[feature] Support setting private notes on accounts (#1982)

* Support setting private notes on accounts

* Reformat comment whitespace

* Add missing license headers

* Use apiutil.ParseID

* Rename Note model and cache to AccountNote

* Update golden cache config in test/envparsing.sh

* Rename gtsmodel/note.go to gtsmodel/accountnote.go

* Update AccountNote uniqueness constraint name

Now has same prefix as other indexes on this table.

---------

Co-authored-by: tobi <31960611+tsmethurst@users.noreply.github.com>

docs/api/swagger.yaml

@@ -2944,6 +2944,45 @@ paths:
             summary: See all lists of yours that contain requested account.
             tags:
                 - accounts
+    /api/v1/accounts/{id}/note:
+        post:
+            consumes:
+                - multipart/form-data
+            operationId: accountNote
+            parameters:
+                - description: The id of the account for which to set a note.
+                  in: path
+                  name: id
+                  required: true
+                  type: string
+                - default: ""
+                  description: The text of the note. Omit this parameter or send an empty string to clear the note.
+                  in: formData
+                  name: comment
+                  type: string
+            produces:
+                - application/json
+            responses:
+                "200":
+                    description: Your relationship to the account.
+                    schema:
+                        $ref: '#/definitions/accountRelationship'
+                "400":
+                    description: bad request
+                "401":
+                    description: unauthorized
+                "404":
+                    description: not found
+                "406":
+                    description: not acceptable
+                "500":
+                    description: internal server error
+            security:
+                - OAuth2 Bearer:
+                    - write:accounts
+            summary: Set a private note for an account with the given id.
+            tags:
+                - accounts
     /api/v1/accounts/{id}/statuses:
         get:
             description: The statuses will be returned in descending chronological order (newest first), with sequential IDs (bigger = newer).

internal/api/client/accounts/accounts.go

@@ -45,6 +45,7 @@ const (
 	FollowPath        = BasePathWithID + "/follow"
 	ListsPath         = BasePathWithID + "/lists"
 	LookupPath        = BasePath + "/lookup"
+	NotePath          = BasePathWithID + "/note"
 	RelationshipsPath = BasePath + "/relationships"
 	SearchPath        = BasePath + "/search"
 	StatusesPath      = BasePathWithID + "/statuses"
@@ -101,6 +102,9 @@ func (m *Module) Route(attachHandler func(method string, path string, f ...gin.H
 	// account lists
 	attachHandler(http.MethodGet, ListsPath, m.AccountListsGETHandler)
 
+	// account note
+	attachHandler(http.MethodPost, NotePath, m.AccountNotePOSTHandler)
+
 	// search for accounts
 	attachHandler(http.MethodGet, SearchPath, m.AccountSearchGETHandler)
 	attachHandler(http.MethodGet, LookupPath, m.AccountLookupGETHandler)

internal/api/client/accounts/note.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 accounts
+
+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"
+)
+
+// AccountNotePOSTHandler swagger:operation POST /api/v1/accounts/{id}/note accountNote
+//
+// Set a private note for an account with the given id.
+//
+//	---
+//	tags:
+//	- accounts
+//
+//	consumes:
+//	- multipart/form-data
+//
+//	produces:
+//	- application/json
+//
+//	parameters:
+//	-
+//		name: id
+//		type: string
+//		description: The id of the account for which to set a note.
+//		in: path
+//		required: true
+//	-
+//		name: comment
+//		type: string
+//		description: The text of the note. Omit this parameter or send an empty string to clear the note.
+//		in: formData
+//		default: ""
+//
+//	security:
+//	- OAuth2 Bearer:
+//		- write:accounts
+//
+//	responses:
+//		'200':
+//			description: Your relationship to the account.
+//			schema:
+//				"$ref": "#/definitions/accountRelationship"
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'404':
+//			description: not found
+//		'406':
+//			description: not acceptable
+//		'500':
+//			description: internal server error
+func (m *Module) AccountNotePOSTHandler(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
+	}
+
+	if _, err := apiutil.NegotiateAccept(c, apiutil.JSONAcceptHeaders...); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	targetAcctID, errWithCode := apiutil.ParseID(c.Param(apiutil.IDKey))
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	form := &apimodel.AccountNoteRequest{}
+	if err := c.ShouldBind(form); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	relationship, errWithCode := m.processor.Account().PutNote(c.Request.Context(), authed.Account, targetAcctID, form.Comment)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	c.JSON(http.StatusOK, relationship)
+}

