[feature] Implement markers API (#1989)

* Implement markers API

Fixes #1856

* Correct import grouping in markers files

* Regenerate Swagger for markers API

* Shorten names for readability

* Cache markers for 6 hours

* Update DB ref

* Update envparsing.sh

docs/api/swagger.yaml

@@ -4988,6 +4988,72 @@ paths:
             summary: Add one or more accounts to the given list.
             tags:
                 - lists
+    /api/v1/markers:
+        get:
+            description: Get timeline markers by name
+            operationId: markersGet
+            parameters:
+                - description: Timelines to retrieve.
+                  in: query
+                  items:
+                    enum:
+                        - home
+                        - notifications
+                    type: string
+                  name: timeline
+                  type: array
+            produces:
+                - application/json
+            responses:
+                "200":
+                    description: Requested markers
+                    schema:
+                        $ref: '#/definitions/markers'
+                "400":
+                    description: bad request
+                "401":
+                    description: unauthorized
+                "500":
+                    description: internal server error
+            security:
+                - OAuth2 Bearer:
+                    - read:statuses
+            tags:
+                - markers
+        post:
+            consumes:
+                - multipart/form-data
+            description: Update timeline markers by name
+            operationId: markersPost
+            parameters:
+                - description: Last status ID read on the home timeline.
+                  in: formData
+                  name: home[last_read_id]
+                  type: string
+                - description: Last notification ID read on the notifications timeline.
+                  in: formData
+                  name: notifications[last_read_id]
+                  type: string
+            produces:
+                - application/json
+            responses:
+                "200":
+                    description: Requested markers
+                    schema:
+                        $ref: '#/definitions/markers'
+                "400":
+                    description: bad request
+                "401":
+                    description: unauthorized
+                "409":
+                    description: conflict (when two clients try to update the same timeline at the same time)
+                "500":
+                    description: internal server error
+            security:
+                - OAuth2 Bearer:
+                    - write:statuses
+            tags:
+                - markers
     /api/v1/media/{id}:
         get:
             operationId: mediaGet

internal/api/client.go

@@ -33,6 +33,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/followrequests"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/instance"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/lists"
+	"github.com/superseriousbusiness/gotosocial/internal/api/client/markers"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/media"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/notifications"
 	"github.com/superseriousbusiness/gotosocial/internal/api/client/preferences"
@@ -64,6 +65,7 @@ type Client struct {
 	followRequests *followrequests.Module // api/v1/follow_requests
 	instance       *instance.Module       // api/v1/instance
 	lists          *lists.Module          // api/v1/lists
+	markers        *markers.Module        // api/v1/markers
 	media          *media.Module          // api/v1/media, api/v2/media
 	notifications  *notifications.Module  // api/v1/notifications
 	preferences    *preferences.Module    // api/v1/preferences
@@ -104,6 +106,7 @@ func (c *Client) Route(r router.Router, m ...gin.HandlerFunc) {
 	c.followRequests.Route(h)
 	c.instance.Route(h)
 	c.lists.Route(h)
+	c.markers.Route(h)
 	c.media.Route(h)
 	c.notifications.Route(h)
 	c.preferences.Route(h)
@@ -132,6 +135,7 @@ func NewClient(db db.DB, p *processing.Processor) *Client {
 		followRequests: followrequests.New(p),
 		instance:       instance.New(p),
 		lists:          lists.New(p),
+		markers:        markers.New(p),
 		media:          media.New(p),
 		notifications:  notifications.New(p),
 		preferences:    preferences.New(p),

internal/api/client/markers/markers.go

@@ -0,0 +1,45 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package markers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/processing"
+)
+
+const (
+	// BasePath is the base path for serving the markers API, minus the 'api' prefix
+	BasePath = "/v1/markers"
+)
+
+type Module struct {
+	processor *processing.Processor
+}
+
+func New(processor *processing.Processor) *Module {
+	return &Module{
+		processor: processor,
+	}
+}
+
+func (m *Module) Route(attachHandler func(method string, path string, f ...gin.HandlerFunc) gin.IRoutes) {
+	attachHandler(http.MethodGet, BasePath, m.MarkersGETHandler)
+	attachHandler(http.MethodPost, BasePath, m.MarkersPOSTHandler)
+}

