refactor: Replace direct access to ImageUrl with GetImageMedia method across multiple relay channels

relay/channel/claude/relay-claude.go

@@ -241,7 +241,7 @@ func RequestOpenAI2ClaudeMessage(textRequest dto.GeneralOpenAIRequest) (*dto.Cla
 					if mediaMessage.Type == "text" {
 						claudeMediaMessage.Text = common.GetPointer[string](mediaMessage.Text)
 					} else {
-						imageUrl := mediaMessage.ImageUrl.(dto.MessageImageUrl)
+						imageUrl := mediaMessage.GetImageMedia()
 						claudeMediaMessage.Type = "image"
 						claudeMediaMessage.Source = &dto.ClaudeMessageSource{
 							Type: "base64",

relay/channel/gemini/relay-gemini.go

@@ -180,9 +180,9 @@ func CovertGemini2OpenAI(textRequest dto.GeneralOpenAIRequest) (*GeminiChatReque
 					return nil, fmt.Errorf("too many images in the message, max allowed is %d", constant.GeminiVisionMaxImageNum)
 				}
 				// 判断是否是url
-				if strings.HasPrefix(part.ImageUrl.(dto.MessageImageUrl).Url, "http") {
+				if strings.HasPrefix(part.GetImageMedia().Url, "http") {
 					// 是url，获取图片的类型和base64编码的数据
-					fileData, err := service.GetFileBase64FromUrl(part.ImageUrl.(dto.MessageImageUrl).Url)
+					fileData, err := service.GetFileBase64FromUrl(part.GetImageMedia().Url)
 					if err != nil {
 						return nil, fmt.Errorf("get file base64 from url failed: %s", err.Error())
 					}
@@ -193,7 +193,7 @@ func CovertGemini2OpenAI(textRequest dto.GeneralOpenAIRequest) (*GeminiChatReque
 						},
 					})
 				} else {
-					format, base64String, err := service.DecodeBase64FileData(part.ImageUrl.(dto.MessageImageUrl).Url)
+					format, base64String, err := service.DecodeBase64FileData(part.GetImageMedia().Url)
 					if err != nil {
 						return nil, fmt.Errorf("decode base64 image data failed: %s", err.Error())
 					}

relay/channel/mistral/text.go

@@ -10,7 +10,7 @@ func requestOpenAI2Mistral(request *dto.GeneralOpenAIRequest) *dto.GeneralOpenAI
 		mediaMessages := message.ParseContent()
 		for j, mediaMessage := range mediaMessages {
 			if mediaMessage.Type == dto.ContentTypeImageURL {
-				imageUrl := mediaMessage.ImageUrl.(dto.MessageImageUrl)
+				imageUrl := mediaMessage.GetImageMedia()
 				mediaMessage.ImageUrl = imageUrl.Url
 				mediaMessages[j] = mediaMessage
 			}

relay/channel/ollama/relay-ollama.go

@@ -19,7 +19,7 @@ func requestOpenAI2Ollama(request dto.GeneralOpenAIRequest) (*OllamaRequest, err
 			mediaMessages := message.ParseContent()
 			for j, mediaMessage := range mediaMessages {
 				if mediaMessage.Type == dto.ContentTypeImageURL {
-					imageUrl := mediaMessage.ImageUrl.(dto.MessageImageUrl)
+					imageUrl := mediaMessage.GetImageMedia()
 					// check if not base64
 					if strings.HasPrefix(imageUrl.Url, "http") {
 						fileData, err := service.GetFileBase64FromUrl(imageUrl.Url)

relay/channel/zhipu_4v/relay-zhipu_v4.go

@@ -79,7 +79,7 @@ func requestOpenAI2Zhipu(request dto.GeneralOpenAIRequest) *dto.GeneralOpenAIReq
 			mediaMessages := message.ParseContent()
 			for j, mediaMessage := range mediaMessages {
 				if mediaMessage.Type == dto.ContentTypeImageURL {
-					imageUrl := mediaMessage.ImageUrl.(dto.MessageImageUrl)
+					imageUrl := mediaMessage.GetImageMedia()
 					// check if base64
 					if strings.HasPrefix(imageUrl.Url, "data:image/") {
 						// 去除base64数据的URL前缀（如果有）