sdk-go/v1/bindings/http/message.go

106 lines
2.4 KiB
Go

package http
import (
"context"
"io"
nethttp "net/http"
"strings"
"github.com/cloudevents/sdk-go/v1/binding"
"github.com/cloudevents/sdk-go/v1/binding/format"
"github.com/cloudevents/sdk-go/v1/binding/spec"
)
const prefix = "Ce-"
var specs = spec.WithPrefix(prefix)
const ContentType = "Content-Type"
// Message holds the Header and Body of a HTTP Request or Response.
type Message struct {
Header nethttp.Header
BodyReader io.ReadCloser
encoding binding.Encoding
OnFinish func(error) error
}
// Check if http.Message implements binding.Message
var _ binding.Message = (*Message)(nil)
// NewMessage returns a Message with header and data from body.
// Reads and closes body.
func NewMessage(header nethttp.Header, body io.ReadCloser) (*Message, error) {
m := Message{Header: header}
if body != nil {
m.BodyReader = body
}
if ft := format.Lookup(header.Get(ContentType)); ft == nil {
m.encoding = binding.EncodingStructured
} else if _, err := specs.FindVersion(m.Header.Get); err != nil {
m.encoding = binding.EncodingBinary
} else {
m.encoding = binding.EncodingUnknown
}
return &m, nil
}
func (m *Message) Encoding() binding.Encoding {
return m.encoding
}
func (m *Message) Structured(ctx context.Context, encoder binding.StructuredEncoder) error {
if ft := format.Lookup(m.Header.Get(ContentType)); ft == nil {
return binding.ErrNotStructured
} else {
return encoder.SetStructuredEvent(ctx, ft, m.BodyReader)
}
}
func (m *Message) Binary(ctx context.Context, encoder binding.BinaryEncoder) error {
version, err := specs.FindVersion(m.Header.Get)
if err != nil {
return binding.ErrNotBinary
}
err = encoder.Start(ctx)
if err != nil {
return err
}
for k, v := range m.Header {
if strings.HasPrefix(k, prefix) {
attr := version.Attribute(k)
if attr != nil {
err = encoder.SetAttribute(attr, v[0])
} else {
err = encoder.SetExtension(strings.ToLower(strings.TrimPrefix(k, prefix)), v[0])
}
} else if k == ContentType {
err = encoder.SetAttribute(version.AttributeFromKind(spec.DataContentType), v[0])
}
if err != nil {
return err
}
}
if m.BodyReader != nil {
err = encoder.SetData(m.BodyReader)
if err != nil {
return err
}
}
return encoder.End()
}
func (m *Message) Finish(err error) error {
if m.BodyReader != nil {
_ = m.BodyReader.Close()
}
if m.OnFinish != nil {
return m.OnFinish(err)
}
return nil
}