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Developing and Deploying a Simple Clojure Web Application
- blueberry 16y agoIf this is an easy way to create a web app that adds two numbers on Clojure, I'd say Clojure is not ready for web development yet.
- kljensen 16y agoThat is a TON if code for such a simple fiction.
- shoover 16y agoThat is a ton of code if the goal is writing a web page that does addition. Maybe that wasn't the goal.
- swannodette 16y agoHuh. 45 LOC for templating, routing, and form processing and you don't need to configure a different webserver since jetty is production quality. Do you have links to something that takes less effort than what is being illustrated here that can be deployed immediately into production and perform well?
- cmurphycode 16y agoAgreed. This strikes me as a more robust walk-through than traditional Hello World-esque tutorials; as such, there is a little more to do than you'd expect. I'd rather have the details provided here, and I suspect many other hackers would too.
- blueberry 16y agoAre you serious? 45 LOC is not a good metric btw, why are you omitting all that boilerplate configuration. Any reasonable tutorial on PHP/python/RoR would build something more sophisticated more concisely. Here is a python tutorial: http://www.turbogears.org/2.0/docs/main/ToscaWidgets/forms.html#a-very-basic-form http://www.turbogears.org/2.0/docs/main/ToscaWidgets/forms.h...
- twism 16y agoNot to mention: middlewares, logging, stack traces, exception handling, testing, production/dev environments, e.t.c. in a similarly succinct manner.
- vegashacker 16y agoIt's interesting. I read your comment through the "backtype version" below the article, and, because it was out of context, I interpreted your meaning to be exactly the opposite of what I see it is now.
- Jach 16y agohttp://pastebin.com/PsecNBvB http://pastebin.com/PsecNBvB (To be honest, I think clojure has its purposes, but a one-off calculator page isn't one of them. Use the right tool for the right job and all that.)
- ataggart 16y agoWhat point are you trying to make? That one can write less code if one does less stuff?
- Jach 16y agoThe parent asked for a link to something that takes less effort, I obliged. I don't think the amount of code is a particularly useful metric in most cases, but I would argue that the PHP+HTML solution is much clearer and easier to deploy, and taking into account everything you wish about such a simple web page (readability, maintainability, cross-server, security, etc.), takes less effort in the end. (I don't have any big issues with jetty or tomcat, since I use one or the other almost daily.) I'm sure there are larger use cases where clojure is simpler than raw PHP, but that's why PHP has frameworks.
- axod 16y agowhy are some people so lazy and short sighted. "time to make trivial webapp" is NOT a good reason to choose anything.
- ikitat 16y agoActually, it's an easy way to: - add two numbers - build the project with dependencies - display stack traces - deliver static files - generate html from code - validate user input - host with a web server - reload the web server during development - handle url routing - log requests - create custom middleware - deploy to EC2 You may have glossed over some of the details.
- blueberry 16y agoNo, I didn't gloss over the details with the possible exception of deployment to EC2. Most of the stuff you listed are a prerequisite to web development. For most other languages/frameworks database connection would be included too.
- frognibble 16y agoPerhaps you meant to say that the framework used in this example is not ready. I didn't see anything about Clojure the language that makes the example complicated. As far as the framework is concerned, the example shows how to build a production deployment of the application. The author is not showing a toy teaser application. There are a lot of details there, but these are things that you would want to know if you actually want to run a production server.
- blueberry 16y agoI agree with this, and yes I used the word 'clojure' to mean any frameworks/web servers/middleware that can be used to code in clojure. Just like when people say "php is good for web programming" most of them actually mean php, apache, mysql and their favorite framework.
- bretthoerner 16y agoYou can thank people like Mark McGranaghan for taking languages that "aren't ready for X" yet and making them so.
- KirinDave 16y agoThere are a contingent of Lisp users who really, really, really like this fgen style, for EVERYTHING. I—as someone who's worked in the industry on lots of startup-level projects—think it's only useful for small, regular snippets. There is also this false-metric effect in play; there are only 45ish lines in one file here, so it must be elegant and great amirite? But a real webapp would have lots of templates and lots of files. Where Clojure really shines in web development is when you mix it with cgrand's Enlive templating engine (http://github.com/cgrand/enlive http://github.com/cgrand/enlive), which is an amazing project with lots of active development. This approach is so cool that even a lot of the Rails and Python startup folks are starting to copy it.
