package main
/*
// list of events
curl localhost:8080/events
// current state
curl localhost:8080/state
// increment counter
curl -d '{"name": "increment", "data": {"n": 1}}' localhost:8080/event
// decrement counter
curl -d '{"name": "decrement", "data": {"n": 1}}' localhost:8080/event
// set counter
curl -d '{"name": "set", "data": {"n": 1}}' localhost:8080/event
// collapse state into single event
curl -X POST localhost:8080/collapse
*/
import (
"encoding/json"
"io/ioutil"
"log"
"net/http"
"strconv"
"github.com/gorilla/pat"
)
var state struct {
Counter int `json:"counter"`
}
type event struct {
Name string `json:"name"`
Data map[string]interface{} `json:"data"`
}
var events = make([]event, 0)
func main() {
p := pat.New()
p.Get("/events", eventsHandler)
p.Post("/event", eventHandler)
p.Get("/state", stateHandler)
// p.Post("/collapse", collapseHandler)
p.Get("/", home)
log.Fatal(http.ListenAndServe(":8080", p))
}
func home(w http.ResponseWriter, req *http.Request) {
w.Write([]byte(htmlPage))
}
// func collapseHandler(w http.ResponseWriter, req *http.Request) {
// events = []event{
// event{"set", map[string]interface{}{"n": state.Counter}},
// }
// }
func stateHandler(w http.ResponseWriter, req *http.Request) {
b, _ := json.Marshal(state)
w.Write(b)
}
func eventsHandler(w http.ResponseWriter, req *http.Request) {
var since int
s := req.URL.Query().Get("since")
if len(s) > 0 {
since, _ = strconv.Atoi(s)
}
b, _ := json.Marshal(events[since:])
w.Write(b)
}
func eventHandler(w http.ResponseWriter, req *http.Request) {
b, _ := ioutil.ReadAll(req.Body)
req.Body.Close()
var e event
json.Unmarshal(b, &e)
events = append(events, e)
switch e.Name {
case "set":
n := e.Data["n"].(float64)
state.Counter = int(n)
case "increment":
n := e.Data["n"].(float64)
state.Counter += int(n)
case "decrement":
n := e.Data["n"].(float64)
state.Counter -= int(n)
default:
w.WriteHeader(400)
}
}
var htmlPage = `
Title of the document
Count: 0
`