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README
¶
Package validator
[](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
- 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
- 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:
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.
Struct & Field validation
package main
import (
"fmt"
"gopkg.in/go-playground/validator.v9"
)
// User contains user information
type User struct {
FirstName string `validate:"required"`
LastName string `validate:"required"`
Age uint8 `validate:"gte=0,lte=130"`
Email string `validate:"required,email"`
FavouriteColor string `validate:"iscolor"` // alias for 'hexcolor|rgb|rgba|hsl|hsla'
Addresses []*Address `validate:"required,dive,required"` // a person can have a home and cottage...
}
// Address houses a users address information
type Address struct {
Street string `validate:"required"`
City string `validate:"required"`
Planet string `validate:"required"`
Phone string `validate:"required"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
validateStruct()
validateVariable()
}
func validateStruct() {
address := &Address{
Street: "Eavesdown Docks",
Planet: "Persphone",
Phone: "none",
}
user := &User{
FirstName: "Badger",
LastName: "Smith",
Age: 135,
Email: "Badger.Smith@gmail.com",
FavouriteColor: "#000-",
Addresses: []*Address{address},
}
// returns nil or ValidationErrors ( map[string]*FieldError )
err := validate.Struct(user)
if err != nil {
// this check is only needed when your code could produce
// an invalid value for validation such as interface with nil
// value most including myself do not usually have code like this.
if _, ok := err.(*validator.InvalidValidationError); ok {
fmt.Println(err)
return
}
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err.Namespace())
fmt.Println(err.Field())
fmt.Println(err.StructNamespace()) // can differ when a custom TagNameFunc is registered or
fmt.Println(err.StructField()) // by passing alt name to ReportError like below
fmt.Println(err.Tag())
fmt.Println(err.ActualTag())
fmt.Println(err.Kind())
fmt.Println(err.Type())
fmt.Println(err.Value())
fmt.Println(err.Param())
fmt.Println()
}
// from here you can create your own error messages in whatever language you wish
return
}
// save user to database
}
func validateVariable() {
myEmail := "joeybloggs.gmail.com"
errs := validate.Var(myEmail, "required,email")
if errs != nil {
fmt.Println(errs) // output: Key: "" Error:Field validation for "" failed on the "email" tag
return
}
// email ok, move on
}
Custom Field Type
package main
import (
"database/sql"
"database/sql/driver"
"fmt"
"reflect"
"gopkg.in/go-playground/validator.v9"
)
// DbBackedUser User struct
type DbBackedUser struct {
Name sql.NullString `validate:"required"`
Age sql.NullInt64 `validate:"required"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
// register all sql.Null* types to use the ValidateValuer CustomTypeFunc
validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
// build object for validation
x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}
err := validate.Struct(x)
if err != nil {
fmt.Printf("Err(s):\n%+v\n", err)
}
}
// ValidateValuer implements validator.CustomTypeFunc
func ValidateValuer(field reflect.Value) interface{} {
if valuer, ok := field.Interface().(driver.Valuer); ok {
val, err := valuer.Value()
if err == nil {
return val
}
// handle the error how you want
}
return nil
}
Struct Level Validation
package main
import (
"fmt"
"gopkg.in/go-playground/validator.v9"
)
// User contains user information
type User struct {
FirstName string `json:"fname"`
LastName string `json:"lname"`
Age uint8 `validate:"gte=0,lte=130"`
Email string `validate:"required,email"`
FavouriteColor string `validate:"hexcolor|rgb|rgba"`
Addresses []*Address `validate:"required,dive,required"` // a person can have a home and cottage...
}
// Address houses a users address information
type Address struct {
Street string `validate:"required"`
City string `validate:"required"`
Planet string `validate:"required"`
Phone string `validate:"required"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
// register validation for 'User'
// NOTE: only have to register a non-pointer type for 'User', validator
// interanlly dereferences during it's type checks.
validate.RegisterStructValidation(UserStructLevelValidation, User{})
// build 'User' info, normally posted data etc...
address := &Address{
Street: "Eavesdown Docks",
Planet: "Persphone",
Phone: "none",
City: "Unknown",
}
user := &User{
FirstName: "",
LastName: "",
Age: 45,
Email: "Badger.Smith@gmail.com",
FavouriteColor: "#000",
Addresses: []*Address{address},
}
// returns InvalidValidationError for bad validation input, nil or ValidationErrors ( []FieldError )
err := validate.Struct(user)
if err != nil {
// this check is only needed when your code could produce
// an invalid value for validation such as interface with nil
// value most including myself do not usually have code like this.
if _, ok := err.(*validator.InvalidValidationError); ok {
fmt.Println(err)
return
}
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err.Namespace())
fmt.Println(err.Field())
fmt.Println(err.StructNamespace()) // can differ when a custom TagNameFunc is registered or
fmt.Println(err.StructField()) // by passing alt name to ReportError like below
fmt.Println(err.Tag())
fmt.Println(err.ActualTag())
fmt.Println(err.Kind())
fmt.Println(err.Type())
fmt.Println(err.Value())
fmt.Println(err.Param())
fmt.Println()
}
// from here you can create your own error messages in whatever language you wish
return
}
// save user to database
}
// UserStructLevelValidation contains custom struct level validations that don't always
// make sense at the field validation level. For Example this function validates that either
// FirstName or LastName exist; could have done that with a custom field validation but then
// would have had to add it to both fields duplicating the logic + overhead, this way it's
// only validated once.
