Enable streaming UI updates for chat responses

This commit is contained in:
2025-10-01 20:09:40 +02:00
parent 4271ee3d73
commit a3e6b105d0
5 changed files with 375 additions and 162 deletions

View File

@@ -87,15 +87,174 @@ func (c *Client) CreateChatCompletion(ctx context.Context, req ChatCompletionReq
defer resp.Body.Close()
if resp.StatusCode >= 200 && resp.StatusCode < 300 {
if req.Stream {
return decodeStream(resp.Body)
}
return decodeSuccess(resp.Body)
}
return nil, decodeError(resp.Body, resp.StatusCode)
}
// StreamChatCompletion issues a streaming chat completion request and invokes handler for each chunk.
func (c *Client) StreamChatCompletion(ctx context.Context, req ChatCompletionRequest, handler ChatCompletionStreamHandler) (*ChatCompletionResponse, error) {
if c == nil {
return nil, errors.New("client is nil")
}
req.Stream = true
payload, err := json.Marshal(req)
if err != nil {
return nil, fmt.Errorf("encode request: %w", err)
}
httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/chat/completions", bytes.NewReader(payload))
if err != nil {
return nil, fmt.Errorf("create request: %w", err)
}
httpReq.Header.Set("Content-Type", "application/json")
httpReq.Header.Set("Authorization", "Bearer "+c.apiKey)
httpReq.Header.Set("Accept", "text/event-stream")
resp, err := c.httpClient.Do(httpReq)
if err != nil {
return nil, fmt.Errorf("execute request: %w", err)
}
defer resp.Body.Close()
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
return nil, decodeError(resp.Body, resp.StatusCode)
}
scanner := bufio.NewScanner(resp.Body)
scanner.Buffer(make([]byte, 0, 64*1024), 1<<20)
type streamChunk struct {
ID string `json:"id"`
Object string `json:"object"`
Choices []struct {
Index int `json:"index"`
Message ChatMessage `json:"message"`
Delta ChatMessage `json:"delta"`
FinishReason string `json:"finish_reason"`
} `json:"choices"`
Usage Usage `json:"usage"`
}
var aggregated ChatCompletionResponse
var builder strings.Builder
role := "assistant"
finish := ""
var usage Usage
usageReceived := false
for scanner.Scan() {
line := scanner.Text()
line = strings.TrimSpace(line)
if line == "" {
continue
}
if !strings.HasPrefix(line, "data:") {
continue
}
payloadLine := strings.TrimSpace(strings.TrimPrefix(line, "data:"))
if payloadLine == "" {
continue
}
if payloadLine == "[DONE]" {
if handler != nil {
if err := handler(ChatCompletionStreamEvent{Done: true}); err != nil {
return nil, err
}
}
break
}
var chunk streamChunk
if err := json.Unmarshal([]byte(payloadLine), &chunk); err != nil {
return nil, fmt.Errorf("decode stream response: %w", err)
}
if aggregated.ID == "" {
aggregated.ID = chunk.ID
}
if aggregated.Object == "" {
aggregated.Object = chunk.Object
}
if chunk.Usage != (Usage{}) {
usage = chunk.Usage
usageReceived = true
}
var chunkText string
finishReason := ""
if len(chunk.Choices) > 0 {
choice := chunk.Choices[0]
if choice.Message.Role != "" {
role = choice.Message.Role
}
if choice.Delta.Role != "" {
role = choice.Delta.Role
}
if choice.Delta.Content != "" {
chunkText = choice.Delta.Content
} else if choice.Message.Content != "" && builder.Len() == 0 {
chunkText = choice.Message.Content
}
if choice.Message.Content != "" && builder.Len() == 0 && chunkText == "" {
chunkText = choice.Message.Content
}
if choice.FinishReason != "" {
finishReason = choice.FinishReason
finish = choice.FinishReason
}
}
if chunkText != "" {
builder.WriteString(chunkText)
}
if handler != nil {
event := ChatCompletionStreamEvent{
ID: chunk.ID,
Role: role,
Content: chunkText,
FinishReason: finishReason,
}
if usageReceived {
u := usage
event.Usage = &u
}
if err := handler(event); err != nil {
return nil, err
}
}
}
if err := scanner.Err(); err != nil {
return nil, fmt.Errorf("read stream: %w", err)
}
content := strings.TrimSpace(builder.String())
if content == "" {
return nil, errors.New("stream response contained no content")
}
aggregated.Choices = []ChatCompletionChoice{{
Index: 0,
Message: ChatMessage{
Role: role,
Content: content,
},
FinishReason: finish,
}}
if usageReceived {
aggregated.Usage = usage
}
return &aggregated, nil
}
func decodeSuccess(r io.Reader) (*ChatCompletionResponse, error) {
data, err := io.ReadAll(r)
if err != nil {
@@ -118,100 +277,6 @@ func decodeSuccess(r io.Reader) (*ChatCompletionResponse, error) {
return &response, nil
}
func decodeStream(r io.Reader) (*ChatCompletionResponse, error) {
scanner := bufio.NewScanner(r)
var payloads []json.RawMessage
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "data: ") {
payload := strings.TrimPrefix(line, "data: ")
if payload == "[DONE]" {
break
}
payloads = append(payloads, json.RawMessage(payload))
}
}
if err := scanner.Err(); err != nil {
return nil, fmt.Errorf("read stream: %w", err)
}
if len(payloads) == 0 {
return nil, errors.New("empty stream response")
}
type streamChunk struct {
ID string `json:"id"`
Object string `json:"object"`
Choices []struct {
Index int `json:"index"`
Message ChatMessage `json:"message"`
Delta ChatMessage `json:"delta"`
FinishReason string `json:"finish_reason"`
} `json:"choices"`
Usage Usage `json:"usage"`
}
var aggregated ChatCompletionResponse
var builder strings.Builder
role := "assistant"
finish := ""
for _, payload := range payloads {
var chunk streamChunk
if err := json.Unmarshal(payload, &chunk); err != nil {
return nil, fmt.Errorf("decode stream response: %w", err)
}
if aggregated.ID == "" {
aggregated.ID = chunk.ID
}
if aggregated.Object == "" {
aggregated.Object = chunk.Object
}
aggregated.Usage.PromptTokens += chunk.Usage.PromptTokens
aggregated.Usage.CompletionTokens += chunk.Usage.CompletionTokens
aggregated.Usage.TotalTokens += chunk.Usage.TotalTokens
if len(chunk.Choices) == 0 {
continue
}
choice := chunk.Choices[0]
if choice.Message.Role != "" {
role = choice.Message.Role
}
if choice.Delta.Role != "" {
role = choice.Delta.Role
}
if choice.Message.Content != "" {
builder.WriteString(choice.Message.Content)
}
if choice.Delta.Content != "" {
builder.WriteString(choice.Delta.Content)
}
if choice.FinishReason != "" {
finish = choice.FinishReason
}
}
content := strings.TrimSpace(builder.String())
if content == "" {
return nil, errors.New("stream response contained no content")
}
aggregated.Choices = []ChatCompletionChoice{{
Index: 0,
FinishReason: finish,
Message: ChatMessage{
Role: role,
Content: content,
},
}}
return &aggregated, nil
}
func decodeError(r io.Reader, status int) error {
var apiErr ErrorResponse
if err := json.NewDecoder(r).Decode(&apiErr); err != nil {