feat: add cancel middleware

net/http/middleware/cancel.go

@@ -0,0 +1,60 @@
+package middleware
+
+import (
+	"net/http"
+
+	httputils "github.com/foomo/keel/utils/net/http"
+	"go.uber.org/zap"
+)
+
+type (
+	CancelOptions struct {
+		Code int
+	}
+	CancelOption func(*CancelOptions)
+)
+
+// GetDefaultCancelOptions returns the default options
+func GetDefaultCancelOptions() CancelOptions {
+	return CancelOptions{
+		Code: 499,
+	}
+}
+
+// CancelWithCode middleware option
+func CancelWithCode(v int) CancelOption {
+	return func(o *CancelOptions) {
+		o.Code = v
+	}
+}
+
+// Cancel middleware
+func Cancel(opts ...CancelOption) Middleware {
+	options := GetDefaultCancelOptions()
+	for _, opt := range opts {
+		if opt != nil {
+			opt(&options)
+		}
+	}
+	return CancelWithOptions(options)
+}
+
+// CancelWithOptions middleware
+func CancelWithOptions(opts CancelOptions) Middleware {
+	return func(l *zap.Logger, name string, next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			done := make(chan struct{})
+			go func() {
+				next.ServeHTTP(w, r)
+				close(done)
+			}()
+
+			select {
+			case <-r.Context().Done():
+				httputils.ServerError(l, w, r, opts.Code, r.Context().Err())
+			case <-done:
+				// If handler completes normally
+			}
+		})
+	}
+}