validator

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Published: Nov 16, 2024 License: MIT Imports: 26 Imported by: 16,306

README

Package validator

Project status Build Status Coverage Status Go Report Card GoDoc License

Package validator implements value validations for structs and individual fields based on tags.

It has the following unique features:

  • Cross Field and Cross Struct validations by using validation tags or custom validators.
  • Slice, Array and Map diving, which allows any or all levels of a multidimensional field to be validated.
  • Ability to dive into both map keys and values for validation
  • Handles type interface by determining it's underlying type prior to validation.
  • Handles custom field types such as sql driver Valuer see Valuer
  • Alias validation tags, which allows for mapping of several validations to a single tag for easier defining of validations on structs
  • Extraction of custom defined Field Name e.g. can specify to extract the JSON name while validating and have it available in the resulting FieldError
  • Customizable i18n aware error messages.
  • Default validator for the gin web framework; upgrading from v8 to v9 in gin see here

Installation

Use go get.

go get github.com/go-playground/validator/v10

Then import the validator package into your own code.

import "github.com/go-playground/validator/v10"

Error Return Value

Validation functions return type error

They return type error to avoid the issue discussed in the following, where err is always != nil:

Validator returns only InvalidValidationError for bad validation input, nil or ValidationErrors as type error; so, in your code all you need to do is check if the error returned is not nil, and if it's not check if error is InvalidValidationError ( if necessary, most of the time it isn't ) type cast it to type ValidationErrors like so:

err := validate.Struct(mystruct)
validationErrors := err.(validator.ValidationErrors)

Usage and documentation

Please see https://pkg.go.dev/github.com/go-playground/validator/v10 for detailed usage docs.

Examples:

Baked-in Validations

Special Notes:
  • If new to using validator it is highly recommended to initialize it using the WithRequiredStructEnabled option which is opt-in to new behaviour that will become the default behaviour in v11+. See documentation for more details.
validate := validator.New(validator.WithRequiredStructEnabled())
Fields:
Tag Description
eqcsfield Field Equals Another Field (relative)
eqfield Field Equals Another Field
fieldcontains Check the indicated characters are present in the Field
fieldexcludes Check the indicated characters are not present in the field
gtcsfield Field Greater Than Another Relative Field
gtecsfield Field Greater Than or Equal To Another Relative Field
gtefield Field Greater Than or Equal To Another Field
gtfield Field Greater Than Another Field
ltcsfield Less Than Another Relative Field
ltecsfield Less Than or Equal To Another Relative Field
ltefield Less Than or Equal To Another Field
ltfield Less Than Another Field
necsfield Field Does Not Equal Another Field (relative)
nefield Field Does Not Equal Another Field
Network:
Tag Description
cidr Classless Inter-Domain Routing CIDR
cidrv4 Classless Inter-Domain Routing CIDRv4
cidrv6 Classless Inter-Domain Routing CIDRv6
datauri Data URL
fqdn Full Qualified Domain Name (FQDN)
hostname Hostname RFC 952
hostname_port HostPort
hostname_rfc1123 Hostname RFC 1123
ip Internet Protocol Address IP
ip4_addr Internet Protocol Address IPv4
ip6_addr Internet Protocol Address IPv6
ip_addr Internet Protocol Address IP
ipv4 Internet Protocol Address IPv4
ipv6 Internet Protocol Address IPv6
mac Media Access Control Address MAC
tcp4_addr Transmission Control Protocol Address TCPv4
tcp6_addr Transmission Control Protocol Address TCPv6
tcp_addr Transmission Control Protocol Address TCP
udp4_addr User Datagram Protocol Address UDPv4
udp6_addr User Datagram Protocol Address UDPv6
udp_addr User Datagram Protocol Address UDP
unix_addr Unix domain socket end point Address
uri URI String
url URL String
http_url HTTP URL String
url_encoded URL Encoded
urn_rfc2141 Urn RFC 2141 String
Strings:
Tag Description
alpha Alpha Only
alphanum Alphanumeric
alphanumunicode Alphanumeric Unicode
alphaunicode Alpha Unicode
ascii ASCII
boolean Boolean
contains Contains
containsany Contains Any
containsrune Contains Rune
endsnotwith Ends Not With
endswith Ends With
excludes Excludes
excludesall Excludes All
excludesrune Excludes Rune
lowercase Lowercase
multibyte Multi-Byte Characters
number Number
numeric Numeric
printascii Printable ASCII
startsnotwith Starts Not With
startswith Starts With
uppercase Uppercase
Format:
Tag Description
base64 Base64 String
base64url Base64URL String
base64rawurl Base64RawURL String
bic Business Identifier Code (ISO 9362)
bcp47_language_tag Language tag (BCP 47)
btc_addr Bitcoin Address
btc_addr_bech32 Bitcoin Bech32 Address (segwit)
credit_card Credit Card Number
mongodb MongoDB ObjectID
mongodb_connection_string MongoDB Connection String
cron Cron
spicedb SpiceDb ObjectID/Permission/Type
datetime Datetime
e164 e164 formatted phone number
email E-mail String
eth_addr Ethereum Address
hexadecimal Hexadecimal String
hexcolor Hexcolor String
hsl HSL String
hsla HSLA String
html HTML Tags
html_encoded HTML Encoded
isbn International Standard Book Number
isbn10 International Standard Book Number 10
isbn13 International Standard Book Number 13
issn International Standard Serial Number
iso3166_1_alpha2 Two-letter country code (ISO 3166-1 alpha-2)
iso3166_1_alpha3 Three-letter country code (ISO 3166-1 alpha-3)
iso3166_1_alpha_numeric Numeric country code (ISO 3166-1 numeric)
iso3166_2 Country subdivision code (ISO 3166-2)
iso4217 Currency code (ISO 4217)
json JSON
jwt JSON Web Token (JWT)
latitude Latitude
longitude Longitude
luhn_checksum Luhn Algorithm Checksum (for strings and (u)int)
postcode_iso3166_alpha2 Postcode
postcode_iso3166_alpha2_field Postcode
rgb RGB String
rgba RGBA String
ssn Social Security Number SSN
timezone Timezone
uuid Universally Unique Identifier UUID
uuid3 Universally Unique Identifier UUID v3
uuid3_rfc4122 Universally Unique Identifier UUID v3 RFC4122
uuid4 Universally Unique Identifier UUID v4
uuid4_rfc4122 Universally Unique Identifier UUID v4 RFC4122
uuid5 Universally Unique Identifier UUID v5
uuid5_rfc4122 Universally Unique Identifier UUID v5 RFC4122
uuid_rfc4122 Universally Unique Identifier UUID RFC4122
md4 MD4 hash
md5 MD5 hash
sha256 SHA256 hash
sha384 SHA384 hash
sha512 SHA512 hash
ripemd128 RIPEMD-128 hash
ripemd128 RIPEMD-160 hash
tiger128 TIGER128 hash
tiger160 TIGER160 hash
tiger192 TIGER192 hash
semver Semantic Versioning 2.0.0
ulid Universally Unique Lexicographically Sortable Identifier ULID
cve Common Vulnerabilities and Exposures Identifier (CVE id)
Comparisons:
Tag Description
eq Equals
eq_ignore_case Equals ignoring case
gt Greater than
gte Greater than or equal
lt Less Than
lte Less Than or Equal
ne Not Equal
ne_ignore_case Not Equal ignoring case
Other:
Tag Description
dir Existing Directory
dirpath Directory Path
file Existing File
filepath File Path
image Image
isdefault Is Default
len Length
max Maximum
min Minimum
oneof One Of
required Required
required_if Required If
required_unless Required Unless
required_with Required With
required_with_all Required With All
required_without Required Without
required_without_all Required Without All
excluded_if Excluded If
excluded_unless Excluded Unless
excluded_with Excluded With
excluded_with_all Excluded With All
excluded_without Excluded Without
excluded_without_all Excluded Without All
unique Unique
Aliases:
Tag Description
iscolor hexcolor|rgb|rgba|hsl|hsla
country_code iso3166_1_alpha2|iso3166_1_alpha3|iso3166_1_alpha_numeric

