openai/streaming.go

// Copyright 2024 Google LLC

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     https://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package openai

import (
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/google-gemini/proxy-to-gemini/internal"
	"github.com/google/generative-ai-go/genai"
	"google.golang.org/api/iterator"
)

func streamingChatCompletionsHandler(w http.ResponseWriter, r *http.Request, model string, chat *genai.ChatSession, lastPart genai.Part) {
	iter := chat.SendMessageStream(r.Context(), lastPart)

	for {
		gresp, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			internal.ErrorHandler(w, r, http.StatusInternalServerError, "failed to stream response: %v", err)
			return
		}
		chunk, err := json.Marshal(toOpenAIResponse(gresp, "chat.completion.chunk", model))
		if err != nil {
			internal.ErrorHandler(w, r, http.StatusInternalServerError, "failed to marshal chunk: %v", err)
			return
		}
		fmt.Fprintf(w, "data: %s\n", chunk)
	}
	fmt.Fprint(w, "data: [DONE]\n")
}