internal/api/client/markers/markersget.go

@@ -0,0 +1,108 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package markers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/validate"
+)
+
+// MarkersGETHandler swagger:operation GET /api/v1/markers markersGet
+//
+// Get timeline markers by name
+//
+//	---
+//	tags:
+//	- markers
+//
+//	produces:
+//	- application/json
+//
+//	parameters:
+//	-
+//		name: timeline
+//		type: array
+//		items:
+//			type: string
+//			enum:
+//				- home
+//				- notifications
+//		description: Timelines to retrieve.
+//		in: query
+//
+//	security:
+//	- OAuth2 Bearer:
+//		- read:statuses
+//
+//	responses:
+//		'200':
+//			description: Requested markers
+//			schema:
+//				"$ref": "#/definitions/markers"
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'500':
+//			description: internal server error
+func (m *Module) MarkersGETHandler(c *gin.Context) {
+	authed, err := oauth.Authed(c, true, true, true, true)
+	if err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	names, errWithCode := parseMarkerNames(c.QueryArray("timeline[]"))
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+	}
+
+	marker, errWithCode := m.processor.Markers().Get(c.Request.Context(), authed.Account, names)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	c.JSON(http.StatusOK, marker)
+}
+
+// parseMarkerNames turns a list of strings into a set of valid marker timeline names, or returns an error.
+func parseMarkerNames(nameStrings []string) ([]apimodel.MarkerName, gtserror.WithCode) {
+	nameSet := make(map[apimodel.MarkerName]struct{}, apimodel.MarkerNameNumValues)
+	for _, timelineString := range nameStrings {
+		if err := validate.MarkerName(timelineString); err != nil {
+			return nil, gtserror.NewErrorBadRequest(err, err.Error())
+		}
+		nameSet[apimodel.MarkerName(timelineString)] = struct{}{}
+	}
+
+	i := 0
+	names := make([]apimodel.MarkerName, len(nameSet))
+	for name := range nameSet {
+		names[i] = name
+		i++
+	}
+
+	return names, nil
+}

internal/api/client/markers/markerspost.go

@@ -0,0 +1,110 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package markers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+)
+
+// MarkersPOSTHandler swagger:operation POST /api/v1/markers markersPost
+//
+// Update timeline markers by name
+//
+//	---
+//	tags:
+//	- markers
+//
+//	consumes:
+//	- multipart/form-data
+//
+//	produces:
+//	- application/json
+//
+//	parameters:
+//	-
+//		name: home[last_read_id]
+//		type: string
+//		description: Last status ID read on the home timeline.
+//		in: formData
+//	-
+//		name: notifications[last_read_id]
+//		type: string
+//		description: Last notification ID read on the notifications timeline.
+//		in: formData
+//
+//	security:
+//	- OAuth2 Bearer:
+//		- write:statuses
+//
+//	responses:
+//		'200':
+//			description: Requested markers
+//			schema:
+//				"$ref": "#/definitions/markers"
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'409':
+//			description: conflict (when two clients try to update the same timeline at the same time)
+//		'500':
+//			description: internal server error
+func (m *Module) MarkersPOSTHandler(c *gin.Context) {
+	authed, err := oauth.Authed(c, true, true, true, true)
+	if err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	form := &apimodel.MarkerPostRequest{}
+	if err := c.ShouldBind(form); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	markers := make([]*gtsmodel.Marker, 0, apimodel.MarkerNameNumValues)
+	if homeLastReadID := form.HomeLastReadID(); homeLastReadID != "" {
+		markers = append(markers, &gtsmodel.Marker{
+			AccountID:  authed.Account.ID,
+			Name:       gtsmodel.MarkerNameHome,
+			LastReadID: homeLastReadID,
+		})
+	}
+	if notificationsLastReadID := form.NotificationsLastReadID(); notificationsLastReadID != "" {
+		markers = append(markers, &gtsmodel.Marker{
+			AccountID:  authed.Account.ID,
+			Name:       gtsmodel.MarkerNameNotifications,
+			LastReadID: notificationsLastReadID,
+		})
+	}
+
+	marker, errWithCode := m.processor.Markers().Update(c.Request.Context(), markers)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	c.JSON(http.StatusOK, marker)
+}

internal/api/model/marker.go

@@ -20,9 +20,9 @@ package model
 // Marker represents the last read position within a user's timelines.
 type Marker struct {
 	// Information about the user's position in the home timeline.
-	Home *TimelineMarker `json:"home"`
+	Home *TimelineMarker `json:"home,omitempty"`
 	// Information about the user's position in their notifications.
-	Notifications *TimelineMarker `json:"notifications"`
+	Notifications *TimelineMarker `json:"notifications,omitempty"`
 }
 
 // TimelineMarker contains information about a user's progress through a specific timeline.
@@ -32,5 +32,46 @@ type TimelineMarker struct {
 	// The timestamp of when the marker was set (ISO 8601 Datetime)
 	UpdatedAt string `json:"updated_at"`
 	// Used for locking to prevent write conflicts.
-	Version string `json:"version"`
+	Version int `json:"version"`
+}
+
+// MarkerName is the name of one of the timelines we can store markers for.
+type MarkerName string
+
+const (
+	MarkerNameHome          MarkerName = "home"
+	MarkerNameNotifications MarkerName = "notifications"
+	MarkerNameNumValues                = 2
+)
+
+// MarkerPostRequest models a request to update one or more markers.
+// This has two sets of fields to support a goofy nested map structure in both form data and JSON bodies.
+//
+// swagger:ignore
+type MarkerPostRequest struct {
+	Home                        *MarkerPostRequestMarker `json:"home"`
+	FormHomeLastReadID          string                   `form:"home[last_read_id]"`
+	Notifications               *MarkerPostRequestMarker `json:"notifications"`
+	FormNotificationsLastReadID string                   `form:"notifications[last_read_id]"`
+}
+
+type MarkerPostRequestMarker struct {
+	// The ID of the most recently viewed entity.
+	LastReadID string `json:"last_read_id"`
+}
+
+// HomeLastReadID should be used instead of Home or FormHomeLastReadID.
+func (r *MarkerPostRequest) HomeLastReadID() string {
+	if r.Home != nil {
+		return r.Home.LastReadID
+	}
+	return r.FormHomeLastReadID
+}
+
+// NotificationsLastReadID should be used instead of Notifications or FormNotificationsLastReadID.
+func (r *MarkerPostRequest) NotificationsLastReadID() string {
+	if r.Notifications != nil {
+		return r.Notifications.LastReadID
+	}
+	return r.FormNotificationsLastReadID
 }

