feat: Added Protobuf and JSON struct validator

* Added Protobuf and JSON struct validator through reflection based on their tags
* Forked from 'github.com/pixel-plaza-dev/uru-databases-2-go-service-common'

field/errors.go

@@ -0,0 +1,9 @@
+package field
+
+import (
+	"errors"
+)
+
+var (
+	InvalidBirthdateError = errors.New("invalid birthdate")
+)

field/mail/errors.go

@@ -0,0 +1,9 @@
+package mail
+
+import (
+	"errors"
+)
+
+var (
+	InvalidMailAddressError = errors.New("invalid mail address")
+)

field/mail/mail_address.go

@@ -0,0 +1,21 @@
+package mail
+
+import (
+	"net/mail"
+)
+
+// ValidMailAddress checks if the mail address is valid
+func ValidMailAddress(address string) (string, error) {
+	// Check if the mail address is empty
+	if address == "" {
+		return "", InvalidMailAddressError
+	}
+
+	// Check if the mail address is valid
+	addr, err := mail.ParseAddress(address)
+	if err != nil {
+		return "", InvalidMailAddressError
+	}
+
+	return addr.Address, nil
+}

go.mod

@@ -0,0 +1,5 @@
+module github.com/ralvarezdev/go-validator
+
+go 1.23.4
+
+require github.com/ralvarezdev/go-flags v0.2.0 // indirect

go.sum

@@ -0,0 +1,3 @@
+github.com/ralvarezdev/go-flags v0.1.0 h1:WG6eMbS2yL+UYtI3X8R/HbisrfEgzLiMKMWqXanwyys=
+github.com/ralvarezdev/go-flags v0.1.0/go.mod h1:pYw9H7NJ07Y5asZDC/EI5bpBLR0kdL2ISsh6X5ws+3s=
+github.com/ralvarezdev/go-flags v0.2.0/go.mod h1:pYw9H7NJ07Y5asZDC/EI5bpBLR0kdL2ISsh6X5ws+3s=

structs/mapper/errors.go

@@ -0,0 +1,10 @@
+package mapper
+
+var (
+	MissingProtobufTagError       = "missing protobuf tag: %s"
+	MissingProtobufTagNameError   = "missing protobuf tag name: %s"
+	DuplicateProtobufTagNameError = "duplicate protobuf tag name: %s"
+	MissingJSONTagError           = "missing json tag: %s"
+	EmptyJSONTagError             = "empty json tag: %s"
+	DuplicateJSONTagNameError     = "duplicate json tag name: %s"
+)