Benchmarks

Run on MacBook Pro (15-inch, 2017) go version go1.10.2 darwin/amd64
go version go1.21.0 darwin/arm64
goos: darwin
goarch: arm64
pkg: github.com/go-playground/validator/v10
BenchmarkFieldSuccess-8                                         33142266                35.94 ns/op            0 B/op          0 allocs/op
BenchmarkFieldSuccessParallel-8                                 200816191                6.568 ns/op           0 B/op          0 allocs/op
BenchmarkFieldFailure-8                                          6779707               175.1 ns/op           200 B/op          4 allocs/op
BenchmarkFieldFailureParallel-8                                 11044147               108.4 ns/op           200 B/op          4 allocs/op
BenchmarkFieldArrayDiveSuccess-8                                 6054232               194.4 ns/op            97 B/op          5 allocs/op
BenchmarkFieldArrayDiveSuccessParallel-8                        12523388                94.07 ns/op           97 B/op          5 allocs/op
BenchmarkFieldArrayDiveFailure-8                                 3587043               334.3 ns/op           300 B/op         10 allocs/op
BenchmarkFieldArrayDiveFailureParallel-8                         5816665               200.8 ns/op           300 B/op         10 allocs/op
BenchmarkFieldMapDiveSuccess-8                                   2217910               540.1 ns/op           288 B/op         14 allocs/op
BenchmarkFieldMapDiveSuccessParallel-8                           4446698               258.7 ns/op           288 B/op         14 allocs/op
BenchmarkFieldMapDiveFailure-8                                   2392759               504.6 ns/op           376 B/op         13 allocs/op
BenchmarkFieldMapDiveFailureParallel-8                           4244199               286.9 ns/op           376 B/op         13 allocs/op
BenchmarkFieldMapDiveWithKeysSuccess-8                           2005857               592.1 ns/op           288 B/op         14 allocs/op
BenchmarkFieldMapDiveWithKeysSuccessParallel-8                   4400850               296.9 ns/op           288 B/op         14 allocs/op
BenchmarkFieldMapDiveWithKeysFailure-8                           1850227               643.8 ns/op           553 B/op         16 allocs/op
BenchmarkFieldMapDiveWithKeysFailureParallel-8                   3293233               375.1 ns/op           553 B/op         16 allocs/op
BenchmarkFieldCustomTypeSuccess-8                               12174412                98.25 ns/op           32 B/op          2 allocs/op
BenchmarkFieldCustomTypeSuccessParallel-8                       34389907                35.49 ns/op           32 B/op          2 allocs/op
BenchmarkFieldCustomTypeFailure-8                                7582524               156.6 ns/op           184 B/op          3 allocs/op
BenchmarkFieldCustomTypeFailureParallel-8                       13019902                92.79 ns/op          184 B/op          3 allocs/op
BenchmarkFieldOrTagSuccess-8                                     3427260               349.4 ns/op            16 B/op          1 allocs/op
BenchmarkFieldOrTagSuccessParallel-8                            15144128                81.25 ns/op           16 B/op          1 allocs/op
BenchmarkFieldOrTagFailure-8                                     5913546               201.9 ns/op           216 B/op          5 allocs/op
BenchmarkFieldOrTagFailureParallel-8                             9810212               113.7 ns/op           216 B/op          5 allocs/op
BenchmarkStructLevelValidationSuccess-8                         13456327                87.66 ns/op           16 B/op          1 allocs/op
BenchmarkStructLevelValidationSuccessParallel-8                 41818888                27.77 ns/op           16 B/op          1 allocs/op
BenchmarkStructLevelValidationFailure-8                          4166284               272.6 ns/op           264 B/op          7 allocs/op
BenchmarkStructLevelValidationFailureParallel-8                  7594581               152.1 ns/op           264 B/op          7 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-8                         6508082               182.6 ns/op            32 B/op          2 allocs/op
BenchmarkStructSimpleCustomTypeSuccessParallel-8                23078605                54.78 ns/op           32 B/op          2 allocs/op
BenchmarkStructSimpleCustomTypeFailure-8                         3118352               381.0 ns/op           416 B/op          9 allocs/op
BenchmarkStructSimpleCustomTypeFailureParallel-8                 5300738               224.1 ns/op           432 B/op         10 allocs/op
BenchmarkStructFilteredSuccess-8                                 4761807               251.1 ns/op           216 B/op          5 allocs/op
BenchmarkStructFilteredSuccessParallel-8                         8792598               128.6 ns/op           216 B/op          5 allocs/op
BenchmarkStructFilteredFailure-8                                 5202573               232.1 ns/op           216 B/op          5 allocs/op
BenchmarkStructFilteredFailureParallel-8                         9591267               121.4 ns/op           216 B/op          5 allocs/op
BenchmarkStructPartialSuccess-8                                  5188512               231.6 ns/op           224 B/op          4 allocs/op
BenchmarkStructPartialSuccessParallel-8                          9179776               123.1 ns/op           224 B/op          4 allocs/op
BenchmarkStructPartialFailure-8                                  3071212               392.5 ns/op           440 B/op          9 allocs/op
BenchmarkStructPartialFailureParallel-8                          5344261               223.7 ns/op           440 B/op          9 allocs/op
BenchmarkStructExceptSuccess-8                                   3184230               375.0 ns/op           424 B/op          8 allocs/op
BenchmarkStructExceptSuccessParallel-8                          10090130               108.9 ns/op           208 B/op          3 allocs/op
BenchmarkStructExceptFailure-8                                   3347226               357.7 ns/op           424 B/op          8 allocs/op
BenchmarkStructExceptFailureParallel-8                           5654923               209.5 ns/op           424 B/op          8 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-8                         5232265               229.1 ns/op            56 B/op          3 allocs/op
BenchmarkStructSimpleCrossFieldSuccessParallel-8                17436674                64.75 ns/op           56 B/op          3 allocs/op
BenchmarkStructSimpleCrossFieldFailure-8                         3128613               383.6 ns/op           272 B/op          8 allocs/op
BenchmarkStructSimpleCrossFieldFailureParallel-8                 6994113               168.8 ns/op           272 B/op          8 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-8              3506487               340.9 ns/op            64 B/op          4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8     13431300                91.77 ns/op           64 B/op          4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-8              2410566               500.9 ns/op           288 B/op          9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8      6344510               188.2 ns/op           288 B/op          9 allocs/op
BenchmarkStructSimpleSuccess-8                                   8922726               133.8 ns/op             0 B/op          0 allocs/op
BenchmarkStructSimpleSuccessParallel-8                          55291153                23.63 ns/op            0 B/op          0 allocs/op
BenchmarkStructSimpleFailure-8                                   3171553               378.4 ns/op           416 B/op          9 allocs/op
BenchmarkStructSimpleFailureParallel-8                           5571692               212.0 ns/op           416 B/op          9 allocs/op
BenchmarkStructComplexSuccess-8                                  1683750               714.5 ns/op           224 B/op          5 allocs/op
BenchmarkStructComplexSuccessParallel-8                          4578046               257.0 ns/op           224 B/op          5 allocs/op
BenchmarkStructComplexFailure-8                                   481585              2547 ns/op            3041 B/op         48 allocs/op
BenchmarkStructComplexFailureParallel-8                           965764              1577 ns/op            3040 B/op         48 allocs/op
BenchmarkOneof-8                                                17380881                68.50 ns/op            0 B/op          0 allocs/op
BenchmarkOneofParallel-8                                         8084733               153.5 ns/op             0 B/op          0 allocs/op

Complementary Software

Here is a list of software that complements using this library either pre or post validation.

  • form - Decodes url.Values into Go value(s) and Encodes Go value(s) into url.Values. Dual Array and Full map support.
  • mold - A general library to help modify or set data within data structures and other objects

How to Contribute

Make a pull request...

License

Distributed under MIT License, please see license file within the code for more details.

Maintainers

This project has grown large enough that more than one person is required to properly support the community. If you are interested in becoming a maintainer please reach out to me https://github.com/deankarn

Documentation

Overview

Package validator implements value validations for structs and individual fields based on tags.

It can also handle Cross-Field and Cross-Struct validation for nested structs and has the ability to dive into arrays and maps of any type.

see more examples https://github.com/go-playground/validator/tree/master/_examples

Singleton

Validator is designed to be thread-safe and used as a singleton instance. It caches information about your struct and validations, in essence only parsing your validation tags once per struct type. Using multiple instances neglects the benefit of caching. The not thread-safe functions are explicitly marked as such in the documentation.

