/**
* Package validator
*
* MISC:
* - anonymous structs - they don't have names so expect the Struct name within StructErrors to be blank
*
*/
package validator
import (
"bytes"
"errors"
"fmt"
"reflect"
"strings"
"sync"
"time"
)
const (
utf8HexComma = "0x2C"
utf8Pipe = "0x7C"
tagSeparator = ","
orSeparator = "|"
tagKeySeparator = "="
structOnlyTag = "structonly"
noStructLevelTag = "nostructlevel"
omitempty = "omitempty"
skipValidationTag = "-"
diveTag = "dive"
existsTag = "exists"
fieldErrMsg = "Key: '%s' Error:Field validation for '%s' failed on the '%s' tag"
arrayIndexFieldName = "%s" + leftBracket + "%d" + rightBracket
mapIndexFieldName = "%s" + leftBracket + "%v" + rightBracket
invalidValidation = "Invalid validation tag on field %s"
undefinedValidation = "Undefined validation function on field %s"
validatorNotInitialized = "Validator instance not initialized"
fieldNameRequired = "Field Name Required"
tagRequired = "Tag Required"
)
var (
timeType = reflect.TypeOf(time.Time{})
timePtrType = reflect.TypeOf(&time.Time{})
emptyStructPtr = new(struct{})
)
// StructLevel contains all of the information and helper methods
// for reporting errors during struct level validation
type StructLevel struct {
TopStruct reflect.Value
CurrentStruct reflect.Value
errPrefix string
nsPrefix string
errs ValidationErrors
v *Validate
}
// ReportValidationErrors accepts the key relative to the top level struct and validatin errors.
// Example: had a triple nested struct User, ContactInfo, Country and ran errs := validate.Struct(country)
// from within a User struct level validation would call this method like so:
// ReportValidationErrors("ContactInfo.", errs)
// NOTE: relativeKey can contain both the Field Relative and Custom name relative paths
// i.e. ReportValidationErrors("ContactInfo.|cInfo", errs) where cInfo represents say the JSON name of
// the relative path; this will be split into 2 variables in the next valiator version.
func (sl *StructLevel) ReportValidationErrors(relativeKey string, errs ValidationErrors) {
for _, e := range errs {
idx := strings.Index(relativeKey, "|")
var rel string
var cRel string
if idx != -1 {
rel = relativeKey[:idx]
cRel = relativeKey[idx+1:]
} else {
rel = relativeKey
}
key := sl.errPrefix + rel + e.Field
e.FieldNamespace = key
e.NameNamespace = sl.nsPrefix + cRel + e.Name
sl.errs[key] = e
}
}
// ReportError reports an error just by passing the field and tag information
// NOTE: tag can be an existing validation tag or just something you make up
// and precess on the flip side it's up to you.
func (sl *StructLevel) ReportError(field reflect.Value, fieldName string, customName string, tag string) {
field, kind := sl.v.ExtractType(field)
if fieldName == blank {
panic(fieldNameRequired)
}
if customName == blank {
customName = fieldName
}
if tag == blank {
panic(tagRequired)
}
ns := sl.errPrefix + fieldName
switch kind {
case reflect.Invalid:
sl.errs[ns] = &FieldError{
FieldNamespace: ns,
NameNamespace: sl.nsPrefix + customName,
Name: customName,
Field: fieldName,
Tag: tag,
ActualTag: tag,
Param: blank,
Kind: kind,
}
default:
sl.errs[ns] = &FieldError{
FieldNamespace: ns,
NameNamespace: sl.nsPrefix + customName,
Name: customName,
Field: fieldName,
Tag: tag,
ActualTag: tag,
Param: blank,
Value: field.Interface(),
Kind: kind,
Type: field.Type(),
}
}
}
// Validate contains the validator settings passed in using the Config struct
type Validate struct {
tagName string
fieldNameTag string
validationFuncs map[string]Func
structLevelFuncs map[reflect.Type]StructLevelFunc
customTypeFuncs map[reflect.Type]CustomTypeFunc
aliasValidators map[string]string
hasCustomFuncs bool
hasAliasValidators bool
hasStructLevelFuncs bool
tagCache *tagCacheMap
structCache *structCacheMap
errsPool *sync.Pool
}
func (v *Validate) initCheck() {
if v == nil {
panic(validatorNotInitialized)
}
}
// Config contains the options that a Validator instance will use.
