[feature] Dereference remote mentions when the account is not already known (#442)v0.2.2

* remove mention util function from db

* add ParseMentionFunc to gtsmodel

* add parseMentionFunc to processor

* refactor search to simplify it a bit

* add parseMentionFunc to account

* add parseMentionFunc to status

* some renaming for clarity

* test dereference of unknown mentioned account

9 files changed, 210 insertions, 35 deletions

diff --git a/internal/processing/account/account.go b/internal/processing/account/account.go
index c670ee24a..1ef92cf85 100644
--- a/internal/processing/account/account.go
+++ b/internal/processing/account/account.go
@@ -87,10 +87,11 @@ type processor struct {
 	formatter     text.Formatter
 	db            db.DB
 	federator     federation.Federator
+	parseMention  gtsmodel.ParseMentionFunc
 }
 
 // New returns a new account processor.
-func New(db db.DB, tc typeutils.TypeConverter, mediaManager media.Manager, oauthServer oauth.Server, fromClientAPI chan messages.FromClientAPI, federator federation.Federator) Processor {
+func New(db db.DB, tc typeutils.TypeConverter, mediaManager media.Manager, oauthServer oauth.Server, fromClientAPI chan messages.FromClientAPI, federator federation.Federator, parseMention gtsmodel.ParseMentionFunc) Processor {
 	return &processor{
 		tc:            tc,
 		mediaManager:  mediaManager,
@@ -100,5 +101,6 @@ func New(db db.DB, tc typeutils.TypeConverter, mediaManager media.Manager, oauth
 		formatter:     text.NewFormatter(db),
 		db:            db,
 		federator:     federator,
+		parseMention:  parseMention,
 	}
 }
diff --git a/internal/processing/account/account_test.go b/internal/processing/account/account_test.go
index 5a9382ed6..aff4f02aa 100644
--- a/internal/processing/account/account_test.go
+++ b/internal/processing/account/account_test.go
@@ -29,6 +29,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/media"
 	"github.com/superseriousbusiness/gotosocial/internal/messages"
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/processing"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/account"
 	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
@@ -88,7 +89,7 @@ func (suite *AccountStandardTestSuite) SetupTest() {
 	suite.federator = testrig.NewTestFederator(suite.db, suite.transportController, suite.storage, suite.mediaManager)
 	suite.sentEmails = make(map[string]string)
 	suite.emailSender = testrig.NewEmailSender("../../../web/template/", suite.sentEmails)
-	suite.accountProcessor = account.New(suite.db, suite.tc, suite.mediaManager, suite.oauthServer, suite.fromClientAPIChan, suite.federator)
+	suite.accountProcessor = account.New(suite.db, suite.tc, suite.mediaManager, suite.oauthServer, suite.fromClientAPIChan, suite.federator, processing.GetParseMentionFunc(suite.db, suite.federator))
 	testrig.StandardDBSetup(suite.db, nil)
 	testrig.StandardStorageSetup(suite.storage, "../../../testrig/media")
 }
diff --git a/internal/processing/account/update.go b/internal/processing/account/update.go
index a96b44bef..a0056563b 100644
--- a/internal/processing/account/update.go
+++ b/internal/processing/account/update.go
@@ -199,10 +199,14 @@ func (p *processor) processNote(ctx context.Context, note string, accountID stri
 		return "", err
 	}
 
-	mentionStrings := util.DeriveMentionsFromText(note)
-	mentions, err := p.db.MentionStringsToMentions(ctx, mentionStrings, accountID, "")
-	if err != nil {
-		return "", err
+	mentionStrings := util.DeriveMentionNamesFromText(note)
+	mentions := []*gtsmodel.Mention{}
+	for _, mentionString := range mentionStrings {
+		mention, err := p.parseMention(ctx, mentionString, accountID, "")
+		if err != nil {
+			continue
+		}
+		mentions = append(mentions, mention)
 	}
 
 	// TODO: support emojis in account notes
diff --git a/internal/processing/processor.go b/internal/processing/processor.go
index 50f4af492..f5d9eab28 100644
--- a/internal/processing/processor.go
+++ b/internal/processing/processor.go
@@ -267,12 +267,14 @@ func NewProcessor(
 	storage *kv.KVStore,
 	db db.DB,
 	emailSender email.Sender) Processor {
+
 	fromClientAPI := make(chan messages.FromClientAPI, 1000)
 	fromFederator := make(chan messages.FromFederator, 1000)
+	parseMentionFunc := GetParseMentionFunc(db, federator)
 
