README
¶
Package validator
Package validator implements value validations for structs and individual fields based on tags. It is even capable of Cross Field and even Cross Field Cross Struct validation.
Installation
Just use go get.
go get gopkg.in/bluesuncorp/validator.v5
or to update
go get -u gopkg.in/bluesuncorp/validator.v5
And then just import the package into your own code.
import "gopkg.in/bluesuncorp/validator.v5"
Usage
Please see http://godoc.org/gopkg.in/bluesuncorp/validator.v5 for detailed usage docs.
Contributing
There will be a development branch for each version of this package i.e. v1-development, please make your pull requests against those branches.
If changes are breaking please create an issue, for discussion and create a pull request against the highest development branch for example this package has a v1 and v1-development branch however, there will also be a v2-development brach even though v2 doesn't exist yet.
I strongly encourage everyone whom creates a custom validation function to contribute them and help make this package even better.
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 validation and even Cross Field Cross Struct validation for nested structs.
Validate
validate := validator.New("validate", validator.BakedInValidators)
errs := validate.Struct(//your struct)
valErr := validate.Field(field, "omitempty,min=1,max=10")
A simple example usage:
type UserDetail {
Details string `validate:"-"`
}
type User struct {
Name string `validate:"required,max=60"`
PreferedName string `validate:"omitempty,max=60"`
Sub UserDetail
}
user := &User {
Name: "",
}
// errs will contain a hierarchical list of errors
// using the StructErrors struct
// or nil if no errors exist
errs := validate.Struct(user)
// in this case 1 error Name is required
errs.Struct will be "User"
errs.StructErrors will be empty <-- fields that were structs
errs.Errors will have 1 error of type FieldError
NOTE: Anonymous Structs - they don't have names so expect the Struct name
within StructErrors to be blank.
Error Handling ¶
The error can be used like so
fieldErr, _ := errs["Name"] fieldErr.Field // "Name" fieldErr.ErrorTag // "required"
Both StructErrors and FieldError implement the Error interface but it's intended use is for development + debugging, not a production error message.
fieldErr.Error() // Field validation for "Name" failed on the "required" tag errs.Error() // Struct: User // Field validation for "Name" failed on the "required" tag
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, for us building an internationalized application I needed to know the field and what validation failed so that I could provide an error in the users specific language.
if fieldErr.Field == "Name" {
switch fieldErr.ErrorTag
case "required":
return "Translated string based on field + error"
default:
return "Translated string based on field"
}
The hierarchical error structure is hard to work with sometimes.. Agreed Flatten function to the rescue! Flatten will return a map of FieldError's but the field name will be namespaced.
// if UserDetail Details field failed validation Field will be "Sub.Details" // for Name Field will be "Name"
Custom Functions ¶
Custom functions can be added
//Structure
func customFunc(top interface{}, current interface{}, field interface{}, param string) bool {
if whatever {
return false
}
return true
}
validate.AddFunction("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 implemented, for example Start & End Date range validation
// NOTE: when calling validate.Struct(val) val 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
//
// Because of the specific requirements and field names within each persons project that
// uses this library it is likely that custom functions will need to be created for your
// Cross Field Validation needs, however there are some build in Generic Cross Field validations,
// see Baked In Validators and Tags below
func isDateRangeValid(val interface{}, field interface{}, param string) bool {
myStruct := val.(myStructType)
if myStruct.Start.After(field.(time.Time)) {
return false
}
return true
}
Multiple Validators ¶
Multiple validators on a field will process in the order defined
type Test struct {
Field `validate:"max=10,min=1"`
}
// max will be checked then min
Bad Validator definitions are not handled by the library
type Test struct {
Field `validate:"min=10,max=0"`
}
// this definition of min max will never validate
Baked In Validators and Tags ¶
NOTE: Baked In Cross field validation only compares fields on the same struct, if cross field + cross struct validation is needed your own custom validator should be implemented.
