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package admin
import (
"bytes"
"errors"
"io"
"net/http"
)
const maxAdminRequestBytes = 8 << 20
// ownerMiddleware is the single execution boundary for ALL editor API routes,
// including reads (which must not observe partial edits) and undo/redo. Planning,
// file writes, runtime callbacks, reloads and history updates stay in one task.
// Register new API routes behind this boundary; handlers must never redispatch.
// Network I/O happens outside the task so slow browsers cannot block gameplay.
func (s *AdminServer) ownerMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
body, err := io.ReadAll(http.MaxBytesReader(w, r.Body, maxAdminRequestBytes))
r.Body.Close()
if err != nil {
status := http.StatusBadRequest
var tooLarge *http.MaxBytesError
if errors.As(err, &tooLarge) {
status = http.StatusRequestEntityTooLarge
}
writeJSONError(w, "cannot read request body: "+err.Error(), status)
return
}
if r.Context().Err() != nil {
return
}
r = r.Clone(r.Context())
r.Body = io.NopCloser(bytes.NewReader(body))
response := &bufferedResponse{header: make(http.Header)}
var panicValue any
if !s.runOnOwner(func() {
// Preserve net/http's panic recovery on the HTTP goroutine;
// a handler panic must not kill the game's owner loop.
defer func() { panicValue = recover() }()
if r.Context().Err() == nil {
next.ServeHTTP(response, r)
}
}) {
writeJSONError(w, "game is shutting down", http.StatusServiceUnavailable)
return
}
if panicValue != nil {
panic(panicValue)
}
for key, values := range response.header {
w.Header()[key] = values
}
if response.status != 0 {
w.WriteHeader(response.status)
}
_, _ = w.Write(response.body.Bytes())
})
}
// bufferedResponse deliberately provides no streaming/hijacking interfaces:
// editor API handlers produce finite responses, never network streams.
type bufferedResponse struct {
header http.Header
status int
body bytes.Buffer
}
func (w *bufferedResponse) Header() http.Header { return w.header }
func (w *bufferedResponse) WriteHeader(status int) {
if w.status == 0 {
w.status = status
}
}
func (w *bufferedResponse) Write(p []byte) (int, error) {
if w.status == 0 {
w.WriteHeader(http.StatusOK)
}
return w.body.Write(p)
}
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