Re-formatting variable names

(Series: From PHP to Clojure)

Here's a simple problem: as part of my Salty lib, I want a function that will take camel-case variable names, as used by Java, and convert them to the dash format that's idiomatic in Clojure. In other words, I want a function that will take the string "someVariableName" (camel case)and return "some-variable-name" (with dashes).

Salty: a Clojure wrapper for the Selenium Java WebDriver

After my last post, I thought it might be fun to make a full-blown clojure library for working with Selenium WebDriver. I want to do a lot of Compojure/Noir development, and I can see where it might be handy to automate logging in and clicking things with Firefox and IE.

Just to get started, I've set up a repository on github, and have written one quick and dirty test function.



It's not really useful, it's just a quick spot-check you can run at the REPL to make sure everything's set up right. Make sure salty is in your classpath, and then, at the REPL, type (salty.impl/test-with-google). You should see Firefox start up, open up the main Google page, search for "clojure", and then quit. The output in your REPL should be:

Original page title is  Google
Page title after searching is  clojure - Google Search
nil

More to come...

Clojure and the Firefox Zombie

Since it's Halloween, I thought it might be fun to use Clojure to turn Firefox into a mindless zombie, slavishly obeying my every command. Muahahaha.

A simple API

I've been watching Rich Hickey's talk on simplicity, and trying to take it to heart. He's right: easy is easy, and simple is hard. It takes a lot of work, and careful use of the right tools, to end up with "simple."

So here's one tool (dare I say pattern?) that might be useful in building a simple API. I'm building on some posts and IRC conversations that I've run across, so most of this is not original with me, but I'm writing it down here for future reference.

In the spirit of classic "design pattern" methodology, here is the scenario we're trying to address. We need to write some functions that refer to some kind of state. The specific example I'm using is connecting to an IMAP server: I want to establish a connection, grab some message headers, selectively grab the message contents, and so on. Obviously, I don't want to negotiate a separate connection for each and ever IMAP operation I write code for. I want to connect once, and then share that connection with each of the functions that needs to use it.

Keeping up with starting out

There seems to be an impedance mismatch between the frequency with which I make posts about the easiest way to get started with Clojure, and the release of even easier ways to get started, so I'm going to just bag that thread. I'll just summarize my advice in a few simple bullet points:

• If you have to choose between adding clojure to an existing environment that's already heavily customized, and creating a fresh/clean environment via VirtualBox or some other equivalent, I recommend the fresh/clean environment. If you have a reasonably decent processor, it should be responsive enough to be useful, and the advice you find on the web will be a lot easier to apply if your OS is clean.
• If you don't know emacs, it's worth learning just to get to use paredit.
• If you like GUI IDE's, Eclipse + CounterClockwise works well.

Feel free to add any other tips in the comments.

Spring Security on Compojure

I've moved away from using Spring Security for my Compojure/Noir-based web app, but I did eventually get an answer to my question on Stack Overflow, so if anyone's interested, they can look up the example in the answer.

http://stackoverflow.com/questions/6901210/compojure-noir-using-spring-security-for-auth-auth

Using Spring Security with Clojure/Compojure/Noir: Preliminaries

I don't know how to use Spring Security with Clojure web apps, but I'd like to learn how. I've got some clues, and I'm going to try and track them down and see how far I can get.

The first obstacle to overcome is that there doesn't seem to be anything in clojars I can just grab. Fortunately leiningen prints out some detailed error messages, which I can use to manually install the jar files I need. First I'll grab the jar files from http://www.springsource.com/download/community. Just the 3.0.5 release is all I need. I unzip the file, which gives me a directory with a number of different jar files in it.

Next, I cheat by editing my project.clj file to ask for a jar that doesn't exist. The lein deps command chugs along for a while, and then spews out a huge error dump, but with a little digging I can find this message somewhere in the middle:

Unable to resolve artifact: Missing:
----------
1) org.springframework.security:spring-security-parent:jar:3.0.5.RELEASE

  Try downloading the file manually from the project website.

  Then, install it using the command: 
      mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-parent -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=/path/to/file

There's the magical incantation I need. I'll just cheat again by editing the suggested maven command so that it installs each of the jar files that I downloaded from springsource. I don't know yet which specific jar files I'll need, so I'll install them all.

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-acl -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-acl-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-aspects -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-aspects-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-cas-client -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-cas-client-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-config -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-config-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-core -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-core-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-ldap -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-ldap-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-openid -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-openid-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-taglibs -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-taglibs-3.0.5.RELEASE.jar

mvn install:install-file -DgroupId=org.springframework.security -DartifactId=spring-security-web -Dversion=3.0.5.RELEASE -Dpackaging=jar -Dfile=./spring-security-web-3.0.5.RELEASE.jar

If I cd into the directory where I extracted the Spring Security jars, I can just cut and paste this code, and have each of the spring-security-* jars installed in my local .m2 directory, where leiningen can find them.

Now I go back and edit project.clj, and add the core spring-security jar to my dependencies:

(defproject mm2 "0.1.0-SNAPSHOT"
            :description "FIXME: write this!"
            :dependencies [[org.clojure/clojure "1.2.1"]
                           [noir "1.1.0"]
                           ;; ADD SPRING SECURITY HERE:
                           [org.springframework.security/spring-security-core
                            "3.0.5.RELEASE"]]
            :main mm2.server)

Run lein deps and ... yup, the jar file is in lib/. It worked! Now I just need to figure out what other jar files I need (if any) and how to hook them into my clojure project. But that's a project for later.