Creating validator.go allowing us to validate received data from our endpoints. Updating errors.go adding failedValidationResponse method allowing us to deliver a StatusUnprocessableEntity error. Updating createMovieHandler with the use of our new validator package.

internal/validator/validator.go

@@ -0,0 +1,66 @@
+package validator
+
+import (
+	"regexp"
+	"slices"
+)
+
+// Declare a regular expression for sanity checking the format of email addresses. This regular expression pattern is taken from https://html.spec.whatwg.org/#valid-e-mail-address.
+/*
+Regex pour l'e-mail à tester :
+1. "^[a-zA-Z0-9.!#$%&'*+/=?^`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"
+2. `^[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$`
+*/
+var (
+	EmailTX, _ = regexp.Compile(`^[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$`)
+)
+
+// Validator : Contains a map of validation errors
+type Validator struct {
+	Errors map[string]string
+}
+
+// New is a helper which creates a new Validator instance with an empty errors map
+func New() *Validator {
+	return &Validator{Errors: make(map[string]string)}
+}
+
+// Valid returns true if the errors map doesn't contain any entries
+func (v *Validator) Valid() bool {
+	return len(v.Errors) == 0
+}
+
+// AddError adds an error message to the map (so long as no entry already exists for the given key)
+func (v *Validator) AddError(key, message string) {
+	if _, exists := v.Errors[key]; !exists {
+		v.Errors[key] = message
+	}
+}
+
+// Check adds an error message to the map only if a validation check is not 'ok'
+func (v *Validator) Check(ok bool, key, message string) {
+	if !ok {
+		v.AddError(key, message)
+	}
+}
+
+// PermittedValue is a generic function which returns true if a specific value is in a list of permitted values
+func PermittedValue[T comparable](value T, permittedValues ...T) bool {
+	return slices.Contains(permittedValues, value)
+}
+
+// Matches returns true if a string value matches a specific regexp pattern
+func Matches(value string, rx *regexp.Regexp) bool {
+	return rx.MatchString(value)
+}
+
+// Unique is a generic function which returns true if all values in a slice are unique
+func Unique[T comparable](values []T) bool {
+	uniqueValues := make(map[T]bool)
+
+	for _, value := range values {
+		uniqueValues[value] = true
+	}
+
+	return len(values) == len(uniqueValues)
+}