internal/cache/gts.go

@@ -39,6 +39,7 @@ type GTSCaches struct {
 	instance      *result.Cache[*gtsmodel.Instance]
 	list          *result.Cache[*gtsmodel.List]
 	listEntry     *result.Cache[*gtsmodel.ListEntry]
+	marker        *result.Cache[*gtsmodel.Marker]
 	media         *result.Cache[*gtsmodel.MediaAttachment]
 	mention       *result.Cache[*gtsmodel.Mention]
 	notification  *result.Cache[*gtsmodel.Notification]
@@ -65,6 +66,7 @@ func (c *GTSCaches) Init() {
 	c.initInstance()
 	c.initList()
 	c.initListEntry()
+	c.initMarker()
 	c.initMedia()
 	c.initMention()
 	c.initNotification()
@@ -88,6 +90,7 @@ func (c *GTSCaches) Start() {
 	tryStart(c.instance, config.GetCacheGTSInstanceSweepFreq())
 	tryStart(c.list, config.GetCacheGTSListSweepFreq())
 	tryStart(c.listEntry, config.GetCacheGTSListEntrySweepFreq())
+	tryStart(c.marker, config.GetCacheGTSMarkerSweepFreq())
 	tryStart(c.media, config.GetCacheGTSMediaSweepFreq())
 	tryStart(c.mention, config.GetCacheGTSMentionSweepFreq())
 	tryStart(c.notification, config.GetCacheGTSNotificationSweepFreq())
@@ -116,6 +119,7 @@ func (c *GTSCaches) Stop() {
 	tryStop(c.instance, config.GetCacheGTSInstanceSweepFreq())
 	tryStop(c.list, config.GetCacheGTSListSweepFreq())
 	tryStop(c.listEntry, config.GetCacheGTSListEntrySweepFreq())
+	tryStop(c.marker, config.GetCacheGTSMarkerSweepFreq())
 	tryStop(c.media, config.GetCacheGTSMediaSweepFreq())
 	tryStop(c.mention, config.GetCacheGTSNotificationSweepFreq())
 	tryStop(c.notification, config.GetCacheGTSNotificationSweepFreq())
@@ -182,6 +186,11 @@ func (c *GTSCaches) ListEntry() *result.Cache[*gtsmodel.ListEntry] {
 	return c.listEntry
 }
 
+// Marker provides access to the gtsmodel Marker database cache.
+func (c *GTSCaches) Marker() *result.Cache[*gtsmodel.Marker] {
+	return c.marker
+}
+
 // Media provides access to the gtsmodel Media database cache.
 func (c *GTSCaches) Media() *result.Cache[*gtsmodel.MediaAttachment] {
 	return c.media
@@ -372,6 +381,18 @@ func (c *GTSCaches) initListEntry() {
 	c.list.IgnoreErrors(ignoreErrors)
 }
 
+func (c *GTSCaches) initMarker() {
+	c.marker = result.New([]result.Lookup{
+		{Name: "AccountID.Name"},
+	}, func(m1 *gtsmodel.Marker) *gtsmodel.Marker {
+		m2 := new(gtsmodel.Marker)
+		*m2 = *m1
+		return m2
+	}, config.GetCacheGTSMarkerMaxSize())
+	c.marker.SetTTL(config.GetCacheGTSMarkerTTL(), true)
+	c.marker.IgnoreErrors(ignoreErrors)
+}
+
 func (c *GTSCaches) initMedia() {
 	c.media = result.New([]result.Lookup{
 		{Name: "ID"},

internal/config/config.go

@@ -226,6 +226,10 @@ type GTSCacheConfiguration struct {
 	ListEntryTTL       time.Duration `name:"list-entry-ttl"`
 	ListEntrySweepFreq time.Duration `name:"list-entry-sweep-freq"`
 
+	MarkerMaxSize   int           `name:"marker-max-size"`
+	MarkerTTL       time.Duration `name:"marker-ttl"`
+	MarkerSweepFreq time.Duration `name:"marker-sweep-freq"`
+
 	MediaMaxSize   int           `name:"media-max-size"`
 	MediaTTL       time.Duration `name:"media-ttl"`
 	MediaSweepFreq time.Duration `name:"media-sweep-freq"`

internal/config/defaults.go

@@ -171,6 +171,10 @@ var Defaults = Configuration{
 			ListEntryTTL:       time.Minute * 30,
 			ListEntrySweepFreq: time.Minute,
 