internal/api/model/account.go

@@ -231,3 +231,11 @@ const (
 	AccountRoleAdmin     AccountRoleName = "admin"     // Instance admin
 	AccountRoleUnknown   AccountRoleName = ""          // We don't know / remote account
 )
+
+// AccountNoteRequest models a request to update the private note for an account.
+//
+// swagger:ignore
+type AccountNoteRequest struct {
+	// Comment to use for the note text.
+	Comment string `form:"comment" json:"comment" xml:"comment"`
+}

internal/cache/gts.go

@@ -27,6 +27,7 @@ import (
 
 type GTSCaches struct {
 	account     *result.Cache[*gtsmodel.Account]
+	accountNote *result.Cache[*gtsmodel.AccountNote]
 	block       *result.Cache[*gtsmodel.Block]
 	// TODO: maybe should be moved out of here since it's
 	// not actually doing anything with gtsmodel.DomainBlock.
@@ -54,6 +55,7 @@ type GTSCaches struct {
 // NOTE: the cache MUST NOT be in use anywhere, this is not thread-safe.
 func (c *GTSCaches) Init() {
 	c.initAccount()
+	c.initAccountNote()
 	c.initBlock()
 	c.initDomainBlock()
 	c.initEmoji()
@@ -77,6 +79,7 @@ func (c *GTSCaches) Init() {
 // Start will attempt to start all of the gtsmodel caches, or panic.
 func (c *GTSCaches) Start() {
 	tryStart(c.account, config.GetCacheGTSAccountSweepFreq())
+	tryStart(c.accountNote, config.GetCacheGTSAccountNoteSweepFreq())
 	tryStart(c.block, config.GetCacheGTSBlockSweepFreq())
 	tryStart(c.emoji, config.GetCacheGTSEmojiSweepFreq())
 	tryStart(c.emojiCategory, config.GetCacheGTSEmojiCategorySweepFreq())
@@ -104,6 +107,7 @@ func (c *GTSCaches) Start() {
 // Stop will attempt to stop all of the gtsmodel caches, or panic.
 func (c *GTSCaches) Stop() {
 	tryStop(c.account, config.GetCacheGTSAccountSweepFreq())
+	tryStop(c.accountNote, config.GetCacheGTSAccountNoteSweepFreq())
 	tryStop(c.block, config.GetCacheGTSBlockSweepFreq())
 	tryStop(c.emoji, config.GetCacheGTSEmojiSweepFreq())
 	tryStop(c.emojiCategory, config.GetCacheGTSEmojiCategorySweepFreq())
@@ -128,6 +132,11 @@ func (c *GTSCaches) Account() *result.Cache[*gtsmodel.Account] {
 	return c.account
 }
 
+// AccountNote provides access to the gtsmodel Note database cache.
+func (c *GTSCaches) AccountNote() *result.Cache[*gtsmodel.AccountNote] {
+	return c.accountNote
+}
+
 // Block provides access to the gtsmodel Block (account) database cache.
 func (c *GTSCaches) Block() *result.Cache[*gtsmodel.Block] {
 	return c.block
@@ -238,6 +247,19 @@ func (c *GTSCaches) initAccount() {
 	c.account.IgnoreErrors(ignoreErrors)
 }
 
+func (c *GTSCaches) initAccountNote() {
+	c.accountNote = result.New([]result.Lookup{
+		{Name: "ID"},
+		{Name: "AccountID.TargetAccountID"},
+	}, func(n1 *gtsmodel.AccountNote) *gtsmodel.AccountNote {
+		n2 := new(gtsmodel.AccountNote)
+		*n2 = *n1
+		return n2
+	}, config.GetCacheGTSAccountNoteMaxSize())
+	c.accountNote.SetTTL(config.GetCacheGTSAccountNoteTTL(), true)
+	c.accountNote.IgnoreErrors(ignoreErrors)
+}
+
 func (c *GTSCaches) initBlock() {
 	c.block = result.New([]result.Lookup{
 		{Name: "ID"},

internal/config/config.go

@@ -186,6 +186,10 @@ type GTSCacheConfiguration struct {
 	AccountTTL       time.Duration `name:"account-ttl"`
 	AccountSweepFreq time.Duration `name:"account-sweep-freq"`
 
