README
¶
go-validation
Simple and flexible Go (Golang) validation library.
This library provides an elegant DSL for defining validation constraints in Go.
Installation
Pull in the library using go get:
$ go get github.com/seeruk/go-validation
License
MIT
Documentation
¶
Index ¶
- Constants
- func ConstraintViolationsToProto(violations []ConstraintViolation) []protoadapt.MessageV1
- func CreateValidateFunc(structTag string) func(value any, constraints ...Constraint) []ConstraintViolation
- func FieldName(ctx Context, fieldName string) string
- func IsEmpty(value reflect.Value) bool
- func IsNillable(value reflect.Value) bool
- func MustBe(typ reflect.Type, kinds ...reflect.Kind)
- func UnwrapType(typ reflect.Type) reflect.Type
- func UnwrapValue(val reflect.Value) reflect.Value
- func ViolationsToStatus(violations []ConstraintViolation) *status.Status
- type Constraint
- type ConstraintFunc
- type ConstraintViolation
- func ShouldBe(ctx Context, typ reflect.Type, kinds ...reflect.Kind) []ConstraintViolation
- func Validate(value any, constraints ...Constraint) []ConstraintViolation
- func ValidateContext(ctx Context, constraints ...Constraint) []ConstraintViolation
- func ViolationsFromStatus(sts *status.Status) []ConstraintViolation
- type Constraints
- type Context
- type Elements
- type Fields
- type Keys
- type Lazy
- type Map
- type PathKind
- type Value
Constants ¶
const DefaultNameStructTag = "validation"
DefaultNameStructTag is the default struct tag used to override the name of struct fields in the path that's output.
Variables ¶
This section is empty.
Functions ¶
func ConstraintViolationsToProto ¶
func ConstraintViolationsToProto(violations []ConstraintViolation) []protoadapt.MessageV1
ConstraintViolationsToProto converts a slice of ConstraintViolations into a slice of the ProtoBuf representation of those ConstraintViolations, making them ready to use for example in a gRPC service in a similar way to how ConstraintViolation can already be used in JSON web services.
They're returned as a slice of proto.Message so that they can be passed straight into something like a gRPC status without transformation.
func CreateValidateFunc ¶ added in v0.1.8
func CreateValidateFunc(structTag string) func(value any, constraints ...Constraint) []ConstraintViolation
CreateValidateFunc allows the caller to create a customised validate function, using the given option(s), allowing them to avoid manually creating a context and using the simpler API while maintaining the ability to customise the validation context. TODO: Any more options to add?
func FieldName ¶
FieldName returns the output name for a field of the given field name. The provided Context's value must be a struct, or this function will panic. FieldName will unwrap the value on the given Context, like many Constraints do.
func IsEmpty ¶
IsEmpty checks if a value is "empty". Basically, if it's a value's zero value, nil, or has no length it's considered empty.
func IsNillable ¶
IsNillable returns true if the given value is of a nillable type.
func MustBe ¶
MustBe will panic if the given reflect.Value is not one of the given reflect.Kind kinds.
func UnwrapType ¶
UnwrapType takes the given reflect.Type, and if it's a pointer gets the pointer element's type. This process is recursive, so we always end up with a non-pointer type at the end of the process.
func UnwrapValue ¶
UnwrapValue takes the given reflect.Value, and if it's a pointer gets the pointer element. This process is recursive, so we always end up with a non-pointer type at the end of the process.
func ViolationsToStatus ¶ added in v0.1.2
func ViolationsToStatus(violations []ConstraintViolation) *status.Status
ViolationsToStatus returns the given set of constraint violations as a gRPC status.
Types ¶
type Constraint ¶
type Constraint interface {
Violations(ctx Context) []ConstraintViolation
}
Constraint represents a type that will validate a value and/or adjust the validation scope for further validation (e.g. validating a field on a struct, or an element in a slice).
func LazyDynamic ¶
func LazyDynamic(constraintFn any) Constraint
LazyDynamic is a Constraint that's extremely similar to Lazy, and fulfils mostly the same purpose, but instead expects a function that has a single argument of the type being validated.
type ConstraintFunc ¶
type ConstraintFunc func(ctx Context) []ConstraintViolation
ConstraintFunc provides a convenient way of defining a Constraint as a function instead of a struct, keeping code more compact.
