Adding ability to fetch posts around a specifc post

3 files changed, 205 insertions, 0 deletions

diff --git a/store/sql_post_store.go b/store/sql_post_store.go
index f514d23ed..8b1cae3dd 100644
--- a/store/sql_post_store.go
+++ b/store/sql_post_store.go
@@ -332,6 +332,104 @@ func (s SqlPostStore) GetPostsSince(channelId string, time int64) StoreChannel {
 	return storeChannel
 }
 
+func (s SqlPostStore) GetPostsBefore(channelId string, postId string, numPosts int, offset int) StoreChannel {
+	return s.getPostsAround(channelId, postId, numPosts, offset, true)
+}
+
+func (s SqlPostStore) GetPostsAfter(channelId string, postId string, numPosts int, offset int) StoreChannel {
+	return s.getPostsAround(channelId, postId, numPosts, offset, false)
+}
+
+func (s SqlPostStore) getPostsAround(channelId string, postId string, numPosts int, offset int, before bool) StoreChannel {
+	storeChannel := make(StoreChannel)
+
+	go func() {
+		result := StoreResult{}
+
+		var direction string
+		var sort string
+		if before {
+			direction = "<"
+			sort = "DESC"
+		} else {
+			direction = ">"
+			sort = "ASC"
+		}
+
+		var posts []*model.Post
+		var parents []*model.Post
+		_, err1 := s.GetReplica().Select(&posts,
+			`(SELECT
+			    *
+			FROM
+			    Posts
+			WHERE
+				(CreateAt `+direction+` (SELECT CreateAt FROM Posts WHERE Id = :PostId)
+			        AND ChannelId = :ChannelId
+					AND DeleteAt = 0)
+			ORDER BY CreateAt `+sort+`
+			LIMIT :NumPosts
+			OFFSET :Offset)`,
+			map[string]interface{}{"ChannelId": channelId, "PostId": postId, "NumPosts": numPosts, "Offset": offset})
+		_, err2 := s.GetReplica().Select(&parents,
+			`(SELECT
+			    *
+			FROM
+			    Posts
+			WHERE
+			    Id
+			IN
+			    (SELECT * FROM (SELECT
+			        RootId
+			    FROM
+			        Posts
+			    WHERE
+					(CreateAt `+direction+` (SELECT CreateAt FROM Posts WHERE Id = :PostId)
+						AND ChannelId = :ChannelId
+						AND DeleteAt = 0)
+					ORDER BY CreateAt `+sort+`
+					LIMIT :NumPosts
+					OFFSET :Offset)
+			    temp_tab))
+			ORDER BY CreateAt DESC`,
+			map[string]interface{}{"ChannelId": channelId, "PostId": postId, "NumPosts": numPosts, "Offset": offset})
+
+		if err1 != nil {
+			result.Err = model.NewAppError("SqlPostStore.GetPostContext", "We couldn't get the posts for the channel", "channelId="+channelId+err1.Error())
+		} else if err2 != nil {
+			result.Err = model.NewAppError("SqlPostStore.GetPostContext", "We couldn't get the parent posts for the channel", "channelId="+channelId+err2.Error())
+		} else {
+
+			list := &model.PostList{Order: make([]string, 0, len(posts))}
+
+			// We need to flip the order if we selected backwards
+			if before {
+				for _, p := range posts {
+					list.AddPost(p)
+					list.AddOrder(p.Id)
+				}
+			} else {
+				l := len(posts)
+				for i := range posts {
+					list.AddPost(posts[l-i-1])
+					list.AddOrder(posts[l-i-1].Id)
+				}
+			}
+
+			for _, p := range parents {
+				list.AddPost(p)
+			}
+
+			result.Data = list
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
+
 func (s SqlPostStore) getRootPosts(channelId string, offset int, limit int) StoreChannel {
 	storeChannel := make(StoreChannel)
 
diff --git a/store/sql_post_store_test.go b/store/sql_post_store_test.go
index 872423c5a..c2348b04c 100644
--- a/store/sql_post_store_test.go
+++ b/store/sql_post_store_test.go
@@ -383,6 +383,111 @@ func TestPostStoreGetPostsWtihDetails(t *testing.T) {
 	}
 }
 