-	statusProcessor := status.New(db, tc, fromClientAPI)
+	statusProcessor := status.New(db, tc, fromClientAPI, parseMentionFunc)
 	streamingProcessor := streaming.New(db, oauthServer)
-	accountProcessor := account.New(db, tc, mediaManager, oauthServer, fromClientAPI, federator)
+	accountProcessor := account.New(db, tc, mediaManager, oauthServer, fromClientAPI, federator, parseMentionFunc)
 	adminProcessor := admin.New(db, tc, mediaManager, fromClientAPI)
 	mediaProcessor := mediaProcessor.New(db, tc, mediaManager, federator.TransportController(), storage)
 	userProcessor := user.New(db, emailSender)
diff --git a/internal/processing/search.go b/internal/processing/search.go
index c8c302857..6c3d7da39 100644
--- a/internal/processing/search.go
+++ b/internal/processing/search.go
@@ -194,20 +194,15 @@ func (p *processor) searchAccountByMention(ctx context.Context, authed *oauth.Au
 	// we got a db.ErrNoEntries, so we just don't have the account locally stored -- check if we can dereference it
 	if resolve {
 		// we're allowed to resolve it so let's try
-
 		// first we need to webfinger the remote account to convert the username and domain into the activitypub URI for the account
 		acctURI, err := p.federator.FingerRemoteAccount(ctx, authed.Account.Username, username, domain)
 		if err != nil {
 			// something went wrong doing the webfinger lookup so we can't process the request
-			return nil, fmt.Errorf("searchAccountByMention: error fingering remote account with username %s and domain %s: %s", username, domain, err)
+			return nil, fmt.Errorf("error fingering remote account with username %s and domain %s: %s", username, domain, err)
 		}
 
-		// we don't have it locally so try and dereference it
-		account, err := p.federator.GetRemoteAccount(ctx, authed.Account.Username, acctURI, true, true)
-		if err != nil {
-			return nil, fmt.Errorf("searchAccountByMention: error dereferencing account with uri %s: %s", acctURI.String(), err)
-		}
-		return account, nil
+		// return the attempt to get the remove account
+		return p.federator.GetRemoteAccount(ctx, authed.Account.Username, acctURI, true, true)
 	}
 
 	return nil, nil
diff --git a/internal/processing/status/status.go b/internal/processing/status/status.go
index 3118b23ad..421ab5bbe 100644
--- a/internal/processing/status/status.go
+++ b/internal/processing/status/status.go
@@ -74,15 +74,17 @@ type processor struct {
 	filter        visibility.Filter
 	formatter     text.Formatter
 	fromClientAPI chan messages.FromClientAPI
+	parseMention  gtsmodel.ParseMentionFunc
 }
 
 // New returns a new status processor.
-func New(db db.DB, tc typeutils.TypeConverter, fromClientAPI chan messages.FromClientAPI) Processor {
+func New(db db.DB, tc typeutils.TypeConverter, fromClientAPI chan messages.FromClientAPI, parseMention gtsmodel.ParseMentionFunc) Processor {
 	return &processor{
 		tc:            tc,
 		db:            db,
 		filter:        visibility.NewFilter(db),
 		formatter:     text.NewFormatter(db),
 		fromClientAPI: fromClientAPI,
+		parseMention:  parseMention,
 	}
 }
diff --git a/internal/processing/status/status_test.go b/internal/processing/status/status_test.go
index 803e7a0a5..25794070e 100644
--- a/internal/processing/status/status_test.go
+++ b/internal/processing/status/status_test.go
@@ -19,11 +19,16 @@
 package status_test
 
 import (
+	"codeberg.org/gruf/go-store/kv"
 	"github.com/stretchr/testify/suite"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/federation"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/media"
 	"github.com/superseriousbusiness/gotosocial/internal/messages"
+	"github.com/superseriousbusiness/gotosocial/internal/processing"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/status"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
@@ -32,6 +37,10 @@ type StatusStandardTestSuite struct {
 	suite.Suite
 	db                db.DB
 	typeConverter     typeutils.TypeConverter
+	tc                transport.Controller
+	storage           *kv.KVStore
+	mediaManager      media.Manager
+	federator         federation.Federator
 	fromClientAPIChan chan messages.FromClientAPI
 
 	// standard suite models
@@ -62,17 +71,23 @@ func (suite *StatusStandardTestSuite) SetupSuite() {
 }
 
 func (suite *StatusStandardTestSuite) SetupTest() {
-	testrig.InitTestLog()
 	testrig.InitTestConfig()
+	testrig.InitTestLog()
 
 	suite.db = testrig.NewTestDB()
 	suite.typeConverter = testrig.NewTestTypeConverter(suite.db)
 	suite.fromClientAPIChan = make(chan messages.FromClientAPI, 100)
-	suite.status = status.New(suite.db, suite.typeConverter, suite.fromClientAPIChan)
+	suite.tc = testrig.NewTestTransportController(testrig.NewMockHTTPClient(nil), suite.db)
+	suite.storage = testrig.NewTestStorage()
+	suite.mediaManager = testrig.NewTestMediaManager(suite.db, suite.storage)
+	suite.federator = testrig.NewTestFederator(suite.db, suite.tc, suite.storage, suite.mediaManager)
+	suite.status = status.New(suite.db, suite.typeConverter, suite.fromClientAPIChan, processing.GetParseMentionFunc(suite.db, suite.federator))
 
-	testrig.StandardDBSetup(suite.db, nil)
+	testrig.StandardDBSetup(suite.db, suite.testAccounts)
+	testrig.StandardStorageSetup(suite.storage, "../../../testrig/media")
 }
 
 func (suite *StatusStandardTestSuite) TearDownTest() {
 	testrig.StandardDBTeardown(suite.db)
+	testrig.StandardStorageTeardown(suite.storage)
 }
diff --git a/internal/processing/status/util.go b/internal/processing/status/util.go
index f2640929d..5de66af8a 100644
--- a/internal/processing/status/util.go
+++ b/internal/processing/status/util.go
@@ -23,10 +23,10 @@ import (
 	"errors"
 	"fmt"
 
+	"github.com/sirupsen/logrus"
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
-	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/text"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
@@ -192,27 +192,30 @@ func (p *processor) ProcessLanguage(ctx context.Context, form *apimodel.Advanced
 }
 
 func (p *processor) ProcessMentions(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountID string, status *gtsmodel.Status) error {
-	menchies := []string{}
-	gtsMenchies, err := p.db.MentionStringsToMentions(ctx, util.DeriveMentionsFromText(form.Status), accountID, status.ID)
-	if err != nil {
-		return fmt.Errorf("error generating mentions from status: %s", err)
-	}
-	for _, menchie := range gtsMenchies {
-		menchieID, err := id.NewRandomULID()
+	mentionedAccountNames := util.DeriveMentionNamesFromText(form.Status)
+	mentions := []*gtsmodel.Mention{}
+	mentionIDs := []string{}
+
+	for _, mentionedAccountName := range mentionedAccountNames {
+		gtsMention, err := p.parseMention(ctx, mentionedAccountName, accountID, status.ID)
 		if err != nil {
-			return err
+			logrus.Errorf("ProcessMentions: error parsing mention %s from status: %s", mentionedAccountName, err)
+			continue
 		}
-		menchie.ID = menchieID
 
-		if err := p.db.Put(ctx, menchie); err != nil {
-			return fmt.Errorf("error putting mentions in db: %s", err)
+		if err := p.db.Put(ctx, gtsMention); err != nil {
+			logrus.Errorf("ProcessMentions: error putting mention in db: %s", err)
 		}
-		menchies = append(menchies, menchie.ID)
+
+		mentions = append(mentions, gtsMention)
+		mentionIDs = append(mentionIDs, gtsMention.ID)
 	}
+
 	// add full populated gts menchies to the status for passing them around conveniently
-	status.Mentions = gtsMenchies
+	status.Mentions = mentions
 	// add just the ids of the mentioned accounts to the status for putting in the db
-	status.MentionIDs = menchies
+	status.MentionIDs = mentionIDs
+
 	return nil
 }
 
