Package validator

<img align="right" src="logo.png">

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 and the Valuer interface
• 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

A Call for Maintainers

Please read the discussion started here if you are interested in contributing/helping maintain this package.

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:

• http://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_rfc1123 | Hostname RFC 1123 | | hostname_port | HostPort | | port | Port number | | 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 | | uds_exists | Unix domain socket exists (checks filesystem sockets and Linux abstract sockets) | | uri | URI String | | url | URL String | | http_url | HTTP(s) URL String | | https_url | HTTPS-only URL String | | url_encoded | URL Encoded | | urn_rfc2141 | Urn RFC 2141 String |

Strings:

| Tag | Description | | - | - | | alpha | Alpha Only | | alphaspace | Alpha Space | | alphanum | Alphanumeric | | alphanumspace | Alphanumeric Space | | 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_iso_9362_2014 | Business Identifier Code (ISO 9362:2014) | | bic | Business Identifier Code (ISO 9362:2022) | | 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 | | ein | U.S. Employer Identification Number | | email | E-mail String | eth_addr | Ethereum Address | | hexadecimal | Hexadecimal String | | hexcolor | Hexcolor String | | hsl | HSL String | | hsla | HSLA String | | cmyk | CMYK 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