Validation Functions Return Type error

Doing things this way is actually the way the standard library does, see the file.Open method here:

https://golang.org/pkg/os/#Open.

The authors return type "error" to avoid the issue discussed in the following, where err is always != nil:

http://stackoverflow.com/a/29138676/3158232
https://github.com/go-playground/validator/issues/134

Validator only InvalidValidationError for bad validation input, nil or ValidationErrors as type error; so, in your code all you need to do is check if the error returned is not nil, and if it's not check if error is InvalidValidationError ( if necessary, most of the time it isn't ) type cast it to type ValidationErrors like so err.(validator.ValidationErrors).

Custom Validation Functions

Custom Validation functions can be added. Example:

// Structure
func customFunc(fl validator.FieldLevel) bool {

	if fl.Field().String() == "invalid" {
		return false
	}

	return true
}

validate.RegisterValidation("custom tag name", customFunc)
// NOTES: using the same tag name as an existing function
//        will overwrite the existing one

Cross-Field Validation

Cross-Field Validation can be done via the following tags:

  • eqfield
  • nefield
  • gtfield
  • gtefield
  • ltfield
  • ltefield
  • eqcsfield
  • necsfield
  • gtcsfield
  • gtecsfield
  • ltcsfield
  • ltecsfield

If, however, some custom cross-field validation is required, it can be done using a custom validation.

Why not just have cross-fields validation tags (i.e. only eqcsfield and not eqfield)?

The reason is efficiency. If you want to check a field within the same struct "eqfield" only has to find the field on the same struct (1 level). But, if we used "eqcsfield" it could be multiple levels down. Example:

type Inner struct {
	StartDate time.Time
}

type Outer struct {
	InnerStructField *Inner
	CreatedAt time.Time      `validate:"ltecsfield=InnerStructField.StartDate"`
}

now := time.Now()

inner := &Inner{
	StartDate: now,
}

outer := &Outer{
	InnerStructField: inner,
	CreatedAt: now,
}

errs := validate.Struct(outer)

// NOTE: when calling validate.Struct(val) topStruct will be the top level struct passed
//       into the function
//       when calling validate.VarWithValue(val, field, tag) val will be
//       whatever you pass, struct, field...
//       when calling validate.Field(field, tag) val will be nil

Multiple Validators

Multiple validators on a field will process in the order defined. Example:

type Test struct {
	Field `validate:"max=10,min=1"`
}

// max will be checked then min

Bad Validator definitions are not handled by the library. Example:

type Test struct {
	Field `validate:"min=10,max=0"`
}

// this definition of min max will never succeed

Using Validator Tags

Baked In Cross-Field validation only compares fields on the same struct. If Cross-Field + Cross-Struct validation is needed you should implement your own custom validator.

Comma (",") is the default separator of validation tags. If you wish to have a comma included within the parameter (i.e. excludesall=,) you will need to use the UTF-8 hex representation 0x2C, which is replaced in the code as a comma, so the above will become excludesall=0x2C.

type Test struct {
	Field `validate:"excludesall=,"`    // BAD! Do not include a comma.
	Field `validate:"excludesall=0x2C"` // GOOD! Use the UTF-8 hex representation.
}

Pipe ("|") is the 'or' validation tags deparator. If you wish to have a pipe included within the parameter i.e. excludesall=| you will need to use the UTF-8 hex representation 0x7C, which is replaced in the code as a pipe, so the above will become excludesall=0x7C

type Test struct {
	Field `validate:"excludesall=|"`    // BAD! Do not include a pipe!
	Field `validate:"excludesall=0x7C"` // GOOD! Use the UTF-8 hex representation.
}

Baked In Validators and Tags

Here is a list of the current built in validators:

Skip Field

Tells the validation to skip this struct field; this is particularly handy in ignoring embedded structs from being validated. (Usage: -)

Usage: -

Or Operator

This is the 'or' operator allowing multiple validators to be used and accepted. (Usage: rgb|rgba) <-- this would allow either rgb or rgba colors to be accepted. This can also be combined with 'and' for example ( Usage: omitempty,rgb|rgba)

Usage: |

StructOnly

When a field that is a nested struct is encountered, and contains this flag any validation on the nested struct will be run, but none of the nested struct fields will be validated. This is useful if inside of your program you know the struct will be valid, but need to verify it has been assigned. NOTE: only "required" and "omitempty" can be used on a struct itself.

Usage: structonly

NoStructLevel

Same as structonly tag except that any struct level validations will not run.

Usage: nostructlevel

Omit Empty

Allows conditional validation, for example if a field is not set with a value (Determined by the "required" validator) then other validation such as min or max won't run, but if a value is set validation will run.

Usage: omitempty

Omit Nil

Allows to skip the validation if the value is nil (same as omitempty, but only for the nil-values).

Usage: omitnil

Dive

This tells the validator to dive into a slice, array or map and validate that level of the slice, array or map with the validation tags that follow. Multidimensional nesting is also supported, each level you wish to dive will require another dive tag. dive has some sub-tags, 'keys' & 'endkeys', please see the Keys & EndKeys section just below.

Usage: dive

Example #1

[][]string with validation tag "gt=0,dive,len=1,dive,required"
// gt=0 will be applied to []
// len=1 will be applied to []string
// required will be applied to string

Example #2

[][]string with validation tag "gt=0,dive,dive,required"
// gt=0 will be applied to []
// []string will be spared validation
// required will be applied to string

Keys & EndKeys

These are to be used together directly after the dive tag and tells the validator that anything between 'keys' and 'endkeys' applies to the keys of a map and not the values; think of it like the 'dive' tag, but for map keys instead of values. Multidimensional nesting is also supported, each level you wish to validate will require another 'keys' and 'endkeys' tag. These tags are only valid for maps.

Usage: dive,keys,othertagvalidation(s),endkeys,valuevalidationtags

Example #1

map[string]string with validation tag "gt=0,dive,keys,eq=1|eq=2,endkeys,required"
// gt=0 will be applied to the map itself
// eq=1|eq=2 will be applied to the map keys
// required will be applied to map values

Example #2

map[[2]string]string with validation tag "gt=0,dive,keys,dive,eq=1|eq=2,endkeys,required"
// gt=0 will be applied to the map itself
// eq=1|eq=2 will be applied to each array element in the map keys
// required will be applied to map values

Required

This validates that the value is not the data types default zero value. For numbers ensures value is not zero. For strings ensures value is not "". For booleans ensures value is not false. For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value when using WithRequiredStructEnabled.

Usage: required

Required If

The field under validation must be present and not empty only if all the other specified fields are equal to the value following the specified field. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: required_if

Examples:

// require the field if the Field1 is equal to the parameter given:
Usage: required_if=Field1 foobar

// require the field if the Field1 and Field2 is equal to the value respectively:
Usage: required_if=Field1 foo Field2 bar

Required Unless

The field under validation must be present and not empty unless all the other specified fields are equal to the value following the specified field. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: required_unless

Examples:

// require the field unless the Field1 is equal to the parameter given:
Usage: required_unless=Field1 foobar

// require the field unless the Field1 and Field2 is equal to the value respectively:
Usage: required_unless=Field1 foo Field2 bar

Required With

The field under validation must be present and not empty only if any of the other specified fields are present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: required_with

Examples:

// require the field if the Field1 is present:
Usage: required_with=Field1

// require the field if the Field1 or Field2 is present:
Usage: required_with=Field1 Field2

Required With All

The field under validation must be present and not empty only if all of the other specified fields are present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: required_with_all

Example:

// require the field if the Field1 and Field2 is present:
Usage: required_with_all=Field1 Field2

Required Without

The field under validation must be present and not empty only when any of the other specified fields are not present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: required_without

Examples:

// require the field if the Field1 is not present:
Usage: required_without=Field1

// require the field if the Field1 or Field2 is not present:
Usage: required_without=Field1 Field2

Required Without All

The field under validation must be present and not empty only when all of the other specified fields are not present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: required_without_all

Example:

// require the field if the Field1 and Field2 is not present:
Usage: required_without_all=Field1 Field2

Excluded If

The field under validation must not be present or not empty only if all the other specified fields are equal to the value following the specified field. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: excluded_if

Examples:

// exclude the field if the Field1 is equal to the parameter given:
Usage: excluded_if=Field1 foobar

// exclude the field if the Field1 and Field2 is equal to the value respectively:
Usage: excluded_if=Field1 foo Field2 bar

Excluded Unless

The field under validation must not be present or empty unless all the other specified fields are equal to the value following the specified field. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. For structs ensures value is not the zero value.