// It is passed to the New() function
type Config struct {
TagName string
FieldNameTag string
}
// 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 CustomTypeFunc func(field reflect.Value) interface{}
// Func accepts all values needed for file and cross field validation
// v = validator instance, needed but some built in functions for it's custom types
// topStruct = top level struct when validating by struct otherwise nil
// currentStruct = current level struct when validating by struct otherwise optional comparison value
// field = field value for validation
// param = parameter used in validation i.e. gt=0 param would be 0
type Func func(v *Validate, topStruct reflect.Value, currentStruct reflect.Value, field reflect.Value, fieldtype reflect.Type, fieldKind reflect.Kind, param string) bool
// StructLevelFunc accepts all values needed for struct level validation
type StructLevelFunc func(v *Validate, structLevel *StructLevel)
// ValidationErrors is a type of map[string]*FieldError
// it exists to allow for multiple errors to be passed from this library
// and yet still subscribe to the error interface
type ValidationErrors map[string]*FieldError
// 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 map
func (ve ValidationErrors) Error() string {
buff := bytes.NewBufferString(blank)
for key, err := range ve {
buff.WriteString(fmt.Sprintf(fieldErrMsg, key, err.Field, err.Tag))
buff.WriteString("\n")
}
return strings.TrimSpace(buff.String())
}
// FieldError contains a single field's validation error along
// with other properties that may be needed for error message creation
type FieldError struct {
FieldNamespace string
NameNamespace string
Field string
Name string
Tag string
ActualTag string
Kind reflect.Kind
Type reflect.Type
Param string
Value interface{}
}
// New creates a new Validate instance for use.
func New(config *Config) *Validate {
v := &Validate{
tagName: config.TagName,
fieldNameTag: config.FieldNameTag,
tagCache: &tagCacheMap{m: map[string]*cachedTag{}},
structCache: &structCacheMap{m: map[reflect.Type]*cachedStruct{}},
errsPool: &sync.Pool{New: func() interface{} {
return ValidationErrors{}
}}}
if len(v.aliasValidators) == 0 {
// must copy alias validators for separate validations to be used in each validator instance
v.aliasValidators = map[string]string{}
for k, val := range bakedInAliasValidators {
v.RegisterAliasValidation(k, val)
}
}
if len(v.validationFuncs) == 0 {
// must copy validators for separate validations to be used in each instance
v.validationFuncs = map[string]Func{}
for k, val := range bakedInValidators {
v.RegisterValidation(k, val)
}
}
return v
}
// RegisterStructValidation registers a StructLevelFunc 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 (v *Validate) RegisterStructValidation(fn StructLevelFunc, types ...interface{}) {
v.initCheck()
if v.structLevelFuncs == nil {
v.structLevelFuncs = map[reflect.Type]StructLevelFunc{}
}
for _, t := range types {
v.structLevelFuncs[reflect.TypeOf(t)] = fn
}
v.hasStructLevelFuncs = true
}
// RegisterValidation adds a validation Func to a Validate's map of validators denoted by the key
// NOTE: if the key already exists, the previous validation function will be replaced.
// NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation
func (v *Validate) RegisterValidation(key string, fn Func) error {
v.initCheck()
if key == blank {
return errors.New("Function Key cannot be empty")
}
if fn == nil {
return errors.New("Function cannot be empty")
}
_, ok := restrictedTags[key]
if ok || strings.ContainsAny(key, restrictedTagChars) {
panic(fmt.Sprintf(restrictedTagErr, key))
}
v.validationFuncs[key] = fn
return nil
}
// 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 (v *Validate) RegisterCustomTypeFunc(fn CustomTypeFunc, types ...interface{}) {
v.initCheck()
if v.customTypeFuncs == nil {
v.customTypeFuncs = map[reflect.Type]CustomTypeFunc{}
}
for _, t := range types {
v.customTypeFuncs[reflect.TypeOf(t)] = fn
}
v.hasCustomFuncs = true
}
// RegisterAliasValidation registers a mapping of a single validationstag that
// defines a common or complex set of validation(s) to simplify adding validation
// to structs. 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.
// NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation
func (v *Validate) RegisterAliasValidation(alias, tags string) {
v.initCheck()
_, ok := restrictedTags[alias]
if ok || strings.ContainsAny(alias, restrictedTagChars) {
panic(fmt.Sprintf(restrictedAliasErr, alias))
}
v.aliasValidators[alias] = tags
v.hasAliasValidators = true
}
// Field validates a single field using tag style validation and returns nil or ValidationErrors as type error.
// You will need to assert the error if it's not nil i.e. err.(validator.ValidationErrors) to access the map of errors.
