README.md
1Package validator
2================
3<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)
4
5[](https://travis-ci.org/go-playground/validator)
6[](https://coveralls.io/github/go-playground/validator?branch=master)
7[](https://goreportcard.com/report/github.com/go-playground/validator)
8[](https://godoc.org/github.com/go-playground/validator)
9
10
11Package validator implements value validations for structs and individual fields based on tags.
12
13It has the following **unique** features:
14
15- Cross Field and Cross Struct validations by using validation tags or custom validators.
16- Slice, Array and Map diving, which allows any or all levels of a multidimensional field to be validated.
17- Ability to dive into both map keys and values for validation
18- Handles type interface by determining it's underlying type prior to validation.
19- Handles custom field types such as sql driver Valuer see [Valuer](https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29)
20- Alias validation tags, which allows for mapping of several validations to a single tag for easier defining of validations on structs
21- 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
22- Customizable i18n aware error messages.
23- 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/master/_examples/gin-upgrading-overriding)
24
25Installation
26------------
27
28Use go get.
29
30 go get github.com/go-playground/validator/v10
31
32Then import the validator package into your own code.
33
34 import "github.com/go-playground/validator/v10"
35
36Error Return Value
37-------
38
39Validation functions return type error
40
41They return type error to avoid the issue discussed in the following, where err is always != nil:
42
43* http://stackoverflow.com/a/29138676/3158232
44* https://github.com/go-playground/validator/issues/134
45
46Validator 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:
47
48```go
49err := validate.Struct(mystruct)
50validationErrors := err.(validator.ValidationErrors)
51 ```
52
53Usage and documentation
54------
55
56Please see https://godoc.org/github.com/go-playground/validator for detailed usage docs.
57
58##### Examples:
59
60- [Simple](https://github.com/go-playground/validator/blob/master/_examples/simple/main.go)
61- [Custom Field Types](https://github.com/go-playground/validator/blob/master/_examples/custom/main.go)
62- [Struct Level](https://github.com/go-playground/validator/blob/master/_examples/struct-level/main.go)
63- [Translations & Custom Errors](https://github.com/go-playground/validator/blob/master/_examples/translations/main.go)
64- [Gin upgrade and/or override validator](https://github.com/go-playground/validator/tree/v9/_examples/gin-upgrading-overriding)
65- [wash - an example application putting it all together](https://github.com/bluesuncorp/wash)
66
67Benchmarks
68------
69###### Run on MacBook Pro (15-inch, 2017) go version go1.10.2 darwin/amd64
70```go
71goos: darwin
72goarch: amd64
73pkg: github.com/go-playground/validator
74BenchmarkFieldSuccess-8 20000000 83.6 ns/op 0 B/op 0 allocs/op
75BenchmarkFieldSuccessParallel-8 50000000 26.8 ns/op 0 B/op 0 allocs/op
76BenchmarkFieldFailure-8 5000000 291 ns/op 208 B/op 4 allocs/op
77BenchmarkFieldFailureParallel-8 20000000 107 ns/op 208 B/op 4 allocs/op
78BenchmarkFieldArrayDiveSuccess-8 2000000 623 ns/op 201 B/op 11 allocs/op
79BenchmarkFieldArrayDiveSuccessParallel-8 10000000 237 ns/op 201 B/op 11 allocs/op
80BenchmarkFieldArrayDiveFailure-8 2000000 859 ns/op 412 B/op 16 allocs/op
81BenchmarkFieldArrayDiveFailureParallel-8 5000000 335 ns/op 413 B/op 16 allocs/op
82BenchmarkFieldMapDiveSuccess-8 1000000 1292 ns/op 432 B/op 18 allocs/op
83BenchmarkFieldMapDiveSuccessParallel-8 3000000 467 ns/op 432 B/op 18 allocs/op
84BenchmarkFieldMapDiveFailure-8 1000000 1082 ns/op 512 B/op 16 allocs/op
85BenchmarkFieldMapDiveFailureParallel-8 5000000 425 ns/op 512 B/op 16 allocs/op
86BenchmarkFieldMapDiveWithKeysSuccess-8 1000000 1539 ns/op 480 B/op 21 allocs/op
87BenchmarkFieldMapDiveWithKeysSuccessParallel-8 3000000 613 ns/op 480 B/op 21 allocs/op
88BenchmarkFieldMapDiveWithKeysFailure-8 1000000 1413 ns/op 721 B/op 21 allocs/op
89BenchmarkFieldMapDiveWithKeysFailureParallel-8 3000000 575 ns/op 721 B/op 21 allocs/op
90BenchmarkFieldCustomTypeSuccess-8 10000000 216 ns/op 32 B/op 2 allocs/op