//
// NOTE: you may ask why wouldn't I just do this outside of validator, because doing this way
// hooks right into validator and you can combine with validation tags and still have a
// common error output format.
func UserStructLevelValidation(sl validator.StructLevel) {
user := sl.Current().Interface().(User)
if len(user.FirstName) == 0 && len(user.LastName) == 0 {
sl.ReportError(user.FirstName, "FirstName", "fname", "fnameorlname", "")
sl.ReportError(user.LastName, "LastName", "lname", "fnameorlname", "")
}
// plus can to more, even with different tag than "fnameorlname"
}
Benchmarks
BenchmarkFieldSuccess-8 20000000 108 ns/op 0 B/op 0 allocs/op
BenchmarkFieldSuccessParallel-8 50000000 35.7 ns/op 0 B/op 0 allocs/op
BenchmarkFieldFailure-8 5000000 320 ns/op 192 B/op 4 allocs/op
BenchmarkFieldFailureParallel-8 20000000 113 ns/op 192 B/op 4 allocs/op
BenchmarkFieldDiveSuccess-8 2000000 726 ns/op 201 B/op 11 allocs/op
BenchmarkFieldDiveSuccessParallel-8 10000000 263 ns/op 201 B/op 11 allocs/op
BenchmarkFieldDiveFailure-8 2000000 939 ns/op 396 B/op 16 allocs/op
BenchmarkFieldDiveFailureParallel-8 5000000 382 ns/op 397 B/op 16 allocs/op
BenchmarkFieldCustomTypeSuccess-8 5000000 268 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeSuccessParallel-8 20000000 87.8 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeFailure-8 5000000 310 ns/op 192 B/op 4 allocs/op
BenchmarkFieldCustomTypeFailureParallel-8 20000000 131 ns/op 192 B/op 4 allocs/op
BenchmarkFieldOrTagSuccess-8 2000000 889 ns/op 16 B/op 1 allocs/op
BenchmarkFieldOrTagSuccessParallel-8 5000000 418 ns/op 16 B/op 1 allocs/op
BenchmarkFieldOrTagFailure-8 3000000 546 ns/op 208 B/op 5 allocs/op
BenchmarkFieldOrTagFailureParallel-8 3000000 450 ns/op 208 B/op 5 allocs/op
BenchmarkStructLevelValidationSuccess-8 5000000 336 ns/op 32 B/op 2 allocs/op
BenchmarkStructLevelValidationSuccessParallel-8 20000000 123 ns/op 32 B/op 2 allocs/op
BenchmarkStructLevelValidationFailure-8 2000000 611 ns/op 288 B/op 8 allocs/op
BenchmarkStructLevelValidationFailureParallel-8 5000000 298 ns/op 288 B/op 8 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-8 2000000 555 ns/op 32 B/op 2 allocs/op
BenchmarkStructSimpleCustomTypeSuccessParallel-8 10000000 197 ns/op 32 B/op 2 allocs/op
BenchmarkStructSimpleCustomTypeFailure-8 2000000 811 ns/op 392 B/op 9 allocs/op
BenchmarkStructSimpleCustomTypeFailureParallel-8 5000000 370 ns/op 408 B/op 10 allocs/op
BenchmarkStructPartialSuccess-8 2000000 676 ns/op 256 B/op 6 allocs/op
BenchmarkStructPartialSuccessParallel-8 5000000 301 ns/op 256 B/op 6 allocs/op
BenchmarkStructPartialFailure-8 1000000 1001 ns/op 464 B/op 11 allocs/op
BenchmarkStructPartialFailureParallel-8 3000000 436 ns/op 464 B/op 11 allocs/op
BenchmarkStructExceptSuccess-8 1000000 1038 ns/op 480 B/op 12 allocs/op
BenchmarkStructExceptSuccessParallel-8 10000000 281 ns/op 240 B/op 5 allocs/op
BenchmarkStructExceptFailure-8 2000000 863 ns/op 448 B/op 10 allocs/op
BenchmarkStructExceptFailureParallel-8 3000000 379 ns/op 448 B/op 10 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-8 3000000 549 ns/op 72 B/op 3 allocs/op
BenchmarkStructSimpleCrossFieldSuccessParallel-8 10000000 192 ns/op 72 B/op 3 allocs/op
BenchmarkStructSimpleCrossFieldFailure-8 2000000 783 ns/op 288 B/op 8 allocs/op
BenchmarkStructSimpleCrossFieldFailureParallel-8 5000000 296 ns/op 288 B/op 8 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 2000000 837 ns/op 80 B/op 4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8 5000000 284 ns/op 80 B/op 4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-8 1000000 1110 ns/op 304 B/op 9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8 3000000 416 ns/op 304 B/op 9 allocs/op
BenchmarkStructSimpleSuccess-8 5000000 380 ns/op 0 B/op 0 allocs/op
BenchmarkStructSimpleSuccessParallel-8 20000000 114 ns/op 0 B/op 0 allocs/op
BenchmarkStructSimpleFailure-8 2000000 760 ns/op 392 B/op 9 allocs/op
BenchmarkStructSimpleFailureParallel-8 5000000 353 ns/op 392 B/op 9 allocs/op