+	AccountNoteMaxSize   int           `name:"account-note-max-size"`
+	AccountNoteTTL       time.Duration `name:"account-note-ttl"`
+	AccountNoteSweepFreq time.Duration `name:"account-note-sweep-freq"`
+
 	BlockMaxSize   int           `name:"block-max-size"`
 	BlockTTL       time.Duration `name:"block-ttl"`
 	BlockSweepFreq time.Duration `name:"block-sweep-freq"`

internal/config/defaults.go

@@ -131,6 +131,10 @@ var Defaults = Configuration{
 			AccountTTL:       time.Minute * 30,
 			AccountSweepFreq: time.Minute,
 
+			AccountNoteMaxSize:   1000,
+			AccountNoteTTL:       time.Minute * 30,
+			AccountNoteSweepFreq: time.Minute,
+
 			BlockMaxSize:   1000,
 			BlockTTL:       time.Minute * 30,
 			BlockSweepFreq: time.Minute,

internal/config/helpers.gen.go

@@ -2474,6 +2474,81 @@ func GetCacheGTSAccountSweepFreq() time.Duration { return global.GetCacheGTSAcco
 // SetCacheGTSAccountSweepFreq safely sets the value for global configuration 'Cache.GTS.AccountSweepFreq' field
 func SetCacheGTSAccountSweepFreq(v time.Duration) { global.SetCacheGTSAccountSweepFreq(v) }
 
+// GetCacheGTSAccountNoteMaxSize safely fetches the Configuration value for state's 'Cache.GTS.AccountNoteMaxSize' field
+func (st *ConfigState) GetCacheGTSAccountNoteMaxSize() (v int) {
+	st.mutex.RLock()
+	v = st.config.Cache.GTS.AccountNoteMaxSize
+	st.mutex.RUnlock()
+	return
+}
+
+// SetCacheGTSAccountNoteMaxSize safely sets the Configuration value for state's 'Cache.GTS.AccountNoteMaxSize' field
+func (st *ConfigState) SetCacheGTSAccountNoteMaxSize(v int) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.AccountNoteMaxSize = v
+	st.reloadToViper()
+}
+
+// CacheGTSAccountNoteMaxSizeFlag returns the flag name for the 'Cache.GTS.AccountNoteMaxSize' field
+func CacheGTSAccountNoteMaxSizeFlag() string { return "cache-gts-account-note-max-size" }
+
+// GetCacheGTSAccountNoteMaxSize safely fetches the value for global configuration 'Cache.GTS.AccountNoteMaxSize' field
+func GetCacheGTSAccountNoteMaxSize() int { return global.GetCacheGTSAccountNoteMaxSize() }
+
+// SetCacheGTSAccountNoteMaxSize safely sets the value for global configuration 'Cache.GTS.AccountNoteMaxSize' field
+func SetCacheGTSAccountNoteMaxSize(v int) { global.SetCacheGTSAccountNoteMaxSize(v) }
+
+// GetCacheGTSAccountNoteTTL safely fetches the Configuration value for state's 'Cache.GTS.AccountNoteTTL' field
+func (st *ConfigState) GetCacheGTSAccountNoteTTL() (v time.Duration) {
+	st.mutex.RLock()
+	v = st.config.Cache.GTS.AccountNoteTTL
+	st.mutex.RUnlock()
+	return
+}
+
+// SetCacheGTSAccountNoteTTL safely sets the Configuration value for state's 'Cache.GTS.AccountNoteTTL' field
+func (st *ConfigState) SetCacheGTSAccountNoteTTL(v time.Duration) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.AccountNoteTTL = v
+	st.reloadToViper()
+}
+
+// CacheGTSAccountNoteTTLFlag returns the flag name for the 'Cache.GTS.AccountNoteTTL' field
+func CacheGTSAccountNoteTTLFlag() string { return "cache-gts-account-note-ttl" }
+
+// GetCacheGTSAccountNoteTTL safely fetches the value for global configuration 'Cache.GTS.AccountNoteTTL' field
+func GetCacheGTSAccountNoteTTL() time.Duration { return global.GetCacheGTSAccountNoteTTL() }
+
+// SetCacheGTSAccountNoteTTL safely sets the value for global configuration 'Cache.GTS.AccountNoteTTL' field
+func SetCacheGTSAccountNoteTTL(v time.Duration) { global.SetCacheGTSAccountNoteTTL(v) }
+
+// GetCacheGTSAccountNoteSweepFreq safely fetches the Configuration value for state's 'Cache.GTS.AccountNoteSweepFreq' field
+func (st *ConfigState) GetCacheGTSAccountNoteSweepFreq() (v time.Duration) {
+	st.mutex.RLock()
+	v = st.config.Cache.GTS.AccountNoteSweepFreq
+	st.mutex.RUnlock()
+	return
+}
+
+// SetCacheGTSAccountNoteSweepFreq safely sets the Configuration value for state's 'Cache.GTS.AccountNoteSweepFreq' field
+func (st *ConfigState) SetCacheGTSAccountNoteSweepFreq(v time.Duration) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.Cache.GTS.AccountNoteSweepFreq = v
+	st.reloadToViper()
+}
+
+// CacheGTSAccountNoteSweepFreqFlag returns the flag name for the 'Cache.GTS.AccountNoteSweepFreq' field
+func CacheGTSAccountNoteSweepFreqFlag() string { return "cache-gts-account-note-sweep-freq" }
+
+// GetCacheGTSAccountNoteSweepFreq safely fetches the value for global configuration 'Cache.GTS.AccountNoteSweepFreq' field
+func GetCacheGTSAccountNoteSweepFreq() time.Duration { return global.GetCacheGTSAccountNoteSweepFreq() }
+
+// SetCacheGTSAccountNoteSweepFreq safely sets the value for global configuration 'Cache.GTS.AccountNoteSweepFreq' field
+func SetCacheGTSAccountNoteSweepFreq(v time.Duration) { global.SetCacheGTSAccountNoteSweepFreq(v) }
+
 // GetCacheGTSBlockMaxSize safely fetches the Configuration value for state's 'Cache.GTS.BlockMaxSize' field
 func (st *ConfigState) GetCacheGTSBlockMaxSize() (v int) {
 	st.mutex.RLock()

