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 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:

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

Benchmarks

Run on MacBook Pro (15-inch, 2017) Go version go1.9.2 darwin/amd64

go test -bench=. -benchmem=true
BenchmarkFieldSuccess-8                                       	20000000	        79.9 ns/op	       0 B/op	       0 allocs/op
BenchmarkFieldSuccessParallel-8                               	50000000	        25.0 ns/op	       0 B/op	       0 allocs/op
BenchmarkFieldFailure-8                                       	 5000000	       281 ns/op	     208 B/op	       4 allocs/op
BenchmarkFieldFailureParallel-8                               	20000000	        97.0 ns/op	     208 B/op	       4 allocs/op
BenchmarkFieldArrayDiveSuccess-8                              	 3000000	       591 ns/op	     201 B/op	      11 allocs/op
BenchmarkFieldArrayDiveSuccessParallel-8                      	10000000	       195 ns/op	     201 B/op	      11 allocs/op
BenchmarkFieldArrayDiveFailure-8                              	 2000000	       878 ns/op	     412 B/op	      16 allocs/op
BenchmarkFieldArrayDiveFailureParallel-8                      	 5000000	       274 ns/op	     413 B/op	      16 allocs/op
BenchmarkFieldMapDiveSuccess-8                                	 1000000	      1279 ns/op	     432 B/op	      18 allocs/op
BenchmarkFieldMapDiveSuccessParallel-8                        	 5000000	       401 ns/op	     432 B/op	      18 allocs/op
BenchmarkFieldMapDiveFailure-8                                	 1000000	      1060 ns/op	     512 B/op	      16 allocs/op
BenchmarkFieldMapDiveFailureParallel-8                        	 5000000	       334 ns/op	     512 B/op	      16 allocs/op
BenchmarkFieldMapDiveWithKeysSuccess-8                        	 1000000	      1462 ns/op	     480 B/op	      21 allocs/op
BenchmarkFieldMapDiveWithKeysSuccessParallel-8                	 3000000	       463 ns/op	     480 B/op	      21 allocs/op
BenchmarkFieldMapDiveWithKeysFailure-8                        	 1000000	      1414 ns/op	     721 B/op	      21 allocs/op
BenchmarkFieldMapDiveWithKeysFailureParallel-8                	 3000000	       446 ns/op	     721 B/op	      21 allocs/op
BenchmarkFieldCustomTypeSuccess-8                             	10000000	       211 ns/op	      32 B/op	       2 allocs/op
BenchmarkFieldCustomTypeSuccessParallel-8                     	20000000	        65.9 ns/op	      32 B/op	       2 allocs/op
BenchmarkFieldCustomTypeFailure-8                             	 5000000	       270 ns/op	     208 B/op	       4 allocs/op
BenchmarkFieldCustomTypeFailureParallel-8                     	20000000	        93.3 ns/op	     208 B/op	       4 allocs/op
BenchmarkFieldOrTagSuccess-8                                  	 2000000	       729 ns/op	      16 B/op	       1 allocs/op
BenchmarkFieldOrTagSuccessParallel-8                          	 5000000	       367 ns/op	      16 B/op	       1 allocs/op
BenchmarkFieldOrTagFailure-8                                  	 3000000	       472 ns/op	     224 B/op	       5 allocs/op
BenchmarkFieldOrTagFailureParallel-8                          	 5000000	       373 ns/op	     224 B/op	       5 allocs/op
BenchmarkStructLevelValidationSuccess-8                       	10000000	       201 ns/op	      32 B/op	       2 allocs/op
BenchmarkStructLevelValidationSuccessParallel-8               	20000000	        66.3 ns/op	      32 B/op	       2 allocs/op
BenchmarkStructLevelValidationFailure-8                       	 3000000	       468 ns/op	     304 B/op	       8 allocs/op
BenchmarkStructLevelValidationFailureParallel-8               	10000000	       172 ns/op	     304 B/op	       8 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-8                      	 5000000	       376 ns/op	      32 B/op	       2 allocs/op
BenchmarkStructSimpleCustomTypeSuccessParallel-8              	20000000	       126 ns/op	      32 B/op	       2 allocs/op
BenchmarkStructSimpleCustomTypeFailure-8                      	 2000000	       646 ns/op	     424 B/op	       9 allocs/op
BenchmarkStructSimpleCustomTypeFailureParallel-8              	10000000	       240 ns/op	     440 B/op	      10 allocs/op
BenchmarkStructFilteredSuccess-8                              	 3000000	       582 ns/op	     288 B/op	       9 allocs/op
BenchmarkStructFilteredSuccessParallel-8                      	10000000	       198 ns/op	     288 B/op	       9 allocs/op
BenchmarkStructFilteredFailure-8                              	 3000000	       447 ns/op	     256 B/op	       7 allocs/op
BenchmarkStructFilteredFailureParallel-8                      	10000000	       156 ns/op	     256 B/op	       7 allocs/op
BenchmarkStructPartialSuccess-8                               	 3000000	       536 ns/op	     256 B/op	       6 allocs/op
BenchmarkStructPartialSuccessParallel-8                       	10000000	       175 ns/op	     256 B/op	       6 allocs/op
BenchmarkStructPartialFailure-8                               	 2000000	       738 ns/op	     480 B/op	      11 allocs/op
BenchmarkStructPartialFailureParallel-8                       	 5000000	       256 ns/op	     480 B/op	      11 allocs/op
BenchmarkStructExceptSuccess-8                                	 2000000	       835 ns/op	     496 B/op	      12 allocs/op
BenchmarkStructExceptSuccessParallel-8                        	10000000	       163 ns/op	     240 B/op	       5 allocs/op
BenchmarkStructExceptFailure-8                                	 2000000	       682 ns/op	     464 B/op	      10 allocs/op
BenchmarkStructExceptFailureParallel-8                        	10000000	       244 ns/op	     464 B/op	      10 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-8                      	 5000000	       392 ns/op	      72 B/op	       3 allocs/op
BenchmarkStructSimpleCrossFieldSuccessParallel-8              	20000000	       126 ns/op	      72 B/op	       3 allocs/op
BenchmarkStructSimpleCrossFieldFailure-8                      	 2000000	       611 ns/op	     304 B/op	       8 allocs/op
BenchmarkStructSimpleCrossFieldFailureParallel-8              	10000000	       214 ns/op	     304 B/op	       8 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-8           	 3000000	       567 ns/op	      80 B/op	       4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8   	10000000	       177 ns/op	      80 B/op	       4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-8           	 2000000	       807 ns/op	     320 B/op	       9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8   	 5000000	       268 ns/op	     320 B/op	       9 allocs/op
BenchmarkStructSimpleSuccess-8                                	 5000000	       256 ns/op	       0 B/op	       0 allocs/op
BenchmarkStructSimpleSuccessParallel-8                        	20000000	        76.3 ns/op	       0 B/op	       0 allocs/op
BenchmarkStructSimpleFailure-8                                	 2000000	       625 ns/op	     424 B/op	       9 allocs/op
BenchmarkStructSimpleFailureParallel-8                        	10000000	       219 ns/op	     424 B/op	       9 allocs/op
BenchmarkStructComplexSuccess-8                               	 1000000	      1431 ns/op	     128 B/op	       8 allocs/op
BenchmarkStructComplexSuccessParallel-8                       	 3000000	       427 ns/op	     128 B/op	       8 allocs/op
BenchmarkStructComplexFailure-8                               	  300000	      4065 ns/op	    3041 B/op	      53 allocs/op
BenchmarkStructComplexFailureParallel-8                       	 1000000	      1478 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 - 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.