- swannodette 16y agoI think the point of the article is to cover the absolute basics using Ring, not advocate any particular style of development. I mean the title of the blog post does say it all. Having written a lengthy Enlive tutorial, http://github.com/swannodette/enlive-tutorial http://github.com/swannodette/enlive-tutorial, I of course swear by it and scoff at inline html generation :D So I prefer coupling Ring+Enlive+Moustache (and tasty Aleph) myself but that would be an awful lot to cover in a single blog post now wouldn't it ;) All in good time.
- KirinDave 16y agoI suspect we could do it easily. Talk to me on twitter (my name here is my name on twitter) and let's see if we can hammer out an elegant way to describe that coupling. I need the writing practice anyways.
- pjscott 16y agoYour Enlive tutorial is excellent. Thank you.
- mmcgrana 16y agoI'd love to see a fork of adder that used Ring+Enlive+Moustache.
- seanwoods 16y agoThis is a great tutorial. Over the past few months I've been struggling with getting a "barebones" app up and running with Clojure. Leiningen has really come into its own in 2010 and tutorials like this will be great for people who need a basic template in order to bootstrap them into the whole experience.
- pietrofmaggi 16y agoAnother nice example can be found in the last "Functional Web" column on IEEE Internet Computing by Steve Vinosky: http://steve.vinoski.net/pdf/IC-Getting_Started_with_Google_App_Engine_and_Clojure.pdf http://steve.vinoski.net/pdf/IC-Getting_Started_with_Google_... In the July/August 2010 column, Getting Started with Google App Engine and Clojure, guest columnist Aaron Bedra shows how to use Clojure, a relatively new but robust Lisp implementation on the Java Virtual Machine, create and deploy an application using the Compojure web framework on the Google App Engine platform.
- TY 16y agoGreat article, thanks for the link. Couple more helpful links for some basics not covered in the article (all work in progress): Compojure docs: http://www.compojure.org http://www.compojure.org Stub for "Clojure Web Development" book: https://docs.google.com/Doc?docid=0AQqGP1CDN0uIZGhmZjJmcGZfMjNjNHIycGZu&hl=en https://docs.google.com/Doc?docid=0AQqGP1CDN0uIZGhmZjJmcGZfM...
- deweller 16y agoThis is great information. I'd love to see a similar tutorial for NodeJS for comparison.
- mahmud 16y agoIn Common Lisp (without cheating or handwaving; this is it): (defpackage :add-nums (:use :cl :hunchentoot :cl-who)) (in-package :add-nums) (defmacro with-html (&body body) `(with-html-output-to-string (*standard-output* nil :prologue t :indent t) ,@body)) (define-easy-handler (add-nums :uri "/add-nums") ((a :parameter-type 'integer) (b :parameter-type 'integer)) (with-html (:html (:head (:title "Add two numbers")) (:body (if (and a b) (htm (:p (str (+ a b))))) (:form :method :get (:input :type :text :name "a") (:input :type :text :name "b") (:input :type :submit)))))) (defparameter *site* (make-instance 'acceptor :port 8080)) (start *site*)
- swannodette 16y agoEr, Clojure has CL style macros so you can easily get to this level of brevity if that is desired.
- mahmud 16y agoThe one custom macro I wrote is already in there. The rest is just the web server and cl-who. I have been screaming for ages telling Clojurists to rip CL APIs and implement them in clojure. They're more tasteful and cultured than that entrerprisey crap that java is smearing all over this nice Lisp dialect. The majority of open source clojure code that I have seen looks like Java FFI stubs; you need to tuck those loose ends in and tidy them up with macros. But this probably wont happen until Clojure is ported to another runtime/platform; portability is a surefire way to distill the essence of a language from its implementation detail.
- ikbear 16y agoClojure is cool.