internal/db/bundb/bundb_test.go

@@ -49,6 +49,7 @@ type BunDBStandardTestSuite struct {
 	testFaves        map[string]*gtsmodel.StatusFave
 	testLists        map[string]*gtsmodel.List
 	testListEntries  map[string]*gtsmodel.ListEntry
+	testAccountNotes map[string]*gtsmodel.AccountNote
 }
 
 func (suite *BunDBStandardTestSuite) SetupSuite() {
@@ -68,6 +69,7 @@ func (suite *BunDBStandardTestSuite) SetupSuite() {
 	suite.testFaves = testrig.NewTestFaves()
 	suite.testLists = testrig.NewTestLists()
 	suite.testListEntries = testrig.NewTestListEntries()
+	suite.testAccountNotes = testrig.NewTestAccountNotes()
 }
 
 func (suite *BunDBStandardTestSuite) SetupTest() {

internal/db/bundb/migrations/20230711214815_account_notes.go

@@ -0,0 +1,62 @@
+// 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 {
+			// Account note table.
+			if _, err := tx.
+				NewCreateTable().
+				Model(&gtsmodel.AccountNote{}).
+				IfNotExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// Add IDs index to the account note table.
+			if _, err := tx.
+				NewCreateIndex().
+				Model(&gtsmodel.AccountNote{}).
+				Index("account_notes_account_id_target_account_id_idx").
+				Column("account_id", "target_account_id").
+				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/bundb/relationship.go

@@ -85,6 +85,19 @@ func (r *relationshipDB) GetRelationship(ctx context.Context, requestingAccount
 		return nil, fmt.Errorf("GetRelationship: error checking blockedBy: %w", err)
 	}
 
+	// retrieve a note by the requesting account on the target account, if there is one
+	note, err := r.GetNote(
+		gtscontext.SetBarebones(ctx),
+		requestingAccount,
+		targetAccount,
+	)
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
+		return nil, fmt.Errorf("GetRelationship: error fetching note: %w", err)
+	}
+	if note != nil {
+		rel.Note = note.Comment
+	}
+
 	return &rel, nil
 }
 