BenchmarkStructComplexSuccess-8 1000000 2100 ns/op 128 B/op 8 allocs/op
BenchmarkStructComplexSuccessParallel-8 2000000 662 ns/op 128 B/op 8 allocs/op
BenchmarkStructComplexFailure-8 200000 5080 ns/op 2833 B/op 53 allocs/op
BenchmarkStructComplexFailureParallel-8 1000000 2159 ns/op 2833 B/op 53 allocs/op
Complimentary Software
Here is a list of software that compliments 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.
- 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.
Documentation
¶
Overview ¶
Package validator implements value validations for structs and individual fields based on tags.
It can also handle Cross-Field and Cross-Struct validation for nested structs and has the ability to dive into arrays and maps of any type.
Why not a better error message? Because this library intends for you to handle your own error messages.
Why should I handle my own errors? Many reasons. We built an internationalized application and needed to know the field, and what validation failed so we could provide a localized error.
if fieldErr.Field() == "Name" {
switch fieldErr.Tag()
case "required":
return "Translated string based on field + error"
default:
return "Translated string based on field"
}
Validation Functions Return Type error ¶
Doing things this way is actually the way the standard library does, see the file.Open method here:
https://golang.org/pkg/os/#Open.
The authors 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.(validator.ValidationErrors).
Custom Validation Functions ¶
Custom Validation functions can be added. Example:
// Structure
func customFunc(fl FielddLevel) bool {
if fl.Field().String() == "invalid" {
return false
}
return true
}
validate.RegisterValidation("custom tag name", customFunc)
// NOTES: using the same tag name as an existing function
// will overwrite the existing one
Cross-Field Validation ¶
Cross-Field Validation can be done via the following tags:
- eqfield
- nefield
- gtfield
- gtefield
- ltfield
- ltefield
- eqcsfield
- necsfield
- gtcsfield
- ftecsfield
- ltcsfield
- ltecsfield
If, however, some custom cross-field validation is required, it can be done using a custom validation.
Why not just have cross-fields validation tags (i.e. only eqcsfield and not eqfield)?
The reason is efficiency. If you want to check a field within the same struct "eqfield" only has to find the field on the same struct (1 level). But, if we used "eqcsfield" it could be multiple levels down. Example:
type Inner struct {
StartDate time.Time
}
type Outer struct {
InnerStructField *Inner
CreatedAt time.Time `validate:"ltecsfield=InnerStructField.StartDate"`
}
now := time.Now()
inner := &Inner{
StartDate: now,
}
outer := &Outer{
InnerStructField: inner,
CreatedAt: now,
}
errs := validate.Struct(outer)
// NOTE: when calling validate.Struct(val) topStruct will be the top level struct passed
// into the function
// when calling validate.FieldWithValue(val, field, tag) val will be
// whatever you pass, struct, field...
// when calling validate.Field(field, tag) val will be nil
Multiple Validators ¶
Multiple validators on a field will process in the order defined. Example:
type Test struct {
Field `validate:"max=10,min=1"`
}
// max will be checked then min
Bad Validator definitions are not handled by the library. Example:
type Test struct {
Field `validate:"min=10,max=0"`
}
// this definition of min max will never succeed
Using Validator Tags ¶
Baked In Cross-Field validation only compares fields on the same struct. If Cross-Field + Cross-Struct validation is needed you should implement your own custom validator.
Comma (",") is the default separator of validation tags. If you wish to have a comma included within the parameter (i.e. excludesall=,) you will need to use the UTF-8 hex representation 0x2C, which is replaced in the code as a comma, so the above will become excludesall=0x2C.
type Test struct {
Field `validate:"excludesall=,"` // BAD! Do not include a comma.
Field `validate:"excludesall=0x2C"` // GOOD! Use the UTF-8 hex representation.
