xvalid

package module
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 Go to latest Published: Apr 30, 2024 License: MIT Imports: 7 Imported by: 0

README

xvalid

xvalid is a lightweight validation library that uses methods, and can be export as JSON.

Documentation at godoc.org

Goals

  1. Must be able to export rules so clients can consume them.
  2. Only support common rules such as those found in browsers and GUI libraries e.g. length, min, max etc.
  3. Must be easy to maintain as number of rules grows and becomes complex.

Comparison

Popular validation libraries like go-playground/validate and govalidator are great libraries but they suffer from a few problems.

  1. Since rules are defined in struct tags, errors are less easy to detect, and it becomes too difficult to read when there are many rules and many other struct tags defined. By using methods to define rules, we can rely on compilation checks and can format our code freely.
  2. They compile more regex validators than most project will ever need. By defining only common validators, we reduce unnecessary performance hit; and it is also trivial to copy/paste regex defined by other libraries.
  3. Without being able to export validation rules to client apps, developers will need to be mindful of keeping the rules in sync. By reusing validation rules, you reduce the chance of client and server validating wrongly.
  4. Rules are inflexible since they are defined with struct tags. By using methods instead of struct tags, we can dynamically define rules based on runtime data.

Examples

Define rules, validate, and export as JSON:

// Store model
type Store struct {
	Name        string `json:"name"`
	Address     string `json:"address"`
	Description string `json:"description"`
	Tax         int    `json:"tax"`
	Revenue     int    `json:"revenue"`
}

// Rules for this model.
func (store Store) Rules() xvalid.Rules {
	return xvalid.New(&store).
		Field(&store.Name, xvalid.MinLength(4).SetOptional().SetMessage("Please lengthen name to 4 characters or more"),
			xvalid.MaxLength(80).SetMessage("Please shorten name to 80 characters or less"),
			xvalid.Pattern("^[a-zA-Z0-9_]+$").SetOptional().SetMessage("Name may contain alphabets, numbers and underscores"),
			xvalid.Pattern("[a-zA-Z]").SetOptional().SetMessage("Name must contain at least 1 alphabet"),
			xvalid.FieldFunc(func(fieldName string, value any) xvalid.Error {
				name := value.(string)
				if name == "" {
					return nil
				}
				if name == "admin" {
					return xvalid.NewError("This name is not allowed", fieldName)
				}
				return nil
			})).
		Field(&store.Address, xvalid.Required(), xvalid.MaxLength(120)).
		Field(&store.Description, xvalid.MaxLength(1500)).
		Field(&store.Tax, xvalid.Min(0), xvalid.Max(100)).
		Struct(xvalid.StructFunc(func(v any) xvalid.Error {
			s := v.(Store)
			if s.Revenue > 1000 && s.Tax == 0 {
				return xvalid.NewError("Tax cannot be empty if revenue is more than $1000", "tax")
			}
			return nil
		}))
}

// validate
store := Store{}
err := store.Rules().Validate(store)
if err != nil {
    panic(err)
}

// export rules as JSON
rules := store.Rules()
b, err := json.MarshalIndent(rules, "", "	")
if err != nil {
    panic(err)
}
fmt.Println(string(b))

// generate dynamic rules
runtimeRules := xvalid.New(&store).
    Field(&store.Name, xvalid.Required())
if userInput == "example" {
    runtimeRules = runtimeRules.Field(&store.Address, xvalid.MinLength(getMinLength()))
}
err := runtimeRules.Validate(store)

Custom Validators

To define your own validator, you must implement the Validator interface. For examples, see any of the validators in validators.go.

Documentation

Overview

Package xvalid is a lightweight validation library that can export rules as JSON so browsers can apply the same rules.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func IsEmail 

func IsEmail(email string) bool

IsEmail returns true if the string is an email

Types

type EmailValidator 

type EmailValidator struct {
	Validator
	// contains filtered or unexported fields
}

EmailValidator field must be a valid email address

func Email 

func Email() *EmailValidator

Email field must be a valid email address

func (*EmailValidator) CanExport 

func (c *EmailValidator) CanExport() bool

CanExport for this validator

func (*EmailValidator) MarshalJSON 

func (c *EmailValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*EmailValidator) Name 

func (c *EmailValidator) Name() string

Name of the field

func (*EmailValidator) SetMessage 

func (c *EmailValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*EmailValidator) SetName 

func (c *EmailValidator) SetName(name string)

