MM-11781: Basic Data Export Command Line. (#9296)

* MM-11781: Basic Data Export Command Line.

* ChannelStore new unit tests.

* TeamStore new unit tests.

* Unit test for new UserStore function.

* Unit tests for post store new methods.

* Review fixes.

* Fix duplicate command name.

store/sqlstore/post_store.go

@@ -1308,3 +1308,68 @@ func (s *SqlPostStore) GetMaxPostSize() store.StoreChannel {
 		result.Data = s.maxPostSizeCached
 	})
 }
+
+func (s *SqlPostStore) GetParentsForExportAfter(limit int, afterId string) store.StoreChannel {
+	return store.Do(func(result *store.StoreResult) {
+		var posts []*model.PostForExport
+		_, err1 := s.GetSearchReplica().Select(&posts, `
+                SELECT
+                    p1.*,
+                    Users.Username as Username,
+                    Teams.Name as TeamName,
+                    Channels.Name as ChannelName
+                FROM
+                    Posts p1
+                INNER JOIN
+                    Channels ON p1.ChannelId = Channels.Id
+                INNER JOIN
+                    Teams ON Channels.TeamId = Teams.Id
+                INNER JOIN
+                    Users ON p1.UserId = Users.Id
+                WHERE
+                    p1.Id > :AfterId
+                    AND p1.ParentId = ''
+                    AND p1.DeleteAt = 0
+					AND Channels.DeleteAt = 0
+					AND Teams.DeleteAt = 0
+					AND Users.DeleteAt = 0
+                ORDER BY
+                    p1.Id
+                LIMIT
+                    :Limit`,
+			map[string]interface{}{"Limit": limit, "AfterId": afterId})
+
+		if err1 != nil {
+			result.Err = model.NewAppError("SqlPostStore.GetAllAfterForExport", "store.sql_post.get_posts.app_error", nil, err1.Error(), http.StatusInternalServerError)
+		} else {
+			result.Data = posts
+		}
+	})
+}
+
+func (s *SqlPostStore) GetRepliesForExport(parentId string) store.StoreChannel {
+	return store.Do(func(result *store.StoreResult) {
+		var posts []*model.ReplyForExport
+		_, err1 := s.GetSearchReplica().Select(&posts, `
+                SELECT
+                    Posts.*,
+                    Users.Username as Username
+                FROM
+                    Posts
+                INNER JOIN
+                    Users ON Posts.UserId = Users.Id
+                WHERE
+                    Posts.ParentId = :ParentId
+                    AND Posts.DeleteAt = 0
+					AND Users.DeleteAt = 0
+                ORDER BY
+                    Posts.Id`,
+			map[string]interface{}{"ParentId": parentId})
+
+		if err1 != nil {
+			result.Err = model.NewAppError("SqlPostStore.GetAllAfterForExport", "store.sql_post.get_posts.app_error", nil, err1.Error(), http.StatusInternalServerError)
+		} else {
+			result.Data = posts
+		}
+	})
+}