}
Pipe ("|") is the default separator of validation tags. If you wish to have a pipe included within the parameter i.e. excludesall=| you will need to use the UTF-8 hex representation 0x7C, which is replaced in the code as a pipe, so the above will become excludesall=0x7C
type Test struct {
Field `validate:"excludesall=|"` // BAD! Do not include a a pipe!
Field `validate:"excludesall=0x7C"` // GOOD! Use the UTF-8 hex representation.
}
Baked In Validators and Tags ¶
Here is a list of the current built in validators:
Skip Field ¶
Tells the validation to skip this struct field; this is particularly handy in ignoring embedded structs from being validated. (Usage: -)
Usage: -
Or Operator ¶
This is the 'or' operator allowing multiple validators to be used and accepted. (Usage: rbg|rgba) <-- this would allow either rgb or rgba colors to be accepted. This can also be combined with 'and' for example ( Usage: omitempty,rgb|rgba)
Usage: |
StructOnly ¶
When a field that is a nested struct is encountered, and contains this flag any validation on the nested struct will be run, but none of the nested struct fields will be validated. This is usefull if inside of you program you know the struct will be valid, but need to verify it has been assigned. NOTE: only "required" and "omitempty" can be used on a struct itself.
Usage: structonly
NoStructLevel ¶
Same as structonly tag except that any struct level validations will not run.
Usage: nostructlevel
Omit Empty ¶
Allows conditional validation, for example if a field is not set with a value (Determined by the "required" validator) then other validation such as min or max won't run, but if a value is set validation will run.
Usage: omitempty
Dive ¶
This tells the validator to dive into a slice, array or map and validate that level of the slice, array or map with the validation tags that follow. Multidimensional nesting is also supported, each level you wish to dive will require another dive tag.
Usage: dive
Example #1
[][]string with validation tag "gt=0,dive,len=1,dive,required" // gt=0 will be applied to [] // len=1 will be applied to []string // required will be applied to string
Example #2
[][]string with validation tag "gt=0,dive,dive,required" // gt=0 will be applied to [] // []string will be spared validation // required will be applied to string
Required ¶
This validates that the value is not the data types default zero value. For numbers ensures value is not zero. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil.
Usage: required
Length ¶
For numbers, max will ensure that the value is equal to the parameter given. For strings, it checks that the string length is exactly that number of characters. For slices, arrays, and maps, validates the number of items.
Usage: len=10
Maximum ¶
For numbers, max will ensure that the value is less than or equal to the parameter given. For strings, it checks that the string length is at most that number of characters. For slices, arrays, and maps, validates the number of items.
Usage: max=10
Mininum ¶
For numbers, min will ensure that the value is greater or equal to the parameter given. For strings, it checks that the string length is at least that number of characters. For slices, arrays, and maps, validates the number of items.
Usage: min=10
Equals ¶
For strings & numbers, eq will ensure that the value is equal to the parameter given. For slices, arrays, and maps, validates the number of items.
Usage: eq=10
Not Equal ¶
For strings & numbers, ne will ensure that the value is not equal to the parameter given. For slices, arrays, and maps, validates the number of items.
Usage: ne=10
Greater Than ¶
For numbers, this will ensure that the value is greater than the parameter given. For strings, it checks that the string length is greater than that number of characters. For slices, arrays and maps it validates the number of items.
Example #1
Usage: gt=10
Example #2 (time.Time)
For time.Time ensures the time value is greater than time.Now.UTC().
Usage: gt
Greater Than or Equal ¶
Same as 'min' above. Kept both to make terminology with 'len' easier.
Example #1
Usage: gte=10
Example #2 (time.Time)
For time.Time ensures the time value is greater than or equal to time.Now.UTC().
Usage: gte
Less Than ¶
For numbers, this will ensure that the value is less than the parameter given. For strings, it checks that the string length is less than that number of characters. For slices, arrays, and maps it validates the number of items.
Example #1
Usage: lt=10
Example #2 (time.Time) For time.Time ensures the time value is less than time.Now.UTC().
Usage: lt
Less Than or Equal ¶
Same as 'max' above. Kept both to make terminology with 'len' easier.
Example #1
Usage: lte=10
Example #2 (time.Time)
For time.Time ensures the time value is less than or equal to time.Now.UTC().
Usage: lte
Field Equals Another Field ¶
This will validate the field value against another fields value either within a struct or passed in field.
Example #1:
// Validation on Password field using: Usage: eqfield=ConfirmPassword
Example #2:
// Validating by field: validate.FieldWithValue(password, confirmpassword, "eqfield")
Field Equals Another Field (relative)
This does the same as eqfield except that it validates the field provided relative to the top level struct.
Usage: eqcsfield=InnerStructField.Field)
Field Does Not Equal Another Field ¶
This will validate the field value against another fields value either within a struct or passed in field.