Usage: excluded_unless

Examples:

// exclude the field unless the Field1 is equal to the parameter given:
Usage: excluded_unless=Field1 foobar

// exclude the field unless the Field1 and Field2 is equal to the value respectively:
Usage: excluded_unless=Field1 foo Field2 bar

Is Default

This validates that the value is the default value and is almost the opposite of required.

Usage: isdefault

Length

For numbers, length will ensure that the value is equal to the parameter given. For strings, it checks that the string length is exactly that number of characters. For slices, arrays, and maps, validates the number of items.

Example #1

Usage: len=10

Example #2 (time.Duration)

For time.Duration, len will ensure that the value is equal to the duration given in the parameter.

Usage: len=1h30m

Maximum

For numbers, max will ensure that the value is less than or equal to the parameter given. For strings, it checks that the string length is at most that number of characters. For slices, arrays, and maps, validates the number of items.

Example #1

Usage: max=10

Example #2 (time.Duration)

For time.Duration, max will ensure that the value is less than or equal to the duration given in the parameter.

Usage: max=1h30m

Minimum

For numbers, min will ensure that the value is greater or equal to the parameter given. For strings, it checks that the string length is at least that number of characters. For slices, arrays, and maps, validates the number of items.

Example #1

Usage: min=10

Example #2 (time.Duration)

For time.Duration, min will ensure that the value is greater than or equal to the duration given in the parameter.

Usage: min=1h30m

Equals

For strings & numbers, eq will ensure that the value is equal to the parameter given. For slices, arrays, and maps, validates the number of items.

Example #1

Usage: eq=10

Example #2 (time.Duration)

For time.Duration, eq will ensure that the value is equal to the duration given in the parameter.

Usage: eq=1h30m

Not Equal

For strings & numbers, ne will ensure that the value is not equal to the parameter given. For slices, arrays, and maps, validates the number of items.

Example #1

Usage: ne=10

Example #2 (time.Duration)

For time.Duration, ne will ensure that the value is not equal to the duration given in the parameter.

Usage: ne=1h30m

One Of

For strings, ints, and uints, oneof will ensure that the value is one of the values in the parameter. The parameter should be a list of values separated by whitespace. Values may be strings or numbers. To match strings with spaces in them, include the target string between single quotes. Kind of like an 'enum'.

Usage: oneof=red green
       oneof='red green' 'blue yellow'
       oneof=5 7 9

One Of Case Insensitive

Works the same as oneof but is case insensitive and therefore only accepts strings.

Usage: oneofci=red green
       oneofci='red green' 'blue yellow'

Greater Than

For numbers, this will ensure that the value is greater than the parameter given. For strings, it checks that the string length is greater than that number of characters. For slices, arrays and maps it validates the number of items.

Example #1

Usage: gt=10

Example #2 (time.Time)

For time.Time ensures the time value is greater than time.Now.UTC().

Usage: gt

Example #3 (time.Duration)

For time.Duration, gt will ensure that the value is greater than the duration given in the parameter.

Usage: gt=1h30m

Greater Than or Equal

Same as 'min' above. Kept both to make terminology with 'len' easier.

Example #1

Usage: gte=10

Example #2 (time.Time)

For time.Time ensures the time value is greater than or equal to time.Now.UTC().

Usage: gte

Example #3 (time.Duration)

For time.Duration, gte will ensure that the value is greater than or equal to the duration given in the parameter.

Usage: gte=1h30m

Less Than

For numbers, this will ensure that the value is less than the parameter given. For strings, it checks that the string length is less than that number of characters. For slices, arrays, and maps it validates the number of items.

Example #1

Usage: lt=10

Example #2 (time.Time)

For time.Time ensures the time value is less than time.Now.UTC().

Usage: lt

Example #3 (time.Duration)

For time.Duration, lt will ensure that the value is less than the duration given in the parameter.

Usage: lt=1h30m

Less Than or Equal

Same as 'max' above. Kept both to make terminology with 'len' easier.

Example #1

Usage: lte=10

Example #2 (time.Time)

For time.Time ensures the time value is less than or equal to time.Now.UTC().

Usage: lte

Example #3 (time.Duration)

For time.Duration, lte will ensure that the value is less than or equal to the duration given in the parameter.

Usage: lte=1h30m

Field Equals Another Field

This will validate the field value against another fields value either within a struct or passed in field.

Example #1:

// Validation on Password field using:
Usage: eqfield=ConfirmPassword

Example #2:

// Validating by field:
validate.VarWithValue(password, confirmpassword, "eqfield")

Field Equals Another Field (relative)

This does the same as eqfield except that it validates the field provided relative to the top level struct.

Usage: eqcsfield=InnerStructField.Field)

Field Does Not Equal Another Field

This will validate the field value against another fields value either within a struct or passed in field.

Examples:

// Confirm two colors are not the same:
//
// Validation on Color field:
Usage: nefield=Color2

// Validating by field:
validate.VarWithValue(color1, color2, "nefield")

Field Does Not Equal Another Field (relative)

This does the same as nefield except that it validates the field provided relative to the top level struct.

Usage: necsfield=InnerStructField.Field

Field Greater Than Another Field

Only valid for Numbers, time.Duration and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:

Example #1:

// Validation on End field using:
validate.Struct Usage(gtfield=Start)

Example #2:

// Validating by field:
validate.VarWithValue(start, end, "gtfield")

Field Greater Than Another Relative Field

This does the same as gtfield except that it validates the field provided relative to the top level struct.

Usage: gtcsfield=InnerStructField.Field

Field Greater Than or Equal To Another Field

Only valid for Numbers, time.Duration and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:

Example #1:

// Validation on End field using:
validate.Struct Usage(gtefield=Start)

Example #2:

// Validating by field:
validate.VarWithValue(start, end, "gtefield")

Field Greater Than or Equal To Another Relative Field

This does the same as gtefield except that it validates the field provided relative to the top level struct.

Usage: gtecsfield=InnerStructField.Field

Less Than Another Field

Only valid for Numbers, time.Duration and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:

Example #1:

// Validation on End field using:
validate.Struct Usage(ltfield=Start)

Example #2:

// Validating by field:
validate.VarWithValue(start, end, "ltfield")

Less Than Another Relative Field

This does the same as ltfield except that it validates the field provided relative to the top level struct.

Usage: ltcsfield=InnerStructField.Field

Less Than or Equal To Another Field

Only valid for Numbers, time.Duration and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:

Example #1:

// Validation on End field using:
validate.Struct Usage(ltefield=Start)

Example #2:

// Validating by field:
validate.VarWithValue(start, end, "ltefield")

Less Than or Equal To Another Relative Field

This does the same as ltefield except that it validates the field provided relative to the top level struct.

Usage: ltecsfield=InnerStructField.Field

Field Contains Another Field

This does the same as contains except for struct fields. It should only be used with string types. See the behavior of reflect.Value.String() for behavior on other types.

Usage: containsfield=InnerStructField.Field

Field Excludes Another Field

This does the same as excludes except for struct fields. It should only be used with string types. See the behavior of reflect.Value.String() for behavior on other types.

Usage: excludesfield=InnerStructField.Field

Unique

For arrays & slices, unique will ensure that there are no duplicates. For maps, unique will ensure that there are no duplicate values. For slices of struct, unique will ensure that there are no duplicate values in a field of the struct specified via a parameter.

// For arrays, slices, and maps:
Usage: unique

// For slices of struct:
Usage: unique=field

Alpha Only

This validates that a string value contains ASCII alpha characters only

Usage: alpha

Alphanumeric

This validates that a string value contains ASCII alphanumeric characters only

Usage: alphanum

Alpha Unicode

This validates that a string value contains unicode alpha characters only

Usage: alphaunicode

Alphanumeric Unicode

This validates that a string value contains unicode alphanumeric characters only

Usage: alphanumunicode

Boolean

This validates that a string value can successfully be parsed into a boolean with strconv.ParseBool

Usage: boolean

Number

This validates that a string value contains number values only. For integers or float it returns true.

