[feature] Fetch + display custom emoji in statuses from remote instances (#807)

* start implementing remote emoji fetcher

* update status where pk

* aaa

* tidy up a little

* check size limits for emojis

* thank you linter, i love you <3

* update swagger docs

* add emoji dereference test

* make emoji max sizes configurable

* normalize db.ErrAlreadyExists

5 files changed, 211 insertions, 15 deletions

diff --git a/internal/federation/dereferencing/dereferencer.go b/internal/federation/dereferencing/dereferencer.go
index 4f7559be3..0fad2405e 100644
--- a/internal/federation/dereferencing/dereferencer.go
+++ b/internal/federation/dereferencing/dereferencer.go
@@ -41,6 +41,7 @@ type Dereferencer interface {
 	GetRemoteInstance(ctx context.Context, username string, remoteInstanceURI *url.URL) (*gtsmodel.Instance, error)
 
 	GetRemoteMedia(ctx context.Context, requestingUsername string, accountID string, remoteURL string, ai *media.AdditionalMediaInfo) (*media.ProcessingMedia, error)
+	GetRemoteEmoji(ctx context.Context, requestingUsername string, remoteURL string, shortcode string, id string, emojiURI string, ai *media.AdditionalEmojiInfo) (*media.ProcessingEmoji, error)
 
