[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

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))
+}