Examples:
// Confirm two colors are not the same: // // Validation on Color field: Usage: nefield=Color2 // Validating by field: validate.FieldWithValue(color1, color2, "nefield")
Field Does Not Equal Another Field (relative)
This does the same as nefield except that it validates the field provided relative to the top level struct.
Usage: necsfield=InnerStructField.Field
Field Greater Than Another Field ¶
Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:
Example #1:
// Validation on End field using: validate.Struct Usage(gtfield=Start)
Example #2:
// Validating by field: validate.FieldWithValue(start, end, "gtfield")
Field Greater Than Another Relative Field ¶
This does the same as gtfield except that it validates the field provided relative to the top level struct.
Usage: gtcsfield=InnerStructField.Field
Field Greater Than or Equal To Another Field ¶
Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:
Example #1:
// Validation on End field using: validate.Struct Usage(gtefield=Start)
Example #2:
// Validating by field: validate.FieldWithValue(start, end, "gtefield")
Field Greater Than or Equal To Another Relative Field ¶
This does the same as gtefield except that it validates the field provided relative to the top level struct.
Usage: gtecsfield=InnerStructField.Field
Less Than Another Field ¶
Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:
Example #1:
// Validation on End field using: validate.Struct Usage(ltfield=Start)
Example #2:
// Validating by field: validate.FieldWithValue(start, end, "ltfield")
Less Than Another Relative Field ¶
This does the same as ltfield except that it validates the field provided relative to the top level struct.
Usage: ltcsfield=InnerStructField.Field
Less Than or Equal To Another Field ¶
Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date:
Example #1:
// Validation on End field using: validate.Struct Usage(ltefield=Start)
Example #2:
// Validating by field: validate.FieldWithValue(start, end, "ltefield")
Less Than or Equal To Another Relative Field ¶
This does the same as ltefield except that it validates the field provided relative to the top level struct.
Usage: ltecsfield=InnerStructField.Field
Alpha Only ¶
This validates that a string value contains alpha characters only
Usage: alpha
Alphanumeric ¶
This validates that a string value contains alphanumeric characters only
Usage: alphanum
Numeric ¶
This validates that a string value contains a basic numeric value. basic excludes exponents etc...
Usage: numeric
Hexadecimal String ¶
This validates that a string value contains a valid hexadecimal.
Usage: hexadecimal
Hexcolor String ¶
This validates that a string value contains a valid hex color including hashtag (#)
Usage: hexcolor
RGB String ¶
This validates that a string value contains a valid rgb color
Usage: rgb
RGBA String ¶
This validates that a string value contains a valid rgba color
Usage: rgba
HSL String ¶
This validates that a string value contains a valid hsl color
Usage: hsl
HSLA String ¶
This validates that a string value contains a valid hsla color
Usage: hsla
E-mail String ¶
This validates that a string value contains a valid email This may not conform to all possibilities of any rfc standard, but neither does any email provider accept all posibilities.
Usage: email
URL String ¶
This validates that a string value contains a valid url This will accept any url the golang request uri accepts but must contain a schema for example http:// or rtmp://
Usage: url
URI String ¶
This validates that a string value contains a valid uri This will accept any uri the golang request uri accepts
Usage: uri
Base64 String ¶
This validates that a string value contains a valid base64 value. Although an empty string is valid base64 this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag.
Usage: base64
Contains ¶
This validates that a string value contains the substring value.
Usage: contains=@
Contains Any ¶
This validates that a string value contains any Unicode code points in the substring value.
Usage: containsany=!@#?
Contains Rune ¶
This validates that a string value contains the supplied rune value.
Usage: containsrune=@
Excludes ¶
This validates that a string value does not contain the substring value.
Usage: excludes=@
Excludes All ¶
This validates that a string value does not contain any Unicode code points in the substring value.
Usage: excludesall=!@#?
Excludes Rune ¶
This validates that a string value does not contain the supplied rune value.
Usage: excludesrune=@
International Standard Book Number ¶
This validates that a string value contains a valid isbn10 or isbn13 value.
Usage: isbn
International Standard Book Number 10 ¶
This validates that a string value contains a valid isbn10 value.
Usage: isbn10
International Standard Book Number 13 ¶
This validates that a string value contains a valid isbn13 value.
Usage: isbn13
Universally Unique Identifier UUID ¶
This validates that a string value contains a valid UUID.
Usage: uuid
Universally Unique Identifier UUID v3 ¶
This validates that a string value contains a valid version 3 UUID.
Usage: uuid3
Universally Unique Identifier UUID v4 ¶
This validates that a string value contains a valid version 4 UUID.
Usage: uuid4
Universally Unique Identifier UUID v5 ¶
This validates that a string value contains a valid version 5 UUID.
Usage: uuid5
ASCII ¶
This validates that a string value contains only ASCII characters. NOTE: if the string is blank, this validates as true.
