Package validator
================
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[](https://semaphoreci.com/joeybloggs/validator)
[](https://coveralls.io/github/go-playground/validator?branch=v9)
[](https://goreportcard.com/report/github.com/go-playground/validator)
[](https://godoc.org/gopkg.in/go-playground/validator.v9)
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.
- Handles type interface by determining it's underlying type prior to validation.
- Handles custom field types such as sql driver Valuer see [Valuer ](https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29 )
- 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 ](https://github.com/gin-gonic/gin ) web framework; upgrading from v8 to v9 in gin see [here ](https://github.com/go-playground/validator/tree/v9/_examples/gin-upgrading-overriding )
Installation
------------
Use go get.
go get gopkg.in/go-playground/validator.v9
Then import the validator package into your own code.
import "gopkg.in/go-playground/validator.v9"
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 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:
```go
err := validate.Struct(mystruct)
validationErrors := err.(validator.ValidationErrors)
```
Usage and documentation
------
Please see http://godoc.org/gopkg.in/go-playground/validator.v9 for detailed usage docs.
##### Examples:
- [Simple ](https://github.com/go-playground/validator/blob/v9/_examples/simple/main.go )
- [Custom Field Types ](https://github.com/go-playground/validator/blob/v9/_examples/custom/main.go )
- [Struct Level ](https://github.com/go-playground/validator/blob/v9/_examples/struct-level/main.go )
- [Translations & Custom Errors ](https://github.com/go-playground/validator/blob/v9/_examples/translations/main.go )
- [Gin upgrade and/or override validator ](https://github.com/go-playground/validator/tree/v9/_examples/gin-upgrading-overriding )
- [wash - an example application putting it all together ](https://github.com/bluesuncorp/wash )
Benchmarks
------
###### Run on Dell XPS 15 i7-7700HQ 32GB Go version go1.8.3 linux/amd64
```go
go test -run=XXX -bench=. -benchmem=true
BenchmarkFieldSuccess-8 20000000 88.3 ns/op 0 B/op 0 allocs/op
BenchmarkFieldSuccessParallel-8 50000000 30.4 ns/op 0 B/op 0 allocs/op
BenchmarkFieldFailure-8 3000000 428 ns/op 208 B/op 4 allocs/op
BenchmarkFieldFailureParallel-8 20000000 96.0 ns/op 208 B/op 4 allocs/op
BenchmarkFieldDiveSuccess-8 2000000 695 ns/op 201 B/op 11 allocs/op
BenchmarkFieldDiveSuccessParallel-8 10000000 205 ns/op 201 B/op 11 allocs/op
BenchmarkFieldDiveFailure-8 1000000 1083 ns/op 412 B/op 16 allocs/op
BenchmarkFieldDiveFailureParallel-8 5000000 278 ns/op 413 B/op 16 allocs/op
BenchmarkFieldCustomTypeSuccess-8 10000000 229 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeSuccessParallel-8 20000000 72.4 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeFailure-8 5000000 377 ns/op 208 B/op 4 allocs/op
BenchmarkFieldCustomTypeFailureParallel-8 20000000 93.0 ns/op 208 B/op 4 allocs/op
BenchmarkFieldOrTagSuccess-8 2000000 767 ns/op 16 B/op 1 allocs/op
BenchmarkFieldOrTagSuccessParallel-8 3000000 425 ns/op 16 B/op 1 allocs/op
BenchmarkFieldOrTagFailure-8 2000000 548 ns/op 224 B/op 5 allocs/op
BenchmarkFieldOrTagFailureParallel-8 3000000 411 ns/op 224 B/op 5 allocs/op
BenchmarkStructLevelValidationSuccess-8 10000000 219 ns/op 32 B/op 2 allocs/op
