package pointer
import (
"fmt"
"html/template"
"math/rand"
"net/http"
"strings"
"appengine"
"appengine/channel"
"appengine/memcache"
)
const key = "ids"
func init() {
http.HandleFunc("/", main)
http.HandleFunc("/update", update)
http.HandleFunc("/leave", leave)
}
func main(w http.ResponseWriter, r *http.Request) {
c := appengine.NewContext(r)
ids := getIDs(c)
id := fmt.Sprintf("%d", rand.Int())
found := false
for _, mid := range ids {
if id == mid {
found = true
}
}
if !found {
ids = append(ids, id)
_ = memcache.Set(c, &memcache.Item{
Key: key,
Value: []byte(strings.Join(ids, ",")),
})
}
tok, _ := channel.Create(c, id)
tmpl.Execute(w, struct{ Token, ClientID string }{tok, id})
}
func update(w http.ResponseWriter, r *http.Request) {
c := appengine.NewContext(r)
ids := getIDs(c)
x := r.FormValue("x")
y := r.FormValue("y")
from := r.FormValue("id")
msg := fmt.Sprintf("{\"x\":%s,\"y\":%s,\"id\":\"%s\"}", x, y, from)
for _, id := range ids {
if id != from {
_ = channel.Send(c, id, msg)
}
}
}
func leave(w http.ResponseWriter, r *http.Request) {
c := appengine.NewContext(r)
ids := getIDs(c)
i := -1
id := r.FormValue("id")
for ni, mid := range ids {
if id == mid {
i = ni
break
}
}
if i != -1 {
ids = append(ids[:i], ids[i+1:]...)
_ = memcache.Set(c, &memcache.Item{
Key: key,
Value: []byte(strings.Join(ids, ",")),
})
}
msg := fmt.Sprintf("{\"x\":-1,\"y\":-1,\"id\":\"%s\"}", id)
for _, id := range ids {
_ = channel.Send(c, id, msg)
}
}
func getIDs(c appengine.Context) []string {
var ids []string
if i, err := memcache.Get(c, key); err == nil {
ids = strings.Split(string(i.Value), ",")
}
return ids
}
var tmpl = template.Must(template.New("n").Parse(`
Pointer Party!
Welcome to Pointer Party!
Directions: Move your mouse pointer. See the mouse pointers of other users on this page.
Built using App Engine Channel API (src)
`))