
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<link xlink:href="http://www.springsource.com/products/sts">SpringSource Tool Suite</link>
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- as it has special features for working with the Spring portfolio namespaces.
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+ as it has special features for working with the Spring portfolio namespaces.
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</para>
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<para>
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To start using the security namespace in your application context, all you need to do is add
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the schema declaration to your application context file:
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-<programlisting>
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+ <programlisting>
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<![CDATA[
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<beans xmlns="http://www.springframework.org/schema/beans"
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xmlns:security="http://www.springframework.org/schema/security"
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@@ -50,10 +51,11 @@
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...
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</beans>
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]]></programlisting>
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- In many of the examples you will see (and in the sample) applications, we will often use "security" as the default
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- namespace rather than "beans", which means we can omit the prefix on all the security namespace elements,
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- making the context easier to read. You may also want to do this if you have your application context divided up
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- into separate files and have most of your security configuration in one of them. Your security application context file would then
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+ In many of the examples you will see (and in the sample) applications, we will often use
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+ "security" as the default namespace rather than "beans", which means we can omit the prefix on
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+ all the security namespace elements, making the context easier to read. You may also want to
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+ do this if you have your application context divided up into separate files and have most of
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+ your security configuration in one of them. Your security application context file would then
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start like this
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<programlisting><![CDATA[
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<beans:beans xmlns="http://www.springframework.org/schema/security"
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@@ -64,44 +66,71 @@
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We'll assume this syntax is being used from now on in this chapter.
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</para>
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<section>
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- <info>
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- <title>Design of the Namespace</title>
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- </info>
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+ <title>Design of the Namespace</title>
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<para>
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- The namespace is designed to capture the most common uses of the framework and provide a simplified and concise
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- syntax for enabling them within an application. The design is largely based around the large-scale dependencies
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- within the framework, and can be divided up into the following areas:
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+ The namespace is designed to capture the most common uses of the framework and provide a
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+ simplified and concise syntax for enabling them within an application. The design is largely
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+ based around the large-scale dependencies within the framework, and can be divided up into
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+ the following areas:
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<itemizedlist>
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- <listitem><para><emphasis>Web/HTTP Security</emphasis> - the most complex part. Sets up the filters and
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- related service beans used to apply the framework authentication mechanisms, to secure URLs, render login and error pages and much more.</para></listitem>
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- <listitem><para><emphasis>Business Object (Method) Security</emphasis> - options for securing the service layer.</para></listitem>
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- <listitem><para><emphasis>AuthenticationManager</emphasis> - handles authentication requests from other parts of the framework.</para></listitem>
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- <listitem><para><emphasis>AccessDecisionManager</emphasis> - provides access decisions for web and method security. A default one will be registered, but you can also
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- choose to use a custom one, declared using normal Spring bean syntax.</para></listitem>
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- <listitem><para><emphasis>AuthenticationProvider</emphasis>s - mechanisms against which the authentication manager authenticates users.
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- The namespace provides supports for several standard options and also a means of adding custom beans declared using a traditional syntax. </para></listitem>
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- <listitem><para><emphasis>UserDetailsService</emphasis> - closely related to authentication providers, but often also required by other beans.</para></listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>Web/HTTP Security</emphasis>
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+ - the most complex part. Sets up the filters and related service beans used to apply
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+ the framework authentication mechanisms, to secure URLs, render login and error pages
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+ and much more.</para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>Business Object (Method) Security</emphasis>
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+ - options for securing the service layer.</para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>AuthenticationManager</emphasis>
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+ - handles authentication requests from other parts of the framework.</para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>AccessDecisionManager</emphasis>
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+ - provides access decisions for web and method security. A default one will be
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+ registered, but you can also choose to use a custom one, declared using normal Spring
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+ bean syntax.</para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>AuthenticationProvider</emphasis>s - mechanisms against which the
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+ authentication manager authenticates users. The namespace provides supports for
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+ several standard options and also a means of adding custom beans declared using a
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+ traditional syntax.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>UserDetailsService</emphasis>
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+ - closely related to authentication providers, but often also required by other beans.</para>
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+ </listitem>
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<!-- todo: diagram and link to other sections which describe the interfaces -->
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- </itemizedlist>
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+ </itemizedlist>
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</para>
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<para>We'll see how these work together in the next section.</para>
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-
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</section>
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</section>
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<section>
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- <info><title>Example Configurations</title></info>
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+ <title>Example Configurations</title>
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<para>
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- In this section, we'll look at how you can build up a namespace configuration to use different features of the framework.