BenchmarkStructLevelValidationSuccessParallel-8 20000000 69.2 ns/op 32 B/op 2 allocs/op
BenchmarkStructLevelValidationFailure-8 2000000 628 ns/op 304 B/op 8 allocs/op
BenchmarkStructLevelValidationFailureParallel-8 10000000 165 ns/op 304 B/op 8 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-8 3000000 411 ns/op 32 B/op 2 allocs/op
BenchmarkStructSimpleCustomTypeSuccessParallel-8 10000000 122 ns/op 32 B/op 2 allocs/op
BenchmarkStructSimpleCustomTypeFailure-8 1000000 1022 ns/op 424 B/op 9 allocs/op
BenchmarkStructSimpleCustomTypeFailureParallel-8 10000000 228 ns/op 440 B/op 10 allocs/op
BenchmarkStructFilteredSuccess-8 2000000 737 ns/op 288 B/op 9 allocs/op
BenchmarkStructFilteredSuccessParallel-8 10000000 192 ns/op 288 B/op 9 allocs/op
BenchmarkStructFilteredFailure-8 3000000 583 ns/op 256 B/op 7 allocs/op
BenchmarkStructFilteredFailureParallel-8 10000000 152 ns/op 256 B/op 7 allocs/op
BenchmarkStructPartialSuccess-8 2000000 731 ns/op 256 B/op 6 allocs/op
BenchmarkStructPartialSuccessParallel-8 10000000 173 ns/op 256 B/op 6 allocs/op
BenchmarkStructPartialFailure-8 1000000 1164 ns/op 480 B/op 11 allocs/op
BenchmarkStructPartialFailureParallel-8 5000000 253 ns/op 480 B/op 11 allocs/op
BenchmarkStructExceptSuccess-8 1000000 1337 ns/op 496 B/op 12 allocs/op
BenchmarkStructExceptSuccessParallel-8 10000000 153 ns/op 240 B/op 5 allocs/op
BenchmarkStructExceptFailure-8 2000000 954 ns/op 464 B/op 10 allocs/op
BenchmarkStructExceptFailureParallel-8 5000000 234 ns/op 464 B/op 10 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-8 3000000 420 ns/op 72 B/op 3 allocs/op
BenchmarkStructSimpleCrossFieldSuccessParallel-8 10000000 125 ns/op 72 B/op 3 allocs/op
BenchmarkStructSimpleCrossFieldFailure-8 2000000 790 ns/op 304 B/op 8 allocs/op
BenchmarkStructSimpleCrossFieldFailureParallel-8 10000000 205 ns/op 304 B/op 8 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 2000000 611 ns/op 80 B/op 4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8 10000000 172 ns/op 80 B/op 4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-8 1000000 1112 ns/op 320 B/op 9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8 5000000 258 ns/op 320 B/op 9 allocs/op
BenchmarkStructSimpleSuccess-8 5000000 263 ns/op 0 B/op 0 allocs/op
BenchmarkStructSimpleSuccessParallel-8 20000000 83.1 ns/op 0 B/op 0 allocs/op
BenchmarkStructSimpleFailure-8 2000000 964 ns/op 424 B/op 9 allocs/op
BenchmarkStructSimpleFailureParallel-8 10000000 212 ns/op 424 B/op 9 allocs/op
BenchmarkStructComplexSuccess-8 1000000 1504 ns/op 128 B/op 8 allocs/op
BenchmarkStructComplexSuccessParallel-8 3000000 427 ns/op 128 B/op 8 allocs/op
BenchmarkStructComplexFailure-8 300000 7585 ns/op 3041 B/op 53 allocs/op
BenchmarkStructComplexFailureParallel-8 1000000 1387 ns/op 3041 B/op 53 allocs/op
```
Complementary Software
----------------------
Here is a list of software that complements using this library either pre or post validation.
* [form ](https://github.com/go-playground/form ) - Decodes url.Values into Go value(s) and Encodes Go value(s) into url.Values. Dual Array and Full map support.
* [Conform ](https://github.com/leebenson/conform ) - Trims, sanitizes & scrubs data based on struct tags.
How to Contribute
------
Make a pull request...
License
------
Distributed under MIT License, please see license file within the code for more details.