// NOTE: it returns ValidationErrors instead of a single FieldError because this can also
// validate Array, Slice and maps fields which may contain more than one error
func (v *Validate) Field(field interface{}, tag string) error {
v.initCheck()
errs := v.errsPool.Get().(ValidationErrors)
fieldVal := reflect.ValueOf(field)
v.traverseField(fieldVal, fieldVal, fieldVal, blank, blank, errs, false, tag, blank, blank, false, false, nil, nil)
if len(errs) == 0 {
v.errsPool.Put(errs)
return nil
}
return errs
}
// FieldWithValue validates a single field, against another fields value using tag style validation and returns nil or ValidationErrors.
// You will need to assert the error if it's not nil i.e. err.(validator.ValidationErrors) to access the map of errors.
// NOTE: it returns ValidationErrors instead of a single FieldError because this can also
// validate Array, Slice and maps fields which may contain more than one error
func (v *Validate) FieldWithValue(val interface{}, field interface{}, tag string) error {
v.initCheck()
errs := v.errsPool.Get().(ValidationErrors)
topVal := reflect.ValueOf(val)
v.traverseField(topVal, topVal, reflect.ValueOf(field), blank, blank, errs, false, tag, blank, blank, false, false, nil, nil)
if len(errs) == 0 {
v.errsPool.Put(errs)
return nil
}
return errs
}
// StructPartial validates the fields passed in only, ignoring all others.
// Fields may be provided in a namespaced fashion relative to the struct provided
// i.e. NestedStruct.Field or NestedArrayField[0].Struct.Name and returns nil or ValidationErrors as error
// You will need to assert the error if it's not nil i.e. err.(validator.ValidationErrors) to access the map of errors.
func (v *Validate) StructPartial(current interface{}, fields ...string) error {
v.initCheck()
sv, _ := v.ExtractType(reflect.ValueOf(current))
name := sv.Type().Name()
m := map[string]*struct{}{}
if fields != nil {
for _, k := range fields {
flds := strings.Split(k, namespaceSeparator)
if len(flds) > 0 {
key := name + namespaceSeparator
for _, s := range flds {
idx := strings.Index(s, leftBracket)
if idx != -1 {
for idx != -1 {
key += s[:idx]
m[key] = emptyStructPtr
idx2 := strings.Index(s, rightBracket)
idx2++
key += s[idx:idx2]
m[key] = emptyStructPtr
s = s[idx2:]
idx = strings.Index(s, leftBracket)
}
} else {
key += s
m[key] = emptyStructPtr
}
key += namespaceSeparator
}
}
}
}
errs := v.errsPool.Get().(ValidationErrors)
v.tranverseStruct(sv, sv, sv, blank, blank, errs, true, len(m) != 0, false, m, false)
if len(errs) == 0 {
v.errsPool.Put(errs)
return nil
}
return errs
}
// 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 and returns nil or ValidationErrors as error
// You will need to assert the error if it's not nil i.e. err.(validator.ValidationErrors) to access the map of errors.
func (v *Validate) StructExcept(current interface{}, fields ...string) error {
v.initCheck()
sv, _ := v.ExtractType(reflect.ValueOf(current))
name := sv.Type().Name()
m := map[string]*struct{}{}
for _, key := range fields {
m[name+namespaceSeparator+key] = emptyStructPtr
}
errs := v.errsPool.Get().(ValidationErrors)
v.tranverseStruct(sv, sv, sv, blank, blank, errs, true, len(m) != 0, true, m, false)
if len(errs) == 0 {
v.errsPool.Put(errs)
return nil
}
return errs
}
// Struct validates a structs exposed fields, and automatically validates nested structs, unless otherwise specified.
// it returns nil or ValidationErrors as error.
// You will need to assert the error if it's not nil i.e. err.(validator.ValidationErrors) to access the map of errors.
