go-web.go

package main

import (
    "fmt"
    "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
    fmt.Printf(w, "Hello World!")
}

func main() {
    http.HandleFunc("/", handler)
    http.ListenAndServe(":8080", nil)
}

python-redis-counter.py

from redis import Redis

def application(env, start_response):
  redis = Redis(host='redis', port=6379)
  redis.incr('hits') # increment
  start_response('200 OK', [('Content-Type','text/html')])
  return ['Hello World! I have been seen %s times.' % redis.get('hits')]

if __name__ == "__main__":
  from wsgiref.simple_server import make_server
  httpd = make_server('', 8080, application)
  httpd.serve_forever()

python-web.py

def application(env, start_response):
    start_response('200 OK', [('Content-Type','text/html')])
    return ["Hello World!"]

if __name__ == "__main__":
    from wsgiref.simple_server import make_server
    httpd = make_server('', 8080, application)
    httpd.serve_forever()

ruby-web.rb

run Proc.new { |env|
  [ 200,
    {'Content-Type' => 'text/html'},
    [ "Hello world!" ]
  ]
}