Usage: number

Numeric

This validates that a string value contains a basic numeric value. basic excludes exponents etc... for integers or float it returns true.

Usage: numeric

Hexadecimal String

This validates that a string value contains a valid hexadecimal.

Usage: hexadecimal

Hexcolor String

This validates that a string value contains a valid hex color including hashtag (#)

Usage: hexcolor

Lowercase String

This validates that a string value contains only lowercase characters. An empty string is not a valid lowercase string.

Usage: lowercase

Uppercase String

This validates that a string value contains only uppercase characters. An empty string is not a valid uppercase string.

Usage: uppercase

RGB String

This validates that a string value contains a valid rgb color

Usage: rgb

RGBA String

This validates that a string value contains a valid rgba color

Usage: rgba

HSL String

This validates that a string value contains a valid hsl color

Usage: hsl

HSLA String

This validates that a string value contains a valid hsla color

Usage: hsla

E.164 Phone Number String

This validates that a string value contains a valid E.164 Phone number https://en.wikipedia.org/wiki/E.164 (ex. +1123456789)

Usage: e164

E-mail String

This validates that a string value contains a valid email This may not conform to all possibilities of any rfc standard, but neither does any email provider accept all possibilities.

Usage: email

JSON String

This validates that a string value is valid JSON

Usage: json

JWT String

This validates that a string value is a valid JWT

Usage: jwt

File

This validates that a string value contains a valid file path and that the file exists on the machine. This is done using os.Stat, which is a platform independent function.

Usage: file

Image path

This validates that a string value contains a valid file path and that the file exists on the machine and is an image. This is done using os.Stat and github.com/gabriel-vasile/mimetype

Usage: image

File Path

This validates that a string value contains a valid file path but does not validate the existence of that file. This is done using os.Stat, which is a platform independent function.

Usage: filepath

URL String

This validates that a string value contains a valid url This will accept any url the golang request uri accepts but must contain a schema for example http:// or rtmp://

Usage: url

URI String

This validates that a string value contains a valid uri This will accept any uri the golang request uri accepts

Usage: uri

Urn RFC 2141 String RFC 2141 String" aria-label="Go to Urn RFC 2141 String">¶

This validates that a string value contains a valid URN according to the RFC 2141 spec.

Usage: urn_rfc2141

Base32 String

This validates that a string value contains a valid bas324 value. Although an empty string is valid base32 this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag.

Usage: base32

Base64 String

This validates that a string value contains a valid base64 value. Although an empty string is valid base64 this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag.

Usage: base64

Base64URL String

This validates that a string value contains a valid base64 URL safe value according the RFC4648 spec. Although an empty string is a valid base64 URL safe value, this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag.

Usage: base64url

Base64RawURL String

This validates that a string value contains a valid base64 URL safe value, but without = padding, according the RFC4648 spec, section 3.2. Although an empty string is a valid base64 URL safe value, this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag.

Usage: base64url

Bitcoin Address

This validates that a string value contains a valid bitcoin address. The format of the string is checked to ensure it matches one of the three formats P2PKH, P2SH and performs checksum validation.

Usage: btc_addr

Bitcoin Bech32 Address (segwit)

This validates that a string value contains a valid bitcoin Bech32 address as defined by bip-0173 (https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki) Special thanks to Pieter Wuille for providing reference implementations.

Usage: btc_addr_bech32

Ethereum Address

This validates that a string value contains a valid ethereum address. The format of the string is checked to ensure it matches the standard Ethereum address format.

Usage: eth_addr

Contains

This validates that a string value contains the substring value.

Usage: contains=@

Contains Any

This validates that a string value contains any Unicode code points in the substring value.

Usage: containsany=!@#?

Contains Rune

This validates that a string value contains the supplied rune value.

Usage: containsrune=@

Excludes

This validates that a string value does not contain the substring value.

Usage: excludes=@

Excludes All

This validates that a string value does not contain any Unicode code points in the substring value.

Usage: excludesall=!@#?

Excludes Rune

This validates that a string value does not contain the supplied rune value.

Usage: excludesrune=@

Starts With

This validates that a string value starts with the supplied string value

Usage: startswith=hello

Ends With

This validates that a string value ends with the supplied string value

Usage: endswith=goodbye

Does Not Start With

This validates that a string value does not start with the supplied string value

Usage: startsnotwith=hello

Does Not End With

This validates that a string value does not end with the supplied string value

Usage: endsnotwith=goodbye

International Standard Book Number

This validates that a string value contains a valid isbn10 or isbn13 value.

Usage: isbn

International Standard Book Number 10

This validates that a string value contains a valid isbn10 value.

Usage: isbn10

International Standard Book Number 13

This validates that a string value contains a valid isbn13 value.

Usage: isbn13

Universally Unique Identifier UUID

This validates that a string value contains a valid UUID. Uppercase UUID values will not pass - use `uuid_rfc4122` instead.

Usage: uuid

Universally Unique Identifier UUID v3

This validates that a string value contains a valid version 3 UUID. Uppercase UUID values will not pass - use `uuid3_rfc4122` instead.

Usage: uuid3

Universally Unique Identifier UUID v4

This validates that a string value contains a valid version 4 UUID. Uppercase UUID values will not pass - use `uuid4_rfc4122` instead.

Usage: uuid4

Universally Unique Identifier UUID v5

This validates that a string value contains a valid version 5 UUID. Uppercase UUID values will not pass - use `uuid5_rfc4122` instead.

Usage: uuid5

Universally Unique Lexicographically Sortable Identifier ULID

This validates that a string value contains a valid ULID value.

Usage: ulid

ASCII

This validates that a string value contains only ASCII characters. NOTE: if the string is blank, this validates as true.

Usage: ascii

Printable ASCII

This validates that a string value contains only printable ASCII characters. NOTE: if the string is blank, this validates as true.

Usage: printascii

Multi-Byte Characters

This validates that a string value contains one or more multibyte characters. NOTE: if the string is blank, this validates as true.

Usage: multibyte

Data URL

This validates that a string value contains a valid DataURI. NOTE: this will also validate that the data portion is valid base64

Usage: datauri

Latitude

This validates that a string value contains a valid latitude.

Usage: latitude

Longitude

This validates that a string value contains a valid longitude.

Usage: longitude

Social Security Number SSN

This validates that a string value contains a valid U.S. Social Security Number.

Usage: ssn

Internet Protocol Address IP

This validates that a string value contains a valid IP Address.

Usage: ip

Internet Protocol Address IPv4

This validates that a string value contains a valid v4 IP Address.

Usage: ipv4

Internet Protocol Address IPv6

This validates that a string value contains a valid v6 IP Address.

Usage: ipv6

Classless Inter-Domain Routing CIDR

This validates that a string value contains a valid CIDR Address.

Usage: cidr

Classless Inter-Domain Routing CIDRv4

This validates that a string value contains a valid v4 CIDR Address.

Usage: cidrv4

Classless Inter-Domain Routing CIDRv6

This validates that a string value contains a valid v6 CIDR Address.

Usage: cidrv6

Transmission Control Protocol Address TCP

This validates that a string value contains a valid resolvable TCP Address.

Usage: tcp_addr

Transmission Control Protocol Address TCPv4

This validates that a string value contains a valid resolvable v4 TCP Address.

Usage: tcp4_addr

Transmission Control Protocol Address TCPv6

This validates that a string value contains a valid resolvable v6 TCP Address.

Usage: tcp6_addr

User Datagram Protocol Address UDP

This validates that a string value contains a valid resolvable UDP Address.

Usage: udp_addr

User Datagram Protocol Address UDPv4

This validates that a string value contains a valid resolvable v4 UDP Address.

Usage: udp4_addr

User Datagram Protocol Address UDPv6

This validates that a string value contains a valid resolvable v6 UDP Address.

Usage: udp6_addr

Internet Protocol Address IP

This validates that a string value contains a valid resolvable IP Address.

Usage: ip_addr

Internet Protocol Address IPv4

This validates that a string value contains a valid resolvable v4 IP Address.

Usage: ip4_addr

Internet Protocol Address IPv6

This validates that a string value contains a valid resolvable v6 IP Address.

