wg-quicker/vendor/github.com/alecthomas/jsonschema/reflect.go

838 lines
24 KiB
Go

// Package jsonschema uses reflection to generate JSON Schemas from Go types [1].
//
// If json tags are present on struct fields, they will be used to infer
// property names and if a property is required (omitempty is present).
//
// [1] http://json-schema.org/latest/json-schema-validation.html
package jsonschema
import (
"encoding/json"
"net"
"net/url"
"reflect"
"strconv"
"strings"
"time"
"github.com/iancoleman/orderedmap"
)
// Version is the JSON Schema version.
// If extending JSON Schema with custom values use a custom URI.
// RFC draft-wright-json-schema-00, section 6
var Version = "http://json-schema.org/draft-04/schema#"
// Schema is the root schema.
// RFC draft-wright-json-schema-00, section 4.5
type Schema struct {
*Type
Definitions Definitions
}
// customSchemaType is used to detect if the structure provides it's own
// custom Schema Type definition to use instead. Very useful for situations
// where there are custom JSON Marshal and Unmarshal methods.
type customSchemaType interface {
JSONSchemaType() *Type
}
var customStructType = reflect.TypeOf((*customSchemaType)(nil)).Elem()
// customSchemaGetFieldDocString
type customSchemaGetFieldDocString interface {
GetFieldDocString(fieldName string) string
}
type customGetFieldDocString func(fieldName string) string
var customStructGetFieldDocString = reflect.TypeOf((*customSchemaGetFieldDocString)(nil)).Elem()
// Type represents a JSON Schema object type.
type Type struct {
// RFC draft-wright-json-schema-00
Version string `json:"$schema,omitempty"` // section 6.1
Ref string `json:"$ref,omitempty"` // section 7
// RFC draft-wright-json-schema-validation-00, section 5
MultipleOf int `json:"multipleOf,omitempty"` // section 5.1
Maximum int `json:"maximum,omitempty"` // section 5.2
ExclusiveMaximum bool `json:"exclusiveMaximum,omitempty"` // section 5.3
Minimum int `json:"minimum,omitempty"` // section 5.4
ExclusiveMinimum bool `json:"exclusiveMinimum,omitempty"` // section 5.5
MaxLength int `json:"maxLength,omitempty"` // section 5.6
MinLength int `json:"minLength,omitempty"` // section 5.7
Pattern string `json:"pattern,omitempty"` // section 5.8
AdditionalItems *Type `json:"additionalItems,omitempty"` // section 5.9
Items *Type `json:"items,omitempty"` // section 5.9
MaxItems int `json:"maxItems,omitempty"` // section 5.10
MinItems int `json:"minItems,omitempty"` // section 5.11
UniqueItems bool `json:"uniqueItems,omitempty"` // section 5.12
MaxProperties int `json:"maxProperties,omitempty"` // section 5.13
MinProperties int `json:"minProperties,omitempty"` // section 5.14
Required []string `json:"required,omitempty"` // section 5.15
Properties *orderedmap.OrderedMap `json:"properties,omitempty"` // section 5.16
PatternProperties map[string]*Type `json:"patternProperties,omitempty"` // section 5.17
AdditionalProperties json.RawMessage `json:"additionalProperties,omitempty"` // section 5.18
Dependencies map[string]*Type `json:"dependencies,omitempty"` // section 5.19
Enum []interface{} `json:"enum,omitempty"` // section 5.20
Type string `json:"type,omitempty"` // section 5.21
AllOf []*Type `json:"allOf,omitempty"` // section 5.22
AnyOf []*Type `json:"anyOf,omitempty"` // section 5.23
OneOf []*Type `json:"oneOf,omitempty"` // section 5.24
Not *Type `json:"not,omitempty"` // section 5.25
Definitions Definitions `json:"definitions,omitempty"` // section 5.26
// RFC draft-wright-json-schema-validation-00, section 6, 7
Title string `json:"title,omitempty"` // section 6.1
Description string `json:"description,omitempty"` // section 6.1
Default interface{} `json:"default,omitempty"` // section 6.2
Format string `json:"format,omitempty"` // section 7
Examples []interface{} `json:"examples,omitempty"` // section 7.4
// RFC draft-wright-json-schema-hyperschema-00, section 4
Media *Type `json:"media,omitempty"` // section 4.3
BinaryEncoding string `json:"binaryEncoding,omitempty"` // section 4.3
Extras map[string]interface{} `json:"-"`
}
// Reflect reflects to Schema from a value using the default Reflector
func Reflect(v interface{}) *Schema {
return ReflectFromType(reflect.TypeOf(v))
}
// ReflectFromType generates root schema using the default Reflector
func ReflectFromType(t reflect.Type) *Schema {
r := &Reflector{}
return r.ReflectFromType(t)
}
// A Reflector reflects values into a Schema.