internal/db/bundb/relationship_note.go

@@ -0,0 +1,99 @@
+// 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"
+	"fmt"
+	"time"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/uptrace/bun"
+)
+
+func (r *relationshipDB) GetNote(ctx context.Context, sourceAccountID string, targetAccountID string) (*gtsmodel.AccountNote, error) {
+	return r.getNote(
+		ctx,
+		"AccountID.TargetAccountID",
+		func(note *gtsmodel.AccountNote) error {
+			return r.conn.NewSelect().Model(note).
+				Where("? = ?", bun.Ident("account_id"), sourceAccountID).
+				Where("? = ?", bun.Ident("target_account_id"), targetAccountID).
+				Scan(ctx)
+		},
+		sourceAccountID,
+		targetAccountID,
+	)
+}
+
+func (r *relationshipDB) getNote(ctx context.Context, lookup string, dbQuery func(*gtsmodel.AccountNote) error, keyParts ...any) (*gtsmodel.AccountNote, error) {
+	// Fetch note from cache with loader callback
+	note, err := r.state.Caches.GTS.AccountNote().Load(lookup, func() (*gtsmodel.AccountNote, error) {
+		var note gtsmodel.AccountNote
+
+		// Not cached! Perform database query
+		if err := dbQuery(&note); err != nil {
+			return nil, r.conn.ProcessError(err)
+		}
+
+		return &note, nil
+	}, keyParts...)
+	if err != nil {
+		// already processed
+		return nil, err
+	}
+
+	if gtscontext.Barebones(ctx) {
+		// Only a barebones model was requested.
+		return note, nil
+	}
+
+	// Set the note source account
+	note.Account, err = r.state.DB.GetAccountByID(
+		gtscontext.SetBarebones(ctx),
+		note.AccountID,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("error getting note source account: %w", err)
+	}
+
+	// Set the note target account
+	note.TargetAccount, err = r.state.DB.GetAccountByID(
+		gtscontext.SetBarebones(ctx),
+		note.TargetAccountID,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("error getting note target account: %w", err)
+	}
+
+	return note, nil
+}
+
+func (r *relationshipDB) PutNote(ctx context.Context, note *gtsmodel.AccountNote) error {
+	note.UpdatedAt = time.Now()
+	return r.state.Caches.GTS.AccountNote().Store(note, func() error {
+		_, err := r.conn.
+			NewInsert().
+			Model(note).
+			On("CONFLICT (?, ?) DO UPDATE", bun.Ident("account_id"), bun.Ident("target_account_id")).
+			Set("? = ?, ? = ?", bun.Ident("updated_at"), note.UpdatedAt, bun.Ident("comment"), note.Comment).
+			Exec(ctx)
+		return r.conn.ProcessError(err)
+	})
+}

internal/db/bundb/relationship_test.go

@@ -912,6 +912,53 @@ func (suite *RelationshipTestSuite) TestUpdateFollow() {
 	suite.True(relationship.Notifying)
 }
 
+func (suite *RelationshipTestSuite) TestGetNote() {
+	ctx := context.Background()
+
+	// Retrieve a fixture note
+	account1 := suite.testAccounts["local_account_1"].ID
+	account2 := suite.testAccounts["local_account_2"].ID
+	expectedNote := suite.testAccountNotes["local_account_2_note_on_1"]
+	note, err := suite.db.GetNote(ctx, account2, account1)
+	suite.NoError(err)
+	suite.NotNil(note)
+	suite.Equal(expectedNote.ID, note.ID)
+	suite.Equal(expectedNote.Comment, note.Comment)
+}
+
+func (suite *RelationshipTestSuite) TestPutNote() {
+	ctx := context.Background()
+
+	// put a note in
+	account1 := suite.testAccounts["local_account_1"].ID
+	account2 := suite.testAccounts["local_account_2"].ID
+	err := suite.db.PutNote(ctx, &gtsmodel.AccountNote{
+		ID:              "01H539R2NA0M83JX15Y5RWKE97",
+		AccountID:       account1,
+		TargetAccountID: account2,
+		Comment:         "foo",
+	})
+	suite.NoError(err)
+
+	// make sure the note is in the db
+	note, err := suite.db.GetNote(ctx, account1, account2)
+	suite.NoError(err)
+	suite.NotNil(note)
+	suite.Equal("01H539R2NA0M83JX15Y5RWKE97", note.ID)
+	suite.Equal("foo", note.Comment)
+
+	// update the note
+	note.Comment = "bar"
+	err = suite.db.PutNote(ctx, note)
+	suite.NoError(err)
+
+	// make sure the comment changes
+	note, err = suite.db.GetNote(ctx, account1, account2)
+	suite.NoError(err)
+	suite.NotNil(note)
+	suite.Equal("bar", note.Comment)
+}
+
 func TestRelationshipTestSuite(t *testing.T) {
 	suite.Run(t, new(RelationshipTestSuite))
 }

