/
server.go
132 lines (117 loc) · 2.56 KB
/
server.go
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package api
import (
"bytes"
"io"
"log"
"net/http"
"github.com/badgerodon/s"
"code.google.com/p/go.net/websocket"
)
type (
HandlerFunc func(Listener,s.Expression) interface{}
Handler func(Listener,s.List)
result struct {
id uint64
value interface{}
}
)
func (this result) EncodeS() (exp s.Expression, err error) {
var v1, v2, v3 s.Expression
v1 = s.Identifier("result")
v2, err = s.Encode(this.id)
if err != nil {
return
}
v3, err = s.Encode(this.value)
if err != nil {
return
}
exp = s.NewList(v1, v2, v3)
return
}
var (
handlers = map[string]Handler{}
)
func WebSocketHandler(conn *websocket.Conn) {
// Make a new listener which we'll close when the websocket is closed
listener := NewListener()
defer listener.Close()
// Read messages from the user
go func() {
for {
exp, err := s.Read(conn)
if err != nil {
if err != io.EOF {
log.Printf("<- [ERROR] %v", err)
}
close(listener)
return
}
log.Printf("<- %v", exp)
lst, ok := exp.(s.List)
if !ok {
listener.Errorf("Invalid request: expected List")
continue
}
n, err := lst.Head()
if err != nil {
listener.Errorf("Invalid request: expected at least one item")
continue
}
var action string
err = n.Scan(&action)
if err != nil {
listener.Errorf("Invalid request: expected string")
continue
}
h, ok := handlers[action]
if !ok {
listener.Errorf("Unknown action: %v", action)
continue
}
tail, _ := lst.Tail()
h(listener, tail)
}
}()
// Write messages from the server
for {
val, ok := <- listener
if !ok {
break
}
exp, err := s.Encode(val)
if err != nil {
exp, _ = s.Encode(err)
}
var buf bytes.Buffer
err = exp.Write(&buf)
if err != nil {
break
}
str := buf.String()
log.Printf("-> %v", str)
_, err = io.WriteString(conn, str)
if err != nil {
break
}
}
}
func HandleFunc(name string, handler HandlerFunc) {
handlers[name] = func(listener Listener, args s.List) {
if len(args) != 2 {
listener.Errorf("Expected request id & arguments")
return
}
var id uint64
err := args[0].Scan(&id)
if err != nil {
listener.Errorf("Expected request id to be a number got %v", args[1])
return
}
val := handler(listener, args[1])
listener <- result{id,val}
}
}
func init() {
http.Handle("/ws", websocket.Handler(WebSocketHandler))
}