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package jsonapi
import (
"encoding/json"
"errors"
"fmt"
"io"
"reflect"
"strconv"
"strings"
"time"
)
var (
// ErrBadJSONAPIStructTag is returned when the Struct field's JSON API
// annotation is invalid.
ErrBadJSONAPIStructTag = errors.New("Bad jsonapi struct tag format")
// ErrBadJSONAPIID is returned when the Struct JSON API annotated "id" field
// was not a valid numeric type.
ErrBadJSONAPIID = errors.New(
"id should be either string, int(8,16,32,64) or uint(8,16,32,64)")
// ErrExpectedSlice is returned when a variable or argument was expected to
// be a slice of *Structs; MarshalMany will return this error when its
// interface{} argument is invalid.
ErrExpectedSlice = errors.New("models should be a slice of struct pointers")
// ErrUnexpectedType is returned when marshalling an interface; the interface
// had to be a pointer or a slice; otherwise this error is returned.
ErrUnexpectedType = errors.New("models should be a struct pointer or slice of struct pointers")
)
// MarshalPayload writes a jsonapi response for one or many records. The
// related records are sideloaded into the "included" array. If this method is
// given a struct pointer as an argument it will serialize in the form
// "data": {...}. If this method is given a slice of pointers, this method will
// serialize in the form "data": [...]
//
// One Example: you could pass it, w, your http.ResponseWriter, and, models, a
// ptr to a Blog to be written to the response body:
//
// func ShowBlog(w http.ResponseWriter, r *http.Request) {
// blog := &Blog{}
//
// w.Header().Set("Content-Type", jsonapi.MediaType)
// w.WriteHeader(http.StatusOK)
//
// if err := jsonapi.MarshalPayload(w, blog); err != nil {
// http.Error(w, err.Error(), http.StatusInternalServerError)
// }
// }
//
// Many Example: you could pass it, w, your http.ResponseWriter, and, models, a
// slice of Blog struct instance pointers to be written to the response body:
//
// func ListBlogs(w http.ResponseWriter, r *http.Request) {
// blogs := []*Blog{}
//
// w.Header().Set("Content-Type", jsonapi.MediaType)
// w.WriteHeader(http.StatusOK)
//
// if err := jsonapi.MarshalPayload(w, blogs); err != nil {
// http.Error(w, err.Error(), http.StatusInternalServerError)
// }
// }
//
func MarshalPayload(w io.Writer, models interface{}) error {
payload, err := Marshal(models)
if err != nil {
return err
}
if err := json.NewEncoder(w).Encode(payload); err != nil {
return err
}
return nil
}
// Marshal does the same as MarshalPayload except it just returns the payload
// and doesn't write out results. Useful if you use your own JSON rendering
// library.
func Marshal(models interface{}) (Payloader, error) {
switch vals := reflect.ValueOf(models); vals.Kind() {
case reflect.Slice:
m, err := convertToSliceInterface(&models)
if err != nil {
return nil, err
}
payload, err := marshalMany(m)
if err != nil {
return nil, err
}
if linkableModels, isLinkable := models.(Linkable); isLinkable {
jl := linkableModels.JSONAPILinks()
if er := jl.validate(); er != nil {
return nil, er
}
payload.Links = linkableModels.JSONAPILinks()
}
if metableModels, ok := models.(Metable); ok {
payload.Meta = metableModels.JSONAPIMeta()
}
return payload, nil
case reflect.Ptr:
// Check that the pointer was to a struct
if reflect.Indirect(vals).Kind() != reflect.Struct {
return nil, ErrUnexpectedType
}
return marshalOne(models)
default:
return nil, ErrUnexpectedType
}
}
// MarshalPayloadWithoutIncluded writes a jsonapi response with one or many
// records, without the related records sideloaded into "included" array.
// If you want to serialize the relations into the "included" array see
// MarshalPayload.
//
// models interface{} should be either a struct pointer or a slice of struct
// pointers.
func MarshalPayloadWithoutIncluded(w io.Writer, model interface{}) error {
payload, err := Marshal(model)
if err != nil {
return err
}
payload.clearIncluded()
if err := json.NewEncoder(w).Encode(payload); err != nil {
return err
}
return nil
}
// marshalOne does the same as MarshalOnePayload except it just returns the
// payload and doesn't write out results. Useful is you use your JSON rendering
// library.
func marshalOne(model interface{}) (*OnePayload, error) {
included := make(map[string]*Node)
rootNode, err := visitModelNode(model, &included, true)
if err != nil {
return nil, err
}
payload := &OnePayload{Data: rootNode}
payload.Included = nodeMapValues(&included)
return payload, nil
}
// marshalMany does the same as MarshalManyPayload except it just returns the
// payload and doesn't write out results. Useful is you use your JSON rendering
// library.