 	DereferenceAnnounce(ctx context.Context, announce *gtsmodel.Status, requestingUsername string) error
 	DereferenceThread(ctx context.Context, username string, statusIRI *url.URL) error
diff --git a/internal/federation/dereferencing/emoji.go b/internal/federation/dereferencing/emoji.go
new file mode 100644
index 000000000..49811b131
--- /dev/null
+++ b/internal/federation/dereferencing/emoji.go
@@ -0,0 +1,51 @@
+/*
+   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 dereferencing
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/url"
+
+	"github.com/superseriousbusiness/gotosocial/internal/media"
+)
+
+func (d *deref) GetRemoteEmoji(ctx context.Context, requestingUsername string, remoteURL string, shortcode string, id string, emojiURI string, ai *media.AdditionalEmojiInfo) (*media.ProcessingEmoji, error) {
+	t, err := d.transportController.NewTransportForUsername(ctx, requestingUsername)
+	if err != nil {
+		return nil, fmt.Errorf("GetRemoteEmoji: error creating transport: %s", err)
+	}
+
+	derefURI, err := url.Parse(remoteURL)
+	if err != nil {
+		return nil, fmt.Errorf("GetRemoteEmoji: error parsing url: %s", err)
+	}
+
+	dataFunc := func(innerCtx context.Context) (io.Reader, int, error) {
+		return t.DereferenceMedia(innerCtx, derefURI)
+	}
+
+	processingMedia, err := d.mediaManager.ProcessEmoji(ctx, dataFunc, nil, shortcode, id, emojiURI, ai)
+	if err != nil {
+		return nil, fmt.Errorf("GetRemoteEmoji: error processing emoji: %s", err)
+	}
+
+	return processingMedia, nil
+}
diff --git a/internal/federation/dereferencing/emoji_test.go b/internal/federation/dereferencing/emoji_test.go
new file mode 100644
index 000000000..b03d839ce
--- /dev/null
+++ b/internal/federation/dereferencing/emoji_test.go
@@ -0,0 +1,95 @@
+/*
+   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 dereferencing_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/media"
+)
+
+type EmojiTestSuite struct {
+	DereferencerStandardTestSuite
+}
+
+func (suite *EmojiTestSuite) TestDereferenceEmojiBlocking() {
+	ctx := context.Background()
+	fetchingAccount := suite.testAccounts["local_account_1"]
+	emojiImageRemoteURL := "http://example.org/media/emojis/1781772.gif"
+	emojiImageStaticRemoteURL := "http://example.org/media/emojis/1781772.gif"
+	emojiURI := "http://example.org/emojis/1781772"
+	emojiShortcode := "peglin"
+	emojiID := "01GCBMGNZBKMEE1KTZ6PMJEW5D"
+	emojiDomain := "example.org"
+	emojiDisabled := false
+	emojiVisibleInPicker := false
+
+	ai := &media.AdditionalEmojiInfo{
+		Domain:               &emojiDomain,
+		ImageRemoteURL:       &emojiImageRemoteURL,
+		ImageStaticRemoteURL: &emojiImageStaticRemoteURL,
+		Disabled:             &emojiDisabled,
+		VisibleInPicker:      &emojiVisibleInPicker,
+	}
+
+	processingEmoji, err := suite.dereferencer.GetRemoteEmoji(ctx, fetchingAccount.Username, emojiImageRemoteURL, emojiShortcode, emojiID, emojiURI, ai)
+	suite.NoError(err)
+
+	// make a blocking call to load the emoji from the in-process media
+	emoji, err := processingEmoji.LoadEmoji(ctx)
+	suite.NoError(err)
+	suite.NotNil(emoji)
+
+	suite.Equal(emojiID, emoji.ID)
+	suite.WithinDuration(time.Now(), emoji.CreatedAt, 10*time.Second)
+	suite.WithinDuration(time.Now(), emoji.UpdatedAt, 10*time.Second)
+	suite.Equal(emojiShortcode, emoji.Shortcode)
+	suite.Equal(emojiDomain, emoji.Domain)
+	suite.Equal(emojiImageRemoteURL, emoji.ImageRemoteURL)
+	suite.Equal(emojiImageStaticRemoteURL, emoji.ImageStaticRemoteURL)
+	suite.Contains(emoji.ImageURL, "/emoji/original/01GCBMGNZBKMEE1KTZ6PMJEW5D.gif")
+	suite.Contains(emoji.ImageStaticURL, "emoji/static/01GCBMGNZBKMEE1KTZ6PMJEW5D.png")
+	suite.Contains(emoji.ImagePath, "/emoji/original/01GCBMGNZBKMEE1KTZ6PMJEW5D.gif")
+	suite.Contains(emoji.ImageStaticPath, "/emoji/static/01GCBMGNZBKMEE1KTZ6PMJEW5D.png")
+	suite.Equal("image/gif", emoji.ImageContentType)
+	suite.Equal("image/png", emoji.ImageStaticContentType)
+	suite.Equal(37796, emoji.ImageFileSize)
+	suite.Equal(7951, emoji.ImageStaticFileSize)
+	suite.WithinDuration(time.Now(), emoji.ImageUpdatedAt, 10*time.Second)
+	suite.False(*emoji.Disabled)
+	suite.Equal(emojiURI, emoji.URI)
+	suite.False(*emoji.VisibleInPicker)
+	suite.Empty(emoji.CategoryID)
+
+	// ensure that emoji is now in storage
+	stored, err := suite.storage.Get(ctx, emoji.ImagePath)
+	suite.NoError(err)
+	suite.Len(stored, emoji.ImageFileSize)
+
+	storedStatic, err := suite.storage.Get(ctx, emoji.ImageStaticPath)
+	suite.NoError(err)
+	suite.Len(storedStatic, emoji.ImageStaticFileSize)
+}
+
+func TestEmojiTestSuite(t *testing.T) {
+	suite.Run(t, new(EmojiTestSuite))
+}
diff --git a/internal/federation/dereferencing/status.go b/internal/federation/dereferencing/status.go
index e6e03646c..f3b7ee96e 100644
--- a/internal/federation/dereferencing/status.go
+++ b/internal/federation/dereferencing/status.go
@@ -26,10 +26,10 @@ import (
 	"net/url"
 	"strings"
 
-	"codeberg.org/gruf/go-kv"
 	"github.com/superseriousbusiness/activity/streams"
 	"github.com/superseriousbusiness/activity/streams/vocab"
 	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -46,11 +46,7 @@ func (d *deref) EnrichRemoteStatus(ctx context.Context, username string, status
 		return nil, err
 	}
 
-	if err := d.db.UpdateByPrimaryKey(ctx, status); err != nil {
-		return nil, fmt.Errorf("EnrichRemoteStatus: error updating status: %s", err)
-	}
-
-	return status, nil
+	return d.db.UpdateStatus(ctx, status)
 }
 
 // GetRemoteStatus completely dereferences a remote status, converts it to a GtS model status,
@@ -225,12 +221,6 @@ func (d *deref) dereferenceStatusable(ctx context.Context, username string, remo
 // and attach them to the status. The status itself will not be added to the database yet,
 // that's up the caller to do.
 func (d *deref) populateStatusFields(ctx context.Context, status *gtsmodel.Status, requestingUsername string, includeParent bool) error {
-	l := log.WithFields(kv.Fields{
-
-		{"status", status},
-	}...)
-	l.Debug("entering function")
-
 	statusIRI, err := url.Parse(status.URI)
 	if err != nil {
 		return fmt.Errorf("populateStatusFields: couldn't parse status URI %s: %s", status.URI, err)
@@ -262,7 +252,9 @@ func (d *deref) populateStatusFields(ctx context.Context, status *gtsmodel.Statu
 	// TODO
 