Usage: ascii
Printable ASCII ¶
This validates that a string value contains only printable ASCII characters. NOTE: if the string is blank, this validates as true.
Usage: asciiprint
Multi-Byte Characters ¶
This validates that a string value contains one or more multibyte characters. NOTE: if the string is blank, this validates as true.
Usage: multibyte
Data URL ¶
This validates that a string value contains a valid DataURI. NOTE: this will also validate that the data portion is valid base64
Usage: datauri
Latitude ¶
This validates that a string value contains a valid latitude.
Usage: latitude
Longitude ¶
This validates that a string value contains a valid longitude.
Usage: longitude
Social Security Number SSN ¶
This validates that a string value contains a valid U.S. Social Security Number.
Usage: ssn
Internet Protocol Address IP ¶
This validates that a string value contains a valid IP Adress.
Usage: ip
Internet Protocol Address IPv4 ¶
This validates that a string value contains a valid v4 IP Adress.
Usage: ipv4
Internet Protocol Address IPv6 ¶
This validates that a string value contains a valid v6 IP Adress.
Usage: ipv6
Classless Inter-Domain Routing CIDR ¶
This validates that a string value contains a valid CIDR Adress.
Usage: cidr
Classless Inter-Domain Routing CIDRv4 ¶
This validates that a string value contains a valid v4 CIDR Adress.
Usage: cidrv4
Classless Inter-Domain Routing CIDRv6 ¶
This validates that a string value contains a valid v6 CIDR Adress.
Usage: cidrv6
Transmission Control Protocol Address TCP ¶
This validates that a string value contains a valid resolvable TCP Adress.
Usage: tcp_addr
Transmission Control Protocol Address TCPv4 ¶
This validates that a string value contains a valid resolvable v4 TCP Adress.
Usage: tcp4_addr
Transmission Control Protocol Address TCPv6 ¶
This validates that a string value contains a valid resolvable v6 TCP Adress.
Usage: tcp6_addr
User Datagram Protocol Address UDP ¶
This validates that a string value contains a valid resolvable UDP Adress.
Usage: udp_addr
User Datagram Protocol Address UDPv4 ¶
This validates that a string value contains a valid resolvable v4 UDP Adress.
Usage: udp4_addr
User Datagram Protocol Address UDPv6 ¶
This validates that a string value contains a valid resolvable v6 UDP Adress.
Usage: udp6_addr
Internet Protocol Address IP ¶
This validates that a string value contains a valid resolvable IP Adress.
Usage: ip_addr
Internet Protocol Address IPv4 ¶
This validates that a string value contains a valid resolvable v4 IP Adress.
Usage: ip4_addr
Internet Protocol Address IPv6 ¶
This validates that a string value contains a valid resolvable v6 IP Adress.
Usage: ip6_addr
Unix domain socket end point Address ¶
This validates that a string value contains a valid Unix Adress.
Usage: unix_addr
Media Access Control Address MAC ¶
This validates that a string value contains a valid MAC Adress.
Usage: mac
Note: See Go's ParseMAC for accepted formats and types:
http://golang.org/src/net/mac.go?s=866:918#L29
Alias Validators and Tags ¶
NOTE: When returning an error, the tag returned in "FieldError" will be the alias tag unless the dive tag is part of the alias. Everything after the dive tag is not reported as the alias tag. Also, the "ActualTag" in the before case will be the actual tag within the alias that failed.
Here is a list of the current built in alias tags:
"iscolor" alias is "hexcolor|rgb|rgba|hsl|hsla" (Usage: iscolor)
Validator notes:
regex a regex validator won't be added because commas and = signs can be part of a regex which conflict with the validation definitions. Although workarounds can be made, they take away from using pure regex's. Furthermore it's quick and dirty but the regex's become harder to maintain and are not reusable, so it's as much a programming philosiphy as anything. In place of this new validator functions should be created; a regex can be used within the validator function and even be precompiled for better efficiency within regexes.go. And the best reason, you can submit a pull request and we can keep on adding to the validation library of this package!
Panics ¶
This package panics when bad input is provided, this is by design, bad code like that should not make it to production.
