fix: Add image support to Gemini relay

- Add support for getting base64-encoded images via openAI's image_url.
- Add `context` as a parameter for the function `LogError`.
- Handle the error from `image.GetImageFromUrl` by logging it.
- Convert the role to `user` if it is `system` and add a dummy model message to make Gemini happy.

common/image/image.go

@@ -44,6 +44,11 @@ func GetImageSizeFromUrl(url string) (width int, height int, err error) {
 }
 
 func GetImageFromUrl(url string) (mimeType string, data string, err error) {
+	// openai's image_url support base64 encoded image
+	if strings.HasPrefix(url, "data:image/jpeg;base64,") {
+		return "image/jpeg", strings.TrimPrefix(url, "data:image/jpeg;base64,"), nil
+	}
+
 	isImage, err := IsImageUrl(url)
 	if !isImage {
 		return

controller/relay-gemini.go

@@ -2,6 +2,7 @@ package controller
 
 import (
 	"bufio"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -117,7 +118,12 @@ func requestOpenAI2Gemini(textRequest GeneralOpenAIRequest) *GeminiChatRequest {
 				if imageNum > GeminiVisionMaxImageNum {
 					continue
 				}
-				mimeType, data, _ := image.GetImageFromUrl(part.ImageURL.Url)
+
+				mimeType, data, err := image.GetImageFromUrl(part.ImageURL.Url)
+				if err != nil {
+					common.LogError(context.TODO(),
+						fmt.Sprintf("get image from url %s got %+v", part.ImageURL.Url, err))
+				}
 				parts = append(parts, GeminiPart{
 					InlineData: &GeminiInlineData{
 						MimeType: mimeType,

controller/relay-text.go

@@ -262,7 +262,9 @@ func relayTextHelper(c *gin.Context, relayMode int) *OpenAIErrorWithStatusCode {
 		requestBody = c.Request.Body
 	}
 
-	common.LogInfo(c.Request.Context(), fmt.Sprintf("convert to apitype %d", apiType))
+	common.LogInfo(c.Request.Context(), fmt.Sprintf(
+		"convert to apitype %d, channel_type %d, channel_id %d",
+		apiType, channelType, channelId))
 	switch apiType {
 	case APITypeClaude:
 		claudeRequest := requestOpenAI2Claude(textRequest)
@@ -300,6 +302,7 @@ func relayTextHelper(c *gin.Context, relayMode int) *OpenAIErrorWithStatusCode {
 			return errorWrapper(err, "marshal_text_request_failed", http.StatusInternalServerError)
 		}
 		requestBody = bytes.NewBuffer(jsonStr)
+		fmt.Println(">> convert request body to gemini: " + string(jsonStr)) // FIXME
 	// case APITypeZhipu:
 	// 	zhipuRequest := requestOpenAI2Zhipu(textRequest)
 	// 	jsonStr, err := json.Marshal(zhipuRequest)
@@ -431,7 +434,7 @@ func relayTextHelper(c *gin.Context, relayMode int) *OpenAIErrorWithStatusCode {
 			}
 
 			{ // more error info
-				if reqdata, err := json.Marshal(textRequest); err != nil {
+				if reqdata, err := json.Marshal(req.Body); err != nil {
 					fmt.Printf("[ERROR] marshal relay text error: %s\n", err.Error())
 				} else {
 					if respdata, err := io.ReadAll(resp.Body); err != nil {