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app/service/bbq/topic/internal/dao/common.go

@@ -0,0 +1,75 @@
+package dao
+
+import (
+	"context"
+	"encoding/json"
+	"go-common/app/service/bbq/topic/internal/model"
+	"go-common/library/cache/redis"
+	"go-common/library/ecode"
+	"go-common/library/log"
+	"go-common/library/xstr"
+)
+
+/*各种情况下，是否需要查询db，前三列表示情景条件
+NEXT	offset		rank		是否需要db操作
+1									1
+0		 1			  0				0
+0		n>1			  0				1
+0		 0			 n>0			0
+*/
+func parseCursor(ctx context.Context, cursorPrev, cursorNext string) (cursor model.CursorValue, directionNext bool, err error) {
+	// 判断是向前还是向后查询
+	directionNext = true
+	cursorStr := cursorNext
+	if len(cursorNext) == 0 && len(cursorPrev) > 0 {
+		directionNext = false
+		cursorStr = cursorPrev
+	}
+	// 解析cursor中的cursor_id
+	if len(cursorStr) != 0 {
+		var cursorData = []byte(cursorStr)
+		err = json.Unmarshal(cursorData, &cursor)
+		if err != nil {
+			err = ecode.ReqParamErr
+			return
+		}
+	}
+
+	// 最后做一次校验，保证cursor的值是对的
+	if (cursor.StickRank > 0 && cursor.Offset > 0) || (!directionNext && cursor.Offset == 0 && cursor.StickRank == 0) {
+		err = ecode.TopicReqParamErr
+		log.Errorw(ctx, "log", "cursor value error", "prev", cursorPrev, "next", cursorNext)
+		return
+	}
+
+	return
+}
+
+func (d *Dao) getRedisList(ctx context.Context, key string) (list []int64, err error) {
+	conn := d.redis.Get(ctx)
+	defer conn.Close()
+	str, err := redis.String(conn.Do("GET", key))
+	if err == redis.ErrNil {
+		err = nil
+		return
+	}
+	if err != nil {
+		log.Errorw(ctx, "log", "get redis list fail", "key", key)
+		return
+	}
+	list, err = xstr.SplitInts(str)
+	if err != nil {
+		log.Errorw(ctx, "log", "split list_str fail", "key", key, "str", str)
+		return
+	}
+	return
+}
+func (d *Dao) setRedisList(ctx context.Context, key string, list []int64) (err error) {
+	conn := d.redis.Get(ctx)
+	defer conn.Close()
+	if _, err = conn.Do("SET", key, xstr.JoinInts(list)); err != nil {
+		log.Errorw(ctx, "log", "set redis list fail", "key", key, "list", list)
+		return
+	}
+	return
+}