+			MarkerMaxSize:   2000,
+			MarkerTTL:       time.Hour * 6,
+			MarkerSweepFreq: time.Minute,
+
 			MediaMaxSize:   1000,
 			MediaTTL:       time.Minute * 30,
 			MediaSweepFreq: time.Minute,

internal/config/helpers.gen.go

@@ -3228,6 +3228,81 @@ func GetCacheGTSListEntrySweepFreq() time.Duration { return global.GetCacheGTSLi
 // SetCacheGTSListEntrySweepFreq safely sets the value for global configuration 'Cache.GTS.ListEntrySweepFreq' field
 func SetCacheGTSListEntrySweepFreq(v time.Duration) { global.SetCacheGTSListEntrySweepFreq(v) }
 
+// GetCacheGTSMarkerMaxSize safely fetches the Configuration value for state's 'Cache.GTS.MarkerMaxSize' field
+func (st *ConfigState) GetCacheGTSMarkerMaxSize() (v int) {
+	st.mutex.RLock()
+	v = st.config.Cache.GTS.MarkerMaxSize
+	st.mutex.RUnlock()
+	return
+}
+
+// SetCacheGTSMarkerMaxSize safely sets the Configuration value for state's 'Cache.GTS.MarkerMaxSize' field
+func (st *ConfigState) SetCacheGTSMarkerMaxSize(v int) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.MarkerMaxSize = v
+	st.reloadToViper()
+}
+
+// CacheGTSMarkerMaxSizeFlag returns the flag name for the 'Cache.GTS.MarkerMaxSize' field
+func CacheGTSMarkerMaxSizeFlag() string { return "cache-gts-marker-max-size" }
+
+// GetCacheGTSMarkerMaxSize safely fetches the value for global configuration 'Cache.GTS.MarkerMaxSize' field
+func GetCacheGTSMarkerMaxSize() int { return global.GetCacheGTSMarkerMaxSize() }
+
+// SetCacheGTSMarkerMaxSize safely sets the value for global configuration 'Cache.GTS.MarkerMaxSize' field
+func SetCacheGTSMarkerMaxSize(v int) { global.SetCacheGTSMarkerMaxSize(v) }
+
+// GetCacheGTSMarkerTTL safely fetches the Configuration value for state's 'Cache.GTS.MarkerTTL' field
+func (st *ConfigState) GetCacheGTSMarkerTTL() (v time.Duration) {
+	st.mutex.RLock()
+	v = st.config.Cache.GTS.MarkerTTL
+	st.mutex.RUnlock()
+	return
+}
+
+// SetCacheGTSMarkerTTL safely sets the Configuration value for state's 'Cache.GTS.MarkerTTL' field
+func (st *ConfigState) SetCacheGTSMarkerTTL(v time.Duration) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.MarkerTTL = v
+	st.reloadToViper()
+}
+
+// CacheGTSMarkerTTLFlag returns the flag name for the 'Cache.GTS.MarkerTTL' field
+func CacheGTSMarkerTTLFlag() string { return "cache-gts-marker-ttl" }
+
+// GetCacheGTSMarkerTTL safely fetches the value for global configuration 'Cache.GTS.MarkerTTL' field
+func GetCacheGTSMarkerTTL() time.Duration { return global.GetCacheGTSMarkerTTL() }
+
+// SetCacheGTSMarkerTTL safely sets the value for global configuration 'Cache.GTS.MarkerTTL' field
+func SetCacheGTSMarkerTTL(v time.Duration) { global.SetCacheGTSMarkerTTL(v) }
+
+// GetCacheGTSMarkerSweepFreq safely fetches the Configuration value for state's 'Cache.GTS.MarkerSweepFreq' field
+func (st *ConfigState) GetCacheGTSMarkerSweepFreq() (v time.Duration) {
+	st.mutex.RLock()
+	v = st.config.Cache.GTS.MarkerSweepFreq
+	st.mutex.RUnlock()
+	return
+}
+
+// SetCacheGTSMarkerSweepFreq safely sets the Configuration value for state's 'Cache.GTS.MarkerSweepFreq' field
+func (st *ConfigState) SetCacheGTSMarkerSweepFreq(v time.Duration) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.MarkerSweepFreq = v
+	st.reloadToViper()
+}
+
+// CacheGTSMarkerSweepFreqFlag returns the flag name for the 'Cache.GTS.MarkerSweepFreq' field
+func CacheGTSMarkerSweepFreqFlag() string { return "cache-gts-marker-sweep-freq" }
+
+// GetCacheGTSMarkerSweepFreq safely fetches the value for global configuration 'Cache.GTS.MarkerSweepFreq' field
+func GetCacheGTSMarkerSweepFreq() time.Duration { return global.GetCacheGTSMarkerSweepFreq() }
+
+// SetCacheGTSMarkerSweepFreq safely sets the value for global configuration 'Cache.GTS.MarkerSweepFreq' field
+func SetCacheGTSMarkerSweepFreq(v time.Duration) { global.SetCacheGTSMarkerSweepFreq(v) }
+
 // GetCacheGTSMediaMaxSize safely fetches the Configuration value for state's 'Cache.GTS.MediaMaxSize' field
 func (st *ConfigState) GetCacheGTSMediaMaxSize() (v int) {
 	st.mutex.RLock()