func When ¶
func When(predicate bool, constraints ...Constraint) ConstraintFunc
When conditionally runs some constraints. The predicate is set up at the time of creating the constraints. If you want a more dynamic approach, you should use WhenFn instead. You can also build up constraints programmatically and use the value being validated to build the constraints.
func WhenFn ¶
func WhenFn(predicateFn func(ctx Context) bool, constraints ...Constraint) ConstraintFunc
WhenFn lazily conditionally runs some constraints. The predicate function is called during the validation process. If you need an even more dynamic approach, you can also build up constraints programmatically and use the value being validated to build the constraints.
func (ConstraintFunc) Violations ¶
func (c ConstraintFunc) Violations(ctx Context) []ConstraintViolation
Violations ...
type ConstraintViolation ¶
type ConstraintViolation struct {
Path string `json:"path"`
PathKind PathKind `json:"path_kind"`
Message string `json:"message"`
Details map[string]any `json:"details,omitempty"`
}
ConstraintViolation contains information to highlight a value failing to fulfil the requirements of a Constraint. It contains information to find the value that is failing, and how to resolve the violation.
func ShouldBe ¶
ShouldBe is the non-panicking alternative to MustBe. Instead of panicking it returns a slice of ConstraintViolation which can be directly returned from a Constraint.
func Validate ¶
func Validate(value any, constraints ...Constraint) []ConstraintViolation
Validate executes the given constraint(s) against the given value, returning any violations of those constraints.
func ValidateContext ¶
func ValidateContext(ctx Context, constraints ...Constraint) []ConstraintViolation
ValidateContext is exactly like Validate, except it doesn't create a Context for you. This allows for more granular configuration provided by the Context type (and means we can avoid creating a Validator struct type to do this).
func ViolationsFromStatus ¶ added in v0.2.4
func ViolationsFromStatus(sts *status.Status) []ConstraintViolation
ViolationsFromStatus returns the constraint violations from the given gRPC status. If the status doesn't contain any constraint violations, an empty slice is returned.
type Constraints ¶
type Constraints []Constraint
Constraints is simply a collection of many constraints. All of the constraints will be run, and their results will be aggregated and returned.
func (Constraints) Violations ¶
func (cc Constraints) Violations(ctx Context) []ConstraintViolation
Violations ...
type Context ¶
Context contains useful information for a Constraint, including the value(s) being validated.
func NewContext ¶
NewContext returns a new Context, with a Value created for the given any value.
func (*Context) Violation ¶
func (c *Context) Violation(message string, details map[string]any) ConstraintViolation
Violation provides a convenient way to produce a ConstraintViolation using the information found on the Context. If a custom violation is needed, one can always be made using the information on the Context manually.
func (Context) WithPathKind ¶
WithPathKind returns a shallow copy of this Context with the given PathKind assigned, not modifying the original Context.
type Elements ¶
type Elements []Constraint
Elements is a Constraint used to validate every value (element) in an array, a map, or a slice.
func (Elements) Violations ¶
func (e Elements) Violations(ctx Context) []ConstraintViolation
Violations ...
type Fields ¶
type Fields map[string]Constraint
Fields is a Constraint used to validate the values of specific fields on a struct.
func (Fields) Violations ¶
func (f Fields) Violations(ctx Context) []ConstraintViolation
Violations ...
type Lazy ¶
type Lazy func() Constraint
Lazy is a Constraint that allows a function that returns Constraints to be evaluated at validation-time. This enables things like defining constraints for recursive structures.
type Map ¶
type Map map[any]Constraint
Map is a Constraint used to validate a map. This Constraint validates the values in the map, by specific keys. If you want to use the same validation on all keys of a map, use Elements instead. If you want to validate the keys of the map, use Keys instead.
type PathKind ¶
type PathKind int
PathKind enumerates the different possible kinds of values that we validate. This is used to remove the ambiguity in what is being validated in cases where the path could either refer to a key, or a value (e.g. you might want to validate a map's key, but the path to the key would be the same as the path to the value under that key).
func (PathKind) MarshalJSON ¶
MarshalJSON returns a JSON encoded version of the string representation of this PathKind.
func (*PathKind) UnmarshalJSON ¶ added in v0.1.13
UnmarshalJSON takes the given bytes and attempts to mutate this PathKind to the appropriate value, if a valid value is given.
Source Files
Directories