/** * 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 TagNamespace 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, errTagName string, baseTagName string) error { v.initCheck() errs := v.errsPool.Get().(ValidationErrors) fieldVal := reflect.ValueOf(field) v.traverseField(fieldVal, fieldVal, fieldVal, blank, blank, baseTagName, errTagName, 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, errTagName string, baseTagName string) error { v.initCheck() errs := v.errsPool.Get().(ValidationErrors) topVal := reflect.ValueOf(val) v.traverseField(topVal, topVal, reflect.ValueOf(field), blank, blank, baseTagName, errTagName, 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{}, errTagName string, baseTagName string, 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, baseTagName, errTagName, 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{}, errTagName string, baseTagName string, 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, baseTagName, errTagName, 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{}, errTagName string, baseTagName string) error { v.initCheck() errs := v.errsPool.Get().(ValidationErrors) sv := reflect.ValueOf(current) fmt.Println(errs) v.tranverseStruct(sv, sv, sv, blank, blank, baseTagName, errTagName, 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, errTagPrefix string, errTagName 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, errTagPrefix+namespaceSeparator+fld.Tag.Get(errTagName), errTagName, 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, errTagPrefix+namespaceSeparator+fld.Tag.Get(errTagName), errTagName, 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, errTagPrefix string, errTagName 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, TagNamespace: errTagPrefix, 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, TagNamespace: errTagPrefix, 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, errTagPrefix, errTagName, 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, errTagPrefix, errTagName, 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, errTagPrefix, errTagName, errs, diveSubTag, name, customName, partial, exclude, includeExclude, nil) case reflect.Map: v.traverseMap(topStruct, currentStruct, current, errPrefix, nsPrefix, errTagPrefix, errTagName, 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, errTagPrefix string, errTagName 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, fmt.Sprintf(arrayIndexFieldName, errTagPrefix, i), errTagName, 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, errTagPrefix string, errTagName 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, fmt.Sprintf(mapIndexFieldName, errTagPrefix, key.Interface()), errTagName, 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, errTagPrefix string, errTagName 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, TagNamespace: errTagPrefix, 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, TagNamespace: errTagPrefix, 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, TagNamespace: errTagPrefix, 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 }