internal/db/bundb/bundb.go

@@ -66,6 +66,7 @@ type DBService struct {
 	db.Emoji
 	db.Instance
 	db.List
+	db.Marker
 	db.Media
 	db.Mention
 	db.Notification
@@ -186,6 +187,10 @@ func NewBunDBService(ctx context.Context, state *state.State) (db.DB, error) {
 			db:    db,
 			state: state,
 		},
+		Marker: &markerDB{
+			db:    db,
+			state: state,
+		},
 		Media: &mediaDB{
 			db:    db,
 			state: state,

internal/db/bundb/bundb_test.go

@@ -50,6 +50,7 @@ type BunDBStandardTestSuite struct {
 	testLists        map[string]*gtsmodel.List
 	testListEntries  map[string]*gtsmodel.ListEntry
 	testAccountNotes map[string]*gtsmodel.AccountNote
+	testMarkers      map[string]*gtsmodel.Marker
 }
 
 func (suite *BunDBStandardTestSuite) SetupSuite() {
@@ -70,6 +71,7 @@ func (suite *BunDBStandardTestSuite) SetupSuite() {
 	suite.testLists = testrig.NewTestLists()
 	suite.testListEntries = testrig.NewTestListEntries()
 	suite.testAccountNotes = testrig.NewTestAccountNotes()
+	suite.testMarkers = testrig.NewTestMarkers()
 }
 
 func (suite *BunDBStandardTestSuite) SetupTest() {

internal/db/bundb/marker.go

@@ -0,0 +1,115 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bundb
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/state"
+	"github.com/uptrace/bun"
+)
+
+type markerDB struct {
+	db    *WrappedDB
+	state *state.State
+}
+
+/*
+	MARKER FUNCTIONS
+*/
+
+func (m *markerDB) GetMarker(ctx context.Context, accountID string, name gtsmodel.MarkerName) (*gtsmodel.Marker, error) {
+	marker, err := m.state.Caches.GTS.Marker().Load(
+		"AccountID.Name",
+		func() (*gtsmodel.Marker, error) {
+			var marker gtsmodel.Marker
+
+			if err := m.db.NewSelect().
+				Model(&marker).
+				Where("? = ? AND ? = ?", bun.Ident("account_id"), accountID, bun.Ident("name"), name).
+				Scan(ctx); err != nil {
+				return nil, m.db.ProcessError(err)
+			}
+
+			return &marker, nil
+		},
+		accountID,
+		name,
+	)
+	if err != nil {
+		return nil, err // already processed
+	}
+
+	return marker, nil
+}
+
+func (m *markerDB) UpdateMarker(ctx context.Context, marker *gtsmodel.Marker) error {
+	prevMarker, err := m.GetMarker(ctx, marker.AccountID, marker.Name)
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
+		return fmt.Errorf("UpdateMarker: error fetching previous version of marker: %w", err)
+	}
+
+	marker.UpdatedAt = time.Now()
+	if prevMarker != nil {
+		marker.Version = prevMarker.Version + 1
+	}
+
+	return m.state.Caches.GTS.Marker().Store(marker, func() error {
+		if prevMarker == nil {
+			if _, err := m.db.NewInsert().
+				Model(marker).
+				Exec(ctx); err != nil {
+				return m.db.ProcessError(err)
+			}
+			return nil
+		}
+
+		// Optimistic concurrency control: start a transaction, try to update a row with a previously retrieved version.
+		// If the update in the transaction fails to actually change anything, another update happened concurrently, and
+		// this update should be retried by the caller, which in this case involves sending HTTP 409 to the API client.
+		return m.db.RunInTx(ctx, func(tx bun.Tx) error {
+			result, err := tx.NewUpdate().
+				Model(marker).
+				WherePK().
+				Where("? = ?", bun.Ident("version"), prevMarker.Version).
+				Exec(ctx)
+			if err != nil {
+				return m.db.ProcessError(err)
+			}
+
+			rowsAffected, err := result.RowsAffected()
+			if err != nil {
+				return m.db.ProcessError(err)
+			}
+			if rowsAffected == 0 {
+				// Will trigger a rollback, although there should be no changes to roll back.
+				return db.ErrAlreadyExists
+			} else if rowsAffected > 1 {
+				// This shouldn't happen.
+				return db.ErrNoEntries
+			}
+
+			return nil
+		})
+	})
+}

