gyag

1. Tibetan for yak (or so I am told).
2. An opinionated Leiningen template for developing web applications using Clojure and ClojureScript.

Features

• Reliable and fast code reloads for Clojure code during development
• Based on the Clojure de facto standard Ring
• Hiccup server-side rendered HTML pages
• Easy REST Api using Liberator
• Fast, debuggable, ClojureScript builds with source maps
• In-browser ClojureScript REPL via Austin

Usage

Prerequisite

Install Leiningen.

Initializing the template

Initialize your new Leiningen project: lein new gyag $your-project

ClojureScript compilation (browser-side)

Contains two ClojureScript build profiles:

• dev : Source maps and no optimizations, multiple js-files
• production : Advanced optimization to a single js-file

Build command examples:

• Continuous builds of dev profile (occupies one terminal) and will rebuild the js-files from all changes in src-cljs: lein cljsbuild auto dev
• Building production profile once: lein cljsbuild once production

Clojure compilation / dev cycle (server-side)

The project uses the excellent component and tools.nrepl libraries to enable fast and reliable code reloads. See component on github and REPL-driven development workflow.

Example:

1. Start a nRepl for your project:

• M-x cider-jack-in or M-x nrepl-jack-in in Emacs
• lein repl from the command-line

2. In the REPL start the server-side by issuing (go) which should produce something similar to this:

user> (go)
2014-feb-05 21:52:00 +0100 Aero.local INFO [myone.app] - Starting Myone App
2014-feb-05 21:52:00 +0100 Aero.local INFO [myone.web-server] - Starting Web Server
2014-feb-05 21:52:00 +0100 Aero.local INFO [myone.web-server] - Web Server running on port: 8080
2014-feb-05 21:52:00 +0100 Aero.local INFO [myone.repl] - Starting Hosted REPL
2014-feb-05 21:52:00 +0100 Aero.local INFO [myone.repl] - REPL running on port 12345
:ok

3. The server-side is split into multiple components, which is what is logged out in the above:

• The app: Ring handler and route compositions
• The web-server: a Jetty-instance serving the app on HTTP
• The in-app hosted REPL: live code changes everywhere, whats not to like? (caveat emptor)

4. You can now open http://localhost:8080 to connect to your running application.
5. During development, to reload code changes, perform the following in the REPL which launched to app: (user/reset). This performs the following steps:
6. Stops the currently running components, releasing acquired resources (bound ports etc)
7. Uses tools.nrepl to reload code under src/
8. Restarts the components
9. NOTE: In the case of problems reloading code, eg. compilation errors, first resolve these and then perform (clojure.tools.namespace.repl/refresh) followed by (user/reset)

License

Copyright © 2014 Thomas Christensen

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.