type Test struct {
TestField string `validate:"nonexistantfunction=1"`
}
t := &Test{
TestField: "Test"
}
validate.Struct(t) // this will panic
Index ¶
- type CustomTypeFunc
- type FieldError
- type FieldLevel
- type Func
- type InvalidValidationError
- type StructLevel
- type StructLevelFunc
- type TagNameFunc
- type Validate
- func (v *Validate) RegisterAlias(alias, tags string)
- func (v *Validate) RegisterCustomTypeFunc(fn CustomTypeFunc, types ...interface{})
- func (v *Validate) RegisterStructValidation(fn StructLevelFunc, types ...interface{})
- func (v *Validate) RegisterTagNameFunc(fn TagNameFunc)
- func (v *Validate) RegisterValidation(tag string, fn Func) error
- func (v *Validate) SetTagName(name string)
- func (v *Validate) Struct(s interface{}) (err error)
- func (v *Validate) StructExcept(s interface{}, fields ...string) (err error)
- func (v *Validate) StructPartial(s interface{}, fields ...string) (err error)
- func (v *Validate) Var(field interface{}, tag string) (err error)
- func (v *Validate) VarWithValue(field interface{}, other interface{}, tag string) (err error)
- type ValidationErrors
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type CustomTypeFunc ¶
CustomTypeFunc allows for overriding or adding custom field type handler functions field = field value of the type to return a value to be validated example Valuer from sql drive see https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29
type FieldError ¶
type FieldError interface {
// returns the validation tag that failed. if the
// validation was an alias, this will return the
// alias name and not the underlying tag that failed.
//
// eg. alias "iscolor": "hexcolor|rgb|rgba|hsl|hsla"
// will return "iscolor"
Tag() string
// returns the validation tag that failed, even if an
// alias the actual tag within the alias will be returned.
// If an 'or' validation fails the entire or will be returned.
//
// eg. alias "iscolor": "hexcolor|rgb|rgba|hsl|hsla"
// will return "hexcolor|rgb|rgba|hsl|hsla"
ActualTag() string
// returns the namespace for the field error, with the tag
// name taking precedence over the fields actual name.
//
// eq. JSON name "User.fname" see ActualNamespace for comparison
//
// NOTE: this field can be blank when validating a single primitive field
// using validate.Field(...) as there is no way to extract it's name
Namespace() string
// returns the namespace for the field error, with the fields
// actual name.
//
// eq. "User.FirstName" see Namespace for comparison
//
// NOTE: this field can be blank when validating a single primitive field
// using validate.Field(...) as there is no way to extract it's name
StructNamespace() string
// returns the fields name with the tag name taking precedence over the
// fields actual name.
//
// eq. JSON name "fname"
// see ActualField for comparison
Field() string
// returns the fields actual name from the struct, when able to determine.
//
// eq. "FirstName"
// see Field for comparison
StructField() string
// returns the actual fields value in case needed for creating the error
// message
Value() interface{}
// returns the param value, in string form for comparison; this will also
// help with generating an error message
Param() string
// Kind returns the Field's reflect Kind
//
// eg. time.Time's kind is a struct
Kind() reflect.Kind
// Type returns the Field's reflect Type
//
// // eg. time.Time's type is time.Time
Type() reflect.Type
}
FieldError contains all functions to get error details
type FieldLevel ¶
type FieldLevel interface {
// returns the top level struct, if any
Top() reflect.Value
// returns the current fields parent struct, if any or
// the comparison value if called 'VarWithValue'
Parent() reflect.Value
// returns current field for validation
Field() reflect.Value
// returns param for validation against current field
Param() string
// ExtractType gets the actual underlying type of field value.
// It will dive into pointers, customTypes and return you the
// underlying value and it's kind.
ExtractType(field reflect.Value) (value reflect.Value, kind reflect.Kind, nullable bool)
// traverses the parent struct to retrieve a specific field denoted by the provided namespace
// in the param and returns the field, field kind and whether is was successful in retrieving
// the field at all.
//
// NOTE: when not successful ok will be false, this can happen when a nested struct is nil and so the field
// could not be retrieved because it didn't exist.
GetStructFieldOK() (reflect.Value, reflect.Kind, bool)
}
FieldLevel contains all the information and helper functions to validate a field
type Func ¶
type Func func(fl FieldLevel) bool
Func accepts all values needed for file and cross field validation fl = FieldLevel validation helper field = field value for validation fieldType = fields param = parameter used in validation i.e. gt=0 param would be 0
type InvalidValidationError ¶
InvalidValidationError describes an invalid argument passed to `Struct`, `StructExcept`, StructPartial` or `Field`
func (*InvalidValidationError) Error ¶
func (e *InvalidValidationError) Error() string
Error returns InvalidValidationError message
type StructLevel ¶
type StructLevel interface {
// returns the main validation object, in case one want to call validations internally.
// this is so you don;t have to use anonymous functoins to get access to the validate
// instance.
Validator() *Validate
// returns the top level struct, if any
Top() reflect.Value
// returns the current fields parent struct, if any
Parent() reflect.Value
// returns the current struct.
// this is not needed when implementing 'Validatable' interface,
// only when a StructLevel is registered
Current() reflect.Value
// ExtractType gets the actual underlying type of field value.
// It will dive into pointers, customTypes and return you the
// underlying value and it's kind.
ExtractType(field reflect.Value) (value reflect.Value, kind reflect.Kind, nullable bool)
// reports an error just by passing the field and tag information
//
// NOTES:
//
// fieldName and altName get appended to the existing namespace that
// validator is on. eg. pass 'FirstName' or 'Names[0]' depending
// on the nesting
//
// tag can be an existing validation tag or just something you make up
// and process on the flip side it's up to you.