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- </para>
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-
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+ In this section, we'll look at how you can build up a namespace configuration to use different
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+ features of the framework. Let's assume you initially want to get up and running as quickly as possible
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+ and add authentication support and access control to an existing web application, with a few
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+ test logins.</para>
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<section>
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- <info><title>A Minimal Configuration</title></info>
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- <para>
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- Let's assume you want to get up and running as quickly as possible and add authentication support and access control to an existing
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- web application, with a few test logins. The first thing you need to do is add the follwing fiter declaration to your <literal>web.xml</literal>
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+ <info><title><literal>web.xml</literal> Configuration</title></info>
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+ <para>
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+ The first thing you need to do is add the following fiter declaration to your
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+ <literal>web.xml</literal>
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file:
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-<programlisting>
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-<![CDATA[
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+ <programlisting>
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+ <![CDATA[
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<filter>
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<filter-name>springSecurityFilterChain</filter-name>
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<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
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@@ -111,20 +140,32 @@
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<filter-name>springSecurityFilterChain</filter-name>
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<url-pattern>/*</url-pattern>
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</filter-mapping>]]>
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-</programlisting>
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- This provides a hook into the Spring Security web infrastructure. You can find more details of how this works in
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- <link xlink:href="#todo">TODO</link>. You're then ready to start editing your application context file.
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- Web security services are configured using the <literal><http></literal> element.
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- All you need to begin with is
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-<programlisting><![CDATA[
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+ </programlisting>
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+ This provides a hook into the Spring Security web infrastructure. You can find more details
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+ of how this works in
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+ <link xlink:href="#todo">TODO</link>. You're then ready to start editing your application
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+ context file. Web security services are configured using the <literal><http></literal>
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+ element.
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+ </para>
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+ </section>
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+
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+ <section>
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+ <info>
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+ <title>A Minimal <literal><http></literal>Configuration</title>
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+ </info>
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+ <para>
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+ All you need to enable web security to begin with is
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+ <programlisting><![CDATA[
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<http auto-config='true'>
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<intercept-url pattern="/**" access="ROLE_USER" />
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</http>
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]]>
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</programlisting>
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- Which says that we want all URLs within our application to be secured, requiring the role <literal>ROLE_USER</literal>
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- to access them. To add some users, you can define a set of test data directly in the namespace:
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- <programlisting><![CDATA[
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+ Which says that we want all URLs within our application to be secured, requiring the role
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+ <literal>ROLE_USER</literal>
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+ to access them. To add some users, you can define a set of test data directly in the
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+ namespace:
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+ <programlisting><![CDATA[
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<authentication-provider>
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<user-service>
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<user name="jimi" password="jimispassword" authorities="ROLE_USER, ROLE_ADMIN" />
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@@ -133,22 +174,133 @@
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</authentication-provider>
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]]>
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</programlisting>
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- This defines two users, their passwords and their roles within the application (which will be used for access control). The
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- <literal><authentication-provider></literal> element specifies that the user information will be registered with the authentication
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- manager and used to process authentication requests.
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- <sidebar><para>If you are familiar with previous versions of the framework, the <literal><authentication-provider></literal>
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- element creates a <literal>DaoAuthenticationProvider</literal> bean and the <literal><user-service></literal> element creates
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- an <classname>InMemoryDaoImpl</classname>. A <literal>ProviderManager</literal> bean is always created by the namespace processing system
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- and the <literal>AuthenticationProvider</literal> is automatically registered with it.</para></sidebar>
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- </para>
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- <para>
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- At this point you should be able to start up your application and you will be required to log in to proceed. Try it out, or try
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- experimenting with the "tutorial" sample applicaition that comes with the project.
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- This configuration actually adds quite a few services to the application automatically (mainly because we have added the <literal>auto-config</literal>
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- attribute. For example, form login processing and "remember-me" services are automatically enabled. You might also be wondering where the
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- login form came from when you were prompted to log in. This was also generated automatically, since we didn't explicitly configure a login page URL, but the namespace offers plenty
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- of options to allow you to custmize this kind of thing.
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- </para>
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+ This defines two users, their passwords and their roles within the application (which will
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+ be used for access control). The
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+ <literal><authentication-provider></literal>
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+ element specifies that the user information will be registered with the authentication
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+ manager and used to process authentication requests.
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+ <sidebar>
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+ <para>If you are familiar with previous versions of the framework, you can probably
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+ already guess roughly what's going on here. The <http> element is
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+ responsible for creating a <classname>FilterChainProxy</classname> and the required
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+ list filter beans which it uses. Common issues like filter incorrect ordering are no
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+ longer an issue as the filter positions are predefined.</para>
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+ <para>The <literal><authentication-provider></literal>
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+ element creates a <classname>DaoAuthenticationProvider</classname>
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+ bean and the <literal><user-service></literal> element creates an
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+ <classname>InMemoryDaoImpl</classname>. A <literal>ProviderManager</literal>
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+ bean is always created by the namespace processing system and the
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+ <classname>AuthenticationProvider</classname>
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+ is automatically registered with it.</para>
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+ </sidebar>
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+ </para>
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+ <para>
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+ At this point you should be able to start up your application and you will be required to
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+ log in to proceed. Try it out, or try experimenting with the "tutorial" sample applicaition
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+ that comes with the project. The above configuration actually adds quite a few services to
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+ the application because we have used the
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+ <literal>auto-config</literal>
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+ attribute. For example, form login processing and "remember-me" services are automatically
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+ enabled. You might also be wondering where the login form came from when you were prompted
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+ to log in. This was also generated automatically, since we didn't explicitly set a URL for the
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+ login page, but the namespace offers plenty of options to allow you to customize this
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+ kind of thing.
