ian-kent/main.go

## main.go
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 = `
<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
    <script>
      var state = {
        position: 0,
        count: 0
      };
      $(document).ready(function() {
        $("#increment").click(function() {
          $.post("/event", JSON.stringify({
            "name": "increment",
            "data": {
              "n": 1
            }
          }));
        });
        $("#decrement").click(function() {
          $.post("/event", JSON.stringify({
            "name": "decrement",
            "data": {
              "n": 1
            }
          }));
        });
        setInterval(function() {
          $.get("/events?since="+state.position, function(data) {
            data = JSON.parse(data);
            state.position += data.length;
            $.each(data, function(i, v) {
              console.log(v);
              switch(v.name) {
                case "increment":
                  state.count += v.data.n;
                  break;
                case "decrement":
                  state.count -= v.data.n;
                  break;
                case "set":
                  state.count = v.data.n;
                  break;
              }
            });
            $('#count').text(state.count);
          });
        }, 1000);
      });
    </script>
  </head>
  <body>
    <p>
      <strong>Count:</strong> <span id="count">0</span>
    </p>
    <div>
      <button id="increment">Increment</button>
      <button id="decrement">Decrement</button>
    </div>
  </body>
</html>
`
	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 = `
	<!DOCTYPE html>
	<html>
	<head>
	<title>Title of the document</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
	<script>
	var state = {
	position: 0,
	count: 0
	};
	$(document).ready(function() {
	$("#increment").click(function() {
	$.post("/event", JSON.stringify({
	"name": "increment",
	"data": {
	"n": 1
	}
	}));
	});
	$("#decrement").click(function() {
	$.post("/event", JSON.stringify({
	"name": "decrement",
	"data": {
	"n": 1
	}
	}));
	});
	setInterval(function() {
	$.get("/events?since="+state.position, function(data) {
	data = JSON.parse(data);
	state.position += data.length;
	$.each(data, function(i, v) {
	console.log(v);
	switch(v.name) {
	case "increment":
	state.count += v.data.n;
	break;
	case "decrement":
	state.count -= v.data.n;
	break;
	case "set":
	state.count = v.data.n;
	break;
	}
	});
	$('#count').text(state.count);
	});
	}, 1000);
	});
	</script>
	</head>
	<body>
	<p>
	<strong>Count:</strong> <span id="count">0</span>
	</p>
	<div>
	<button id="increment">Increment</button>
	<button id="decrement">Decrement</button>
	</div>
	</body>
	</html>
	`