fix(client): use scanner for streaming

Author: stainless-app[bot]

packages/ssestream/ssestream.go

@@ -31,7 +31,9 @@ func NewDecoder(res *http.Response) Decoder {
 	if t, ok := decoderTypes[contentType]; ok {
 		decoder = t(res.Body)
 	} else {
-		decoder = &eventStreamDecoder{rc: res.Body, rdr: bufio.NewReader(res.Body)}
+		scn := bufio.NewScanner(res.Body)
+		scn.Buffer(nil, bufio.MaxScanTokenSize<<2)
+		decoder = &eventStreamDecoder{rc: res.Body, scn: scn}
 	}
 	return decoder
 }
@@ -51,48 +53,10 @@ type Event struct {
 type eventStreamDecoder struct {
 	evt Event
 	rc  io.ReadCloser
-	rdr *bufio.Reader
+	scn *bufio.Scanner
 	err error
 }
 
-func line(r *bufio.Reader) ([]byte, error) {
-	var overflow bytes.Buffer
-
-	// To prevent infinite loops, the failsafe stops when a line is
-	// 100 times longer than the [io.Reader] default buffer size,
-	// or after 20 failed attempts to find an end of line.
-	for f := 0; f < 100; f++ {
-		part, isPrefix, err := r.ReadLine()
-		if err != nil {
-			return nil, err
-		}
-
-		// Happy case, the line fits in the default buffer.
-		if !isPrefix && overflow.Len() == 0 {
-			return part, nil
-		}
-
-		// Overflow case, append to the buffer.
-		if isPrefix || overflow.Len() > 0 {
-			n, err := overflow.Write(part)
-			if err != nil {
-				return nil, err
-			}
-
-			// Didn't find an end of line, heavily increment the failsafe.
-			if n != r.Size() {
-				f += 5
-			}
-		}
-
-		if !isPrefix {
-			return overflow.Bytes(), nil
-		}
-	}
-
-	return nil, fmt.Errorf("ssestream: too many attempts to read a line")
-}
-
 func (s *eventStreamDecoder) Next() bool {
 	if s.err != nil {
 		return false
@@ -101,16 +65,8 @@ func (s *eventStreamDecoder) Next() bool {
 	event := ""
 	data := bytes.NewBuffer(nil)
 
-	for {
-		txt, err := line(s.rdr)
-		if err == io.EOF {
-			return false
-		}
-
-		if err != nil {
-			s.err = err
-			break
-		}
+	for s.scn.Scan() {
+		txt := s.scn.Bytes()
 
 		// Dispatch event on an empty line
 		if len(txt) == 0 {
@@ -147,6 +103,10 @@ func (s *eventStreamDecoder) Next() bool {
 		}
 	}
 
+	if s.scn.Err() != nil {
+		s.err = s.scn.Err()
+	}
+
 	return false
 }