diff --git a/internal/processing/util.go b/internal/processing/util.go
new file mode 100644
index 000000000..7ae7b8604
--- /dev/null
+++ b/internal/processing/util.go
@@ -0,0 +1,151 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   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 processing
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/federation"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+)
+
+func GetParseMentionFunc(dbConn db.DB, federator federation.Federator) gtsmodel.ParseMentionFunc {
+	return func(ctx context.Context, targetAccount string, originAccountID string, statusID string) (*gtsmodel.Mention, error) {
+		// get the origin account first since we'll need it to create the mention
+		originAccount, err := dbConn.GetAccountByID(ctx, originAccountID)
+		if err != nil {
+			return nil, fmt.Errorf("couldn't get mention origin account with id %s", originAccountID)
+		}
+
+		// A mentioned account looks like "@test@example.org" or just "@test" for a local account
+		// -- we can guarantee this from the regex that targetAccounts should have been derived from.
+		// But we still need to do a bit of fiddling to get what we need here -- the username and domain (if given).
+
+		// 1.  trim off the first @
+		trimmed := strings.TrimPrefix(targetAccount, "@")
+
+		// 2. split the username and domain
+		split := strings.Split(trimmed, "@")
+
+		// 3. if it's length 1 it's a local account, length 2 means remote, anything else means something is wrong
+
+		var local bool
+		switch len(split) {
+		case 1:
+			local = true
+		case 2:
+			local = false
+		default:
+			return nil, fmt.Errorf("mentioned account format '%s' was not valid", targetAccount)
+		}
+
+		var username, domain string
+		username = split[0]
+		if !local {
+			domain = split[1]
+		}
+
+		// 4. check we now have a proper username and domain
+		if username == "" || (!local && domain == "") {
+			return nil, fmt.Errorf("username or domain for '%s' was nil", targetAccount)
+		}
+
+		var mentionedAccount *gtsmodel.Account
+
+		if local {
+			localAccount, err := dbConn.GetLocalAccountByUsername(ctx, username)
+			if err != nil {
+				return nil, err
+			}
+			mentionedAccount = localAccount
+		} else {
+			remoteAccount := &gtsmodel.Account{}
+
+			where := []db.Where{
+				{
+					Key:             "username",
+					Value:           username,
+					CaseInsensitive: true,
+				},
+				{
+					Key:             "domain",
+					Value:           domain,
+					CaseInsensitive: true,
+				},
+			}
+
+			err := dbConn.GetWhere(ctx, where, remoteAccount)
+			if err == nil {
+				// the account was already in the database
+				mentionedAccount = remoteAccount
+			} else {
+				// we couldn't get it from the database
+				if err != db.ErrNoEntries {
+					// a serious error has happened so bail
+					return nil, fmt.Errorf("error getting account with username '%s' and domain '%s': %s", username, domain, err)
+				}
+
+				// We just don't have the account, so try webfingering it.
+				//
+				// If the mention originates from our instance we should use the username of the origin account to do the dereferencing,
+				// otherwise we should just use our instance account (that is, provide an empty string), since obviously we can't use
+				// a remote account to do remote dereferencing!
+				var fingeringUsername string
+				if originAccount.Domain == "" {
+					fingeringUsername = originAccount.Username
+				}
+
+				acctURI, err := federator.FingerRemoteAccount(ctx, fingeringUsername, username, domain)
+				if err != nil {
+					// something went wrong doing the webfinger lookup so we can't process the request
+					return nil, fmt.Errorf("error fingering remote account with username %s and domain %s: %s", username, domain, err)
+				}
+
+				resolvedAccount, err := federator.GetRemoteAccount(ctx, fingeringUsername, acctURI, true, true)
+				if err != nil {
+					return nil, fmt.Errorf("error dereferencing account with uri %s: %s", acctURI.String(), err)
+				}
+
+				// we were able to resolve it!
+				mentionedAccount = resolvedAccount
+			}
+		}
+
+		mentionID, err := id.NewRandomULID()
+		if err != nil {
+			return nil, err
+		}
+
+		return &gtsmodel.Mention{
+			ID:               mentionID,
+			StatusID:         statusID,
+			OriginAccountID:  originAccount.ID,
+			OriginAccountURI: originAccount.URI,
+			TargetAccountID:  mentionedAccount.ID,
+			NameString:       targetAccount,
+			TargetAccountURI: mentionedAccount.URI,
+			TargetAccountURL: mentionedAccount.URL,
+			OriginAccount:    mentionedAccount,
+		}, nil
+	}
+}