feat: convert gemini format to openai chat completions

relay/channel/openai/helper.go

@@ -2,6 +2,8 @@ package openai
 
 import (
 	"encoding/json"
+	"errors"
+	"net/http"
 	"one-api/common"
 	"one-api/dto"
 	relaycommon "one-api/relay/common"
@@ -16,11 +18,14 @@ import (
 // 辅助函数
 func HandleStreamFormat(c *gin.Context, info *relaycommon.RelayInfo, data string, forceFormat bool, thinkToContent bool) error {
 	info.SendResponseCount++
+
 	switch info.RelayFormat {
 	case relaycommon.RelayFormatOpenAI:
 		return sendStreamData(c, info, data, forceFormat, thinkToContent)
 	case relaycommon.RelayFormatClaude:
 		return handleClaudeFormat(c, data, info)
+	case relaycommon.RelayFormatGemini:
+		return handleGeminiFormat(c, data, info)
 	}
 	return nil
 }
@@ -41,6 +46,46 @@ func handleClaudeFormat(c *gin.Context, data string, info *relaycommon.RelayInfo
 	return nil
 }
 
+func handleGeminiFormat(c *gin.Context, data string, info *relaycommon.RelayInfo) error {
+	// 截取前50个字符用于调试
+	debugData := data
+	if len(data) > 50 {
+		debugData = data[:50] + "..."
+	}
+	common.LogInfo(c, "handleGeminiFormat called with data: "+debugData)
+
+	var streamResponse dto.ChatCompletionsStreamResponse
+	if err := common.Unmarshal(common.StringToByteSlice(data), &streamResponse); err != nil {
+		common.LogError(c, "failed to unmarshal stream response: "+err.Error())
+		return err
+	}
+
+	common.LogInfo(c, "successfully unmarshaled stream response")
+	geminiResponse := service.StreamResponseOpenAI2Gemini(&streamResponse, info)
+
+	// 如果返回 nil，表示没有实际内容，跳过发送
+	if geminiResponse == nil {
+		common.LogInfo(c, "handleGeminiFormat: no content to send, skipping")
+		return nil
+	}
+
+	geminiResponseStr, err := common.Marshal(geminiResponse)
+	if err != nil {
+		common.LogError(c, "failed to marshal gemini response: "+err.Error())
+		return err
+	}
+
+	common.LogInfo(c, "sending gemini format response")
+	// send gemini format response
+	c.Render(-1, common.CustomEvent{Data: "data: " + string(geminiResponseStr)})
+	if flusher, ok := c.Writer.(http.Flusher); ok {
+		flusher.Flush()
+	} else {
+		return errors.New("streaming error: flusher not found")
+	}
+	return nil
+}
+
 func ProcessStreamResponse(streamResponse dto.ChatCompletionsStreamResponse, responseTextBuilder *strings.Builder, toolCount *int) error {
 	for _, choice := range streamResponse.Choices {
 		responseTextBuilder.WriteString(choice.Delta.GetContentString())
@@ -185,6 +230,37 @@ func HandleFinalResponse(c *gin.Context, info *relaycommon.RelayInfo, lastStream
 		for _, resp := range claudeResponses {
 			_ = helper.ClaudeData(c, *resp)
 		}
+
+	case relaycommon.RelayFormatGemini:
+		var streamResponse dto.ChatCompletionsStreamResponse
+		if err := common.Unmarshal(common.StringToByteSlice(lastStreamData), &streamResponse); err != nil {
+			common.SysError("error unmarshalling stream response: " + err.Error())
+			return
+		}
+
+		// 这里处理的是 openai 最后一个流响应，其 delta 为空，有 finish_reason 字段
+		// 因此相比较于 google 官方的流响应，由 openai 转换而来会多一个 parts 为空，finishReason 为 STOP 的响应
+		// 而包含最后一段文本输出的响应（倒数第二个）的 finishReason 为 null
+		// 暂不知是否有程序会不兼容。
+
+		geminiResponse := service.StreamResponseOpenAI2Gemini(&streamResponse, info)
+
+		// openai 流响应开头的空数据
+		if geminiResponse == nil {
+			return
+		}
+
+		geminiResponseStr, err := common.Marshal(geminiResponse)
+		if err != nil {
+			common.SysError("error marshalling gemini response: " + err.Error())
+			return
+		}
+
+		// 发送最终的 Gemini 响应
+		c.Render(-1, common.CustomEvent{Data: "data: " + string(geminiResponseStr)})
+		if flusher, ok := c.Writer.(http.Flusher); ok {
+			flusher.Flush()
+		}
 	}
 }