func marshalMany(models []interface{}) (*ManyPayload, error) {
payload := &ManyPayload{
Data: []*Node{},
}
included := map[string]*Node{}
for _, model := range models {
node, err := visitModelNode(model, &included, true)
if err != nil {
return nil, err
}
payload.Data = append(payload.Data, node)
}
payload.Included = nodeMapValues(&included)
return payload, nil
}
// MarshalOnePayloadEmbedded - This method not meant to for use in
// implementation code, although feel free. The purpose of this
// method is for use in tests. In most cases, your request
// payloads for create will be embedded rather than sideloaded for
// related records. This method will serialize a single struct
// pointer into an embedded json response. In other words, there
// will be no, "included", array in the json all relationships will
// be serailized inline in the data.
//
// However, in tests, you may want to construct payloads to post
// to create methods that are embedded to most closely resemble
// the payloads that will be produced by the client. This is what
// this method is intended for.
//
// model interface{} should be a pointer to a struct.
func MarshalOnePayloadEmbedded(w io.Writer, model interface{}) error {
rootNode, err := visitModelNode(model, nil, false)
if err != nil {
return err
}
payload := &OnePayload{Data: rootNode}
if err := json.NewEncoder(w).Encode(payload); err != nil {
return err
}
return nil
}
func visitModelNode(model interface{}, included *map[string]*Node,
sideload bool) (*Node, error) {
node := new(Node)
var er error
modelValue := reflect.ValueOf(model).Elem()
modelType := reflect.ValueOf(model).Type().Elem()
for i := 0; i < modelValue.NumField(); i++ {
structField := modelValue.Type().Field(i)
tag := structField.Tag.Get(annotationJSONAPI)
if tag == "" {
continue
}
fieldValue := modelValue.Field(i)
fieldType := modelType.Field(i)
args := strings.Split(tag, annotationSeperator)
if len(args) < 1 {
er = ErrBadJSONAPIStructTag
break
}
annotation := args[0]
if (annotation == annotationClientID && len(args) != 1) ||
(annotation != annotationClientID && len(args) < 2) {
er = ErrBadJSONAPIStructTag
break
}
if annotation == annotationPrimary {
v := fieldValue
// Deal with PTRS
var kind reflect.Kind
if fieldValue.Kind() == reflect.Ptr {
kind = fieldType.Type.Elem().Kind()
v = reflect.Indirect(fieldValue)
} else {
kind = fieldType.Type.Kind()
}
// Handle allowed types
switch kind {
case reflect.String:
node.ID = v.Interface().(string)
case reflect.Int:
node.ID = strconv.FormatInt(int64(v.Interface().(int)), 10)
case reflect.Int8:
node.ID = strconv.FormatInt(int64(v.Interface().(int8)), 10)
case reflect.Int16:
node.ID = strconv.FormatInt(int64(v.Interface().(int16)), 10)
case reflect.Int32:
node.ID = strconv.FormatInt(int64(v.Interface().(int32)), 10)
case reflect.Int64:
node.ID = strconv.FormatInt(v.Interface().(int64), 10)
case reflect.Uint:
node.ID = strconv.FormatUint(uint64(v.Interface().(uint)), 10)
case reflect.Uint8:
node.ID = strconv.FormatUint(uint64(v.Interface().(uint8)), 10)
case reflect.Uint16:
node.ID = strconv.FormatUint(uint64(v.Interface().(uint16)), 10)
case reflect.Uint32:
node.ID = strconv.FormatUint(uint64(v.Interface().(uint32)), 10)
case reflect.Uint64:
node.ID = strconv.FormatUint(v.Interface().(uint64), 10)
default:
// We had a JSON float (numeric), but our field was not one of the
// allowed numeric types
er = ErrBadJSONAPIID
break
}
node.Type = args[1]
} else if annotation == annotationClientID {
clientID := fieldValue.String()
if clientID != "" {
node.ClientID = clientID
}
} else if annotation == annotationAttribute {
var omitEmpty, iso8601 bool
if len(args) > 2 {
for _, arg := range args[2:] {
switch arg {
case annotationOmitEmpty:
omitEmpty = true
case annotationISO8601:
iso8601 = true
}
}
}
if node.Attributes == nil {
node.Attributes = make(map[string]interface{})
}
if fieldValue.Type() == reflect.TypeOf(time.Time{}) {
t := fieldValue.Interface().(time.Time)
if t.IsZero() {
continue
}
if iso8601 {
node.Attributes[args[1]] = t.UTC().Format(iso8601TimeFormat)
} else {
node.Attributes[args[1]] = t.Unix()
}