type Reflector struct {
// AllowAdditionalProperties will cause the Reflector to generate a schema
// with additionalProperties to 'true' for all struct types. This means
// the presence of additional keys in JSON objects will not cause validation
// to fail. Note said additional keys will simply be dropped when the
// validated JSON is unmarshaled.
AllowAdditionalProperties bool
// RequiredFromJSONSchemaTags will cause the Reflector to generate a schema
// that requires any key tagged with `jsonschema:required`, overriding the
// default of requiring any key *not* tagged with `json:,omitempty`.
RequiredFromJSONSchemaTags bool
// YAMLEmbeddedStructs will cause the Reflector to generate a schema that does
// not inline embedded structs. This should be enabled if the JSON schemas are
// used with yaml.Marshal/Unmarshal.
YAMLEmbeddedStructs bool
// Prefer yaml: tags over json: tags to generate the schema even if json: tags
// are present
PreferYAMLSchema bool
// ExpandedStruct will cause the toplevel definitions of the schema not
// be referenced itself to a definition.
ExpandedStruct bool
// Do not reference definitions.
// All types are still registered under the "definitions" top-level object,
// but instead of $ref fields in containing types, the entire definition
// of the contained type is inserted.
// This will cause the entire structure of types to be output in one tree.
DoNotReference bool
// Use package paths as well as type names, to avoid conflicts.
// Without this setting, if two packages contain a type with the same name,
// and both are present in a schema, they will conflict and overwrite in
// the definition map and produce bad output. This is particularly
// noticeable when using DoNotReference.
FullyQualifyTypeNames bool
// IgnoredTypes defines a slice of types that should be ignored in the schema,
// switching to just allowing additional properties instead.
IgnoredTypes []interface{}
// TypeMapper is a function that can be used to map custom Go types to jsonschema types.
TypeMapper func(reflect.Type) *Type
// TypeNamer allows customizing of type names
TypeNamer func(reflect.Type) string
// AdditionalFields allows adding structfields for a given type
AdditionalFields func(reflect.Type) []reflect.StructField
}
// Reflect reflects to Schema from a value.
func (r *Reflector) Reflect(v interface{}) *Schema {
return r.ReflectFromType(reflect.TypeOf(v))
}
// ReflectFromType generates root schema
func (r *Reflector) ReflectFromType(t reflect.Type) *Schema {
definitions := Definitions{}
if r.ExpandedStruct {
st := &Type{
Version: Version,
Type: "object",
Properties: orderedmap.New(),
AdditionalProperties: []byte("false"),
}
if r.AllowAdditionalProperties {
st.AdditionalProperties = []byte("true")
}
r.reflectStructFields(st, definitions, t)
r.reflectStruct(definitions, t)
delete(definitions, r.typeName(t))
return &Schema{Type: st, Definitions: definitions}
}
s := &Schema{
Type: r.reflectTypeToSchema(definitions, t),
Definitions: definitions,
}
return s
}
// Definitions hold schema definitions.
// http://json-schema.org/latest/json-schema-validation.html#rfc.section.5.26
// RFC draft-wright-json-schema-validation-00, section 5.26
type Definitions map[string]*Type
// Available Go defined types for JSON Schema Validation.
