/
event_unmarshal.go
480 lines (423 loc) · 13.4 KB
/
event_unmarshal.go
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/*
Copyright 2021 The CloudEvents Authors
SPDX-License-Identifier: Apache-2.0
*/
package event
import (
"encoding/base64"
"errors"
"fmt"
"io"
"sync"
jsoniter "github.com/json-iterator/go"
"github.com/cloudevents/sdk-go/v2/types"
)
const specVersionV03Flag uint8 = 1 << 4
const specVersionV1Flag uint8 = 1 << 5
const dataBase64Flag uint8 = 1 << 6
const dataContentTypeFlag uint8 = 1 << 7
func checkFlag(state uint8, flag uint8) bool {
return state&flag != 0
}
func appendFlag(state *uint8, flag uint8) {
*state = (*state) | flag
}
var iterPool = sync.Pool{
New: func() interface{} {
return jsoniter.Parse(jsoniter.ConfigFastest, nil, 1024)
},
}
func borrowIterator(reader io.Reader) *jsoniter.Iterator {
iter := iterPool.Get().(*jsoniter.Iterator)
iter.Reset(reader)
return iter
}
func returnIterator(iter *jsoniter.Iterator) {
iter.Error = nil
iter.Attachment = nil
iterPool.Put(iter)
}
func ReadJson(out *Event, reader io.Reader) error {
iterator := borrowIterator(reader)
defer returnIterator(iterator)
return readJsonFromIterator(out, iterator)
}
// ReadJson allows you to read the bytes reader as an event
func readJsonFromIterator(out *Event, iterator *jsoniter.Iterator) error {
// Parsing dependency graph:
// SpecVersion
// ^ ^
// | +--------------+
// + +
// All Attributes datacontenttype (and datacontentencoding for v0.3)
// (except datacontenttype) ^
// |
// |
// +
// Data
var state uint8 = 0
var cachedData []byte
var (
// Universally parseable fields.
id string
typ string
source types.URIRef
subject *string
time *types.Timestamp
datacontenttype *string
extensions = make(map[string]interface{})
// These fields require knowledge about the specversion to be parsed.
schemaurl jsoniter.Any
datacontentencoding jsoniter.Any
dataschema jsoniter.Any
dataBase64 jsoniter.Any
)
for key := iterator.ReadObject(); key != ""; key = iterator.ReadObject() {
// Check if we have some error in our error cache
if iterator.Error != nil {
return iterator.Error
}
// We have a key, now we need to figure out what to do
// depending on the parsing state
// If it's a specversion, trigger state change
if key == "specversion" {
if checkFlag(state, specVersionV1Flag|specVersionV03Flag) {
return fmt.Errorf("specversion was already provided")
}
sv := iterator.ReadString()
// Check proper specversion
switch sv {
case CloudEventsVersionV1:
con := &EventContextV1{
ID: id,
Type: typ,
Source: source,
Subject: subject,
Time: time,
DataContentType: datacontenttype,
}
// Add the fields relevant for the version ...
if dataschema != nil {
var err error
con.DataSchema, err = toUriPtr(dataschema)
if err != nil {
return err
}
}
if dataBase64 != nil {
stream := jsoniter.ConfigFastest.BorrowStream(nil)
defer jsoniter.ConfigFastest.ReturnStream(stream)
dataBase64.WriteTo(stream)
cachedData = stream.Buffer()
if stream.Error != nil {
return stream.Error
}
appendFlag(&state, dataBase64Flag)
}
// ... add all remaining fields as extensions.
if schemaurl != nil {
extensions["schemaurl"] = schemaurl.GetInterface()
}
if datacontentencoding != nil {
extensions["datacontentencoding"] = datacontentencoding.GetInterface()
}
out.Context = con
appendFlag(&state, specVersionV1Flag)
case CloudEventsVersionV03:
con := &EventContextV03{
ID: id,
Type: typ,
Source: source,
Subject: subject,
Time: time,
DataContentType: datacontenttype,
}
var err error
// Add the fields relevant for the version ...
if schemaurl != nil {
con.SchemaURL, err = toUriRefPtr(schemaurl)
if err != nil {
return err
}
}
if datacontentencoding != nil {
con.DataContentEncoding, err = toStrPtr(datacontentencoding)
if *con.DataContentEncoding != Base64 {
err = ValidationError{"datacontentencoding": errors.New("invalid datacontentencoding value, the only allowed value is 'base64'")}
}
if err != nil {
return err
}
appendFlag(&state, dataBase64Flag)
}
// ... add all remaining fields as extensions.
