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Fix SSE streaming by preserving event: lines in proxy #32

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Fix SSE streaming by preserving event: lines in proxy #32

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4b67a19
Fix SSE streaming by preserving event: lines in proxy
torarnv Mar 31, 2026
8e36267
Include SSE event: lines in raw streaming data display
torarnv Mar 31, 2026
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21 changes: 15 additions & 6 deletions proxy/internal/handler/handlers.go
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Original file line number Diff line number Diff line change
Expand Up @@ -282,14 +282,23 @@ func (h *Handler) handleStreamingResponse(w http.ResponseWriter, resp *http.Resp
scanner := bufio.NewScanner(resp.Body)
for scanner.Scan() {
line := scanner.Text()
if line == "" || !strings.HasPrefix(line, "data:") {
continue

// Forward every line to the client as-is, preserving the full SSE
// protocol (event: lines, data: lines, and blank separators).
fmt.Fprintf(w, "%s\n", line)
if line == "" {
// Blank line = SSE event boundary; flush to client.
if f, ok := w.(http.Flusher); ok {
f.Flush()
}
}

streamingChunks = append(streamingChunks, line)
fmt.Fprintf(w, "%s\n\n", line)
if f, ok := w.(http.Flusher); ok {
f.Flush()
if line != "" {
streamingChunks = append(streamingChunks, line)
}

if !strings.HasPrefix(line, "data:") {
continue
}

jsonData := strings.TrimPrefix(line, "data: ")
Expand Down
14 changes: 7 additions & 7 deletions proxy/internal/provider/openai.go
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Original file line number Diff line number Diff line change
Expand Up @@ -602,11 +602,11 @@ func transformOpenAIStreamToAnthropic(openAIStream io.ReadCloser, anthropicStrea
if data == "[DONE]" {
// Send Anthropic-style completion
if contentStarted {
fmt.Fprintf(anthropicStream, "data: {\"type\":\"content_block_stop\",\"index\":0}\n\n")
fmt.Fprintf(anthropicStream, "event: content_block_stop\ndata: {\"type\":\"content_block_stop\",\"index\":0}\n\n")
}
if messageStarted {
fmt.Fprintf(anthropicStream, "data: {\"type\":\"message_delta\",\"delta\":{\"stop_reason\":\"end_turn\",\"stop_sequence\":null}}\n\n")
fmt.Fprintf(anthropicStream, "data: {\"type\":\"message_stop\"}\n\n")
fmt.Fprintf(anthropicStream, "event: message_delta\ndata: {\"type\":\"message_delta\",\"delta\":{\"stop_reason\":\"end_turn\",\"stop_sequence\":null}}\n\n")
fmt.Fprintf(anthropicStream, "event: message_stop\ndata: {\"type\":\"message_stop\"}\n\n")
}
break
}
Expand Down Expand Up @@ -644,7 +644,7 @@ func transformOpenAIStreamToAnthropic(openAIStream io.ReadCloser, anthropicStrea
"usage": anthropicUsage,
}
usageJSON, _ := json.Marshal(usageDelta)
fmt.Fprintf(anthropicStream, "data: %s\n\n", usageJSON)
fmt.Fprintf(anthropicStream, "event: message_delta\ndata: %s\n\n", usageJSON)
}
}

Expand Down Expand Up @@ -684,7 +684,7 @@ func transformOpenAIStreamToAnthropic(openAIStream io.ReadCloser, anthropicStrea
},
}
startJSON, _ := json.Marshal(messageStart)
fmt.Fprintf(anthropicStream, "data: %s\n\n", startJSON)
fmt.Fprintf(anthropicStream, "event: message_start\ndata: %s\n\n", startJSON)
}

// Handle content
Expand All @@ -701,7 +701,7 @@ func transformOpenAIStreamToAnthropic(openAIStream io.ReadCloser, anthropicStrea
},
}
blockStartJSON, _ := json.Marshal(blockStart)
fmt.Fprintf(anthropicStream, "data: %s\n\n", blockStartJSON)
fmt.Fprintf(anthropicStream, "event: content_block_start\ndata: %s\n\n", blockStartJSON)
}

// Send content_block_delta
Expand All @@ -714,7 +714,7 @@ func transformOpenAIStreamToAnthropic(openAIStream io.ReadCloser, anthropicStrea
},
}
deltaJSON, _ := json.Marshal(contentDelta)
fmt.Fprintf(anthropicStream, "data: %s\n\n", deltaJSON)
fmt.Fprintf(anthropicStream, "event: content_block_delta\ndata: %s\n\n", deltaJSON)
}

}
Expand Down
2 changes: 1 addition & 1 deletion web/app/components/RequestDetailContent.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -513,7 +513,7 @@ function ResponseDetails({ response }: { response: NonNullable<Request['response
// Parse streaming chunks to extract the final assembled text
const parseStreamingResponse = (chunks: string[]) => {
let assembledText = '';
let rawData = chunks.join('');
let rawData = chunks.join('\n');

try {
// Split by lines and process each SSE event
Expand Down