func (v *Validate) Struct(current interface{}) error {
v.initCheck()
errs := v.errsPool.Get().(ValidationErrors)
sv := reflect.ValueOf(current)
v.tranverseStruct(sv, sv, sv, blank, blank, errs, true, false, false, nil, false)
if len(errs) == 0 {
v.errsPool.Put(errs)
return nil
}
return errs
}
// tranverseStruct traverses a structs fields and then passes them to be validated by traverseField
func (v *Validate) tranverseStruct(topStruct reflect.Value, currentStruct reflect.Value, current reflect.Value, errPrefix string, nsPrefix string, errs ValidationErrors, useStructName bool, partial bool, exclude bool, includeExclude map[string]*struct{}, isStructOnly bool) {
if current.Kind() == reflect.Ptr && !current.IsNil() {
current = current.Elem()
}
if current.Kind() != reflect.Struct && current.Kind() != reflect.Interface {
panic("value passed for validation is not a struct")
}
// var ok bool
typ := current.Type()
sName := typ.Name()
if useStructName {
errPrefix += sName + namespaceSeparator
if v.fieldNameTag != blank {
nsPrefix += sName + namespaceSeparator
}
}
// structonly tag present don't tranverseFields
// but must still check and run below struct level validation
// if present
if !isStructOnly {
var fld reflect.StructField
// is anonymous struct, cannot parse or cache as
// it has no name to index by
if sName == blank {
var customName string
var ok bool
numFields := current.NumField()
for i := 0; i < numFields; i++ {
fld = typ.Field(i)
if fld.PkgPath != blank && !fld.Anonymous {
continue
}
if partial {
_, ok = includeExclude[errPrefix+fld.Name]
if (ok && exclude) || (!ok && !exclude) {
continue
}
}
customName = fld.Name
if v.fieldNameTag != blank {
name := strings.SplitN(fld.Tag.Get(v.fieldNameTag), ",", 2)[0]
// dash check is for json "-" means don't output in json
if name != blank && name != dash {
customName = name
}
}
v.traverseField(topStruct, currentStruct, current.Field(i), errPrefix, nsPrefix, errs, true, fld.Tag.Get(v.tagName), fld.Name, customName, partial, exclude, includeExclude, nil)
}
} else {
s, ok := v.structCache.Get(typ)
if !ok {
s = v.parseStruct(current, sName)
}
for i, f := range s.fields {
if partial {
_, ok = includeExclude[errPrefix+f.Name]
if (ok && exclude) || (!ok && !exclude) {
continue
}
}
fld = typ.Field(i)
v.traverseField(topStruct, currentStruct, current.Field(i), errPrefix, nsPrefix, errs, true, f.CachedTag.tag, fld.Name, f.AltName, partial, exclude, includeExclude, f.CachedTag)
}
}
}
// check if any struct level validations, after all field validations already checked.
if v.hasStructLevelFuncs {
if fn, ok := v.structLevelFuncs[current.Type()]; ok {
fn(v, &StructLevel{v: v, TopStruct: topStruct, CurrentStruct: current, errPrefix: errPrefix, nsPrefix: nsPrefix, errs: errs})
}
}
}
// traverseField validates any field, be it a struct or single field, ensures it's validity and passes it along to be validated via it's tag options
func (v *Validate) traverseField(topStruct reflect.Value, currentStruct reflect.Value, current reflect.Value, errPrefix string, nsPrefix string, errs ValidationErrors, isStructField bool, tag, name, customName string, partial bool, exclude bool, includeExclude map[string]*struct{}, cTag *cachedTag) {
if tag == skipValidationTag {
return
}
if cTag == nil {
var isCached bool
cTag, isCached = v.tagCache.Get(tag)
if !isCached {
cTag = v.parseTags(tag, name)
}
}
current, kind := v.ExtractType(current)
var typ reflect.Type
switch kind {
case reflect.Ptr, reflect.Interface, reflect.Invalid:
if cTag.isOmitEmpty {
return
}
if tag != blank {
ns := errPrefix + name
if kind == reflect.Invalid {
errs[ns] = &FieldError{
FieldNamespace: ns,
NameNamespace: nsPrefix + customName,
Name: customName,
Field: name,
Tag: cTag.tags[0].tag,
ActualTag: cTag.tags[0].tagVals[0][0],
Param: cTag.tags[0].tagVals[0][1],
Kind: kind,
}
return
}
errs[ns] = &FieldError{
FieldNamespace: ns,
NameNamespace: nsPrefix + customName,
Name: customName,
Field: name,
Tag: cTag.tags[0].tag,
ActualTag: cTag.tags[0].tagVals[0][0],
Param: cTag.tags[0].tagVals[0][1],
Value: current.Interface(),
Kind: kind,
Type: current.Type(),
}
return
}
// if we get here tag length is zero and we can leave
if kind == reflect.Invalid {
return
}
case reflect.Struct:
typ = current.Type()
if typ != timeType {
if cTag.isNoStructLevel {
return
}