91BenchmarkFieldCustomTypeSuccessParallel-8 20000000 82.2 ns/op 32 B/op 2 allocs/op
92BenchmarkFieldCustomTypeFailure-8 5000000 274 ns/op 208 B/op 4 allocs/op
93BenchmarkFieldCustomTypeFailureParallel-8 20000000 116 ns/op 208 B/op 4 allocs/op
94BenchmarkFieldOrTagSuccess-8 2000000 740 ns/op 16 B/op 1 allocs/op
95BenchmarkFieldOrTagSuccessParallel-8 3000000 474 ns/op 16 B/op 1 allocs/op
96BenchmarkFieldOrTagFailure-8 3000000 471 ns/op 224 B/op 5 allocs/op
97BenchmarkFieldOrTagFailureParallel-8 3000000 414 ns/op 224 B/op 5 allocs/op
98BenchmarkStructLevelValidationSuccess-8 10000000 213 ns/op 32 B/op 2 allocs/op
99BenchmarkStructLevelValidationSuccessParallel-8 20000000 91.8 ns/op 32 B/op 2 allocs/op
100BenchmarkStructLevelValidationFailure-8 3000000 473 ns/op 304 B/op 8 allocs/op
101BenchmarkStructLevelValidationFailureParallel-8 10000000 234 ns/op 304 B/op 8 allocs/op
102BenchmarkStructSimpleCustomTypeSuccess-8 5000000 385 ns/op 32 B/op 2 allocs/op
103BenchmarkStructSimpleCustomTypeSuccessParallel-8 10000000 161 ns/op 32 B/op 2 allocs/op
104BenchmarkStructSimpleCustomTypeFailure-8 2000000 640 ns/op 424 B/op 9 allocs/op
105BenchmarkStructSimpleCustomTypeFailureParallel-8 5000000 318 ns/op 440 B/op 10 allocs/op
106BenchmarkStructFilteredSuccess-8 2000000 597 ns/op 288 B/op 9 allocs/op
107BenchmarkStructFilteredSuccessParallel-8 10000000 266 ns/op 288 B/op 9 allocs/op
108BenchmarkStructFilteredFailure-8 3000000 454 ns/op 256 B/op 7 allocs/op
109BenchmarkStructFilteredFailureParallel-8 10000000 214 ns/op 256 B/op 7 allocs/op
110BenchmarkStructPartialSuccess-8 3000000 502 ns/op 256 B/op 6 allocs/op
111BenchmarkStructPartialSuccessParallel-8 10000000 225 ns/op 256 B/op 6 allocs/op
112BenchmarkStructPartialFailure-8 2000000 702 ns/op 480 B/op 11 allocs/op
113BenchmarkStructPartialFailureParallel-8 5000000 329 ns/op 480 B/op 11 allocs/op
114BenchmarkStructExceptSuccess-8 2000000 793 ns/op 496 B/op 12 allocs/op
115BenchmarkStructExceptSuccessParallel-8 10000000 193 ns/op 240 B/op 5 allocs/op
116BenchmarkStructExceptFailure-8 2000000 639 ns/op 464 B/op 10 allocs/op
117BenchmarkStructExceptFailureParallel-8 5000000 300 ns/op 464 B/op 10 allocs/op
118BenchmarkStructSimpleCrossFieldSuccess-8 3000000 417 ns/op 72 B/op 3 allocs/op
119BenchmarkStructSimpleCrossFieldSuccessParallel-8 10000000 163 ns/op 72 B/op 3 allocs/op
120BenchmarkStructSimpleCrossFieldFailure-8 2000000 645 ns/op 304 B/op 8 allocs/op
121BenchmarkStructSimpleCrossFieldFailureParallel-8 5000000 285 ns/op 304 B/op 8 allocs/op
122BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 3000000 588 ns/op 80 B/op 4 allocs/op
123BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8 10000000 221 ns/op 80 B/op 4 allocs/op
124BenchmarkStructSimpleCrossStructCrossFieldFailure-8 2000000 868 ns/op 320 B/op 9 allocs/op
125BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8 5000000 337 ns/op 320 B/op 9 allocs/op
126BenchmarkStructSimpleSuccess-8 5000000 260 ns/op 0 B/op 0 allocs/op
127BenchmarkStructSimpleSuccessParallel-8 20000000 90.6 ns/op 0 B/op 0 allocs/op
128BenchmarkStructSimpleFailure-8 2000000 619 ns/op 424 B/op 9 allocs/op
129BenchmarkStructSimpleFailureParallel-8 5000000 296 ns/op 424 B/op 9 allocs/op
130BenchmarkStructComplexSuccess-8 1000000 1454 ns/op 128 B/op 8 allocs/op
131BenchmarkStructComplexSuccessParallel-8 3000000 579 ns/op 128 B/op 8 allocs/op
132BenchmarkStructComplexFailure-8 300000 4140 ns/op 3041 B/op 53 allocs/op
133BenchmarkStructComplexFailureParallel-8 1000000 2127 ns/op 3041 B/op 53 allocs/op
134BenchmarkOneof-8 10000000 140 ns/op 0 B/op 0 allocs/op
135BenchmarkOneofParallel-8 20000000 70.1 ns/op 0 B/op 0 allocs/op
136```
137
138Complementary Software
139----------------------
140
141Here is a list of software that complements using this library either pre or post validation.
142
143* [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.
144* [mold](https://github.com/go-playground/mold) - A general library to help modify or set data within data structures and other objects
145
146How to Contribute
147------
148
149Make a pull request...
150
151License
152------
153Distributed under MIT License, please see license file within the code for more details.
154
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