structs/mapper/mapper.go

@@ -0,0 +1,218 @@
+package mapper
+
+import (
+	"fmt"
+	goflagsmode "github.com/ralvarezdev/go-flags/mode"
+	"reflect"
+	"strings"
+)
+
+// Protobuf fields generated by the protoc compiler
+const (
+	State              = "state"
+	SizeCache          = "sizeCache"
+	UnknownFields      = "unknownFields"
+	ProtobufTag        = "protobuf"
+	ProtobufOneOf      = "oneof"
+	ProtobufNamePrefix = "name="
+	JSONTag            = "json"
+	JSONOmitempty      = "omitempty"
+)
+
+// Mapper is a map of fields to validate from a struct
+type Mapper struct {
+	Fields        map[string]string // Key is the field name and value is the name used in the validation error
+	NestedMappers map[string]*Mapper
+}
+
+// CreateProtobufMapper creates the fields to validate from a Protobuf compiled struct
+func CreateProtobufMapper(structInstance interface{}, mode *goflagsmode.Flag) (
+	*Mapper,
+	error,
+) {
+	// Reflection of data
+	typeReflection := reflect.TypeOf(structInstance)
+
+	// If data is a pointer, dereference it
+	if typeReflection.Kind() == reflect.Ptr {
+		typeReflection = typeReflection.Elem()
+	}
+
+	// Initialize the map fields and the map of nested mappers
+	rootMapper := make(map[string]string)
+	rootNestedMappers := make(map[string]*Mapper)
+
+	// Reflection of the type of data
+	var protobufTag string
+	var protobufName string
+	for i := 0; i < typeReflection.NumField(); i++ {
+		// Get the field type through reflection
+		field := typeReflection.Field(i)
+
+		// Check if the field is a protoc generated field
+		if field.Name == State || field.Name == SizeCache || field.Name == UnknownFields {
+			continue
+		}
+
+		// Print field on debug mode
+		fieldType := field.Type
+		if mode != nil && mode.IsDebug() {
+			fmt.Printf("field '%v' type: %v\n", field.Name, fieldType)
+		}
+
+		// Check if the field is a pointer
+		if fieldType.Kind() != reflect.Ptr {
+			// Get the Protobuf tag of the field
+			protobufTag = field.Tag.Get(ProtobufTag)
+			if protobufTag == "" {
+				return nil, fmt.Errorf(MissingProtobufTagError, field.Name)
+			}
+		} else {
+			fieldType = fieldType.Elem()
+
+			// Check if the element type is not a struct, which would mean that it is an optional scalar type
+			if fieldType.Kind() != reflect.Struct {
+				continue
+			}
+
+			// Get the Protobuf tag of the field
+			protobufTag = field.Tag.Get(ProtobufTag)
+			if protobufTag == "" {
+				return nil, fmt.Errorf(MissingProtobufTagError, field.Name)
+			}
+
+			// Check the tag to determine if it contains 'oneof', which means it is an optional struct field
+			if ok := strings.Contains(protobufTag, ProtobufOneOf); ok {
+				continue
+			}
+
+			// Create a new Mapper for the nested struct field
+			fieldNestedMapper, err := CreateProtobufMapper(
+				reflect.New(fieldType).Interface(),
+				mode,
+			)
+			if err != nil {
+				return nil, err
+			}
+
+			// Add the nested fields to the map
+			rootNestedMappers[field.Name] = fieldNestedMapper
+		}
+
+		// Get the field name from the Protobuf tag
+		tagParts := strings.Split(protobufTag, ",")
+		protobufName = ""
+		for _, part := range tagParts {
+			if strings.HasPrefix(part, ProtobufNamePrefix) {
+				protobufName = strings.TrimPrefix(part, ProtobufNamePrefix)
+				break
+			}
+		}
+
+		// Check if the field name is empty
+		if protobufName == "" {
+			return nil, fmt.Errorf(MissingProtobufTagNameError, field.Name)
+		}
+
+		// Check if the field name has already been assigned
+		if _, ok := rootMapper[protobufName]; ok {
+			return nil, fmt.Errorf(DuplicateProtobufTagNameError, protobufName)
+		}
+
+		// Add the field to the map
+		rootMapper[field.Name] = protobufName
+	}
+
+	return &Mapper{
+		Fields:        rootMapper,
+		NestedMappers: rootNestedMappers,
+	}, nil
+}
+
+// CreateJSONMapper creates the fields to validate from a JSON struct
+func CreateJSONMapper(structInstance interface{}, mode *goflagsmode.Flag) (
+	*Mapper,
+	error,
+) {
+	// Reflection of data
+	typeReflection := reflect.TypeOf(structInstance)
+
+	// If data is a pointer, dereference it
+	if typeReflection.Kind() == reflect.Ptr {
+		typeReflection = typeReflection.Elem()
+	}
+
+	// Initialize the map fields and the map of nested mappers
+	rootMapper := make(map[string]string)
+	rootNestedMappers := make(map[string]*Mapper)
+
+	// Reflection of the type of data
+	var jsonTag string
+	var jsonName string
+	for i := 0; i < typeReflection.NumField(); i++ {
+		// Get the field type through reflection
+		field := typeReflection.Field(i)
+
+		// Print field on debug mode
+		fieldType := field.Type
+		if mode != nil && mode.IsDebug() {
+			fmt.Printf("field '%v' type: %v\n", field.Name, fieldType)
+		}
+
+		// Get the JSON tag of the field
+		jsonTag = field.Tag.Get(JSONTag)
+		if jsonTag == "" {
+			return nil, fmt.Errorf(MissingJSONTagError, field.Name)
+		}
+
+		// Check if the JSON tag is unassigned
+		if jsonTag == "-" {
+			continue
+		}
+
+		// Check the tag to determine if it contains 'omitempty', which means it is an optional field
+		if ok := strings.Contains(jsonTag, JSONOmitempty); ok {
+			continue
+		}
+
+		// Check if the field is a pointer
+		if fieldType.Kind() == reflect.Ptr {
+			fieldType = fieldType.Elem()
+		}
+
+		// Check if the element type is a struct
+		if fieldType.Kind() == reflect.Struct {
+			// Create a new Mapper for the nested struct field
+			fieldNestedMapper, err := CreateJSONMapper(
+				reflect.New(fieldType).Interface(),
+				mode,
+			)
+			if err != nil {
+				return nil, err
+			}
+
+			// Add the nested fields to the map
+			rootNestedMappers[field.Name] = fieldNestedMapper
+		}
+
+		// Get the field name from the JSON tag
+		tagParts := strings.Split(jsonTag, ",")
+		if len(tagParts) == 0 {
+			return nil, fmt.Errorf(EmptyJSONTagError, field.Name)
+		}
+		jsonName = tagParts[0]
+
+		// Check if the field name has already been assigned
+		if _, ok := rootMapper[jsonName]; ok {
+			return nil, fmt.Errorf(DuplicateJSONTagNameError, jsonName)
+		}
+
+		// Add the field to the map
+		rootMapper[field.Name] = jsonName
+	}
+
+	return &Mapper{
+		Fields:        rootMapper,
+		NestedMappers: rootNestedMappers,
+	}, nil
+}

structs/validations/errors.go

@@ -0,0 +1,11 @@
+package validations
+
+import (
+	"errors"
+)
+
+var (
+	NilDataError       = errors.New("data cannot be nil")
+	NilMapperError     = errors.New("mapper cannot be nil")
+	FieldNotFoundError = errors.New("field not found")
+)