if dataschema != nil {
extensions["dataschema"] = dataschema.GetInterface()
}
if dataBase64 != nil {
extensions["data_base64"] = dataBase64.GetInterface()
}
out.Context = con
appendFlag(&state, specVersionV03Flag)
default:
return ValidationError{"specversion": errors.New("unknown value: " + sv)}
}
// Apply all extensions to the context object.
for key, val := range extensions {
if err := out.Context.SetExtension(key, val); err != nil {
return err
}
}
continue
}
// If no specversion ...
if !checkFlag(state, specVersionV03Flag|specVersionV1Flag) {
switch key {
case "id":
id = iterator.ReadString()
case "type":
typ = iterator.ReadString()
case "source":
source = readUriRef(iterator)
case "subject":
subject = readStrPtr(iterator)
case "time":
time = readTimestamp(iterator)
case "datacontenttype":
datacontenttype = readStrPtr(iterator)
appendFlag(&state, dataContentTypeFlag)
case "data":
cachedData = iterator.SkipAndReturnBytes()
case "data_base64":
dataBase64 = iterator.ReadAny()
case "dataschema":
dataschema = iterator.ReadAny()
case "schemaurl":
schemaurl = iterator.ReadAny()
case "datacontentencoding":
datacontentencoding = iterator.ReadAny()
default:
extensions[key] = iterator.Read()
}
continue
}
// From this point downward -> we can assume the event has a context pointer non nil
// If it's a datacontenttype, trigger state change
if key == "datacontenttype" {
if checkFlag(state, dataContentTypeFlag) {
return fmt.Errorf("datacontenttype was already provided")
}
dct := iterator.ReadString()
switch ctx := out.Context.(type) {
case *EventContextV03:
ctx.DataContentType = &dct
case *EventContextV1:
ctx.DataContentType = &dct
}
appendFlag(&state, dataContentTypeFlag)
continue
}
// If it's a datacontentencoding and it's v0.3, trigger state change
if checkFlag(state, specVersionV03Flag) && key == "datacontentencoding" {
if checkFlag(state, dataBase64Flag) {
return ValidationError{"datacontentencoding": errors.New("datacontentencoding was specified twice")}
}
dce := iterator.ReadString()
if dce != Base64 {
return ValidationError{"datacontentencoding": errors.New("invalid datacontentencoding value, the only allowed value is 'base64'")}
}
out.Context.(*EventContextV03).DataContentEncoding = &dce
appendFlag(&state, dataBase64Flag)
continue
}
// We can parse all attributes, except data.
// If it's data or data_base64 and we don't have the attributes to process it, then we cache it
// The expanded form of this condition is:
// (checkFlag(state, specVersionV1Flag) && !checkFlag(state, dataContentTypeFlag) && (key == "data" || key == "data_base64")) ||
// (checkFlag(state, specVersionV03Flag) && !(checkFlag(state, dataContentTypeFlag) && checkFlag(state, dataBase64Flag)) && key == "data")
if (state&(specVersionV1Flag|dataContentTypeFlag) == specVersionV1Flag && (key == "data" || key == "data_base64")) ||
((state&specVersionV03Flag == specVersionV03Flag) && (state&(dataContentTypeFlag|dataBase64Flag) != (dataContentTypeFlag | dataBase64Flag)) && key == "data") {
if key == "data_base64" {
appendFlag(&state, dataBase64Flag)
}
cachedData = iterator.SkipAndReturnBytes()
continue
}
// At this point or this value is an attribute (excluding datacontenttype and datacontentencoding), or this value is data and this condition is valid:
// (specVersionV1Flag & dataContentTypeFlag) || (specVersionV03Flag & dataContentTypeFlag & dataBase64Flag)
switch eventContext := out.Context.(type) {
case *EventContextV03:
switch key {
case "id":
eventContext.ID = iterator.ReadString()
case "type":
eventContext.Type = iterator.ReadString()
case "source":
eventContext.Source = readUriRef(iterator)
case "subject":
eventContext.Subject = readStrPtr(iterator)
case "time":
eventContext.Time = readTimestamp(iterator)
case "schemaurl":
eventContext.SchemaURL = readUriRefPtr(iterator)
case "data":
iterator.Error = consumeData(out, checkFlag(state, dataBase64Flag), iterator)
default:
if eventContext.Extensions == nil {
eventContext.Extensions = make(map[string]interface{}, 1)
}
iterator.Error = eventContext.SetExtension(key, iterator.Read())
}
case *EventContextV1:
switch key {
case "id":
eventContext.ID = iterator.ReadString()
case "type":
eventContext.Type = iterator.ReadString()
case "source":
eventContext.Source = readUriRef(iterator)
case "subject":
eventContext.Subject = readStrPtr(iterator)
case "time":
eventContext.Time = readTimestamp(iterator)
case "dataschema":
eventContext.DataSchema = readUriPtr(iterator)
case "data":
iterator.Error = consumeData(out, false, iterator)
case "data_base64":
iterator.Error = consumeData(out, true, iterator)
default:
if eventContext.Extensions == nil {
eventContext.Extensions = make(map[string]interface{}, 1)
}
iterator.Error = eventContext.SetExtension(key, iterator.Read())
}
}
}
if state&(specVersionV03Flag|specVersionV1Flag) == 0 {
return ValidationError{"specversion": errors.New("no specversion")}
}
if iterator.Error != nil {
return iterator.Error
}
// If there is a dataToken cached, we always defer at the end the processing
// because nor datacontenttype or datacontentencoding are mandatory.
