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http_stream.go
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/
http_stream.go
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package client
import (
"bufio"
"context"
"encoding/json"
"fmt"
"io"
"net/http"
messagev1 "github.com/xmtp/proto/v3/go/message_api/v1"
"github.com/xmtp/xmtpd/pkg/zap"
"google.golang.org/protobuf/encoding/protojson"
)
type httpStream struct {
respC chan *http.Response
errC chan error
bodyReader *bufio.Reader
body io.ReadCloser
closed bool
}
func newHTTPStream(log *zap.Logger, reqFn func() (*http.Response, error)) (*httpStream, error) {
s := &httpStream{
respC: make(chan *http.Response, 1),
errC: make(chan error, 1),
}
go func() {
// Streaming requests block until the first byte is sent, at which
// point we can consume from the response body reader as a stream.
resp, err := reqFn()
if err != nil {
if !s.closed {
s.errC <- err
} else {
log.Error("requesting", zap.Error(err))
}
return
}
if resp.StatusCode != http.StatusOK {
defer resp.Body.Close()
body, err := io.ReadAll(resp.Body)
if err == nil {
err = fmt.Errorf("%s: %s", resp.Status, string(body))
}
if !s.closed {
s.errC <- err
} else {
log.Error("reading body", zap.Error(err))
}
return
}
if s.closed {
return
}
s.respC <- resp
}()
return s, nil
}
func (s *httpStream) reader(ctx context.Context) (*bufio.Reader, error) {
if s.bodyReader != nil {
return s.bodyReader, nil
}
select {
case err := <-s.errC:
return nil, err
case resp := <-s.respC:
s.body = resp.Body
s.bodyReader = bufio.NewReader(s.body)
return s.bodyReader, nil
case <-ctx.Done():
return nil, ctx.Err()
}
}
func (s *httpStream) Next(ctx context.Context) (*messagev1.Envelope, error) {
reader, err := s.reader(ctx)
if err != nil {
return nil, err
}
if s.body == nil { // stream was closed
return nil, io.EOF
}
lineC := make(chan []byte)
errC := make(chan error)
go func() {
line, err := reader.ReadBytes('\n')
if ctx.Err() != nil {
// If the context has already closed, then just return out of this.
return
}
if err != nil {
errC <- err
return
}
lineC <- line
}()
var wrapper struct {
Result interface{}
}
var line []byte
select {
case v := <-lineC:
line = v
case err := <-errC:
return nil, err
case <-ctx.Done():
return nil, ctx.Err()
}
err = json.Unmarshal(line, &wrapper)
if err != nil {
return nil, err
}
envJSON, err := json.Marshal(wrapper.Result)
if err != nil {
return nil, err
}
var env messagev1.Envelope
err = protojson.Unmarshal(envJSON, &env)
return &env, err
}
func (s *httpStream) Close() error {
if !s.closed {
defer close(s.respC)
defer close(s.errC)
}
s.closed = true
if s.body == nil {
return nil
}
err := s.body.Close()
s.body = nil
return err
}