 	// 3. Emojis
-	// TODO
+	if err := d.populateStatusEmojis(ctx, status, requestingUsername); err != nil {
+		return fmt.Errorf("populateStatusFields: error populating status emojis: %s", err)
+	}
 
 	// 4. Mentions
 	// TODO: do we need to handle removing empty mention objects and just using mention IDs slice?
@@ -413,6 +405,64 @@ func (d *deref) populateStatusAttachments(ctx context.Context, status *gtsmodel.
 	return nil
 }
 
+func (d *deref) populateStatusEmojis(ctx context.Context, status *gtsmodel.Status, requestingUsername string) error {
+	// At this point we should know:
+	// * the AP uri of the emoji
+	// * the domain of the emoji
+	// * the shortcode of the emoji
+	// * the remote URL of the image
+	// This should be enough to dereference the emoji
+
+	gotEmojis := make([]*gtsmodel.Emoji, 0, len(status.Emojis))
+	emojiIDs := make([]string, 0, len(status.Emojis))
+
+	for _, e := range status.Emojis {
+		var gotEmoji *gtsmodel.Emoji
+		var err error
+
+		// check if we've already got this emoji in the db
+		if gotEmoji, err = d.db.GetEmojiByURI(ctx, e.URI); err != nil && err != db.ErrNoEntries {
+			log.Errorf("populateStatusEmojis: error checking database for emoji %s: %s", e.URI, err)
+			continue
+		}
+
+		if gotEmoji == nil {
+			// it's new! go get it!
+			newEmojiID, err := id.NewRandomULID()
+			if err != nil {
+				log.Errorf("populateStatusEmojis: error generating id for remote emoji %s: %s", e.URI, err)
+				continue
+			}
+
+			processingEmoji, err := d.GetRemoteEmoji(ctx, requestingUsername, e.ImageRemoteURL, e.Shortcode, newEmojiID, e.URI, &media.AdditionalEmojiInfo{
+				Domain:               &e.Domain,
+				ImageRemoteURL:       &e.ImageRemoteURL,
+				ImageStaticRemoteURL: &e.ImageRemoteURL,
+				Disabled:             e.Disabled,
+				VisibleInPicker:      e.VisibleInPicker,
+			})
+
+			if err != nil {
+				log.Errorf("populateStatusEmojis: couldn't get remote emoji %s: %s", e.URI, err)
+				continue
+			}
+
+			if gotEmoji, err = processingEmoji.LoadEmoji(ctx); err != nil {
+				log.Errorf("populateStatusEmojis: couldn't load remote emoji %s: %s", e.URI, err)
+				continue
+			}
+		}
+
+		// if we get here, we either had the emoji already or we successfully fetched it
+		gotEmojis = append(gotEmojis, gotEmoji)
+		emojiIDs = append(emojiIDs, gotEmoji.ID)
+	}
+
+	status.Emojis = gotEmojis
+	status.EmojiIDs = emojiIDs
+	return nil
+}
+
 func (d *deref) populateStatusRepliedTo(ctx context.Context, status *gtsmodel.Status, requestingUsername string) error {
 	if status.InReplyToURI != "" && status.InReplyToID == "" {
 		statusURI, err := url.Parse(status.InReplyToURI)
diff --git a/internal/federation/federatingdb/create.go b/internal/federation/federatingdb/create.go
index a6e55f2ad..25e961bc3 100644
--- a/internal/federation/federatingdb/create.go
+++ b/internal/federation/federatingdb/create.go
@@ -226,8 +226,7 @@ func (f *federatingDB) createNote(ctx context.Context, note vocab.ActivityStream
 	status.ID = statusID
 
 	if err := f.db.PutStatus(ctx, status); err != nil {
-		var alreadyExistsError *db.ErrAlreadyExists
-		if errors.As(err, &alreadyExistsError) {
+		if errors.Is(err, db.ErrAlreadyExists) {
 			// the status already exists in the database, which means we've already handled everything else,
 			// so we can just return nil here and be done with it.
 			return nil