SetName of the field

func (*EmailValidator) SetOptional 

func (c *EmailValidator) SetOptional() Validator

SetOptional don't validate if the value is zero

func (*EmailValidator) Validate 

func (c *EmailValidator) Validate(value any) Error

Validate the value

type Error 

type Error interface {
	Error() string
	Field() string
}

Error when a rule is broken

func NewError 

func NewError(message, fieldName string) Error

NewError creates new validation error

type Errors 

type Errors []Error

Errors is a list of Error

func (Errors) Error 

func (v Errors) Error() string

Error will combine all errors into a list of sentences

type FieldFuncValidator 

type FieldFuncValidator struct {
	// contains filtered or unexported fields
}

FieldFuncValidator for validating with custom function

func (*FieldFuncValidator) CanExport 

func (c *FieldFuncValidator) CanExport() bool

CanExport for this validator

func (*FieldFuncValidator) Name 

func (c *FieldFuncValidator) Name() string

Name of the field

func (*FieldFuncValidator) SetMessage 

func (c *FieldFuncValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*FieldFuncValidator) SetName 

func (c *FieldFuncValidator) SetName(name string)

SetName of the field

func (*FieldFuncValidator) Validate 

func (c *FieldFuncValidator) Validate(value any) Error

Validate the value

type MaxLengthValidator 

type MaxLengthValidator struct {
	// contains filtered or unexported fields
}

MaxLengthValidator field have maximum length

func MaxLength 

func MaxLength(max int64) *MaxLengthValidator

MaxLength field have maximum length

func (*MaxLengthValidator) CanExport 

func (c *MaxLengthValidator) CanExport() bool

CanExport for this validator

func (*MaxLengthValidator) MarshalJSON 

func (c *MaxLengthValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*MaxLengthValidator) Name 

func (c *MaxLengthValidator) Name() string

Name of the field

func (*MaxLengthValidator) SetMessage 

func (c *MaxLengthValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*MaxLengthValidator) SetName 

func (c *MaxLengthValidator) SetName(name string)

SetName of the field

func (*MaxLengthValidator) Validate 

func (c *MaxLengthValidator) Validate(value any) Error

Validate the value

type MaxValidator 

type MaxValidator struct {
	// contains filtered or unexported fields
}

MaxValidator field have maximum value

func Max 

func Max(max int64) *MaxValidator

Max field have maximum value

func (*MaxValidator) CanExport 

func (c *MaxValidator) CanExport() bool

CanExport for this validator

func (*MaxValidator) MarshalJSON 

func (c *MaxValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*MaxValidator) Name 

func (c *MaxValidator) Name() string

Name of the field

func (*MaxValidator) SetMessage 

func (c *MaxValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*MaxValidator) SetName 

func (c *MaxValidator) SetName(name string)

SetName of the field

func (*MaxValidator) Validate 

func (c *MaxValidator) Validate(value any) Error

Validate the value

type MinLengthValidator 

type MinLengthValidator struct {
	// contains filtered or unexported fields
}

MinLengthValidator field must have minimum length

func MinLength 

func MinLength(min int64) *MinLengthValidator

MinLength field must have minimum length

func (*MinLengthValidator) CanExport 

func (c *MinLengthValidator) CanExport() bool

CanExport for this validator

func (*MinLengthValidator) MarshalJSON 

func (c *MinLengthValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*MinLengthValidator) Name 

func (c *MinLengthValidator) Name() string

Name of the field

func (*MinLengthValidator) SetMessage 

func (c *MinLengthValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*MinLengthValidator) SetName 

func (c *MinLengthValidator) SetName(name string)

SetName of the field

func (*MinLengthValidator) SetOptional 

func (c *MinLengthValidator) SetOptional() Validator

SetOptional don't validate if the value is zero

func (*MinLengthValidator) Validate 

func (c *MinLengthValidator) Validate(value any) Error

Validate the value

type MinValidator 

type MinValidator struct {
	// contains filtered or unexported fields
}

MinValidator field have minimum value

func Min 

func Min(min int64) *MinValidator

Min field have minimum value

func (*MinValidator) CanExport 

func (c *MinValidator) CanExport() bool

CanExport for this validator

func (*MinValidator) MarshalJSON 

func (c *MinValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*MinValidator) Name 

func (c *MinValidator) Name() string

Name of the field

func (*MinValidator) SetMessage 

func (c *MinValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*MinValidator) SetName 

func (c *MinValidator) SetName(name string)