ReportError(field interface{}, fieldName, altName, tag, param string)
// reports an error just by passing ValidationErrors
//
// NOTES:
//
// relativeNamespace and relativeActualNamespace get appended to the
// existing namespace that validator is on.
// eg. pass 'User.FirstName' or 'Users[0].FirstName' depending
// on the nesting. most of the time they will be blank, unless you validate
// at a level lower the the current field depth
//
// tag can be an existing validation tag or just something you make up
// and process on the flip side it's up to you.
ReportValidationErrors(relativeNamespace, relativeActualNamespace string, errs ValidationErrors)
}
StructLevel contains all the information and helper functions to validate a struct
type StructLevelFunc ¶
type StructLevelFunc func(sl StructLevel)
StructLevelFunc accepts all values needed for struct level validation
type TagNameFunc ¶
type TagNameFunc func(field reflect.StructField) string
TagNameFunc allows for adding of a custom tag name parser
type Validate ¶
type Validate struct {
// contains filtered or unexported fields
}
Validate contains the validator settings and cache
func (*Validate) RegisterAlias ¶
RegisterAlias registers a mapping of a single validation tag that defines a common or complex set of validation(s) to simplify adding validation to structs.
NOTE: this function is not thread-safe it is intended that these all be registered prior to any validation
func (*Validate) RegisterCustomTypeFunc ¶
func (v *Validate) RegisterCustomTypeFunc(fn CustomTypeFunc, types ...interface{})
RegisterCustomTypeFunc registers a CustomTypeFunc against a number of types
NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation
func (*Validate) RegisterStructValidation ¶
func (v *Validate) RegisterStructValidation(fn StructLevelFunc, types ...interface{})
RegisterStructValidation registers a StructLevelFunc against a number of types. This is akin to implementing the 'Validatable' interface, but for structs for which you may not have access or rights to change.
NOTES: - if this and the 'Validatable' interface are implemented the Struct Level takes precedence as to enable a struct out of your control's validation to be overridden - this method is not thread-safe it is intended that these all be registered prior to any validation
func (*Validate) RegisterTagNameFunc ¶
func (v *Validate) RegisterTagNameFunc(fn TagNameFunc)
RegisterTagNameFunc registers a function to get another name from the StructField eg. the JSON name
func (*Validate) RegisterValidation ¶
RegisterValidation adds a validation with the given tag
NOTES: - if the key already exists, the previous validation function will be replaced. - this method is not thread-safe it is intended that these all be registered prior to any validation
func (*Validate) SetTagName ¶
SetTagName allows for changing of the default tag name of 'validate'
func (*Validate) Struct ¶
Struct validates a structs exposed fields, and automatically validates nested structs, unless otherwise specified.
It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.
func (*Validate) StructExcept ¶
StructExcept validates all fields except the ones passed in. Fields may be provided in a namespaced fashion relative to the struct provided i.e. NestedStruct.Field or NestedArrayField[0].Struct.Name
It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.
func (*Validate) StructPartial ¶
StructPartial validates the fields passed in only, ignoring all others. Fields may be provided in a namespaced fashion relative to the struct provided eg. NestedStruct.Field or NestedArrayField[0].Struct.Name
It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors.
func (*Validate) Var ¶
Var validates a single variable using tag style validation. eg. var i int validate.Var(i, "gt=1,lt=10")
WARNING: a struct can be passed for validation eg. time.Time is a struct or if you have a custom type and have registered
a custom type handler, so must allow it; however unforseen validations will occur if trying to validate a struct that is meant to be passed to 'validate.Struct'
It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors. validate Array, Slice and maps fields which may contain more than one error
func (*Validate) VarWithValue ¶
VarWithValue validates a single variable, against another variable/field's value using tag style validation eg. s1 := "abcd" s2 := "abcd" validate.VarWithValue(s1, s2, "eqcsfield") // returns true
WARNING: a struct can be passed for validation eg. time.Time is a struct or if you have a custom type and have registered
a custom type handler, so must allow it; however unforseen validations will occur if trying to validate a struct that is meant to be passed to 'validate.Struct'
It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise. You will need to assert the error if it's not nil eg. err.(validator.ValidationErrors) to access the array of errors. validate Array, Slice and maps fields which may contain more than one error
type ValidationErrors ¶
type ValidationErrors []FieldError
ValidationErrors is an array of FieldError's for use in custom error messages post validation.
func (ValidationErrors) Error ¶
func (ve ValidationErrors) Error() string
Error is intended for use in development + debugging and not intended to be a production error message. It allows ValidationErrors to subscribe to the Error interface. All information to create an error message specific to your application is contained within the FieldError found within the ValidationErrors array
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