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Fix stream for OpenAI #187

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Merged
merged 2 commits into from
Oct 15, 2025
Merged

Fix stream for OpenAI #187

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54a84ca
Fix response buffer
dongri Oct 15, 2025
a6821db
Refactoring chat completion stream
dongri Oct 15, 2025
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146 changes: 95 additions & 51 deletions src/v1/chat_completion/chat_completion_stream.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -113,70 +113,114 @@ pub struct ChatCompletionStream<S: Stream<Item = Result<bytes::Bytes, reqwest::E
pub first_chunk: bool,
}

impl<S> ChatCompletionStream<S>
where
S: Stream<Item = Result<bytes::Bytes, reqwest::Error>> + Unpin,
{
fn find_event_delimiter(buffer: &str) -> Option<(usize, usize)> {
let carriage_idx = buffer.find("\r\n\r\n");
let newline_idx = buffer.find("\n\n");

match (carriage_idx, newline_idx) {
(Some(r_idx), Some(n_idx)) => {
if r_idx <= n_idx {
Some((r_idx, 4))
} else {
Some((n_idx, 2))
}
}
(Some(r_idx), None) => Some((r_idx, 4)),
(None, Some(n_idx)) => Some((n_idx, 2)),
(None, None) => None,
}
}

fn next_response_from_buffer(&mut self) -> Option<ChatCompletionStreamResponse> {
while let Some((idx, delimiter_len)) = Self::find_event_delimiter(&self.buffer) {
let event = self.buffer[..idx].to_owned();
self.buffer = self.buffer[idx + delimiter_len..].to_owned();

let mut data_payload = String::new();
for line in event.lines() {
let trimmed_line = line.trim_end_matches('\r');
if let Some(content) = trimmed_line
.strip_prefix("data: ")
.or_else(|| trimmed_line.strip_prefix("data:"))
{
if !content.is_empty() {
if !data_payload.is_empty() {
data_payload.push('\n');
}
data_payload.push_str(content);
}
}
}

if data_payload.is_empty() {
continue;
}

if data_payload == "[DONE]" {
return Some(ChatCompletionStreamResponse::Done);
}

match serde_json::from_str::<Value>(&data_payload) {
Ok(json) => {
if let Some(delta) = json
.get("choices")
.and_then(|choices| choices.get(0))
.and_then(|choice| choice.get("delta"))
{
if let Some(tool_call_response) = delta
.get("tool_calls")
.and_then(|tool_calls| tool_calls.as_array())
.map(|tool_calls_array| {
tool_calls_array
.iter()
.filter_map(|v| serde_json::from_value(v.clone()).ok())
.collect::<Vec<ToolCall>>()
})
.filter(|tool_calls_vec| !tool_calls_vec.is_empty())
.map(ChatCompletionStreamResponse::ToolCall)
{
return Some(tool_call_response);
}

if let Some(content) = delta.get("content").and_then(|c| c.as_str()) {
let output = content.replace("\\n", "\n");
return Some(ChatCompletionStreamResponse::Content(output));
}
}
}
Err(error) => {
eprintln!("Failed to parse SSE chunk as JSON: {}", error);
}
}
}

None
}
}

impl<S: Stream<Item = Result<bytes::Bytes, reqwest::Error>> + Unpin> Stream
for ChatCompletionStream<S>
{
type Item = ChatCompletionStreamResponse;

fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
loop {
if let Some(response) = self.next_response_from_buffer() {
return Poll::Ready(Some(response));
}

match Pin::new(&mut self.as_mut().response).poll_next(cx) {
Poll::Ready(Some(Ok(chunk))) => {
let mut utf8_str = String::from_utf8_lossy(&chunk).to_string();
let chunk_str = String::from_utf8_lossy(&chunk).to_string();

if self.first_chunk {
let lines: Vec<&str> = utf8_str.lines().collect();
utf8_str = if lines.len() >= 2 {
lines[lines.len() - 2].to_string()
} else {
utf8_str.clone()
};
self.first_chunk = false;
}

let trimmed_str = utf8_str.trim_start_matches("data: ");
if trimmed_str.contains("[DONE]") {
return Poll::Ready(Some(ChatCompletionStreamResponse::Done));
}

self.buffer.push_str(trimmed_str);
let json_result: Result<Value, _> = serde_json::from_str(&self.buffer);

if let Ok(json) = json_result {
self.buffer.clear();

if let Some(choices) = json.get("choices") {
if let Some(choice) = choices.get(0) {
if let Some(delta) = choice.get("delta") {
if let Some(tool_calls) = delta.get("tool_calls") {
if let Some(tool_calls_array) = tool_calls.as_array() {
let tool_calls_vec: Vec<ToolCall> = tool_calls_array
.iter()
.filter_map(|v| {
serde_json::from_value(v.clone()).ok()
})
.collect();

return Poll::Ready(Some(
ChatCompletionStreamResponse::ToolCall(
tool_calls_vec,
),
));
}
}

if let Some(content) =
delta.get("content").and_then(|c| c.as_str())
{
let output = content.replace("\\n", "\n");
return Poll::Ready(Some(
ChatCompletionStreamResponse::Content(output),
));
}
}
}
}
}
self.buffer.push_str(&chunk_str);
}
Poll::Ready(Some(Err(error))) => {
eprintln!("Error in stream: {:?}", error);
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