Package validator

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:

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

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:

• Simple
• Custom Field Types
• Struct Level
• Translations & Custom Errors
• Gin upgrade and/or override validator
• wash - an example application putting it all together

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
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