Common Lisp and CFFI on OS X can't find your MacPorts libraries?

Consider adding the following to ~/.sbclrc

	#+(and asdf darwin)
	(defmethod asdf:perform :after ((o asdf:load-op) (c (eql (asdf:find-system "cffi"))))
	(let ((library-directories (intern "*FOREIGN-LIBRARY-DIRECTORIES*" (find-package "CFFI"))))
	(set library-directories
	(cons #p"/opt/local/lib/" (symbol-value library-directories)))))

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Cello Finger Board Diagram

I created a cello finger board diagram to learn where each pitch is spatially without having to rely too much on finger numbers or position names. I have a print out of this template for each scale or arpeggio I'm learning and generally annotate it in pencil with the possible fingerings and extensions.

Cello Finger Positions

Using Spring Security with Ring, Jetty, and Compojure

All the source code for this can be found at https://github.com/lispnik/ring-spring-security

Spring Security (formerly Acegi Security) is a great framework for adding authentication and authorization to your Java web app. I wanted to take advantage of it in my Compojure apps. Here's an example of how to do it:

	(defn- boot-spring
	"Initialize a Jetty server for Spring and also Spring Security"
	([server handler context-config-location]
	(let [filter (doto (org.mortbay.jetty.servlet.FilterHolder. org.springframework.web.filter.DelegatingFilterProxy)
	(.setName "springSecurityFilterChain"))
	servlet (doto (org.mortbay.jetty.servlet.ServletHolder. (ring.util.servlet/servlet handler))
	(.setName "default"))
	context (doto (org.mortbay.jetty.servlet.Context. server "/"
	(bit-or org.mortbay.jetty.servlet.Context/SESSIONS
	org.mortbay.jetty.servlet.Context/SECURITY))
	(.addFilter filter "/*" 0)
	(.addServlet servlet "/")
	(.addEventListener (org.springframework.web.context.ContextLoaderListener.)))]
	(when context-config-location
	(.setInitParams context {"contextConfigLocation" context-config-location}))
	(.addHandler server context)))
	([server handler]
	(boot-spring server handler nil)))

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The next step is to wrap this in a ring/ring-adapter-jetty configurator (i.e., a function that takes a server):

	(defn boot []
	(jetty/run-jetty #'app
	{:port 9090
	:join? false
	:configurator (fn [server] (boot-spring server #'app "classpath:security.xml"))
	:default-handler? false}))

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To illustrate the integration, here is an example Spring Security configuration which establishes two users and two roles (user and administration) and applies it to URL patterns. If the user issues a HTTP request with a URL pattern that requires authorization and they are not already authenticated, then Spring Security as configured below will actually render a plain-looking login form before proceeding. We get this basic functionality for free with Spring Security although it can be replaced with a custom form of our own design.

	<?xml version="1.0" encoding="UTF-8"?>
	<beans:beans xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns="http://www.springframework.org/schema/security"
	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.xsd
	http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security.xsd">
	<authentication-manager>
	<authentication-provider>
	<user-service>
	<user name="user" password="1234" authorities="ROLE_USER"/>
	<user name="admin" password="1234" authorities="ROLE_ADMIN,ROLE_USER"/>
	</user-service>
	</authentication-provider>
	</authentication-manager>
	<http auto-config="true">
	<intercept-url pattern="/user**" access="ROLE_USER"/>
	<intercept-url pattern="/admin**" access="ROLE_ADMIN"/>
	<intercept-url pattern="/**" access="IS_AUTHENTICATED_ANONYMOUSLY"/>
	</http>
	</beans:beans>

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The Compojure application this secures looks like this:

	(defroutes main-routes
	(GET "/" req (index-html req))
	(GET "/admin" req (example-html req))
	(GET "/user" req (example-html req))
	(GET "/other" req (example-html req))
	(route/resources "/")
	(route/not-found "Page not found"))

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Here the HTML rendering prints out the Spring context and security context which contain lots of goodies we can use later: