feat(wip): leaderboard pagination (resolve #417) [ci-skip]

models/shared.go

@@ -34,6 +34,11 @@ type KeyedInterval struct {
 	Key *IntervalKey
 }
 
+type PageParams struct {
+	Page     int `json:"page"`
+	PageSize int `json:"page_size"`
+}
+
 // CustomTime is a wrapper type around time.Time, mainly used for the purpose of transparently unmarshalling Python timestamps in the format <sec>.<nsec> (e.g. 1619335137.3324468)
 type CustomTime time.Time
 
@@ -99,3 +104,17 @@ func (j CustomTime) T() time.Time {
 func (j CustomTime) Valid() bool {
 	return j.T().Unix() >= 0
 }
+
+func (p *PageParams) Limit() int {
+	if p.PageSize < 0 {
+		return 0
+	}
+	return p.PageSize
+}
+
+func (p *PageParams) Offset() int {
+	if p.PageSize <= 0 {
+		return 0
+	}
+	return (p.Page - 1) * p.PageSize
+}

models/view/leaderboard.go

@@ -14,6 +14,7 @@ type LeaderboardViewModel struct {
 	TopKeys       []string
 	UserLanguages map[string][]string
 	ApiKey        string
+	PageParams    *models.PageParams
 	Success       string
 	Error         string
 }

repositories/leaderboard.go

@@ -33,13 +33,17 @@ func (r *LeaderboardRepository) CountAllByUser(userId string) (int64, error) {
 	return count, err
 }
 
-func (r *LeaderboardRepository) GetAllAggregatedByInterval(key *models.IntervalKey, by *uint8) ([]*models.LeaderboardItem, error) {
+func (r *LeaderboardRepository) GetAllAggregatedByInterval(key *models.IntervalKey, by *uint8, limit, skip int) ([]*models.LeaderboardItem, error) {
 	// TODO: distinct by (user, key) to filter out potential duplicates ?
 	var items []*models.LeaderboardItem
-	q := r.db.
+	subq := r.db.
+		Table("leaderboard_items").
 		Select("*, rank() over (partition by \"key\" order by total desc) as \"rank\"").
 		Where("\"interval\" in ?", *key)
-	q = utils.WhereNullable(q, "\"by\"", by)
+	subq = utils.WhereNullable(subq, "\"by\"", by)
+
+	q := r.db.Table("(?) as ranked", subq)
+	q = r.withPaging(q, limit, skip)
 
 	if err := q.Find(&items).Error; err != nil {
 		return nil, err
@@ -47,13 +51,17 @@ func (r *LeaderboardRepository) GetAllAggregatedByInterval(key *models.IntervalK
 	return items, nil
 }
 
-func (r *LeaderboardRepository) GetAggregatedByUserAndInterval(userId string, key *models.IntervalKey, by *uint8) ([]*models.LeaderboardItem, error) {
+func (r *LeaderboardRepository) GetAggregatedByUserAndInterval(userId string, key *models.IntervalKey, by *uint8, limit, skip int) ([]*models.LeaderboardItem, error) {
 	var items []*models.LeaderboardItem
-	q := r.db.
+	subq := r.db.
+		Table("leaderboard_items").
 		Select("*, rank() over (partition by \"key\" order by total desc) as \"rank\"").
 		Where("user_id = ?", userId).
 		Where("\"interval\" in ?", *key)
-	q = utils.WhereNullable(q, "\"by\"", by)
+	subq = utils.WhereNullable(subq, "\"by\"", by)
+
+	q := r.db.Table("(?) as ranked", subq)
+	q = r.withPaging(q, limit, skip)
 
 	if err := q.Find(&items).Error; err != nil {
 		return nil, err
@@ -79,3 +87,13 @@ func (r *LeaderboardRepository) DeleteByUserAndInterval(userId string, key *mode
 	}
 	return nil
 }
+
+func (r *LeaderboardRepository) withPaging(q *gorm.DB, limit, skip int) *gorm.DB {
+	if limit > 0 {
+		q = q.Where("\"rank\" <= ?", skip+limit)
+	}
+	if skip > 0 {
+		q = q.Where("\"rank\" > ?", skip)
+	}
+	return q
+}

repositories/repositories.go

@@ -92,6 +92,6 @@ type ILeaderboardRepository interface {
 	CountAllByUser(string) (int64, error)
 	DeleteByUser(string) error
 	DeleteByUserAndInterval(string, *models.IntervalKey) error
-	GetAllAggregatedByInterval(*models.IntervalKey, *uint8) ([]*models.LeaderboardItem, error)
+	GetAllAggregatedByInterval(*models.IntervalKey, *uint8, int, int) ([]*models.LeaderboardItem, error)
-	GetAggregatedByUserAndInterval(string, *models.IntervalKey, *uint8) ([]*models.LeaderboardItem, error)
+	GetAggregatedByUserAndInterval(string, *models.IntervalKey, *uint8, int, int) ([]*models.LeaderboardItem, error)
 }

routes/leaderboard.go

@@ -10,6 +10,7 @@ import (
 	"github.com/muety/wakapi/models"
 	"github.com/muety/wakapi/models/view"
 	"github.com/muety/wakapi/services"
+	"github.com/muety/wakapi/utils"
 	"net/http"
 	"strings"
 )
@@ -56,6 +57,7 @@ func (h *LeaderboardHandler) buildViewModel(r *http.Request) *view.LeaderboardVi
 	user := middlewares.GetPrincipal(r)
 	byParam := strings.ToLower(r.URL.Query().Get("by"))
 	keyParam := strings.ToLower(r.URL.Query().Get("key"))
+	pageParams := utils.ParsePageParams(r)
 
 	var err error
 	var leaderboard models.Leaderboard
@@ -63,14 +65,14 @@ func (h *LeaderboardHandler) buildViewModel(r *http.Request) *view.LeaderboardVi
 	var topKeys []string
 
 	if byParam == "" {
-		leaderboard, err = h.leaderboardService.GetByInterval(models.IntervalPast7Days, true)
+		leaderboard, err = h.leaderboardService.GetByInterval(models.IntervalPast7Days, pageParams, true)
 		if err != nil {
 			conf.Log().Request(r).Error("error while fetching general leaderboard items - %v", err)
 			return &view.LeaderboardViewModel{Error: criticalError}
 		}
 	} else {
 		if by, ok := allowedAggregations[byParam]; ok {
-			leaderboard, err = h.leaderboardService.GetAggregatedByInterval(models.IntervalPast7Days, &by, true)
+			leaderboard, err = h.leaderboardService.GetAggregatedByInterval(models.IntervalPast7Days, &by, pageParams, true)
 			if err != nil {
 				conf.Log().Request(r).Error("error while fetching general leaderboard items - %v", err)
 				return &view.LeaderboardViewModel{Error: criticalError}
@@ -110,6 +112,7 @@ func (h *LeaderboardHandler) buildViewModel(r *http.Request) *view.LeaderboardVi
 		UserLanguages: userLanguages,
 		TopKeys:       topKeys,
 		ApiKey:        apiKey,
+		PageParams:    pageParams,
 		Success:       r.URL.Query().Get("success"),
 		Error:         r.URL.Query().Get("error"),
 	}

services/leaderboard.go

@@ -10,6 +10,7 @@ import (
 	"github.com/muety/wakapi/utils"
 	"github.com/patrickmn/go-cache"
 	"reflect"
+	"strconv"
 	"strings"
 	"time"
 )
@@ -125,18 +126,18 @@ func (srv *LeaderboardService) ExistsAnyByUser(userId string) (bool, error) {
 	return count > 0, err
 }
 
-func (srv *LeaderboardService) GetByInterval(interval *models.IntervalKey, resolveUsers bool) (models.Leaderboard, error) {
+func (srv *LeaderboardService) GetByInterval(interval *models.IntervalKey, pageParams *models.PageParams, resolveUsers bool) (models.Leaderboard, error) {
-	return srv.GetAggregatedByInterval(interval, nil, resolveUsers)
+	return srv.GetAggregatedByInterval(interval, nil, pageParams, resolveUsers)
 }
 
-func (srv *LeaderboardService) GetAggregatedByInterval(interval *models.IntervalKey, by *uint8, resolveUsers bool) (models.Leaderboard, error) {
+func (srv *LeaderboardService) GetAggregatedByInterval(interval *models.IntervalKey, by *uint8, pageParams *models.PageParams, resolveUsers bool) (models.Leaderboard, error) {
 	// check cache
-	cacheKey := srv.getHash(interval, by)
+	cacheKey := srv.getHash(interval, by, pageParams)
 	if cacheResult, ok := srv.cache.Get(cacheKey); ok {
 		return cacheResult.([]*models.LeaderboardItem), nil
 	}
 
-	items, err := srv.repository.GetAllAggregatedByInterval(interval, by)
+	items, err := srv.repository.GetAllAggregatedByInterval(interval, by, pageParams.Limit(), pageParams.Offset())
 	if err != nil {
 		return nil, err
 	}
@@ -208,10 +209,11 @@ func (srv *LeaderboardService) GenerateAggregatedByUser(user *models.User, inter
 	return items, nil
 }
 
-func (srv *LeaderboardService) getHash(interval *models.IntervalKey, by *uint8) string {
+func (srv *LeaderboardService) getHash(interval *models.IntervalKey, by *uint8, pageParams *models.PageParams) string {
 	k := strings.Join(*interval, "__")
 	if by != nil && !reflect.ValueOf(by).IsNil() {
 		k += "__" + models.GetEntityColumn(*by)
 	}
+	k = "__" + strconv.Itoa(pageParams.Page) + "__" + strconv.Itoa(pageParams.PageSize)
 	return k
 }

services/services.go

@@ -101,8 +101,8 @@ type ILeaderboardService interface {
 	ScheduleDefault()
 	Run([]*models.User, *models.IntervalKey, []uint8) error
 	ExistsAnyByUser(string) (bool, error)
-	GetByInterval(*models.IntervalKey, bool) (models.Leaderboard, error)
+	GetByInterval(*models.IntervalKey, *models.PageParams, bool) (models.Leaderboard, error)
-	GetAggregatedByInterval(*models.IntervalKey, *uint8, bool) (models.Leaderboard, error)
+	GetAggregatedByInterval(*models.IntervalKey, *uint8, *models.PageParams, bool) (models.Leaderboard, error)
 	GenerateByUser(*models.User, *models.IntervalKey) (*models.LeaderboardItem, error)
 	GenerateAggregatedByUser(*models.User, *models.IntervalKey, uint8) ([]*models.LeaderboardItem, error)
 }

utils/db.go

@@ -39,3 +39,13 @@ func WhereNullable(query *gorm.DB, col string, val any) *gorm.DB {
 	}
 	return query.Where(fmt.Sprintf("%s = ?", col), val)
 }
+
+func WithPaging(query *gorm.DB, limit, skip int) *gorm.DB {
+	if limit >= 0 {
+		query = query.Limit(limit)
+	}
+	if skip >= 0 {
+		query = query.Offset(skip)
+	}
+	return query
+}

utils/http.go

@@ -3,6 +3,7 @@ package utils
 import (
 	"encoding/json"
 	"github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/models"
 	"net/http"
 	"regexp"
 	"strconv"
@@ -42,3 +43,16 @@ func IsNoCache(r *http.Request, cacheTtl time.Duration) bool {
 	}
 	return false
 }
+
+func ParsePageParams(r *http.Request) *models.PageParams {
+	pageParams := &models.PageParams{}
+	page := r.URL.Query().Get("page")
+	pageSize := r.URL.Query().Get("page_size")
+	if p, err := strconv.Atoi(page); err == nil {
+		pageParams.Page = p
+	}
+	if p, err := strconv.Atoi(pageSize); err == nil && pageParams.Page > 0 {
+		pageParams.PageSize = p
+	}
+	return pageParams
+}