ch4.4

cmd/api/movies.go

@@ -12,7 +12,7 @@ func (app *application) createMovieHandler(w http.ResponseWriter, r *http.Reques
 	var input struct {
 		Title   string       `json:"title"`
 		Year    int32        `json:"year"`
-		Runtime int32    `json:"runtime"`
+		Runtime data.Runtime `json:"runtime"`
 		Genres  []string     `json:"genres"`
 	}
 

internal/data/runtime.go

@@ -1,10 +1,14 @@
 package data
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
+	"strings"
 )
 
+var ErrInvalidRuntimeFormat = errors.New("invalid runtime format")
+
 type Runtime int32
 
 func (r Runtime) MarshalJSON() ([]byte, error) {
@@ -13,3 +17,23 @@ func (r Runtime) MarshalJSON() ([]byte, error) {
 	quotedJSONValue := strconv.Quote(jsonValue)
 	return []byte(quotedJSONValue), nil
 }
+
+func (r *Runtime) UnmarshalJSON(jsonValue []byte) error {
+	unquotedJSONValue, err := strconv.Unquote(string(jsonValue))
+
+	if err != nil {
+		return ErrInvalidRuntimeFormat
+	}
+
+	parts := strings.Split(unquotedJSONValue, " ")
+	if len(parts) != 2 || parts[1] != "mins" {
+		return ErrInvalidRuntimeFormat
+	}
+
+	i, err := strconv.ParseInt(parts[0], 10, 32)
+	if err != nil {
+		return ErrInvalidRuntimeFormat
+	}
+	*r = Runtime(i)
+	return nil
+}