// RFC draft-wright-json-schema-validation-00, section 7.3
var (
timeType = reflect.TypeOf(time.Time{}) // date-time RFC section 7.3.1
ipType = reflect.TypeOf(net.IP{}) // ipv4 and ipv6 RFC section 7.3.4, 7.3.5
uriType = reflect.TypeOf(url.URL{}) // uri RFC section 7.3.6
)
// Byte slices will be encoded as base64
var byteSliceType = reflect.TypeOf([]byte(nil))
// Except for json.RawMessage
var rawMessageType = reflect.TypeOf(json.RawMessage{})
// Go code generated from protobuf enum types should fulfil this interface.
type protoEnum interface {
EnumDescriptor() ([]byte, []int)
}
var protoEnumType = reflect.TypeOf((*protoEnum)(nil)).Elem()
func (r *Reflector) reflectTypeToSchema(definitions Definitions, t reflect.Type) *Type {
// Already added to definitions?
if _, ok := definitions[r.typeName(t)]; ok && !r.DoNotReference {
return &Type{Ref: "#/definitions/" + r.typeName(t)}
}
// jsonpb will marshal protobuf enum options as either strings or integers.
// It will unmarshal either.
if t.Implements(protoEnumType) {
return &Type{OneOf: []*Type{
{Type: "string"},
{Type: "integer"},
}}
}
if r.TypeMapper != nil {
if t := r.TypeMapper(t); t != nil {
return t
}
}
// Defined format types for JSON Schema Validation
// RFC draft-wright-json-schema-validation-00, section 7.3
// TODO email RFC section 7.3.2, hostname RFC section 7.3.3, uriref RFC section 7.3.7
if t == ipType {
// TODO differentiate ipv4 and ipv6 RFC section 7.3.4, 7.3.5
return &Type{Type: "string", Format: "ipv4"} // ipv4 RFC section 7.3.4
}
switch t.Kind() {
case reflect.Struct:
switch t {
case timeType: // date-time RFC section 7.3.1
return &Type{Type: "string", Format: "date-time"}
case uriType: // uri RFC section 7.3.6
return &Type{Type: "string", Format: "uri"}
default:
return r.reflectStruct(definitions, t)
}
case reflect.Map:
if t.Implements(customStructType) {
v := reflect.New(t)
o := v.Interface().(customSchemaType)
return o.JSONSchemaType()
}
switch t.Key().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
rt := &Type{
Type: "object",
PatternProperties: map[string]*Type{
"^[0-9]+$": r.reflectTypeToSchema(definitions, t.Elem()),
},
AdditionalProperties: []byte("false"),
}
return rt
}
rt := &Type{
Type: "object",
PatternProperties: map[string]*Type{
".*": r.reflectTypeToSchema(definitions, t.Elem()),
},
}
delete(rt.PatternProperties, "additionalProperties")
return rt
case reflect.Slice, reflect.Array:
returnType := &Type{}
if t.Implements(customStructType) {
v := reflect.New(t)
o := v.Interface().(customSchemaType)
return o.JSONSchemaType()
}
if t == rawMessageType {
return &Type{
AdditionalProperties: []byte("true"),
}
}
if t.Kind() == reflect.Array {
returnType.MinItems = t.Len()
returnType.MaxItems = returnType.MinItems
}
if t.Kind() == reflect.Slice && t.Elem() == byteSliceType.Elem() {
returnType.Type = "string"
returnType.Media = &Type{BinaryEncoding: "base64"}
return returnType
}
returnType.Type = "array"
returnType.Items = r.reflectTypeToSchema(definitions, t.Elem())
return returnType
case reflect.Interface:
return &Type{
AdditionalProperties: []byte("true"),
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return &Type{Type: "integer"}
case reflect.Float32, reflect.Float64:
return &Type{Type: "number"}
case reflect.Bool:
return &Type{Type: "boolean"}
case reflect.String:
return &Type{Type: "string"}
case reflect.Ptr:
return r.reflectTypeToSchema(definitions, t.Elem())
}
panic("unsupported type " + t.String())
}
// Refects a struct to a JSON Schema type.
