Clojure Train Radiator

A small example project in Clojure. Fetches train information from rata.digitraffic.fi API and displays it.

Getting started

1. Install the Clojure build tool Leiningen.
2. Run lein ring server to start the server and a browser
3. Change the code (file src/handler.clj)
4. Refresh the browser and see your changes

Project structure

• project.clj: the configuration file for Leiningen
• src/handler.clj: the code is here
• resources/public/style.css: the CSS style file
• test/handler_test.clj: unit tests (run these with lein test)

Useful documentation

• ClojureDocs – the Clojure standard library documentation, searchable
• Compojure wiki – the web framework used in this project
• Hiccup wiki - how to generate HTML
• clj-time - how to handle time
• docs for the digitraffic api

Tasks

• make the page prettier
• make the station configurable
• show only time table rows for this station
• only show future events
• collect statistics of late trains

Interactive development

Interactive development means having a REPL (command prompt) where you can interact with the code and try out things, while also running the server.

Here's how:

1. Start an interactive clojure environment, for example:
   • run lein repl in a terminal
   • use M-x cider-jack-in in Emacs (after installing cider)
   • install a Clojure IDE like Cursive for IntelliJ
2. Run (run) to start a server
3. Try out things and edit code
4. Reload code changes with either
   • the reload functionality in your IDE
   • running (refresh) in the repl

Experimental: integrated editor

In case you don't feel like installing a Clojure IDE or editor, you can try out the browser-based editor, Nightlight:

1. Run lein nightlight
2. Point your broser to http://localhost:4000
3. Open the file src/handler.clj
4. You can run the server like this:
   1. Switch to Clojure REPL (on the top left)
   2. Type in (handler/run)
   3. Open another browser tab to http://localhost:3000

Where to go from here?

TODO