Frameworkless Web Development in Clojure

gistfile1.txt

Talk Title: Frameworkless Web Programming in Clojure

Content of the Talk:

1. Why Web Frameworks?
   - Everything from one source (parts fit together)
   - Good tooling support (see Django)
   - Easy to set up
   - Easy to use

2. Why Not?
   - Most of the time not simple
   - If you have to deviate from the framework it gets messy
   - Frameworks are quite rigid most of the time
   - Choosing your own tools and therefore building a
     "framework" creates flexibility
   - (Microframeworks try to solve this problem)

3. Analyzing the contents of the typical web framework
   - HTTP Abstraction
   - HTTP Middlewares
   - Routing
   - Templating
   - Authentication
   - Database abstraction
   - Communication with the frontend

4. Clojure provides libraries for all these needs

   - Starting with a small compojure app directly from the
     the leiningen template I will analyze its parts.

4.1 HTTP Abstraction - Ring

   - How Ring works
     - Request -> Map -> Input Middlewares -> Program -> Output Middlewares -> Response
   - What is a Ring middleware
     - Input Middleware  (fn [handler] (fn [req] do something (handler req)))
     - Output Middleware  (fn [handler] (fn [req] (let [res (handler req)) do something))

4.2 Routing - Clout and Compojure
   - Routing patterns
   - Show clout examples
   - Show compojure examples

4.3 Templating - Hiccup, Enlive, mention some others

   - Hiccup is simple
     - Convert nested Clojure lists into HTML
     - DSL? for HTML
     - You can interact with your HTML in a clojury way

   - Enlive
     - Still write HTML (no DSL)
     - Selector based syntax to interact with HTML snippets
     - Transformations


4.4 Authentication - Friend

   - How to use friend
   - What is a workflow

4.5 Database Abstraction - clojure/java.jdbc, Korma


  - clojure/java.jdbc
    - Simple DSL for SQL
    - A bit like hiccup for SQL
  - Korma
    - Another more fleshed out SQL DSL

4.6 Communication with the Frontend - ClojureScript and EDN

  - You can use the same data structures on the client
    as on the server.

  - Show a funny toy example where a function is created in
    ClojureScript, sent to the server, executed and the result
    sent back to the client.

5. Summary

    - The frameworkless approach works good
    - No interaction problems between the libraries because
      no objects are involved
    - It is easy to swap out the libraries
    - A very flexible approach