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:

• 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:

Network:

Strings:

Format:

Comparisons:

Other:

Aliases:

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