fix: stream return EOF when openai return error (#184)

* fix: stream return EOF when openai return error

* perf: add error accumulator

* fix: golangci-lint

* fix: unmarshal error possibly null

* fix: error accumulator

* test: error accumulator use interface and add test code

* test: error accumulator add test code

* refactor: use stream reader to re-use stream code

* refactor: stream reader use generics

chat_stream.go

@@ -2,11 +2,7 @@ package openai
 
 import (
 	"bufio"
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
-	"net/http"
 )
 
 type ChatCompletionStreamChoiceDelta struct {
@@ -30,52 +26,7 @@ type ChatCompletionStreamResponse struct {
 // ChatCompletionStream
 // Note: Perhaps it is more elegant to abstract Stream using generics.
 type ChatCompletionStream struct {
-	emptyMessagesLimit uint
-	isFinished         bool
-
-	reader   *bufio.Reader
-	response *http.Response
-}
-
-func (stream *ChatCompletionStream) Recv() (response ChatCompletionStreamResponse, err error) {
-	if stream.isFinished {
-		err = io.EOF
-		return
-	}
-
-	var emptyMessagesCount uint
-
-waitForData:
-	line, err := stream.reader.ReadBytes('\n')
-	if err != nil {
-		return
-	}
-
-	var headerData = []byte("data: ")
-	line = bytes.TrimSpace(line)
-	if !bytes.HasPrefix(line, headerData) {
-		emptyMessagesCount++
-		if emptyMessagesCount > stream.emptyMessagesLimit {
-			err = ErrTooManyEmptyStreamMessages
-			return
-		}
-
-		goto waitForData
-	}
-
-	line = bytes.TrimPrefix(line, headerData)
-	if string(line) == "[DONE]" {
-		stream.isFinished = true
-		err = io.EOF
-		return
-	}
-
-	err = json.Unmarshal(line, &response)
-	return
-}
-
-func (stream *ChatCompletionStream) Close() {
-	stream.response.Body.Close()
+	*streamReader[ChatCompletionStreamResponse]
 }
 
 // CreateChatCompletionStream — API call to create a chat completion w/ streaming
@@ -98,9 +49,13 @@ func (c *Client) CreateChatCompletionStream(
 	}
 
 	stream = &ChatCompletionStream{
-		emptyMessagesLimit: c.config.EmptyMessagesLimit,
-		reader:             bufio.NewReader(resp.Body),
-		response:           resp,
+		streamReader: &streamReader[ChatCompletionStreamResponse]{
+			emptyMessagesLimit: c.config.EmptyMessagesLimit,
+			reader:             bufio.NewReader(resp.Body),
+			response:           resp,
+			errAccumulator:     newErrorAccumulator(),
+			unmarshaler:        &jsonUnmarshaler{},
+		},
 	}
 	return
 }