} else if fieldValue.Type() == reflect.TypeOf(new(time.Time)) {
// A time pointer may be nil
if fieldValue.IsNil() {
if omitEmpty {
continue
}
node.Attributes[args[1]] = nil
} else {
tm := fieldValue.Interface().(*time.Time)
if tm.IsZero() && omitEmpty {
continue
}
if iso8601 {
node.Attributes[args[1]] = tm.UTC().Format(iso8601TimeFormat)
} else {
node.Attributes[args[1]] = tm.Unix()
}
}
} else {
// Dealing with a fieldValue that is not a time
emptyValue := reflect.Zero(fieldValue.Type())
// See if we need to omit this field
if omitEmpty && fieldValue.Interface() == emptyValue.Interface() {
continue
}
strAttr, ok := fieldValue.Interface().(string)
if ok {
node.Attributes[args[1]] = strAttr
} else {
node.Attributes[args[1]] = fieldValue.Interface()
}
}
} else if annotation == annotationRelation {
var omitEmpty bool
//add support for 'omitempty' struct tag for marshaling as absent
if len(args) > 2 {
omitEmpty = args[2] == annotationOmitEmpty
}
isSlice := fieldValue.Type().Kind() == reflect.Slice
if omitEmpty &&
(isSlice && fieldValue.Len() < 1 ||
(!isSlice && fieldValue.IsNil())) {
continue
}
if node.Relationships == nil {
node.Relationships = make(map[string]interface{})
}
var relLinks *Links
if linkableModel, ok := model.(RelationshipLinkable); ok {
relLinks = linkableModel.JSONAPIRelationshipLinks(args[1])
}
var relMeta *Meta
if metableModel, ok := model.(RelationshipMetable); ok {
relMeta = metableModel.JSONAPIRelationshipMeta(args[1])
}
if isSlice {
// to-many relationship
relationship, err := visitModelNodeRelationships(
fieldValue,
included,
sideload,
)
if err != nil {
er = err
break
}
relationship.Links = relLinks
relationship.Meta = relMeta
if sideload {
shallowNodes := []*Node{}
for _, n := range relationship.Data {
appendIncluded(included, n)
shallowNodes = append(shallowNodes, toShallowNode(n))
}
node.Relationships[args[1]] = &RelationshipManyNode{
Data: shallowNodes,
Links: relationship.Links,
Meta: relationship.Meta,
}
} else {
node.Relationships[args[1]] = relationship
}
} else {
// to-one relationships
// Handle null relationship case
if fieldValue.IsNil() {
node.Relationships[args[1]] = &RelationshipOneNode{Data: nil}
continue
}
relationship, err := visitModelNode(
fieldValue.Interface(),
included,
sideload,
)
if err != nil {
er = err
break
}
if sideload {
appendIncluded(included, relationship)
node.Relationships[args[1]] = &RelationshipOneNode{
Data: toShallowNode(relationship),
Links: relLinks,
Meta: relMeta,
}
} else {
node.Relationships[args[1]] = &RelationshipOneNode{
Data: relationship,
Links: relLinks,
Meta: relMeta,
}
}
}
} else {
er = ErrBadJSONAPIStructTag
break
}
}
if er != nil {
return nil, er
}
if linkableModel, isLinkable := model.(Linkable); isLinkable {
jl := linkableModel.JSONAPILinks()
if er := jl.validate(); er != nil {
return nil, er
}
node.Links = linkableModel.JSONAPILinks()
}
if metableModel, ok := model.(Metable); ok {
node.Meta = metableModel.JSONAPIMeta()
}
return node, nil
}
func toShallowNode(node *Node) *Node {
return &Node{
ID: node.ID,
Type: node.Type,
}
}
func visitModelNodeRelationships(models reflect.Value, included *map[string]*Node,
sideload bool) (*RelationshipManyNode, error) {
nodes := []*Node{}
for i := 0; i < models.Len(); i++ {
n := models.Index(i).Interface()
node, err := visitModelNode(n, included, sideload)
if err != nil {
return nil, err
}
nodes = append(nodes, node)
}
return &RelationshipManyNode{Data: nodes}, nil
}
func appendIncluded(m *map[string]*Node, nodes ...*Node) {
included := *m
for _, n := range nodes {
k := fmt.Sprintf("%s,%s", n.Type, n.ID)
if _, hasNode := included[k]; hasNode {
continue
}
included[k] = n
}
}
func nodeMapValues(m *map[string]*Node) []*Node {
mp := *m
nodes := make([]*Node, len(mp))
i := 0
for _, n := range mp {
nodes[i] = n
i++
}
return nodes
}
func convertToSliceInterface(i *interface{}) ([]interface{}, error) {
vals := reflect.ValueOf(*i)
if vals.Kind() != reflect.Slice {
return nil, ErrExpectedSlice
}
var response []interface{}
for x := 0; x < vals.Len(); x++ {
response = append(response, vals.Index(x).Interface())
}
return response, nil
}
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