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|
package main
import (
"errors"
"io"
"log"
"net/http"
)
type HTTPRequest struct {
request *http.Request
route string
debug bool
result chan *HTTPResponse
}
type EvalRequest struct {
code string
result chan error
}
type HTTPResponse struct {
Code int
Headers map[string]string
Body string
}
type Worker struct {
read chan interface{}
lua *Lua
api LuaRef
routes map[string]LuaRef
started bool
}
func NewWorker(read chan interface{}) *Worker {
return &Worker {
read: read,
routes: make(map[string]LuaRef),
lua: &Lua{},
}
}
func (w *Worker) Start(filename string) error {
if w.started {
return errors.New("already started")
}
w.lua.Start()
api, err := w.lua.Require(filename)
if err != nil {
return err
}
w.api = api
err = w.initRoutes()
if err != nil {
return err
}
return nil
}
func (w *Worker) Listen() {
for {
resStack := w.lua.RestoreStackFunc()
r := <- w.read
switch r.(type) {
case *HTTPRequest:
r := r.(*HTTPRequest)
// If in debug mode always use handlers from api table
// instead of cached references. Makes it much easier
// to hot-replace route handlers.
if r.debug {
w.lua.PushFromRef(w.api)
w.lua.PushTableItem("routes")
w.lua.PushTableItem(r.route)
} else {
w.lua.PushFromRef(w.routes[r.route])
}
w.lua.PushString(r.request.Method)
w.lua.PushString(r.request.URL.Path)
fh := make(map[string]string)
for k := range r.request.Header {
fh[k] = r.request.Header.Get(k)
}
w.lua.PushTable(fh)
body, err := io.ReadAll(r.request.Body)
if err != nil {
r.result <- &HTTPResponse {
Code: 500,
Headers: make(map[string]string),
Body: "server error",
}
log.Println("could not read a request body")
resStack()
continue
}
w.lua.PushString(string(body))
w.lua.PCall(4, 3)
code := w.lua.ToInt(-3)
rbody := w.lua.ToString(-1)
// Parse headers.
headers := make(map[string]string)
w.lua.Pop(1)
w.lua.PushNil()
for w.lua.Next() {
if !w.lua.IsString(-2) || !w.lua.IsString(-2) {
w.lua.Pop(1)
continue
}
v := w.lua.ToString(-1)
w.lua.Pop(1)
// We must not pop the item key from the stack
// because otherwise C.lua_next won't work
// properly.
k := w.lua.ToString(-1)
headers[k] = v
}
r.result <- &HTTPResponse {
Code: int(code),
Headers: headers,
Body: rbody,
}
case *EvalRequest:
r := r.(*EvalRequest)
err := w.lua.LoadString(r.code)
r.result <- err
default:
log.Fatal("unknown request")
}
resStack()
}
}
func (w *Worker) Request(
route string,
r *http.Request,
debug bool,
) chan *HTTPResponse {
res := make(chan *HTTPResponse)
w.read <- &HTTPRequest{
request: r,
route: route,
debug: debug,
result: res,
}
return res
}
func (w *Worker) Eval(code string) chan error {
res := make(chan error)
w.read <- &EvalRequest{code: code, result: res}
return res
}
func (w *Worker) ListRoutes() []string {
res := []string{}
for route, _ := range w.routes {
res = append(res, route)
}
return res
}
func (w *Worker) Stop() {
w.lua.Close()
}
func (w *Worker) initRoutes() error {
defer w.lua.RestoreStackFunc()()
w.lua.PushFromRef(w.api)
w.lua.PushTableItem("routes")
if !w.lua.IsTable(-1) {
return errors.New("\"routes\" must be a table")
}
w.lua.PushNil()
for w.lua.Next() {
if !w.lua.IsString(-2) || !w.lua.IsFunction(-1) {
w.lua.Pop(1)
continue
}
handlerRef := w.lua.PopToRef()
// we must not pop the item key from the stack because
// otherwise C.lua_next won't work properly
route := w.lua.ToString(-1)
w.routes[route] = handlerRef
}
w.lua.Pop(2)
return nil
}
|
