fix(http): return error in case of panic (#250)

http/errors_test.go

@@ -112,6 +112,18 @@ func TestErrors(t *testing.T) {
 			status:  "200 OK",
 			bodyStr: "the reader call returns a reader.",
 		},
+
+		{
+			path:    []string{"panic"},
+			status:  "500 Internal Server Error",
+			bodyStr: `{"Message":"an error occurred","Code":0,"Type":"error"}` + "\n",
+		},
+		{
+			path:       []string{"latepanic"},
+			status:     "200 OK",
+			bodyStr:    `"some value"` + "\n",
+			errTrailer: "an error occurred",
+		},
 	}
 
 	mkTest := func(tc testcase) func(*testing.T) {

http/handler.go

@@ -89,11 +89,21 @@ type requestLogger interface {
 func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	log.Debug("incoming API request: ", r.URL)
 
+	var re ResponseEmitter
+
 	defer func() {
 		if r := recover(); r != nil {
 			log.Error("a panic has occurred in the commands handler!")
 			log.Error(r)
 			log.Errorf("stack trace:\n%s", debug.Stack())
+
+			if re != nil {
+				if err := re.CloseWithError(errors.New("an error occurred")); err != nil {
+					log.Errorf("error closing ResponseEmitter: %s", err)
+
+					return
+				}
+			}
 		}
 	}()
 
@@ -178,7 +188,7 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 	defer cancel()
 
-	re, err := NewResponseEmitter(w, r.Method, req, withRequestBodyEOFChan(bodyEOFChan))
+	re, err = NewResponseEmitter(w, r.Method, req, withRequestBodyEOFChan(bodyEOFChan))
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return

http/handler_test.go

@@ -287,6 +287,19 @@ var (
 					}),
 				},
 			},
+
+			"panic": {
+				Run: func(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment) error {
+					panic("Invalid memory address or nil pointer dereference")
+				},
+			},
+			"latepanic": {
+				Run: func(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment) error {
+					re.Emit("some value")
+					panic("Invalid memory address or nil pointer dereference")
+				},
+				Type: "",
+			},
 		},
 	}
 )