func (r *Reflector) reflectStruct(definitions Definitions, t reflect.Type) *Type {
for _, ignored := range r.IgnoredTypes {
if reflect.TypeOf(ignored) == t {
st := &Type{
Type: "object",
Properties: orderedmap.New(),
AdditionalProperties: []byte("true"),
}
definitions[r.typeName(t)] = st
if r.DoNotReference {
return st
} else {
return &Type{
Version: Version,
Ref: "#/definitions/" + r.typeName(t),
}
}
}
}
var st *Type
if t.Implements(customStructType) {
v := reflect.New(t)
o := v.Interface().(customSchemaType)
st = o.JSONSchemaType()
definitions[r.typeName(t)] = st
} else {
st = &Type{
Type: "object",
Properties: orderedmap.New(),
AdditionalProperties: []byte("false"),
}
if r.AllowAdditionalProperties {
st.AdditionalProperties = []byte("true")
}
definitions[r.typeName(t)] = st
r.reflectStructFields(st, definitions, t)
}
if r.DoNotReference {
return st
} else {
return &Type{
Version: Version,
Ref: "#/definitions/" + r.typeName(t),
}
}
}
func (r *Reflector) reflectStructFields(st *Type, definitions Definitions, t reflect.Type) {
if t.Kind() == reflect.Ptr {
t = t.Elem()
}
if t.Kind() != reflect.Struct {
return
}
var getFieldDocString customGetFieldDocString
if t.Implements(customStructGetFieldDocString) {
v := reflect.New(t)
o := v.Interface().(customSchemaGetFieldDocString)
getFieldDocString = o.GetFieldDocString
}
handleField := func(f reflect.StructField) {
name, shouldEmbed, required, nullable := r.reflectFieldName(f)
// if anonymous and exported type should be processed recursively
// current type should inherit properties of anonymous one
if name == "" {
if shouldEmbed {
r.reflectStructFields(st, definitions, f.Type)
}
return
}
property := r.reflectTypeToSchema(definitions, f.Type)
property.structKeywordsFromTags(f, st, name)
if getFieldDocString != nil {
property.Description = getFieldDocString(f.Name)
}
if nullable {
property = &Type{
OneOf: []*Type{
property,
{
Type: "null",
},
},
}
}
st.Properties.Set(name, property)
if required {
st.Required = append(st.Required, name)
}
}
for i := 0; i < t.NumField(); i++ {
f := t.Field(i)
handleField(f)
}
if r.AdditionalFields != nil {
if af := r.AdditionalFields(t); af != nil {
for _, sf := range af {
handleField(sf)
}
}
}
}
func (t *Type) structKeywordsFromTags(f reflect.StructField, parentType *Type, propertyName string) {
t.Description = f.Tag.Get("jsonschema_description")
tags := strings.Split(f.Tag.Get("jsonschema"), ",")
t.genericKeywords(tags, parentType, propertyName)
switch t.Type {
case "string":
t.stringKeywords(tags)
case "number":
t.numbericKeywords(tags)
case "integer":
t.numbericKeywords(tags)
case "array":
t.arrayKeywords(tags)
}
extras := strings.Split(f.Tag.Get("jsonschema_extras"), ",")
t.extraKeywords(extras)
}
// read struct tags for generic keyworks
func (t *Type) genericKeywords(tags []string, parentType *Type, propertyName string) {
for _, tag := range tags {
nameValue := strings.Split(tag, "=")
if len(nameValue) == 2 {
name, val := nameValue[0], nameValue[1]
switch name {
case "title":
t.Title = val
case "description":
t.Description = val
case "type":
t.Type = val
case "oneof_required":
var typeFound *Type
for i := range parentType.OneOf {
if parentType.OneOf[i].Title == nameValue[1] {
typeFound = parentType.OneOf[i]
}
}
if typeFound == nil {
typeFound = &Type{
Title: nameValue[1],
Required: []string{},
}
