ch4.5

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"
 
 	"gitea.local.lab/Lbenedar/greenlight/internal/data"
+	"gitea.local.lab/Lbenedar/greenlight/internal/validator"
 )
 
 func (app *application) createMovieHandler(w http.ResponseWriter, r *http.Request) {
@@ -21,6 +22,20 @@ func (app *application) createMovieHandler(w http.ResponseWriter, r *http.Reques
 		app.badRequestResponse(w, r, err)
 		return
 	}
+
+	movie := &data.Movie{
+		Title:   input.Title,
+		Year:    input.Year,
+		Runtime: input.Runtime,
+		Genres:  input.Genres,
+	}
+
+	v := validator.New()
+	if data.ValidateMovie(v, movie); !v.Valid() {
+		app.failedValidationResponse(w, r, v.Errors)
+		return
+	}
+
 	fmt.Fprintf(w, "%+v\n", input)
 }
 

internal/data/movies.go

@@ -1,6 +1,10 @@
 package data
 
-import "time"
+import (
+	"time"
+
+	"gitea.local.lab/Lbenedar/greenlight/internal/validator"
+)
 
 type Movie struct {
 	ID        int64     `json:"id"`
@@ -11,3 +15,20 @@ type Movie struct {
 	Genres    []string  `json:"genres,omitempty"`
 	Version   int32     `json:"version"`
 }
+
+func ValidateMovie(v *validator.Validator, movie *Movie) {
+	v.Check(movie.Title != "", "title", "must be provided")
+	v.Check(len(movie.Title) <= 500, "title", "must not be more than 500 bytes long")
+
+	v.Check(movie.Year != 0, "year", "must be provided")
+	v.Check(movie.Year >= 1988, "year", "must be greater than 1988")
+	v.Check(movie.Year <= int32(time.Now().Year()), "year", "must not be in the future")
+
+	v.Check(movie.Runtime != 0, "runtime", "must be provided")
+	v.Check(movie.Runtime > 0, "runtime", "must be a positive integer")
+
+	v.Check(movie.Genres != nil, "genres", "must be provided")
+	v.Check(len(movie.Genres) >= 1, "genres", "must contain at least 1 genre")
+	v.Check(len(movie.Genres) <= 5, "genres", "must not contain more than 5 genres")
+	v.Check(validator.Unique(movie.Genres), "genres", "must not contain duplicate values")
+}

internal/validator/validator.go

@@ -0,0 +1,53 @@
+package validator
+
+import "regexp"
+
+var (
+	EmailRX = regexp.MustCompile("^[a-zA-Z0-9.!#$%&'*+\\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$")
+)
+
+type Validator struct {
+	Errors map[string]string
+}
+
+func New() *Validator {
+	return &Validator{Errors: make(map[string]string)}
+}
+
+func (v *Validator) Valid() bool {
+	return len(v.Errors) == 0
+}
+
+func (v *Validator) AddError(key, message string) {
+	if _, exists := v.Errors[key]; !exists {
+		v.Errors[key] = message
+	}
+}
+
+func (v *Validator) Check(ok bool, key, message string) {
+	if !ok {
+		v.AddError(key, message)
+	}
+}
+
+func PermittedValue[T comparable](value T, permittedValues ...T) bool {
+	for i := range permittedValues {
+		if value == permittedValues[i] {
+			return true
+		}
+	}
+	return false
+}
+
+func Matches(value string, rx *regexp.Regexp) bool {
+	return rx.MatchString(value)
+}
+
+func Unique[T comparable](values []T) bool {
+	uniqueValues := make(map[T]bool)
+
+	for _, value := range values {
+		uniqueValues[value] = true
+	}
+	return len(values) == len(uniqueValues)
+}