so much

internal/validator/validator.go

@@ -0,0 +1,61 @@
+package validator
+
+import (
+	"regexp"
+)
+
+// Declare a regular expression for sanity checking the format of email addresses (we'll
+// use this later in the book). If you're interested, this regular expression pattern is
+// taken from https://html.spec.whatwg.org/#valid-e-mail-address. Note: if you're
+// reading this in PDF or EPUB format and cannot see the full pattern, please see the
+// note further down the page.
+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 In(value string, list ...string) bool {
+	for i := range list {
+		if value == list[i] {
+			return true
+		}
+	}
+	return false
+}
+
+func Matches(value string, rx *regexp.Regexp) bool {
+	return rx.MatchString(value)
+}
+
+func Unique(values []string) bool {
+	uniqueValues := make(map[string]bool)
+
+	for _, value := range values {
+		uniqueValues[value] = true
+	}
+
+	return len(values) == len(uniqueValues)
+}