internal/db/relationship.go

@@ -165,4 +165,10 @@ type Relationship interface {
 
 	// CountAccountFollowerRequests returns number of follow requests originating from the given account.
 	CountAccountFollowRequesting(ctx context.Context, accountID string) (int, error)
+
+	// GetNote gets a private note from a source account on a target account, if it exists.
+	GetNote(ctx context.Context, sourceAccountID string, targetAccountID string) (*gtsmodel.AccountNote, error)
+
+	// PutNote creates or updates a private note.
+	PutNote(ctx context.Context, note *gtsmodel.AccountNote) error
 }

internal/gtsmodel/accountnote.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 gtsmodel
+
+import "time"
+
+// AccountNote stores a private note from a local account related to any account.
+type AccountNote struct {
+	ID              string    `validate:"required,ulid" bun:"type:CHAR(26),pk,nullzero,notnull,unique"`                                              // id of this item in the database
+	CreatedAt       time.Time `validate:"-" bun:"type:timestamptz,nullzero,notnull,default:current_timestamp"`                                       // when was item created
+	UpdatedAt       time.Time `validate:"-" bun:"type:timestamptz,nullzero,notnull,default:current_timestamp"`                                       // when was item last updated
+	AccountID       string    `validate:"required,ulid" bun:"type:CHAR(26),unique:account_notes_account_id_target_account_id_uniq,notnull,nullzero"` // ID of the local account that created the note
+	Account         *Account  `validate:"-" bun:"rel:belongs-to"`                                                                                    // Account corresponding to accountID
+	TargetAccountID string    `validate:"required,ulid" bun:"type:CHAR(26),unique:account_notes_account_id_target_account_id_uniq,notnull,nullzero"` // Who is the target of this note?
+	TargetAccount   *Account  `validate:"-" bun:"rel:belongs-to"`                                                                                    // Account corresponding to targetAccountID
+	Comment         string    `validate:"-" bun:""`                                                                                                  // The text of the note.
+}

internal/processing/account/note.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 account
+
+import (
+	"context"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+)
+
+// PutNote updates the requesting account's private note on the target account.
+func (p *Processor) PutNote(ctx context.Context, requestingAccount *gtsmodel.Account, targetAccountID string, comment string) (*apimodel.Relationship, gtserror.WithCode) {
+	targetAccount, errWithCode := p.Get(ctx, requestingAccount, targetAccountID)
+	if errWithCode != nil {
+		return nil, errWithCode
+	}
+
+	note := &gtsmodel.AccountNote{
+		ID:              id.NewULID(),
+		AccountID:       requestingAccount.ID,
+		TargetAccountID: targetAccount.ID,
+		Comment:         comment,
+	}
+	err := p.state.DB.PutNote(ctx, note)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return p.RelationshipGet(ctx, requestingAccount, targetAccount.ID)
+}

test/envparsing.sh

@@ -20,6 +20,9 @@ EXPECT=$(cat <<"EOF"
     "cache": {
         "gts": {
             "account-max-size": 99,
+            "account-note-max-size": 1000,
+            "account-note-sweep-freq": 60000000000,
+            "account-note-ttl": 1800000000000,
             "account-sweep-freq": 1000000000,
             "account-ttl": 10800000000000,
             "block-max-size": 1000,

testrig/db.go

@@ -60,6 +60,7 @@ var testModels = []interface{}{
 	&gtsmodel.EmojiCategory{},
 	&gtsmodel.Tombstone{},
 	&gtsmodel.Report{},
+	&gtsmodel.AccountNote{},
 }
 
 // NewTestDB returns a new initialized, empty database for testing.
@@ -280,6 +281,12 @@ func StandardDBSetup(db db.DB, accounts map[string]*gtsmodel.Account) {
 		}
 	}
 
+	for _, v := range NewTestAccountNotes() {
+		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

@@ -1893,6 +1893,18 @@ func NewTestFaves() map[string]*gtsmodel.StatusFave {
 	}
 }
 
+// NewTestAccountNotes returns some account notes for use in testing.
+func NewTestAccountNotes() map[string]*gtsmodel.AccountNote {
+	return map[string]*gtsmodel.AccountNote{
+		"local_account_2_note_on_1": {
+			ID:              "01H53TM628GNC4ZDNRGQGPK8S0",
+			AccountID:       "01F8MH5NBDF2MV7CTC4Q5128HF",
+			TargetAccountID: "01F8MH1H7YV1Z7D2C8K2730QBF",
+			Comment:         "extremely average poster",
+		},
+	}
+}
+
 // NewTestNotifications returns some notifications for use in testing.
 func NewTestNotifications() map[string]*gtsmodel.Notification {
 	return map[string]*gtsmodel.Notification{