internal/db/bundb/markers_test.go

@@ -0,0 +1,127 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http:www.gnu.org/licenses/>.
+
+package bundb_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// MarkersTestSuite uses home timelines for Get tests
+// and notifications timelines for Update tests
+// so that multiple tests running at once can't step on each other.
+type MarkersTestSuite struct {
+	BunDBStandardTestSuite
+}
+
+func (suite *MarkersTestSuite) TestGetExisting() {
+	ctx := context.Background()
+
+	// This account has home and notifications markers set.
+	localAccount1 := suite.testAccounts["local_account_1"]
+	marker, err := suite.db.GetMarker(ctx, localAccount1.ID, gtsmodel.MarkerNameHome)
+	suite.NoError(err)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	// Should match our fixture.
+	suite.Equal("01F8MH82FYRXD2RC6108DAJ5HB", marker.LastReadID)
+}
+
+func (suite *MarkersTestSuite) TestGetUnset() {
+	ctx := context.Background()
+
+	// This account has no markers set.
+	localAccount2 := suite.testAccounts["local_account_2"]
+	marker, err := suite.db.GetMarker(ctx, localAccount2.ID, gtsmodel.MarkerNameHome)
+	// Should not return anything.
+	suite.Nil(marker)
+	suite.ErrorIs(err, db.ErrNoEntries)
+}
+
+func (suite *MarkersTestSuite) TestUpdateExisting() {
+	ctx := context.Background()
+
+	now := time.Now()
+	// This account has home and notifications markers set.
+	localAccount1 := suite.testAccounts["local_account_1"]
+	prevMarker := suite.testMarkers["local_account_1_notification_marker"]
+	marker := &gtsmodel.Marker{
+		AccountID:  localAccount1.ID,
+		Name:       gtsmodel.MarkerNameNotifications,
+		LastReadID: "01H57YZECGJ2ZW39H8TJWAH0KY",
+	}
+	err := suite.db.UpdateMarker(ctx, marker)
+	suite.NoError(err)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	// Modifies the update and version fields of the marker as an intentional side effect.
+	suite.GreaterOrEqual(marker.UpdatedAt, now)
+	suite.Greater(marker.Version, prevMarker.Version)
+
+	// Re-fetch it from the DB and confirm that we got the updated version.
+	marker2, err := suite.db.GetMarker(ctx, localAccount1.ID, gtsmodel.MarkerNameNotifications)
+	suite.NoError(err)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.GreaterOrEqual(marker2.UpdatedAt, now)
+	suite.GreaterOrEqual(marker2.Version, prevMarker.Version)
+	suite.Equal("01H57YZECGJ2ZW39H8TJWAH0KY", marker2.LastReadID)
+}
+
+func (suite *MarkersTestSuite) TestUpdateUnset() {
+	ctx := context.Background()
+
+	now := time.Now()
+	// This account has no markers set.
+	localAccount2 := suite.testAccounts["local_account_2"]
+	marker := &gtsmodel.Marker{
+		AccountID:  localAccount2.ID,
+		Name:       gtsmodel.MarkerNameNotifications,
+		LastReadID: "01H57ZVGMD348ZJD5WENDZDH9Z",
+	}
+	err := suite.db.UpdateMarker(ctx, marker)
+	suite.NoError(err)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	// Modifies the update and version fields of the marker as an intentional side effect.
+	suite.GreaterOrEqual(marker.UpdatedAt, now)
+	suite.GreaterOrEqual(marker.Version, 0)
+
+	// Re-fetch it from the DB and confirm that we got the updated version.
+	marker2, err := suite.db.GetMarker(ctx, localAccount2.ID, gtsmodel.MarkerNameNotifications)
+	suite.NoError(err)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.GreaterOrEqual(marker2.UpdatedAt, now)
+	suite.GreaterOrEqual(marker2.Version, 0)
+	suite.Equal("01H57ZVGMD348ZJD5WENDZDH9Z", marker2.LastReadID)
+}
+
+func TestMarkersTestSuite(t *testing.T) {
+	suite.Run(t, new(MarkersTestSuite))
+}

internal/db/bundb/migrations/20230713025939_markers_api.go

@@ -0,0 +1,66 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package migrations
+
+import (
+	"context"
+
+	gtsmodel "github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/uptrace/bun"
+)
+
+func init() {
+	up := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			// Marker table.
+			if _, err := tx.
+				NewCreateTable().
+				Model(&gtsmodel.Marker{}).
+				IfNotExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// Add indexes to the Marker table.
+			for index, columns := range map[string][]string{
+				"markers_account_id_name_idx": {"account_id", "name"},
+			} {
+				if _, err := tx.
+					NewCreateIndex().
+					Table("markers").
+					Index(index).
+					Column(columns...).
+					Exec(ctx); err != nil {
+					return err
+				}
+			}
+
+			return nil
+		})
+	}
+
+	down := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			return nil
+		})
+	}
+
+	if err := Migrations.Register(up, down); err != nil {
+		panic(err)
+	}
+}

internal/db/db.go

@@ -37,6 +37,7 @@ type DB interface {
 	Emoji
 	Instance
 	List
+	Marker
 	Media
 	Mention
 	Notification

internal/db/marker.go

@@ -0,0 +1,32 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package db
+
+import (
+	"context"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+type Marker interface {
+	// GetMarker gets one marker with the given timeline name.
+	GetMarker(ctx context.Context, accountID string, name gtsmodel.MarkerName) (*gtsmodel.Marker, error)
+
+	// UpdateMarker updates the given marker.
+	UpdateMarker(ctx context.Context, marker *gtsmodel.Marker) error
+}

internal/gtsmodel/marker.go

@@ -0,0 +1,37 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package gtsmodel
+
+import "time"
+
+// Marker stores a local account's read position on a given timeline.
+type Marker struct {
+	AccountID  string     `validate:"required,ulid" bun:"type:CHAR(26),pk,unique:markers_account_id_timeline_uniq,notnull,nullzero"` // ID of the local account that owns the marker
+	Name       MarkerName `validate:"oneof=home notifications" bun:",nullzero,notnull,pk,unique:markers_account_id_timeline_uniq"`   // Name of the marked timeline
+	UpdatedAt  time.Time  `validate:"required" bun:"type:timestamptz,nullzero,notnull,default:current_timestamp"`                    // When marker was last updated
+	Version    int        `validate:"required,min=0" bun:",nullzero,notnull,default:0"`                                              // For optimistic concurrency control
+	LastReadID string     `validate:"required,ulid" bun:"type:CHAR(26),notnull,nullzero"`                                            // Last ID read on this timeline (status ID for home, notification ID for notifications)
+}
+
+// MarkerName is the name of one of the timelines we can store markers for.
+type MarkerName string
+
+const (
+	MarkerNameHome          MarkerName = "home"
+	MarkerNameNotifications MarkerName = "notifications"
+)

internal/processing/markers/get.go

@@ -0,0 +1,54 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package markers
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
+)
+
+// Get returns an API model for the markers of the requested timelines.
+// If a timeline marker hasn't been set yet, it's not included in the response.
+func (p *Processor) Get(ctx context.Context, account *gtsmodel.Account, names []apimodel.MarkerName) (*apimodel.Marker, gtserror.WithCode) {
+	markers := make([]*gtsmodel.Marker, 0, len(names))
+	for _, name := range names {
+		marker, err := p.state.DB.GetMarker(ctx, account.ID, typeutils.APIMarkerNameToMarkerName(name))
+		if err != nil {
+			if errors.Is(err, db.ErrNoEntries) {
+				continue
+			}
+			// Real database error.
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+		markers = append(markers, marker)
+	}
+
+	apiMarker, err := p.tc.MarkersToAPIMarker(ctx, markers)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error converting marker to api: %w", err))
+	}
+
+	return apiMarker, nil
+}

internal/processing/markers/markers.go

@@ -0,0 +1,35 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package markers
+
+import (
+	"github.com/superseriousbusiness/gotosocial/internal/state"
+	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
+)
+
+type Processor struct {
+	state *state.State
+	tc    typeutils.TypeConverter
+}
+
+func New(state *state.State, tc typeutils.TypeConverter) Processor {
+	return Processor{
+		state: state,
+		tc:    tc,
+	}
+}

internal/processing/markers/update.go

@@ -0,0 +1,48 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package markers
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// Update updates the given markers and returns an API model for them.
+func (p *Processor) Update(ctx context.Context, markers []*gtsmodel.Marker) (*apimodel.Marker, gtserror.WithCode) {
+	for _, marker := range markers {
+		if err := p.state.DB.UpdateMarker(ctx, marker); err != nil {
+			if errors.Is(err, db.ErrAlreadyExists) {
+				return nil, gtserror.NewErrorConflict(err, "marker updated by another client")
+			}
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+	}
+
+	apiMarker, err := p.tc.MarkersToAPIMarker(ctx, markers)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error converting marker to api: %w", err))
+	}
+
+	return apiMarker, nil
+}

internal/processing/processor.go

@@ -30,6 +30,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/processing/admin"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/fedi"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/list"
+	"github.com/superseriousbusiness/gotosocial/internal/processing/markers"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/media"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/report"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/search"
@@ -59,6 +60,7 @@ type Processor struct {
 	admin    admin.Processor
 	fedi     fedi.Processor
 	list     list.Processor
+	markers  markers.Processor
 	media    media.Processor
 	report   report.Processor
 	search   search.Processor
@@ -84,6 +86,10 @@ func (p *Processor) List() *list.Processor {
 	return &p.list
 }
 
+func (p *Processor) Markers() *markers.Processor {
+	return &p.markers
+}
+
 func (p *Processor) Media() *media.Processor {
 	return &p.media
 }
@@ -140,6 +146,7 @@ func NewProcessor(
 	processor.admin = admin.New(state, tc, mediaManager, federator.TransportController(), emailSender)
 	processor.fedi = fedi.New(state, tc, federator, filter)
 	processor.list = list.New(state, tc)
+	processor.markers = markers.New(state, tc)
 	processor.media = media.New(state, tc, mediaManager, federator.TransportController())
 	processor.report = report.New(state, tc)
 	processor.timeline = timeline.New(state, tc, filter)

internal/typeutils/converter.go

@@ -94,6 +94,8 @@ type TypeConverter interface {
 	ReportToAdminAPIReport(ctx context.Context, r *gtsmodel.Report, requestingAccount *gtsmodel.Account) (*apimodel.AdminReport, error)
 	// ListToAPIList converts one gts model list into an api model list, for serving at /api/v1/lists/{id}
 	ListToAPIList(ctx context.Context, l *gtsmodel.List) (*apimodel.List, error)
+	// MarkersToAPIMarker converts several gts model markers into an api marker, for serving at /api/v1/markers
+	MarkersToAPIMarker(ctx context.Context, markers []*gtsmodel.Marker) (*apimodel.Marker, error)
 