Usage: ip6_addr

Unix domain socket end point Address

This validates that a string value contains a valid Unix Address.

Usage: unix_addr

Media Access Control Address MAC

This validates that a string value contains a valid MAC Address.

Usage: mac

Note: See Go's ParseMAC for accepted formats and types:

http://golang.org/src/net/mac.go?s=866:918#L29

Hostname RFC 952 RFC 952" aria-label="Go to Hostname RFC 952">¶

This validates that a string value is a valid Hostname according to RFC 952 https://tools.ietf.org/html/rfc952

Usage: hostname

Hostname RFC 1123 RFC 1123" aria-label="Go to Hostname RFC 1123">¶

This validates that a string value is a valid Hostname according to RFC 1123 https://tools.ietf.org/html/rfc1123

Usage: hostname_rfc1123 or if you want to continue to use 'hostname' in your tags, create an alias.

Full Qualified Domain Name (FQDN)

This validates that a string value contains a valid FQDN.

Usage: fqdn

HTML Tags

This validates that a string value appears to be an HTML element tag including those described at https://developer.mozilla.org/en-US/docs/Web/HTML/Element

Usage: html

HTML Encoded

This validates that a string value is a proper character reference in decimal or hexadecimal format

Usage: html_encoded

URL Encoded

This validates that a string value is percent-encoded (URL encoded) according to https://tools.ietf.org/html/rfc3986#section-2.1

Usage: url_encoded

Directory

This validates that a string value contains a valid directory and that it exists on the machine. This is done using os.Stat, which is a platform independent function.

Usage: dir

Directory Path

This validates that a string value contains a valid directory but does not validate the existence of that directory. This is done using os.Stat, which is a platform independent function. It is safest to suffix the string with os.PathSeparator if the directory may not exist at the time of validation.

Usage: dirpath

HostPort

This validates that a string value contains a valid DNS hostname and port that can be used to validate fields typically passed to sockets and connections.

Usage: hostname_port

Datetime

This validates that a string value is a valid datetime based on the supplied datetime format. Supplied format must match the official Go time format layout as documented in https://golang.org/pkg/time/

Usage: datetime=2006-01-02

Iso3166-1 alpha-2

This validates that a string value is a valid country code based on iso3166-1 alpha-2 standard. see: https://www.iso.org/iso-3166-country-codes.html

Usage: iso3166_1_alpha2

Iso3166-1 alpha-3

This validates that a string value is a valid country code based on iso3166-1 alpha-3 standard. see: https://www.iso.org/iso-3166-country-codes.html

Usage: iso3166_1_alpha3

Iso3166-1 alpha-numeric

This validates that a string value is a valid country code based on iso3166-1 alpha-numeric standard. see: https://www.iso.org/iso-3166-country-codes.html

Usage: iso3166_1_alpha3

BCP 47 Language Tag

This validates that a string value is a valid BCP 47 language tag, as parsed by language.Parse. More information on https://pkg.go.dev/golang.org/x/text/language

Usage: bcp47_language_tag

BIC (SWIFT code)

This validates that a string value is a valid Business Identifier Code (SWIFT code), defined in ISO 9362. More information on https://www.iso.org/standard/60390.html

Usage: bic

RFC 1035 label RFC 1035 label" aria-label="Go to RFC 1035 label">¶

This validates that a string value is a valid dns RFC 1035 label, defined in RFC 1035. More information on https://datatracker.ietf.org/doc/html/rfc1035

Usage: dns_rfc1035_label

TimeZone

This validates that a string value is a valid time zone based on the time zone database present on the system. Although empty value and Local value are allowed by time.LoadLocation golang function, they are not allowed by this validator. More information on https://golang.org/pkg/time/#LoadLocation

Usage: timezone

Semantic Version

This validates that a string value is a valid semver version, defined in Semantic Versioning 2.0.0. More information on https://semver.org/

Usage: semver

CVE Identifier

This validates that a string value is a valid cve id, defined in cve mitre. More information on https://cve.mitre.org/

Usage: cve

Credit Card

This validates that a string value contains a valid credit card number using Luhn algorithm.

Usage: credit_card

Luhn Checksum

Usage: luhn_checksum

This validates that a string or (u)int value contains a valid checksum using the Luhn algorithm.

MongoDB

This validates that a string is a valid 24 character hexadecimal string or valid connection string.

Usage: mongodb
       mongodb_connection_string

Example:

type Test struct {
	ObjectIdField         string `validate:"mongodb"`
	ConnectionStringField string `validate:"mongodb_connection_string"`
}

Cron

This validates that a string value contains a valid cron expression.

Usage: cron

SpiceDb ObjectID/Permission/Object Type

This validates that a string is valid for use with SpiceDb for the indicated purpose. If no purpose is given, a purpose of 'id' is assumed.

Usage: spicedb=id|permission|type

Alias Validators and Tags

Alias Validators and Tags NOTE: When returning an error, the tag returned in "FieldError" will be the alias tag unless the dive tag is part of the alias. Everything after the dive tag is not reported as the alias tag. Also, the "ActualTag" in the before case will be the actual tag within the alias that failed.

Here is a list of the current built in alias tags:

"iscolor"
	alias is "hexcolor|rgb|rgba|hsl|hsla" (Usage: iscolor)
"country_code"
	alias is "iso3166_1_alpha2|iso3166_1_alpha3|iso3166_1_alpha_numeric" (Usage: country_code)

Validator notes:

regex
	a regex validator won't be added because commas and = signs can be part
	of a regex which conflict with the validation definitions. Although
	workarounds can be made, they take away from using pure regex's.
	Furthermore it's quick and dirty but the regex's become harder to
	maintain and are not reusable, so it's as much a programming philosophy
	as anything.

	In place of this new validator functions should be created; a regex can
	be used within the validator function and even be precompiled for better
	efficiency within regexes.go.

	And the best reason, you can submit a pull request and we can keep on
	adding to the validation library of this package!

Non standard validators

A collection of validation rules that are frequently needed but are more complex than the ones found in the baked in validators. A non standard validator must be registered manually like you would with your own custom validation functions.

Example of registration and use:

type Test struct {
	TestField string `validate:"yourtag"`
}

t := &Test{
	TestField: "Test"
}

validate := validator.New()
validate.RegisterValidation("yourtag", validators.NotBlank)

Here is a list of the current non standard validators:

NotBlank
	This validates that the value is not blank or with length zero.
	For strings ensures they do not contain only spaces. For channels, maps, slices and arrays
	ensures they don't have zero length. For others, a non empty value is required.

	Usage: notblank

Panics

This package panics when bad input is provided, this is by design, bad code like that should not make it to production.

type Test struct {
	TestField string `validate:"nonexistantfunction=1"`
}

t := &Test{
	TestField: "Test"
}

validate.Struct(t) // this will panic

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type CustomTypeFunc

type CustomTypeFunc func(field reflect.Value) interface{}

CustomTypeFunc allows for overriding or adding custom field type handler functions field = field value of the type to return a value to be validated example Valuer from sql drive see https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29

type FieldError

type FieldError interface {

	// Tag returns the validation tag that failed. if the
	// validation was an alias, this will return the
	// alias name and not the underlying tag that failed.
	//
	// eg. alias "iscolor": "hexcolor|rgb|rgba|hsl|hsla"
	// will return "iscolor"
	Tag() string

	// ActualTag returns the validation tag that failed, even if an
	// alias the actual tag within the alias will be returned.
	// If an 'or' validation fails the entire or will be returned.
	//
	// eg. alias "iscolor": "hexcolor|rgb|rgba|hsl|hsla"
	// will return "hexcolor|rgb|rgba|hsl|hsla"
	ActualTag() string

	// Namespace returns the namespace for the field error, with the tag
	// name taking precedence over the field's actual name.
	//
	// eg. JSON name "User.fname"
	//
	// See StructNamespace() for a version that returns actual names.
	//
	// NOTE: this field can be blank when validating a single primitive field
	// using validate.Field(...) as there is no way to extract it's name
	Namespace() string

	// StructNamespace returns the namespace for the field error, with the field's
	// actual name.
	//
	// eq. "User.FirstName" see Namespace for comparison
	//
	// NOTE: this field can be blank when validating a single primitive field
	// using validate.Field(...) as there is no way to extract its name
	StructNamespace() string

