优化通用平台API请求逻辑

- 为startDate和endDate提供默认值，提高代码的健壮性- 增加返回结果大小，从100条增加到500条，以满足更多数据需求

services/index_data/gn_platform.go

@@ -82,12 +82,18 @@ func GetIndexAndDataFromGn(indexCode, startDate, endDate string) (list []gn.Inde
 
 	var dataDate string
 	dateList := make([]string, 0)
-	if startDate != `` {
-		dateList = append(dateList, startDate)
+
+	// 没有指定开始日期的话，那就默认当前日期
+	if startDate == `` {
+		startDate = `1901-01-01`
 	}
-	if endDate != `` {
-		dateList = append(dateList, endDate)
+	dateList = append(dateList, startDate)
+
+	// 没有的话，就默认往后找一个月
+	if endDate == `` {
+		endDate = time.Now().AddDate(0, 1, 0).Format(utils.FormatDate)
 	}
+	dateList = append(dateList, endDate)
 	if len(dateList) > 0 {
 		dataDate = strings.Join(dateList, ",")
 	}
@@ -95,7 +101,7 @@ func GetIndexAndDataFromGn(indexCode, startDate, endDate string) (list []gn.Inde
 	req := IndexValueReq{
 		IndexId:  indexCode,
 		DataDate: dataDate,
-		Size:     100,
+		Size:     500,
 		PageNo:   1,
 	}