parentType.OneOf = append(parentType.OneOf, typeFound)
}
typeFound.Required = append(typeFound.Required, propertyName)
case "oneof_type":
if t.OneOf == nil {
t.OneOf = make([]*Type, 0, 1)
}
t.Type = ""
types := strings.Split(nameValue[1], ";")
for _, ty := range types {
t.OneOf = append(t.OneOf, &Type{
Type: ty,
})
}
case "enum":
switch t.Type {
case "string":
t.Enum = append(t.Enum, val)
case "integer":
i, _ := strconv.Atoi(val)
t.Enum = append(t.Enum, i)
case "number":
f, _ := strconv.ParseFloat(val, 64)
t.Enum = append(t.Enum, f)
}
}
}
}
}
// read struct tags for string type keyworks
func (t *Type) stringKeywords(tags []string) {
for _, tag := range tags {
nameValue := strings.Split(tag, "=")
if len(nameValue) == 2 {
name, val := nameValue[0], nameValue[1]
switch name {
case "minLength":
i, _ := strconv.Atoi(val)
t.MinLength = i
case "maxLength":
i, _ := strconv.Atoi(val)
t.MaxLength = i
case "pattern":
t.Pattern = val
case "format":
switch val {
case "date-time", "email", "hostname", "ipv4", "ipv6", "uri":
t.Format = val
break
}
case "default":
t.Default = val
case "example":
t.Examples = append(t.Examples, val)
}
}
}
}
// read struct tags for numberic type keyworks
func (t *Type) numbericKeywords(tags []string) {
for _, tag := range tags {
nameValue := strings.Split(tag, "=")
if len(nameValue) == 2 {
name, val := nameValue[0], nameValue[1]
switch name {
case "multipleOf":
i, _ := strconv.Atoi(val)
t.MultipleOf = i
case "minimum":
i, _ := strconv.Atoi(val)
t.Minimum = i
case "maximum":
i, _ := strconv.Atoi(val)
t.Maximum = i
case "exclusiveMaximum":
b, _ := strconv.ParseBool(val)
t.ExclusiveMaximum = b
case "exclusiveMinimum":
b, _ := strconv.ParseBool(val)
t.ExclusiveMinimum = b
case "default":
i, _ := strconv.Atoi(val)
t.Default = i
case "example":
if i, err := strconv.Atoi(val); err == nil {
t.Examples = append(t.Examples, i)
}
}
}
}
}
// read struct tags for object type keyworks
// func (t *Type) objectKeywords(tags []string) {
// for _, tag := range tags{
// nameValue := strings.Split(tag, "=")
// name, val := nameValue[0], nameValue[1]
// switch name{
// case "dependencies":
// t.Dependencies = val
// break;
// case "patternProperties":
// t.PatternProperties = val
// break;
// }
// }
// }
// read struct tags for array type keyworks
func (t *Type) arrayKeywords(tags []string) {
var defaultValues []interface{}
for _, tag := range tags {
nameValue := strings.Split(tag, "=")
if len(nameValue) == 2 {
name, val := nameValue[0], nameValue[1]
switch name {
case "minItems":
i, _ := strconv.Atoi(val)
t.MinItems = i
case "maxItems":
i, _ := strconv.Atoi(val)
t.MaxItems = i
case "uniqueItems":
t.UniqueItems = true
case "default":
defaultValues = append(defaultValues, val)
case "enum":
switch t.Items.Type {
case "string":
t.Items.Enum = append(t.Items.Enum, val)
case "integer":
i, _ := strconv.Atoi(val)
t.Items.Enum = append(t.Items.Enum, i)
case "number":
f, _ := strconv.ParseFloat(val, 64)
t.Items.Enum = append(t.Items.Enum, f)
}
}
}
}
if len(defaultValues) > 0 {
t.Default = defaultValues
}
}
func (t *Type) extraKeywords(tags []string) {
for _, tag := range tags {
nameValue := strings.Split(tag, "=")
if len(nameValue) == 2 {
t.setExtra(nameValue[0], nameValue[1])
}
}
}
func (t *Type) setExtra(key, val string) {
if t.Extras == nil {
t.Extras = map[string]interface{}{}
}
if existingVal, ok := t.Extras[key]; ok {
