Package validator
================
< img align = "right" src = "https://raw.githubusercontent.com/go-playground/validator/v9/logo.png" >
[](https://gitter.im/go-playground/validator?utm_source=badge& utm_medium=badge& utm_campaign=pr-badge& utm_content=badge)
[](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 MacBook Pro (Retina, 15-inch, Late 2013) 2.6 GHz Intel Core i7 16 GB 1600 MHz DDR3 using Go version go1.7.1 darwin/amd64
```go
BenchmarkFieldSuccess-8 20000000 106 ns/op
BenchmarkFieldSuccessParallel-8 50000000 33.7 ns/op
BenchmarkFieldFailure-8 5000000 346 ns/op
BenchmarkFieldFailureParallel-8 20000000 115 ns/op
BenchmarkFieldDiveSuccess-8 2000000 739 ns/op
BenchmarkFieldDiveSuccessParallel-8 10000000 246 ns/op
BenchmarkFieldDiveFailure-8 1000000 1043 ns/op
BenchmarkFieldDiveFailureParallel-8 5000000 381 ns/op
BenchmarkFieldCustomTypeSuccess-8 5000000 270 ns/op
BenchmarkFieldCustomTypeSuccessParallel-8 20000000 92.5 ns/op
BenchmarkFieldCustomTypeFailure-8 5000000 331 ns/op
BenchmarkFieldCustomTypeFailureParallel-8 20000000 132 ns/op
BenchmarkFieldOrTagSuccess-8 2000000 874 ns/op
BenchmarkFieldOrTagSuccessParallel-8 5000000 368 ns/op
BenchmarkFieldOrTagFailure-8 3000000 566 ns/op
BenchmarkFieldOrTagFailureParallel-8 5000000 427 ns/op
BenchmarkStructLevelValidationSuccess-8 5000000 335 ns/op
BenchmarkStructLevelValidationSuccessParallel-8 20000000 124 ns/op
BenchmarkStructLevelValidationFailure-8 2000000 630 ns/op
BenchmarkStructLevelValidationFailureParallel-8 10000000 298 ns/op
BenchmarkStructSimpleCustomTypeSuccess-8 3000000 535 ns/op
BenchmarkStructSimpleCustomTypeSuccessParallel-8 10000000 170 ns/op
BenchmarkStructSimpleCustomTypeFailure-8 2000000 821 ns/op
BenchmarkStructSimpleCustomTypeFailureParallel-8 5000000 379 ns/op
BenchmarkStructFilteredSuccess-8 2000000 769 ns/op
BenchmarkStructFilteredSuccessParallel-8 5000000 328 ns/op
BenchmarkStructFilteredFailure-8 2000000 594 ns/op
BenchmarkStructFilteredFailureParallel-8 10000000 244 ns/op
BenchmarkStructPartialSuccess-8 2000000 682 ns/op
BenchmarkStructPartialSuccessParallel-8 5000000 291 ns/op
BenchmarkStructPartialFailure-8 1000000 1034 ns/op
BenchmarkStructPartialFailureParallel-8 5000000 392 ns/op
BenchmarkStructExceptSuccess-8 1000000 1014 ns/op
BenchmarkStructExceptSuccessParallel-8 10000000 257 ns/op
BenchmarkStructExceptFailure-8 2000000 875 ns/op
BenchmarkStructExceptFailureParallel-8 5000000 405 ns/op
BenchmarkStructSimpleCrossFieldSuccess-8 3000000 545 ns/op
BenchmarkStructSimpleCrossFieldSuccessParallel-8 10000000 177 ns/op
BenchmarkStructSimpleCrossFieldFailure-8 2000000 787 ns/op
BenchmarkStructSimpleCrossFieldFailureParallel-8 5000000 341 ns/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 2000000 795 ns/op
BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8 10000000 267 ns/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-8 1000000 1119 ns/op
BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8 3000000 437 ns/op
BenchmarkStructSimpleSuccess-8 5000000 377 ns/op
BenchmarkStructSimpleSuccessParallel-8 20000000 110 ns/op
BenchmarkStructSimpleFailure-8 2000000 785 ns/op
BenchmarkStructSimpleFailureParallel-8 5000000 302 ns/op
BenchmarkStructComplexSuccess-8 1000000 2159 ns/op
BenchmarkStructComplexSuccessParallel-8 2000000 723 ns/op
BenchmarkStructComplexFailure-8 300000 5237 ns/op
BenchmarkStructComplexFailureParallel-8 1000000 2378 ns/op
```
Complimentary Software
----------------------
Here is a list of software that compliments 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 in code for more details.
