feat: support function call for ali (close #1242)

relay/channel/openai/main.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"github.com/gin-gonic/gin"
 	"github.com/songquanpeng/one-api/common"
+	"github.com/songquanpeng/one-api/common/conv"
 	"github.com/songquanpeng/one-api/common/logger"
 	"github.com/songquanpeng/one-api/relay/constant"
 	"github.com/songquanpeng/one-api/relay/model"
@@ -53,7 +54,7 @@ func StreamHandler(c *gin.Context, resp *http.Response, relayMode int) (*model.E
 						continue // just ignore the error
 					}
 					for _, choice := range streamResponse.Choices {
-						responseText += choice.Delta.Content
+						responseText += conv.AsString(choice.Delta.Content)
 					}
 					if streamResponse.Usage != nil {
 						usage = streamResponse.Usage

relay/channel/openai/model.go

@@ -118,12 +118,9 @@ type ImageResponse struct {
 }
 
 type ChatCompletionsStreamResponseChoice struct {
-	Index int `json:"index"`
-	Delta struct {
-		Content string `json:"content"`
-		Role    string `json:"role,omitempty"`
-	} `json:"delta"`
-	FinishReason *string `json:"finish_reason,omitempty"`
+	Index        int           `json:"index"`
+	Delta        model.Message `json:"delta"`
+	FinishReason *string       `json:"finish_reason,omitempty"`
 }
 
 type ChatCompletionsStreamResponse struct {