v.tranverseStruct(topStruct, current, current, errPrefix+name+namespaceSeparator, nsPrefix+customName+namespaceSeparator, errs, false, partial, exclude, includeExclude, cTag.isStructOnly)
return
}
}
if tag == blank {
return
}
typ = current.Type()
var dive bool
var diveSubTag string
for _, valTag := range cTag.tags {
if valTag.tagVals[0][0] == existsTag {
continue
}
if valTag.tagVals[0][0] == diveTag {
dive = true
diveSubTag = strings.TrimLeft(strings.SplitN(cTag.diveTag, diveTag, 2)[1], ",")
break
}
if valTag.tagVals[0][0] == omitempty {
if !HasValue(v, topStruct, currentStruct, current, typ, kind, blank) {
return
}
continue
}
if v.validateField(topStruct, currentStruct, current, typ, kind, errPrefix, nsPrefix, errs, valTag, name, customName) {
return
}
}
if dive {
// traverse slice or map here
// or panic ;)
switch kind {
case reflect.Slice, reflect.Array:
v.traverseSlice(topStruct, currentStruct, current, errPrefix, nsPrefix, errs, diveSubTag, name, customName, partial, exclude, includeExclude, nil)
case reflect.Map:
v.traverseMap(topStruct, currentStruct, current, errPrefix, nsPrefix, errs, diveSubTag, name, customName, partial, exclude, includeExclude, nil)
default:
// throw error, if not a slice or map then should not have gotten here
// bad dive tag
panic("dive error! can't dive on a non slice or map")
}
}
}
// traverseSlice traverses a Slice or Array's elements and passes them to traverseField for validation
func (v *Validate) traverseSlice(topStruct reflect.Value, currentStruct reflect.Value, current reflect.Value, errPrefix string, nsPrefix string, errs ValidationErrors, tag, name, customName string, partial bool, exclude bool, includeExclude map[string]*struct{}, cTag *cachedTag) {
for i := 0; i < current.Len(); i++ {
v.traverseField(topStruct, currentStruct, current.Index(i), errPrefix, nsPrefix, errs, false, tag, fmt.Sprintf(arrayIndexFieldName, name, i), fmt.Sprintf(arrayIndexFieldName, customName, i), partial, exclude, includeExclude, cTag)
}
}
// traverseMap traverses a map's elements and passes them to traverseField for validation
func (v *Validate) traverseMap(topStruct reflect.Value, currentStruct reflect.Value, current reflect.Value, errPrefix string, nsPrefix string, errs ValidationErrors, tag, name, customName string, partial bool, exclude bool, includeExclude map[string]*struct{}, cTag *cachedTag) {
for _, key := range current.MapKeys() {
v.traverseField(topStruct, currentStruct, current.MapIndex(key), errPrefix, nsPrefix, errs, false, tag, fmt.Sprintf(mapIndexFieldName, name, key.Interface()), fmt.Sprintf(mapIndexFieldName, customName, key.Interface()), partial, exclude, includeExclude, cTag)
}
}
// validateField validates a field based on the provided tag's key and param values and returns true if there is an error or false if all ok
func (v *Validate) validateField(topStruct reflect.Value, currentStruct reflect.Value, current reflect.Value, currentType reflect.Type, currentKind reflect.Kind, errPrefix string, nsPrefix string, errs ValidationErrors, valTag *tagVals, name, customName string) bool {
var valFunc Func
var ok bool
if valTag.isOrVal {
errTag := blank
for _, val := range valTag.tagVals {
valFunc, ok = v.validationFuncs[val[0]]
if !ok {
panic(strings.TrimSpace(fmt.Sprintf(undefinedValidation, name)))
}
if valFunc(v, topStruct, currentStruct, current, currentType, currentKind, val[1]) {
return false
}
errTag += orSeparator + val[0]
}
ns := errPrefix + name
if valTag.isAlias {
errs[ns] = &FieldError{
FieldNamespace: ns,
NameNamespace: nsPrefix + customName,
Name: customName,
Field: name,
Tag: valTag.tag,
ActualTag: errTag[1:],
Value: current.Interface(),
Type: currentType,
Kind: currentKind,
}
} else {
errs[errPrefix+name] = &FieldError{
FieldNamespace: ns,
NameNamespace: nsPrefix + customName,
Name: customName,
Field: name,
Tag: errTag[1:],
ActualTag: errTag[1:],
Value: current.Interface(),
Type: currentType,
Kind: currentKind,
}
}
return true
}
valFunc, ok = v.validationFuncs[valTag.tagVals[0][0]]
if !ok {
panic(strings.TrimSpace(fmt.Sprintf(undefinedValidation, name)))
}
if valFunc(v, topStruct, currentStruct, current, currentType, currentKind, valTag.tagVals[0][1]) {
return false
}
ns := errPrefix + name
errs[ns] = &FieldError{
FieldNamespace: ns,
NameNamespace: nsPrefix + customName,
Name: customName,
Field: name,
Tag: valTag.tag,
ActualTag: valTag.tagVals[0][0],
Value: current.Interface(),
Param: valTag.tagVals[0][1],
Type: currentType,
Kind: currentKind,
}
return true
}