SetName of the field

func (*MinValidator) SetOptional 

func (c *MinValidator) SetOptional() Validator

SetOptional don't validate if the value is zero

func (*MinValidator) Validate 

func (c *MinValidator) Validate(value any) Error

Validate the value

type OptionsValidator 

type OptionsValidator struct {
	// contains filtered or unexported fields
}

OptionsValidator for whitelisting accepted values

func (*OptionsValidator) CanExport 

func (c *OptionsValidator) CanExport() bool

CanExport for this validator

func (*OptionsValidator) MarshalJSON 

func (c *OptionsValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*OptionsValidator) Name 

func (c *OptionsValidator) Name() string

Name of the field

func (*OptionsValidator) SetMessage 

func (c *OptionsValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*OptionsValidator) SetName 

func (c *OptionsValidator) SetName(name string)

SetName of the field

func (*OptionsValidator) Validate 

func (c *OptionsValidator) Validate(value any) Error

Validate the value

type PatternValidator 

type PatternValidator struct {
	// contains filtered or unexported fields
}

PatternValidator field must match regexp

func Pattern 

func Pattern(pattern string) *PatternValidator

Pattern field must match regexp

func (*PatternValidator) CanExport 

func (c *PatternValidator) CanExport() bool

CanExport for this validator

func (*PatternValidator) MarshalJSON 

func (c *PatternValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*PatternValidator) Name 

func (c *PatternValidator) Name() string

Name of the field

func (*PatternValidator) SetMessage 

func (c *PatternValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*PatternValidator) SetName 

func (c *PatternValidator) SetName(name string)

SetName of the field

func (*PatternValidator) SetOptional 

func (c *PatternValidator) SetOptional() Validator

SetOptional don't validate if the value is zero

func (*PatternValidator) Validate 

func (c *PatternValidator) Validate(value any) Error

Validate the value

type RequiredValidator 

type RequiredValidator struct {
	// contains filtered or unexported fields
}

RequiredValidator field must not be zero

func Required 

func Required() *RequiredValidator

Required fields must not be zero

func (*RequiredValidator) CanExport 

func (c *RequiredValidator) CanExport() bool

CanExport for this validator

func (*RequiredValidator) MarshalJSON 

func (c *RequiredValidator) MarshalJSON() ([]byte, error)

MarshalJSON for this validator

func (*RequiredValidator) Name 

func (c *RequiredValidator) Name() string

Name of the field

func (*RequiredValidator) SetMessage 

func (c *RequiredValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*RequiredValidator) SetName 

func (c *RequiredValidator) SetName(name string)

SetName of the field

func (*RequiredValidator) Validate 

func (c *RequiredValidator) Validate(value any) Error

Validate the value

type Rules 

type Rules struct {
	// contains filtered or unexported fields
}

Rules for creating a chain of rules for validating a struct

func New 

func New(structPtr any) Rules

New rule chain

func (Rules) Field 

func (r Rules) Field(fieldPtr any, validators ...Validator) Rules

Field adds validators for a field

func (Rules) MarshalJSON 

func (r Rules) MarshalJSON() ([]byte, error)

func (Rules) Struct 

func (r Rules) Struct(validators ...Validator) Rules

Struct adds validators for the struct

func (Rules) Validate 

func (r Rules) Validate(subject any) error

Validate a struct and return Errors

func (Rules) Validators 

func (r Rules) Validators() []Validator

Validators for this chain

type StructFuncValidator 

type StructFuncValidator struct {
	// contains filtered or unexported fields
}

StructFuncValidator validate struct with custom function. Add to rules with .Struct().

func (*StructFuncValidator) CanExport 

func (c *StructFuncValidator) CanExport() bool

CanExport for this validator

func (*StructFuncValidator) Name 

func (c *StructFuncValidator) Name() string

Name of the field

func (*StructFuncValidator) SetMessage 

func (c *StructFuncValidator) SetMessage(msg string) Validator

SetMessage set error message

func (*StructFuncValidator) SetName 

func (c *StructFuncValidator) SetName(name string)

SetName of the field

func (*StructFuncValidator) Validate 

func (c *StructFuncValidator) Validate(value any) Error

Validate the value

type Validator 

type Validator interface {
	SetName(string)
	Name() string
	CanExport() bool
	SetMessage(string) Validator
	Validate(any) Error
}

Validator to implement a rule

func FieldFunc 

func FieldFunc(f func(string, any) Error) Validator

FieldFunc for validating with custom function

func Options 

func Options(options ...any) Validator

Options for whitelisting accepted values

func StructFunc 

func StructFunc(f func(any) Error) Validator

StructFunc validate struct with custom function

Source Files

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