	// Field returns the fields name with the tag name taking precedence over the
	// field's actual name.
	//
	// eq. JSON name "fname"
	// see StructField for comparison
	Field() string

	// StructField returns the field's actual name from the struct, when able to determine.
	//
	// eq.  "FirstName"
	// see Field for comparison
	StructField() string

	// Value returns the actual field's value in case needed for creating the error
	// message
	Value() interface{}

	// Param returns the param value, in string form for comparison; this will also
	// help with generating an error message
	Param() string

	// Kind returns the Field's reflect Kind
	//
	// eg. time.Time's kind is a struct
	Kind() reflect.Kind

	// Type returns the Field's reflect Type
	//
	// eg. time.Time's type is time.Time
	Type() reflect.Type

	// Translate returns the FieldError's translated error
	// from the provided 'ut.Translator' and registered 'TranslationFunc'
	//
	// NOTE: if no registered translator can be found it returns the same as
	// calling fe.Error()
	Translate(ut ut.Translator) string

	// Error returns the FieldError's message
	Error() string
}

FieldError contains all functions to get error details

type FieldLevel

type FieldLevel interface {

	// Top returns the top level struct, if any
	Top() reflect.Value

	// Parent returns the current fields parent struct, if any or
	// the comparison value if called 'VarWithValue'
	Parent() reflect.Value

	// Field returns current field for validation
	Field() reflect.Value

	// FieldName returns the field's name with the tag
	// name taking precedence over the fields actual name.
	FieldName() string

	// StructFieldName returns the struct field's name
	StructFieldName() string

	// Param returns param for validation against current field
	Param() string

	// GetTag returns the current validations tag name
	GetTag() string

	// ExtractType gets the actual underlying type of field value.
	// It will dive into pointers, customTypes and return you the
	// underlying value and it's kind.
	ExtractType(field reflect.Value) (value reflect.Value, kind reflect.Kind, nullable bool)

	// GetStructFieldOK traverses the parent struct to retrieve a specific field denoted by the provided namespace
	// in the param and returns the field, field kind and whether is was successful in retrieving
	// the field at all.
	//
	// NOTE: when not successful ok will be false, this can happen when a nested struct is nil and so the field
	// could not be retrieved because it didn't exist.
	//
	// Deprecated: Use GetStructFieldOK2() instead which also return if the value is nullable.
	GetStructFieldOK() (reflect.Value, reflect.Kind, bool)

	// GetStructFieldOKAdvanced is the same as GetStructFieldOK except that it accepts the parent struct to start looking for
	// the field and namespace allowing more extensibility for validators.
	//
	// Deprecated: Use GetStructFieldOKAdvanced2() instead which also return if the value is nullable.
	GetStructFieldOKAdvanced(val reflect.Value, namespace string) (reflect.Value, reflect.Kind, bool)

	// GetStructFieldOK2 traverses the parent struct to retrieve a specific field denoted by the provided namespace
	// in the param and returns the field, field kind, if it's a nullable type and whether is was successful in retrieving
	// the field at all.
	//
	// NOTE: when not successful ok will be false, this can happen when a nested struct is nil and so the field
	// could not be retrieved because it didn't exist.
	GetStructFieldOK2() (reflect.Value, reflect.Kind, bool, bool)

	// GetStructFieldOKAdvanced2 is the same as GetStructFieldOK except that it accepts the parent struct to start looking for
	// the field and namespace allowing more extensibility for validators.
	GetStructFieldOKAdvanced2(val reflect.Value, namespace string) (reflect.Value, reflect.Kind, bool, bool)
}

FieldLevel contains all the information and helper functions to validate a field

type FilterFunc

type FilterFunc func(ns []byte) bool

FilterFunc is the type used to filter fields using StructFiltered(...) function. returning true results in the field being filtered/skipped from validation

type Func

type Func func(fl FieldLevel) bool

Func accepts a FieldLevel interface for all validation needs. The return value should be true when validation succeeds.

type FuncCtx

type FuncCtx func(ctx context.Context, fl FieldLevel) bool

FuncCtx accepts a context.Context and FieldLevel interface for all validation needs. The return value should be true when validation succeeds.

type InvalidValidationError

type InvalidValidationError struct {
	Type reflect.Type
}

InvalidValidationError describes an invalid argument passed to `Struct`, `StructExcept`, StructPartial` or `Field`

func (*InvalidValidationError) Error

func (e *InvalidValidationError) Error() string

Error returns InvalidValidationError message

type Option added in v10.15.2

type Option func(*Validate)

Option represents a configurations option to be applied to validator during initialization.

func WithPrivateFieldValidation added in v10.19.0

func WithPrivateFieldValidation() Option

WithPrivateFieldValidation activates validation for unexported fields via the use of the `unsafe` package.

By opting into this feature you are acknowledging that you are aware of the risks and accept any current or future consequences of using this feature.

func WithRequiredStructEnabled added in v10.15.2

func WithRequiredStructEnabled() Option

WithRequiredStructEnabled enables required tag on non-pointer structs to be applied instead of ignored.

This was made opt-in behaviour in order to maintain backward compatibility with the behaviour previous to being able to apply struct level validations on struct fields directly.

It is recommended you enabled this as it will be the default behaviour in v11+

type RegisterTranslationsFunc

type RegisterTranslationsFunc func(ut ut.Translator) error

RegisterTranslationsFunc allows for registering of translations for a 'ut.Translator' for use within the 'TranslationFunc'

type StructLevel

type StructLevel interface {

	// Validator returns the main validation object, in case one wants to call validations internally.
	// this is so you don't have to use anonymous functions to get access to the validate
	// instance.
	Validator() *Validate

	// Top returns the top level struct, if any
	Top() reflect.Value

	// Parent returns the current fields parent struct, if any
	Parent() reflect.Value

	// Current returns the current struct.
	Current() reflect.Value

	// ExtractType gets the actual underlying type of field value.
	// It will dive into pointers, customTypes and return you the
	// underlying value and its kind.
	ExtractType(field reflect.Value) (value reflect.Value, kind reflect.Kind, nullable bool)

	// ReportError reports an error just by passing the field and tag information
	//
	// NOTES:
	//
	// fieldName and altName get appended to the existing namespace that
	// validator is on. e.g. pass 'FirstName' or 'Names[0]' depending
	// on the nesting
	//
	// tag can be an existing validation tag or just something you make up
	// and process on the flip side it's up to you.
	ReportError(field interface{}, fieldName, structFieldName string, tag, param string)

	// ReportValidationErrors reports an error just by passing ValidationErrors
	//
	// NOTES:
	//
	// relativeNamespace and relativeActualNamespace get appended to the
	// existing namespace that validator is on.
	// e.g. pass 'User.FirstName' or 'Users[0].FirstName' depending
	// on the nesting. most of the time they will be blank, unless you validate
	// at a level lower the current field depth
	ReportValidationErrors(relativeNamespace, relativeActualNamespace string, errs ValidationErrors)
}

StructLevel contains all the information and helper functions to validate a struct

type StructLevelFunc

type StructLevelFunc func(sl StructLevel)

StructLevelFunc accepts all values needed for struct level validation

type StructLevelFuncCtx

type StructLevelFuncCtx func(ctx context.Context, sl StructLevel)

StructLevelFuncCtx accepts all values needed for struct level validation but also allows passing of contextual validation information via context.Context.

type TagNameFunc

type TagNameFunc func(field reflect.StructField) string

TagNameFunc allows for adding of a custom tag name parser

type TranslationFunc

type TranslationFunc func(ut ut.Translator, fe FieldError) string

TranslationFunc is the function type used to register or override custom translations

type Validate

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

Validate contains the validator settings and cache

func New

func New(options ...Option) *Validate

New returns a new instance of 'validate' with sane defaults. Validate is designed to be thread-safe and used as a singleton instance. It caches information about your struct and validations, in essence only parsing your validation tags once per struct type. Using multiple instances neglects the benefit of caching.

func (*Validate) RegisterAlias

func (v *Validate) RegisterAlias(alias, tags string)

RegisterAlias registers a mapping of a single validation tag that defines a common or complex set of validation(s) to simplify adding validation to structs.