Here is a list of the current built in validators:
- Tells the validation to skip this struct field; this is particularily handy in ignoring embedded structs from being validated. (Usage: -) | 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) structonly When a field that is a nest struct in encountered and contains this flag any validation on the nested struct such as "required" 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. omitempty Allows conitional 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) required This validates that the value is not the data types default value. For numbers ensures value is not zero. For strings ensures value is not "". For slices, arrays, and maps, ensures the length is not zero. (Usage: required) len 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) max 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) min 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) gt 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. (Usage: gt=10) For time.Time ensures the time value is greater than time.Now.UTC() (Usage: gt) gte Same as 'min' above. Kept both to make terminology with 'len' easier (Usage: gte=10) For time.Time ensures the time value is greater than or equal to time.Now.UTC() (Usage: gte) lt 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. (Usage: lt=10) For time.Time ensures the time value is less than time.Now.UTC() (Usage: lt) lte Same as 'max' above. Kept both to make terminology with 'len' easier (Usage: lte=10) For time.Time ensures the time value is less than or equal to time.Now.UTC() (Usage: lte) gtfield 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: Validation on End field using validate.Struct Usage(gtfield=Start) Validating by field validate.FieldWithValue(start, end, "gtfield") gtefield 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: Validation on End field using validate.Struct Usage(gtefield=Start) Validating by field validate.FieldWithValue(start, end, "gtefield") ltfield 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: Validation on End field using validate.Struct Usage(ltfield=Start) Validating by field validate.FieldWithValue(start, end, "ltfield") ltefield 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: Validation on End field using validate.Struct Usage(ltefield=Start) Validating by field validate.FieldWithValue(start, end, "ltefield") alpha This validates that a strings value contains alpha characters only (Usage: alpha) alphanum This validates that a strings value contains alphanumeric characters only (Usage: alphanum) numeric This validates that a strings value contains a basic numeric value. basic excludes exponents etc... (Usage: numeric) hexadecimal This validates that a strings value contains a valid hexadecimal. (Usage: hexadecimal) hexcolor This validates that a strings value contains a valid hex color including hashtag (#) (Usage: hexcolor) rgb This validates that a strings value contains a valid rgb color (Usage: rgb) rgba This validates that a strings value contains a valid rgba color (Usage: rgba) hsl This validates that a strings value contains a valid hsl color (Usage: hsl) hsla This validates that a strings value contains a valid hsla color (Usage: hsla) email This validates that a strings 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 This validates that a strings 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 This validates that a strings value contains a valid uri This will accept any uri the golang request uri accepts (Usage: uri)
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 sumit 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 ¶
- Variables
- type FieldError
- type Func
- type StructErrors
- type Validate
- func (v *Validate) AddFunction(key string, f Func) error
- func (v *Validate) Field(f interface{}, tag string) *FieldError
- func (v *Validate) FieldWithValue(val interface{}, f interface{}, tag string) *FieldError
- func (v *Validate) SetTag(tagName string)
- func (v *Validate) Struct(s interface{}) *StructErrors
Constants ¶
This section is empty.
Variables ¶
var BakedInValidators = map[string]Func{
"required": hasValue,
"len": hasLengthOf,
"min": hasMinOf,
"max": hasMaxOf,
"lt": isLt,
"lte": isLte,
"gt": isGt,
"gte": isGte,
"gtefield": isGteField,
"gtfield": isGtField,
"ltefield": isLteField,
"ltfield": isLtField,
"alpha": isAlpha,
"alphanum": isAlphanum,
"numeric": isNumeric,
"number": isNumber,
"hexadecimal": isHexadecimal,
"hexcolor": isHexcolor,
"rgb": isRgb,
"rgba": isRgba,
"hsl": isHsl,
"hsla": isHsla,
"email": isEmail,
"url": isURL,
"uri": isURI,
}
BakedInValidators is the default map of ValidationFunc you can add, remove or even replace items to suite your needs, or even disregard and use your own map if so desired.
Functions ¶
This section is empty.
Types ¶
type FieldError ¶
type FieldError struct {
Field string
Tag string
Kind reflect.Kind
Type reflect.Type
Param string
Value interface{}
}
FieldError contains a single field's validation error along with other properties that may be needed for error message creation
func (*FieldError) Error ¶
func (e *FieldError) Error() string
This is intended for use in development + debugging and not intended to be a production error message. it also allows FieldError to be used as an Error interface
type Func ¶
Func accepts all values needed for file and cross field validation top = top level struct when validating by struct otherwise nil current = current level struct when validating by struct otherwise optional comparison value f = field value for validation param = parameter used in validation i.e. gt=0 param would be 0
type StructErrors ¶
type StructErrors struct {
// Name of the Struct
Struct string
// Struct Field Errors
Errors map[string]*FieldError
// Struct Fields of type struct and their errors
// key = Field Name of current struct, but internally Struct will be the actual struct name unless anonymous struct, it will be blank
StructErrors map[string]*StructErrors
}
StructErrors is hierarchical list of field and struct validation errors for a non hierarchical representation please see the Flatten method for StructErrors
func (*StructErrors) Error ¶
func (e *StructErrors) Error() string
This is intended for use in development + debugging and not intended to be a production error message. it also allows StructErrors to be used as an Error interface
func (*StructErrors) Flatten ¶
func (e *StructErrors) Flatten() map[string]*FieldError
Flatten flattens the StructErrors hierarchical structure into a flat namespace style field name for those that want/need it
type Validate ¶
type Validate struct {
// contains filtered or unexported fields
}
Validate implements the Validate Struct NOTE: Fields within are not thread safe and that is on purpose Functions and Tags should all be predifined before use, so subscribe to the philosiphy or make it thread safe on your end
func (*Validate) AddFunction ¶
AddFunction adds a validation Func to a Validate's map of validators denoted by the key NOTE: if the key already exists, it will get replaced.
func (*Validate) Field ¶
func (v *Validate) Field(f interface{}, tag string) *FieldError
Field allows validation of a single field, still using tag style validation to check multiple errors
func (*Validate) FieldWithValue ¶
func (v *Validate) FieldWithValue(val interface{}, f interface{}, tag string) *FieldError
FieldWithValue allows validation of a single field, possibly even against another fields value, still using tag style validation to check multiple errors
func (*Validate) SetTag ¶
SetTag sets tagName of the Validator to one of your choosing after creation perhaps to dodge a tag name conflict in a specific section of code
func (*Validate) Struct ¶
func (v *Validate) Struct(s interface{}) *StructErrors
Struct validates a struct, even it's nested structs, and returns a struct containing the errors NOTE: Nested Arrays, or Maps of structs do not get validated only the Array or Map itself; the reason is that there is no good way to represent or report which struct within the array has the error, besides can validate the struct prior to adding it to the Array or Map.
Source Files