feat: enhance Gemini API to support image response modalities and update model ratios

model/ability.go

@@ -7,6 +7,7 @@ import (
 
 	"gorm.io/gorm"
 
+	"github.com/pkg/errors"
 	"github.com/songquanpeng/one-api/common"
 	"github.com/songquanpeng/one-api/common/utils"
 )
@@ -42,7 +43,7 @@ func GetRandomSatisfiedChannel(group string, model string, ignoreFirstPriority b
 		err = channelQuery.Order("RAND()").First(&ability).Error
 	}
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "get random satisfied channel")
 	}
 	channel := Channel{}
 	channel.Id = ability.ChannelId

relay/adaptor/gemini/main.go

@@ -64,6 +64,9 @@ func ConvertRequest(textRequest model.GeneralOpenAIRequest) *ChatRequest {
 			Temperature:     textRequest.Temperature,
 			TopP:            textRequest.TopP,
 			MaxOutputTokens: textRequest.MaxTokens,
+			ResponseModalities: []string{
+				"TEXT", "IMAGE",
+			},
 		},
 	}
 	if textRequest.ResponseFormat != nil {
@@ -258,19 +261,52 @@ func responseGeminiChat2OpenAI(response *ChatResponse) *openai.TextResponse {
 			if candidate.Content.Parts[0].FunctionCall != nil {
 				choice.Message.ToolCalls = getToolCalls(&candidate)
 			} else {
+				// Handle text and image content
 				var builder strings.Builder
+				var contentItems []model.MessageContent
+
 				for _, part := range candidate.Content.Parts {
-					if i > 0 {
-						builder.WriteString("\n")
+					if part.Text != "" {
+						// For text parts
+						if i > 0 {
+							builder.WriteString("\n")
+						}
+						builder.WriteString(part.Text)
+
+						// Add to content items
+						contentItems = append(contentItems, model.MessageContent{
+							Type: model.ContentTypeText,
+							Text: part.Text,
+						})
+					}
+
+					if part.InlineData != nil && part.InlineData.MimeType != "" && part.InlineData.Data != "" {
+						// For inline image data
+						imageURL := &model.ImageURL{
+							// The data is already base64 encoded
+							Url: fmt.Sprintf("data:%s;base64,%s", part.InlineData.MimeType, part.InlineData.Data),
+						}
+
+						contentItems = append(contentItems, model.MessageContent{
+							Type:     model.ContentTypeImageURL,
+							ImageURL: imageURL,
+						})
 					}
-					builder.WriteString(part.Text)
 				}
-				choice.Message.Content = builder.String()
+
+				// If we have multiple content types, use structured content format
+				if len(contentItems) > 1 || (len(contentItems) == 1 && contentItems[0].Type != model.ContentTypeText) {
+					choice.Message.Content = contentItems
+				} else {
+					// Otherwise use the simple string content format
+					choice.Message.Content = builder.String()
+				}
 			}
 		} else {
 			choice.Message.Content = ""
 			choice.FinishReason = candidate.FinishReason
 		}
+
 		fullTextResponse.Choices = append(fullTextResponse.Choices, choice)
 	}
 	return &fullTextResponse
@@ -361,6 +397,7 @@ func Handler(c *gin.Context, resp *http.Response, promptTokens int, modelName st
 	if err != nil {
 		return openai.ErrorWrapper(err, "read_response_body_failed", http.StatusInternalServerError), nil
 	}
+
 	err = resp.Body.Close()
 	if err != nil {
 		return openai.ErrorWrapper(err, "close_response_body_failed", http.StatusInternalServerError), nil

relay/adaptor/gemini/model.go

@@ -6,6 +6,19 @@ type ChatRequest struct {
 	GenerationConfig  ChatGenerationConfig `json:"generation_config,omitempty"`
 	Tools             []ChatTools          `json:"tools,omitempty"`
 	SystemInstruction *ChatContent         `json:"system_instruction,omitempty"`
+	ModelVersion      string               `json:"model_version,omitempty"`
+	UsageMetadata     *UsageMetadata       `json:"usage_metadata,omitempty"`
+}
+
+type UsageMetadata struct {
+	PromptTokenCount    int                   `json:"promptTokenCount,omitempty"`
+	TotalTokenCount     int                   `json:"totalTokenCount,omitempty"`
+	PromptTokensDetails []PromptTokensDetails `json:"promptTokensDetails,omitempty"`
+}
+
+type PromptTokensDetails struct {
+	Modality   string `json:"modality,omitempty"`
+	TokenCount int    `json:"tokenCount,omitempty"`
 }
 
 type EmbeddingRequest struct {
@@ -66,12 +79,13 @@ type ChatTools struct {
 }
 
 type ChatGenerationConfig struct {
-	ResponseMimeType string   `json:"responseMimeType,omitempty"`
-	ResponseSchema   any      `json:"responseSchema,omitempty"`
-	Temperature      *float64 `json:"temperature,omitempty"`
-	TopP             *float64 `json:"topP,omitempty"`
-	TopK             float64  `json:"topK,omitempty"`
-	MaxOutputTokens  int      `json:"maxOutputTokens,omitempty"`
-	CandidateCount   int      `json:"candidateCount,omitempty"`
-	StopSequences    []string `json:"stopSequences,omitempty"`
+	ResponseMimeType   string   `json:"responseMimeType,omitempty"`
+	ResponseSchema     any      `json:"responseSchema,omitempty"`
+	Temperature        *float64 `json:"temperature,omitempty"`
+	TopP               *float64 `json:"topP,omitempty"`
+	TopK               float64  `json:"topK,omitempty"`
+	MaxOutputTokens    int      `json:"maxOutputTokens,omitempty"`
+	CandidateCount     int      `json:"candidateCount,omitempty"`
+	StopSequences      []string `json:"stopSequences,omitempty"`
+	ResponseModalities []string `json:"responseModalities,omitempty"`
 }

relay/adaptor/geminiv2/constants.go

@@ -12,4 +12,5 @@ var ModelList = []string{
 	"gemini-2.0-flash-lite-preview-02-05",
 	"gemini-2.0-flash-thinking-exp-01-21",
 	"gemini-2.0-pro-exp-02-05",
+	"gemini-2.0-flash-exp-image-generation",
 }