feat: gemini-3-pro-image-preview add extra param

relay/channel/gemini/relay-gemini.go

@@ -1264,3 +1264,70 @@ func GeminiImageHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.
 
 	return usage, nil
 }
+
+func convertToOaiImageResponse(geminiResponse *dto.GeminiChatResponse) (*dto.ImageResponse, error) {
+	openAIResponse := &dto.ImageResponse{
+		Created: common.GetTimestamp(),
+		Data:    make([]dto.ImageData, 0),
+	}
+
+	// extract images from candidates' inlineData
+	for _, candidate := range geminiResponse.Candidates {
+		for _, part := range candidate.Content.Parts {
+			if part.InlineData != nil && strings.HasPrefix(part.InlineData.MimeType, "image") {
+				openAIResponse.Data = append(openAIResponse.Data, dto.ImageData{
+					B64Json: part.InlineData.Data,
+				})
+			}
+		}
+	}
+
+	if len(openAIResponse.Data) == 0 {
+		return nil, errors.New("no images found in response")
+	}
+
+	return openAIResponse, nil
+}
+
+func ChatImageHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
+	responseBody, readErr := io.ReadAll(resp.Body)
+	if readErr != nil {
+		return nil, types.NewOpenAIError(readErr, types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
+	}
+	service.CloseResponseBodyGracefully(resp)
+
+	if common.DebugEnabled {
+		println("ChatImageHandler response:", string(responseBody))
+	}
+
+	var geminiResponse dto.GeminiChatResponse
+	if jsonErr := common.Unmarshal(responseBody, &geminiResponse); jsonErr != nil {
+		return nil, types.NewOpenAIError(jsonErr, types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
+	}
+
+	if len(geminiResponse.Candidates) == 0 {
+		return nil, types.NewOpenAIError(errors.New("no images generated"), types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
+	}
+
+	openAIResponse, err := convertToOaiImageResponse(&geminiResponse)
+	if err != nil {
+		return nil, types.NewOpenAIError(err, types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
+	}
+
+	jsonResponse, jsonErr := json.Marshal(openAIResponse)
+	if jsonErr != nil {
+		return nil, types.NewError(jsonErr, types.ErrorCodeBadResponseBody)
+	}
+
+	c.Writer.Header().Set("Content-Type", "application/json")
+	c.Writer.WriteHeader(resp.StatusCode)
+	_, _ = c.Writer.Write(jsonResponse)
+
+	usage := &dto.Usage{
+		PromptTokens:     geminiResponse.UsageMetadata.PromptTokenCount,
+		CompletionTokens: geminiResponse.UsageMetadata.CandidatesTokenCount,
+		TotalTokens:      geminiResponse.UsageMetadata.TotalTokenCount,
+	}
+
+	return usage, nil
+}