[chore] Deinterface processor and subprocessors (#1501)

* [chore] Deinterface processor and subprocessors

* expose subprocessors via function calls

* missing license header

internal/processing/stream/authorize.go

@@ -0,0 +1,63 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2023 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 stream
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// Authorize returns an oauth2 token info in response to an access token query from the streaming API
+func (p *Processor) Authorize(ctx context.Context, accessToken string) (*gtsmodel.Account, gtserror.WithCode) {
+	ti, err := p.oauthServer.LoadAccessToken(ctx, accessToken)
+	if err != nil {
+		err := fmt.Errorf("could not load access token: %s", err)
+		return nil, gtserror.NewErrorUnauthorized(err)
+	}
+
+	uid := ti.GetUserID()
+	if uid == "" {
+		err := fmt.Errorf("no userid in token")
+		return nil, gtserror.NewErrorUnauthorized(err)
+	}
+
+	user, err := p.db.GetUserByID(ctx, uid)
+	if err != nil {
+		if err == db.ErrNoEntries {
+			err := fmt.Errorf("no user found for validated uid %s", uid)
+			return nil, gtserror.NewErrorUnauthorized(err)
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	acct, err := p.db.GetAccountByID(ctx, user.AccountID)
+	if err != nil {
+		if err == db.ErrNoEntries {
+			err := fmt.Errorf("no account found for validated uid %s", uid)
+			return nil, gtserror.NewErrorUnauthorized(err)
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return acct, nil
+}