[feature] Allow users to set custom css for their profiles + threads (#808)

* add custom css account property + db func to fetch

* allow account to get/set custom css

* serve custom css for an account

* go fmt

* use monospace for customcss, add link

* add custom css to account cache

* fix broken field

* add custom css docs to user guide

* add `accounts-allow-custom-css` config flag

* add allow custom css to /api/v1/instance response

* only show/set custom css if allowed to do so

* only set/serve custom account css if enabled

* update swagger docs

* chain promise

* make bool a bit clearer

* use cache for GetAccountCustomCSSByUsername

2 files changed, 55 insertions, 0 deletions

diff --git a/internal/db/bundb/account.go b/internal/db/bundb/account.go
index 23030c612..2105368d3 100644
--- a/internal/db/bundb/account.go
+++ b/internal/db/bundb/account.go
@@ -231,6 +231,15 @@ func (a *accountDB) SetAccountHeaderOrAvatar(ctx context.Context, mediaAttachmen
 	return nil
 }
 
+func (a *accountDB) GetAccountCustomCSSByUsername(ctx context.Context, username string) (string, db.Error) {
+	account, err := a.GetAccountByUsernameDomain(ctx, username, "")
+	if err != nil {
+		return "", err
+	}
+
+	return account.CustomCSS, nil
+}
+
 func (a *accountDB) GetAccountFaves(ctx context.Context, accountID string) ([]*gtsmodel.StatusFave, db.Error) {
 	faves := new([]*gtsmodel.StatusFave)
 
diff --git a/internal/db/bundb/migrations/20220823140228_user_custom_css.go b/internal/db/bundb/migrations/20220823140228_user_custom_css.go
new file mode 100644
index 000000000..12b093729
--- /dev/null
+++ b/internal/db/bundb/migrations/20220823140228_user_custom_css.go
@@ -0,0 +1,46 @@
+/*
+   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 migrations
+
+import (
+	"context"
+	"strings"
+
+	"github.com/uptrace/bun"
+)
+
+func init() {
+	up := func(ctx context.Context, db *bun.DB) error {
+		_, err := db.ExecContext(ctx, "ALTER TABLE ? ADD COLUMN ? TEXT", bun.Ident("accounts"), bun.Ident("custom_css"))
+		if err != nil && !(strings.Contains(err.Error(), "already exists") || strings.Contains(err.Error(), "duplicate column name") || strings.Contains(err.Error(), "SQLSTATE 42701")) {
+			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)
+	}
+}