 	/*
 		INTERNAL (gts) MODEL TO FRONTEND (rss) MODEL

internal/typeutils/frontendtointernal.go

@@ -37,3 +37,13 @@ func APIVisToVis(m apimodel.Visibility) gtsmodel.Visibility {
 	}
 	return ""
 }
+
+func APIMarkerNameToMarkerName(m apimodel.MarkerName) gtsmodel.MarkerName {
+	switch m {
+	case apimodel.MarkerNameHome:
+		return gtsmodel.MarkerNameHome
+	case apimodel.MarkerNameNotifications:
+		return gtsmodel.MarkerNameNotifications
+	}
+	return ""
+}

internal/typeutils/internaltofrontend.go

@@ -1166,6 +1166,26 @@ func (c *converter) ListToAPIList(ctx context.Context, l *gtsmodel.List) (*apimo
 	}, nil
 }
 
+func (c *converter) MarkersToAPIMarker(ctx context.Context, markers []*gtsmodel.Marker) (*apimodel.Marker, error) {
+	apiMarker := &apimodel.Marker{}
+	for _, marker := range markers {
+		apiTimelineMarker := &apimodel.TimelineMarker{
+			LastReadID: marker.LastReadID,
+			UpdatedAt:  util.FormatISO8601(marker.UpdatedAt),
+			Version:    marker.Version,
+		}
+		switch apimodel.MarkerName(marker.Name) {
+		case apimodel.MarkerNameHome:
+			apiMarker.Home = apiTimelineMarker
+		case apimodel.MarkerNameNotifications:
+			apiMarker.Notifications = apiTimelineMarker
+		default:
+			return nil, fmt.Errorf("unknown marker timeline name: %s", marker.Name)
+		}
+	}
+	return apiMarker, nil
+}
+
 // convertAttachmentsToAPIAttachments will convert a slice of GTS model attachments to frontend API model attachments, falling back to IDs if no GTS models supplied.
 func (c *converter) convertAttachmentsToAPIAttachments(ctx context.Context, attachments []*gtsmodel.MediaAttachment, attachmentIDs []string) ([]apimodel.Attachment, error) {
 	var errs gtserror.MultiError

internal/validate/formvalidation.go

@@ -289,3 +289,15 @@ func ListRepliesPolicy(repliesPolicy gtsmodel.RepliesPolicy) error {
 		return fmt.Errorf("list replies_policy must be either empty or one of 'followed', 'list', 'none'")
 	}
 }
+
+// MarkerName checks that the desired marker timeline name is valid.
+func MarkerName(name string) error {
+	if name == "" {
+		return fmt.Errorf("empty string for marker timeline name not allowed")
+	}
+	switch apimodel.MarkerName(name) {
+	case apimodel.MarkerNameHome, apimodel.MarkerNameNotifications:
+		return nil
+	}
+	return fmt.Errorf("marker timeline name '%s' was not recognized, valid options are '%s', '%s'", name, apimodel.MarkerNameHome, apimodel.MarkerNameNotifications)
+}

test/envparsing.sh

@@ -52,6 +52,9 @@ EXPECT=$(cat <<"EOF"
             "list-max-size": 2000,
             "list-sweep-freq": 60000000000,
             "list-ttl": 1800000000000,
+            "marker-max-size": 2000,
+            "marker-sweep-freq": 60000000000,
+            "marker-ttl": 21600000000000,
             "media-max-size": 1000,
             "media-sweep-freq": 60000000000,
             "media-ttl": 1800000000000,

testrig/db.go

@@ -41,6 +41,7 @@ var testModels = []interface{}{
 	&gtsmodel.FollowRequest{},
 	&gtsmodel.List{},
 	&gtsmodel.ListEntry{},
+	&gtsmodel.Marker{},
 	&gtsmodel.MediaAttachment{},
 	&gtsmodel.Mention{},
 	&gtsmodel.Status{},
@@ -287,6 +288,12 @@ func StandardDBSetup(db db.DB, accounts map[string]*gtsmodel.Account) {
 		}
 	}
 
+	for _, v := range NewTestMarkers() {
+		if err := db.Put(ctx, v); err != nil {
+			log.Panic(nil, err)
+		}
+	}
+
 	if err := db.CreateInstanceAccount(ctx); err != nil {
 		log.Panic(nil, err)
 	}

testrig/testmodels.go

@@ -2007,6 +2007,25 @@ func NewTestListEntries() map[string]*gtsmodel.ListEntry {
 	}
 }
 
+func NewTestMarkers() map[string]*gtsmodel.Marker {
+	return map[string]*gtsmodel.Marker{
+		"local_account_1_home_marker": {
+			AccountID:  "01F8MH1H7YV1Z7D2C8K2730QBF",
+			Name:       gtsmodel.MarkerNameHome,
+			UpdatedAt:  TimeMustParse("2022-05-14T13:21:09+02:00"),
+			Version:    0,
+			LastReadID: "01F8MH82FYRXD2RC6108DAJ5HB",
+		},
+		"local_account_1_notification_marker": {
+			AccountID:  "01F8MH1H7YV1Z7D2C8K2730QBF",
+			Name:       gtsmodel.MarkerNameNotifications,
+			UpdatedAt:  TimeMustParse("2022-05-14T13:21:09+02:00"),
+			Version:    4,
+			LastReadID: "01F8Q0ANPTWW10DAKTX7BRPBJP",
+		},
+	}
+}
+
 func NewTestBlocks() map[string]*gtsmodel.Block {
 	return map[string]*gtsmodel.Block{
 		"local_account_2_block_remote_account_1": {