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+ </para>
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+ <section>
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+ <title>What does <literal>auto-config</literal> Include?</title>
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+ <para>
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+ The <literal>auto-config</literal> attribute, as we have used it above, is just a
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+ shorthand syntax for:
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+ <programlisting><![CDATA[
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+ <http>
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+ <intercept-url pattern="/**" access="ROLE_USER" />
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+ <form-login />
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+ <anonymous />
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+ <http-basic />
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+ <logout />
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+ <remember-me />
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+ </http>
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+ ]]>
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+ </programlisting>
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+ These other elements are responsible for setting up form-login, see
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+ <link xlink:href="#anonymous">anonymous authentication</link>, basic authentication, logout handling and remember-me services
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+ respectively. They each have attributes which can be used to alter their behaviour. For example, if you
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+ want to supply your own login page, you could use:
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+ <programlisting><![CDATA[
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+ <http auto-config='true'>
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+ <intercept-url pattern="/**" access="ROLE_USER" />
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+ <form-login login-page='/login.jsp'/>
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+ </http>
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+ ]]>
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+ </programlisting>
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+ Note that you can still use <literal>auto-config</literal>. The <literal>form-login</literal> element just overrides the
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+ default settings. If you want to use basic authentication instead of form login, then change the configuration to
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+ <programlisting><![CDATA[
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+ <http auto-config='true'>
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+ <intercept-url pattern="/**" access="ROLE_USER" />
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+ <http-basic />
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+ </http>
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+ ]]>
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+ </programlisting>
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+ Basic authentication will then take precedence and will be used to prompt for a login when a user attempts to access
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+ a protected resource. Note that form login is still available in this configuration if you wish to use it, for example
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+ through a login form embedded in another web page.
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+ </para>
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+ </section>
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+ <section>
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+ <title>Configuring other Authentication Providers</title>
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+ <para>
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+ In practice you will need a more scalable source of user information than a few names added to the context file.
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+ Most likely you will want to store your user information in something like a database or an LDAP server. If you have a
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+ custom implementation of Spring Security's <classname>UserDetailsService</classname>, called "myUserDetailsService" in your
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+ application context, then you can authenticate against this using
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+ <programlisting><![CDATA[
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+ <authentication-provider user-service-ref='myUserDetailsService'/>
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+ ]]>
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+ </programlisting>
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+ If you want to use a database, then you can use
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+ <programlisting><![CDATA[
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+ <authentication-provider>
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+ <jdbc-user-service data-source-ref="securityDataSource"/>
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+ </authentication-provider>
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+ ]]>
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+ </programlisting>
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+ Where "securityDataSource" is the name of a <classname>DataSource</classname> bean in the application context,
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+ pointing at a database containing the standard Spring Security user data tables. Alternatively, you could configure
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+ a Spring Security <classname>JdbcDaoImpl</classname> bean and point at that using the <literal>user-service-ref</literal>
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+ attribute.
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+ </para>
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+ <section><title>Adding a Password Encoder</title>
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+ <para>
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+ Often your password data will be encoded using a hashing algorithm. This is supported by the <literal>>password-encoder<</literal>
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+ element. With SHA-encoded passwords, the original authentication provider configuration would look like this:
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+ <programlisting><![CDATA[
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+ <authentication-provider>
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+ <password-encoder hash="sha"/>
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+ <user-service>
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+ <user name="jimi" password="d7e6351eaa13189a5a3641bab846c8e8c69ba39f" authorities="ROLE_USER, ROLE_ADMIN" />
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+ <user name="bob" password="4e7421b1b8765d8f9406d87e7cc6aa784c4ab97f" authorities="ROLE_USER" />
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+ </user-service>
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+ </authentication-provider>
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+ ]]>
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+ </programlisting>
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+ </para>
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+ <para>
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+ When using hashed passwords, it's also a good idea to use a salt value to protect against dictionary attacks and Spring Security supports this too.
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+ Ideally you would want to use a randomly generated salt value for each user, but you can use any property of the <classname>UserDetails</classname>
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+ object which is loaded by your <classname>UserDetailsService</classname>. For example, to use the <literal>username</literal> property, you would use
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+ <programlisting><![CDATA[
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+ <password-encoder hash="sha">
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+ <salt-source user-property="username"/>
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+ </password-encoder>
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+ ]]></programlisting>
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+ You can use a custom password ecoder bean by using the <literal>ref</literal> attribute of <literal>password-encoder</literal>. This should
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+ contain the name of a bean in the application context which is an instance of Spring Security's <interfacename>PasswordEncoder</interfacename>
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+ interface.
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+ </para>
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+ </section>
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+ </section>
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</section>
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+
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</section>
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</chapter>
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Luke Taylor