NOTE: this function is not thread-safe it is intended that these all be registered prior to any validation

func (*Validate) RegisterCustomTypeFunc

func (v *Validate) RegisterCustomTypeFunc(fn CustomTypeFunc, types ...interface{})

RegisterCustomTypeFunc registers a CustomTypeFunc against a number of types

NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation

func (*Validate) RegisterStructValidation

func (v *Validate) RegisterStructValidation(fn StructLevelFunc, types ...interface{})

RegisterStructValidation registers a StructLevelFunc against a number of types.

NOTE: - this method is not thread-safe it is intended that these all be registered prior to any validation

func (*Validate) RegisterStructValidationCtx

func (v *Validate) RegisterStructValidationCtx(fn StructLevelFuncCtx, types ...interface{})

RegisterStructValidationCtx registers a StructLevelFuncCtx against a number of types and allows passing of contextual validation information via context.Context.

NOTE: - this method is not thread-safe it is intended that these all be registered prior to any validation

func (*Validate) RegisterStructValidationMapRules added in v10.11.0

func (v *Validate) RegisterStructValidationMapRules(rules map[string]string, types ...interface{})

RegisterStructValidationMapRules registers validate map rules. Be aware that map validation rules supersede those defined on a/the struct if present.

NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation

func (*Validate) RegisterTagNameFunc

func (v *Validate) RegisterTagNameFunc(fn TagNameFunc)

RegisterTagNameFunc registers a function to get alternate names for StructFields.

eg. to use the names which have been specified for JSON representations of structs, rather than normal Go field names:

validate.RegisterTagNameFunc(func(fld reflect.StructField) string {
    name := strings.SplitN(fld.Tag.Get("json"), ",", 2)[0]
    // skip if tag key says it should be ignored
    if name == "-" {
        return ""
    }
    return name
})

func (*Validate) RegisterTranslation

func (v *Validate) RegisterTranslation(tag string, trans ut.Translator, registerFn RegisterTranslationsFunc, translationFn TranslationFunc) (err error)

RegisterTranslation registers translations against the provided tag.

func (*Validate) RegisterValidation

func (v *Validate) RegisterValidation(tag string, fn Func, callValidationEvenIfNull ...bool) error

RegisterValidation adds a validation with the given tag

NOTES: - if the key already exists, the previous validation function will be replaced. - this method is not thread-safe it is intended that these all be registered prior to any validation

func (*Validate) RegisterValidationCtx

func (v *Validate) RegisterValidationCtx(tag string, fn FuncCtx, callValidationEvenIfNull ...bool) error

RegisterValidationCtx does the same as RegisterValidation on accepts a FuncCtx validation allowing context.Context validation support.

func (*Validate) SetTagName

func (v *Validate) SetTagName(name string)

SetTagName allows for changing of the default tag name of 'validate'

func (*Validate) Struct

func (v *Validate) Struct(s interface{}) error

Struct validates a structs exposed fields, and automatically validates nested structs, unless otherwise specified.

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructCtx

func (v *Validate) StructCtx(ctx context.Context, s interface{}) (err error)

StructCtx validates a structs exposed fields, and automatically validates nested structs, unless otherwise specified and also allows passing of context.Context for contextual validation information.

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructExcept

func (v *Validate) StructExcept(s interface{}, fields ...string) error

StructExcept validates all fields except the ones passed in. Fields may be provided in a namespaced fashion relative to the struct provided i.e. NestedStruct.Field or NestedArrayField[0].Struct.Name

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructExceptCtx

func (v *Validate) StructExceptCtx(ctx context.Context, s interface{}, fields ...string) (err error)

StructExceptCtx validates all fields except the ones passed in and allows passing of contextual validation information via context.Context Fields may be provided in a namespaced fashion relative to the struct provided i.e. NestedStruct.Field or NestedArrayField[0].Struct.Name

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructFiltered

func (v *Validate) StructFiltered(s interface{}, fn FilterFunc) error

StructFiltered validates a structs exposed fields, that pass the FilterFunc check and automatically validates nested structs, unless otherwise specified.

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructFilteredCtx

func (v *Validate) StructFilteredCtx(ctx context.Context, s interface{}, fn FilterFunc) (err error)

StructFilteredCtx validates a structs exposed fields, that pass the FilterFunc check and automatically validates nested structs, unless otherwise specified and also allows passing of contextual validation information via context.Context

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructPartial

func (v *Validate) StructPartial(s interface{}, fields ...string) error

StructPartial validates the fields passed in only, ignoring all others. Fields may be provided in a namespaced fashion relative to the struct provided eg. NestedStruct.Field or NestedArrayField[0].Struct.Name

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) StructPartialCtx

func (v *Validate) StructPartialCtx(ctx context.Context, s interface{}, fields ...string) (err error)

StructPartialCtx validates the fields passed in only, ignoring all others and allows passing of contextual validation information via context.Context Fields may be provided in a namespaced fashion relative to the struct provided eg. NestedStruct.Field or NestedArrayField[0].Struct.Name

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.

func (*Validate) ValidateMap added in v10.6.0

func (v *Validate) ValidateMap(data map[string]interface{}, rules map[string]interface{}) map[string]interface{}

ValidateMap validates map data from a map of tags

func (Validate) ValidateMapCtx added in v10.6.0

func (v Validate) ValidateMapCtx(ctx context.Context, data map[string]interface{}, rules map[string]interface{}) map[string]interface{}

ValidateMapCtx validates a map using a map of validation rules and allows passing of contextual validation information via context.Context.

func (*Validate) Var

func (v *Validate) Var(field interface{}, tag string) error

Var validates a single variable using tag style validation. eg. var i int validate.Var(i, "gt=1,lt=10")

WARNING: a struct can be passed for validation eg. time.Time is a struct or if you have a custom type and have registered a custom type handler, so must allow it; however unforeseen validations will occur if trying to validate a struct that is meant to be passed to 'validate.Struct'

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors. validate Array, Slice and maps fields which may contain more than one error

func (*Validate) VarCtx

func (v *Validate) VarCtx(ctx context.Context, field interface{}, tag string) (err error)

VarCtx validates a single variable using tag style validation and allows passing of contextual validation information via context.Context. eg. var i int validate.Var(i, "gt=1,lt=10")

WARNING: a struct can be passed for validation eg. time.Time is a struct or if you have a custom type and have registered a custom type handler, so must allow it; however unforeseen validations will occur if trying to validate a struct that is meant to be passed to 'validate.Struct'

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors. validate Array, Slice and maps fields which may contain more than one error

func (*Validate) VarWithValue

func (v *Validate) VarWithValue(field interface{}, other interface{}, tag string) error

VarWithValue validates a single variable, against another variable/field's value using tag style validation eg. s1 := "abcd" s2 := "abcd" validate.VarWithValue(s1, s2, "eqcsfield") // returns true

WARNING: a struct can be passed for validation eg. time.Time is a struct or if you have a custom type and have registered a custom type handler, so must allow it; however unforeseen validations will occur if trying to validate a struct that is meant to be passed to 'validate.Struct'

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors. validate Array, Slice and maps fields which may contain more than one error

func (*Validate) VarWithValueCtx

func (v *Validate) VarWithValueCtx(ctx context.Context, field interface{}, other interface{}, tag string) (err error)

VarWithValueCtx validates a single variable, against another variable/field's value using tag style validation and allows passing of contextual validation information via context.Context. eg. s1 := "abcd" s2 := "abcd" validate.VarWithValue(s1, s2, "eqcsfield") // returns true

WARNING: a struct can be passed for validation eg. time.Time is a struct or if you have a custom type and have registered a custom type handler, so must allow it; however unforeseen validations will occur if trying to validate a struct that is meant to be passed to 'validate.Struct'

It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors. validate Array, Slice and maps fields which may contain more than one error

type ValidationErrors

type ValidationErrors []FieldError

ValidationErrors is an array of FieldError's for use in custom error messages post validation.

func (ValidationErrors) Error

func (ve ValidationErrors) Error() string

Error is intended for use in development + debugging and not intended to be a production error message. It allows ValidationErrors to subscribe to the Error interface. All information to create an error message specific to your application is contained within the FieldError found within the ValidationErrors array

func (ValidationErrors) Translate

Translate translates all of the ValidationErrors

type ValidationErrorsTranslations

type ValidationErrorsTranslations map[string]string

ValidationErrorsTranslations is the translation return type

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