adds validation checks json in create movie

cmd/api/errors.go

@@ -39,3 +39,7 @@ func (app *application) methodNotAllowedResponse(w http.ResponseWriter, r *http.
 func (app *application) badRequestResponse(w http.ResponseWriter, r *http.Request, err error) {
 	app.errorResponse(w, r, http.StatusBadRequest, err.Error())
 }
+
+func (app *application) failedValidationResponse(w http.ResponseWriter, r *http.Request, errors map[string]string) {
+	app.errorResponse(w, r, http.StatusUnprocessableEntity, errors)
+}

cmd/api/movies.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"greenlight.ergz/internal/data"
+	"greenlight.ergz/internal/validator"
 )
 
 func (app *application) createMovieHandler(w http.ResponseWriter, r *http.Request) {
@@ -22,6 +23,30 @@ func (app *application) createMovieHandler(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
+	v := validator.New()
+
+	// validate title
+	v.Check(input.Title != "", "title", "must be provided")
+	v.Check(len(input.Title) <= 500, "title", "must not be more than 500 bytes")
+
+	// validate the year
+	v.Check(input.Year != 0, "year", "must be provided")
+	v.Check(input.Year >= 1888, "year", "must be greater than 1888")
+	v.Check(input.Year <= int32(time.Now().Year()), "year", "must not be in the future")
+
+	v.Check(input.Runtime != 0, "runtime", "must be provided")
+	v.Check(input.Runtime > 0, "runtime", "must be a positive integer")
+
+	v.Check(input.Genres != nil, "genres", "must be provided")
+	v.Check(len(input.Genres) >= 1, "genres", "at least one genre must be provided")
+	v.Check(len(input.Genres) <= 5, "genres", "no more than 5 genres can be provided")
+	v.Check(validator.Unique(input.Genres), "genres", "must not contain duplicate genre")
+
+	if !v.Valid() {
+		app.failedValidationResponse(w, r, v.Errors)
+		return
+	}
+
 	fmt.Fprintf(w, "%+v\n", input)
 }