switch existingVal := existingVal.(type) {
case string:
t.Extras[key] = []string{existingVal, val}
case []string:
t.Extras[key] = append(existingVal, val)
case int:
t.Extras[key], _ = strconv.Atoi(val)
}
} else {
switch key {
case "minimum":
t.Extras[key], _ = strconv.Atoi(val)
default:
t.Extras[key] = val
}
}
}
func requiredFromJSONTags(tags []string) bool {
if ignoredByJSONTags(tags) {
return false
}
for _, tag := range tags[1:] {
if tag == "omitempty" {
return false
}
}
return true
}
func requiredFromJSONSchemaTags(tags []string) bool {
if ignoredByJSONSchemaTags(tags) {
return false
}
for _, tag := range tags {
if tag == "required" {
return true
}
}
return false
}
func nullableFromJSONSchemaTags(tags []string) bool {
if ignoredByJSONSchemaTags(tags) {
return false
}
for _, tag := range tags {
if tag == "nullable" {
return true
}
}
return false
}
func inlineYAMLTags(tags []string) bool {
for _, tag := range tags {
if tag == "inline" {
return true
}
}
return false
}
func ignoredByJSONTags(tags []string) bool {
return tags[0] == "-"
}
func ignoredByJSONSchemaTags(tags []string) bool {
return tags[0] == "-"
}
func (r *Reflector) reflectFieldName(f reflect.StructField) (string, bool, bool, bool) {
jsonTags, exist := f.Tag.Lookup("json")
yamlTags, yamlExist := f.Tag.Lookup("yaml")
if !exist || r.PreferYAMLSchema {
jsonTags = yamlTags
exist = yamlExist
}
jsonTagsList := strings.Split(jsonTags, ",")
yamlTagsList := strings.Split(yamlTags, ",")
if ignoredByJSONTags(jsonTagsList) {
return "", false, false, false
}
jsonSchemaTags := strings.Split(f.Tag.Get("jsonschema"), ",")
if ignoredByJSONSchemaTags(jsonSchemaTags) {
return "", false, false, false
}
name := f.Name
required := requiredFromJSONTags(jsonTagsList)
if r.RequiredFromJSONSchemaTags {
required = requiredFromJSONSchemaTags(jsonSchemaTags)
}
nullable := nullableFromJSONSchemaTags(jsonSchemaTags)
if jsonTagsList[0] != "" {
name = jsonTagsList[0]
}
// field not anonymous and not export has no export name
if !f.Anonymous && f.PkgPath != "" {
name = ""
}
embed := false
// field anonymous but without json tag should be inherited by current type
if f.Anonymous && !exist {
if !r.YAMLEmbeddedStructs {
name = ""
embed = true
} else {
name = strings.ToLower(name)
}
}
if yamlExist && inlineYAMLTags(yamlTagsList) {
name = ""
embed = true
}
return name, embed, required, nullable
}
func (s *Schema) MarshalJSON() ([]byte, error) {
b, err := json.Marshal(s.Type)
if err != nil {
return nil, err
}
if s.Definitions == nil || len(s.Definitions) == 0 {
return b, nil
}
d, err := json.Marshal(struct {
Definitions Definitions `json:"definitions,omitempty"`
}{s.Definitions})
if err != nil {
return nil, err
}
if len(b) == 2 {
return d, nil
} else {
b[len(b)-1] = ','
return append(b, d[1:]...), nil
}
}
func (t *Type) MarshalJSON() ([]byte, error) {
type Type_ Type
b, err := json.Marshal((*Type_)(t))
if err != nil {
return nil, err
}
if t.Extras == nil || len(t.Extras) == 0 {
return b, nil
}
m, err := json.Marshal(t.Extras)
if err != nil {
return nil, err
}
if len(b) == 2 {
return m, nil
} else {
b[len(b)-1] = ','
return append(b, m[1:]...), nil
}
}
func (r *Reflector) typeName(t reflect.Type) string {
if r.TypeNamer != nil {
if name := r.TypeNamer(t); name != "" {
return name
}
}
if r.FullyQualifyTypeNames {
return t.PkgPath() + "." + t.Name()
}
return t.Name()
}