if cachedData != nil {
return consumeDataAsBytes(out, checkFlag(state, dataBase64Flag), cachedData)
}
return nil
}
func consumeDataAsBytes(e *Event, isBase64 bool, b []byte) error {
if isBase64 {
e.DataBase64 = true
// Allocate payload byte buffer
base64Encoded := b[1 : len(b)-1] // remove quotes
e.DataEncoded = make([]byte, base64.StdEncoding.DecodedLen(len(base64Encoded)))
length, err := base64.StdEncoding.Decode(e.DataEncoded, base64Encoded)
if err != nil {
return err
}
e.DataEncoded = e.DataEncoded[0:length]
return nil
}
mt, _ := e.Context.GetDataMediaType()
// Empty content type assumes json
if mt != "" && mt != ApplicationJSON && mt != TextJSON {
// If not json, then data is encoded as string
iter := jsoniter.ParseBytes(jsoniter.ConfigFastest, b)
src := iter.ReadString() // handles escaping
e.DataEncoded = []byte(src)
if iter.Error != nil {
return fmt.Errorf("unexpected data payload for media type %q, expected a string: %w", mt, iter.Error)
}
return nil
}
e.DataEncoded = b
return nil
}
func consumeData(e *Event, isBase64 bool, iter *jsoniter.Iterator) error {
if isBase64 {
e.DataBase64 = true
// Allocate payload byte buffer
base64Encoded := iter.ReadStringAsSlice()
e.DataEncoded = make([]byte, base64.StdEncoding.DecodedLen(len(base64Encoded)))
length, err := base64.StdEncoding.Decode(e.DataEncoded, base64Encoded)
if err != nil {
return err
}
e.DataEncoded = e.DataEncoded[0:length]
return nil
}
mt, _ := e.Context.GetDataMediaType()
if mt != ApplicationJSON && mt != TextJSON {
// If not json, then data is encoded as string
src := iter.ReadString() // handles escaping
e.DataEncoded = []byte(src)
if iter.Error != nil {
return fmt.Errorf("unexpected data payload for media type %q, expected a string: %w", mt, iter.Error)
}
return nil
}
e.DataEncoded = iter.SkipAndReturnBytes()
return nil
}
func readUriRef(iter *jsoniter.Iterator) types.URIRef {
str := iter.ReadString()
uriRef := types.ParseURIRef(str)
if uriRef == nil {
iter.Error = fmt.Errorf("cannot parse uri ref: %v", str)
return types.URIRef{}
}
return *uriRef
}
func readStrPtr(iter *jsoniter.Iterator) *string {
str := iter.ReadString()
if str == "" {
return nil
}
return &str
}
func readUriRefPtr(iter *jsoniter.Iterator) *types.URIRef {
return types.ParseURIRef(iter.ReadString())
}
func readUriPtr(iter *jsoniter.Iterator) *types.URI {
return types.ParseURI(iter.ReadString())
}
func readTimestamp(iter *jsoniter.Iterator) *types.Timestamp {
t, err := types.ParseTimestamp(iter.ReadString())
if err != nil {
iter.Error = err
}
return t
}
func toStrPtr(val jsoniter.Any) (*string, error) {
str := val.ToString()
if val.LastError() != nil {
return nil, val.LastError()
}
if str == "" {
return nil, nil
}
return &str, nil
}
func toUriRefPtr(val jsoniter.Any) (*types.URIRef, error) {
str := val.ToString()
if val.LastError() != nil {
return nil, val.LastError()
}
return types.ParseURIRef(str), nil
}
func toUriPtr(val jsoniter.Any) (*types.URI, error) {
str := val.ToString()
if val.LastError() != nil {
return nil, val.LastError()
}
return types.ParseURI(str), nil
}
// UnmarshalJSON implements the json unmarshal method used when this type is
// unmarshaled using json.Unmarshal.
func (e *Event) UnmarshalJSON(b []byte) error {
iterator := jsoniter.ConfigFastest.BorrowIterator(b)
defer jsoniter.ConfigFastest.ReturnIterator(iterator)
return readJsonFromIterator(e, iterator)
}