+func TestPostStoreGetPostsBeforeAfter(t *testing.T) {
+	Setup()
+	o0 := &model.Post{}
+	o0.ChannelId = model.NewId()
+	o0.UserId = model.NewId()
+	o0.Message = "a" + model.NewId() + "b"
+	o0 = (<-store.Post().Save(o0)).Data.(*model.Post)
+	time.Sleep(2 * time.Millisecond)
+
+	o1 := &model.Post{}
+	o1.ChannelId = model.NewId()
+	o1.UserId = model.NewId()
+	o1.Message = "a" + model.NewId() + "b"
+	o1 = (<-store.Post().Save(o1)).Data.(*model.Post)
+	time.Sleep(2 * time.Millisecond)
+
+	o2 := &model.Post{}
+	o2.ChannelId = o1.ChannelId
+	o2.UserId = model.NewId()
+	o2.Message = "a" + model.NewId() + "b"
+	o2.ParentId = o1.Id
+	o2.RootId = o1.Id
+	o2 = (<-store.Post().Save(o2)).Data.(*model.Post)
+	time.Sleep(2 * time.Millisecond)
+
+	o2a := &model.Post{}
+	o2a.ChannelId = o1.ChannelId
+	o2a.UserId = model.NewId()
+	o2a.Message = "a" + model.NewId() + "b"
+	o2a.ParentId = o1.Id
+	o2a.RootId = o1.Id
+	o2a = (<-store.Post().Save(o2a)).Data.(*model.Post)
+	time.Sleep(2 * time.Millisecond)
+
+	o3 := &model.Post{}
+	o3.ChannelId = o1.ChannelId
+	o3.UserId = model.NewId()
+	o3.Message = "a" + model.NewId() + "b"
+	o3.ParentId = o1.Id
+	o3.RootId = o1.Id
+	o3 = (<-store.Post().Save(o3)).Data.(*model.Post)
+	time.Sleep(2 * time.Millisecond)
+
+	o4 := &model.Post{}
+	o4.ChannelId = o1.ChannelId
+	o4.UserId = model.NewId()
+	o4.Message = "a" + model.NewId() + "b"
+	o4 = (<-store.Post().Save(o4)).Data.(*model.Post)
+	time.Sleep(2 * time.Millisecond)
+
+	o5 := &model.Post{}
+	o5.ChannelId = o1.ChannelId
+	o5.UserId = model.NewId()
+	o5.Message = "a" + model.NewId() + "b"
+	o5.ParentId = o4.Id
+	o5.RootId = o4.Id
+	o5 = (<-store.Post().Save(o5)).Data.(*model.Post)
+
+	r1 := (<-store.Post().GetPostsBefore(o1.ChannelId, o1.Id, 4, 0)).Data.(*model.PostList)
+
+	if len(r1.Posts) != 0 {
+		t.Fatal("Wrong size")
+	}
+
+	r2 := (<-store.Post().GetPostsAfter(o1.ChannelId, o1.Id, 4, 0)).Data.(*model.PostList)
+
+	if r2.Order[0] != o4.Id {
+		t.Fatal("invalid order")
+	}
+
+	if r2.Order[1] != o3.Id {
+		t.Fatal("invalid order")
+	}
+
+	if r2.Order[2] != o2a.Id {
+		t.Fatal("invalid order")
+	}
+
+	if r2.Order[3] != o2.Id {
+		t.Fatal("invalid order")
+	}
+
+	if len(r2.Posts) != 5 {
+		t.Fatal("wrong size")
+	}
+
+	r3 := (<-store.Post().GetPostsBefore(o3.ChannelId, o3.Id, 2, 0)).Data.(*model.PostList)
+
+	if r3.Order[0] != o2a.Id {
+		t.Fatal("invalid order")
+	}
+
+	if r3.Order[1] != o2.Id {
+		t.Fatal("invalid order")
+	}
+
+	if len(r3.Posts) != 3 {
+		t.Fatal("wrong size")
+	}
+
+	if r3.Posts[o1.Id].Message != o1.Message {
+		t.Fatal("Missing parent")
+	}
+}
+
 func TestPostStoreGetPostsSince(t *testing.T) {
 	Setup()
 	o0 := &model.Post{}
diff --git a/store/store.go b/store/store.go
index 53a6e053b..ce4d90883 100644
--- a/store/store.go
+++ b/store/store.go
@@ -86,6 +86,8 @@ type PostStore interface {
 	Get(id string) StoreChannel
 	Delete(postId string, time int64) StoreChannel
 	GetPosts(channelId string, offset int, limit int) StoreChannel
+	GetPostsBefore(channelId string, postId string, numPosts int, offset int) StoreChannel
+	GetPostsAfter(channelId string, postId string, numPosts int, offset int) StoreChannel
 	GetPostsSince(channelId string, time int64) StoreChannel
 	GetEtag(channelId string) StoreChannel
 	Search(teamId string, userId string, params *model.SearchParams) StoreChannel