validate

Package validate validates Go struct and types recursively based on tags. It provides powerful syntax to perform validation for substructs, maps, slices, arrays, and pointers. Package also allows to run custom validation methods.

Use this package to make sure that the content of the struct is in the format you need. For example, validate package is useful when unmarshalling YAML or JSON.

Installation

• Use go get to download validate package.

   go get gopkg.in/dealancer/validate.v2
   ``
Import the validate package into your project.
   `go
   import "gopkg.in/dealancer/validate.v2"
   `
Types
This package supports a wide variety of types.
Most of the built-in types:
  
int, int8 int16, int32, int64

  
uint, uint8, uint16, uint32, uint64

  
float32, float64

  
uintptr

  
string

Aliased types:
  
time.Duration

  
byte (uint8)

  
rune (int32)

  
e.g. type Enum string

Complex types:
  
Struct
  
Map
  
Slice
  
Array
  
Pointer
Validators
This package provides the following validators.
eq (equals), ne (not equals), gt (greater than), lt (less than), gte (greater than or equal to), lte (less than or equal to) validators compare a numeric value of a number or compare a count of elements in a string, a map, a slice, or an array.

empty validator checks if a string, a map, a slice, or an array is (not) empty.

nil validator checks if a pointer is (not) nil.

one_of validator checks if a number or a string contains any of the given elements.

format validator checks if a string in one of the following formats: alpha, alnum, alpha_unicode, alnum_unicode, numeric, number, hexadecimal, hexcolor, rgb, rgba, hsl, hsla, email, url, uri, urn_rfc2141, file, base64, base64url, isbn, isbn10, isbn13, eth_addr, btc_addr, btc_addr_bech32, uuid, uuid3, uuid4, uuid5, ascii, ascii_print, datauri, latitude, longitude, ssn, ipv4, ipv6, ip, cidrv4, cidrv6, cidr, mac, hostname, hostname_rfc1123, fqdn, url_encoded, dir, postcode.
Operators
Following operators are used. There are listed in the descending order of their precedence.
[] (brackets) are used to validate map keys.

> (greater-than sign) is used to validate values of maps, slices, arrays or to dereference a pointer.
& (ampersand) is used to perform multiple validators using AND logic.

| (vertical bar) is used to perform multiple validators using OR logic.

= (equal sign) is used to separate validator type from value.

, (comma) is used to specify multiple tokens for a validator (e.g. one_of).
Usage

go type Registration struct { // Username should be between 3 and 25 characters and in alphanumeric unicode format Username string validate:"gte=3 & lte=25 & format=alnum_unicode"

// Email should be empty or in the email format Email string validate:"empty=true | format=email"

// Password is validated using a custom validation method Password string

// Role should be one of "admin", "publisher", or "author" Role string validate:"one_of=admin,publisher,author"

// URLs should not be empty, URLs values should be in the url format URLs []string validate:"empty=false > format=url"

// Retired (pointer) should not be nil Retired *bool validate:"nil=false"

// Some complex field with validation Complex []map[*string]int validate:"gte=1 & lte=2 | eq=4 > empty=false [nil=false > empty=false] > ne=0" }

// Custom validation func (r Registration) Validate() error { if !StrongPass(r.Password) { return errors.New("Password should be strong!") }

return nil }

type Registrations struct { r []Registration validate:"gte=2" // There should be at least two registrations }

go registrations := Registrations{ r: []Registration{ Registration{ Username: "admin", }, }, }

if err := validate.Validate(®istrations); err != nil { panic(err) } ``

See GoDoc for the complete reference.

Credits

This project has been written by Ben Myrgorod before Vibe Coding tools existed. Inspired by go-playground/validator.

--- Tranlated By Open Ai Tx | Last indexed: 2026-07-02 ---