1 files changed, 114 insertions, 0 deletions
diff --git a/internal/processing/search/lookup.go b/internal/processing/search/lookup.go
new file mode 100644
index 000000000..0f2a4191b
--- /dev/null
+++ b/internal/processing/search/lookup.go
@@ -0,0 +1,114 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 search
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	errorsv2 "codeberg.org/gruf/go-errors/v2"
+	"codeberg.org/gruf/go-kv"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+)
+
+// Lookup does a quick, non-resolving search for accounts that
+// match the given query. It expects input that looks like a
+// namestring, and will normalize plaintext to look more like
+// a namestring. Will only ever return one account, and only on
+// an exact match.
+//
+// This behavior aligns more or less with Mastodon's API.
+// See https://docs.joinmastodon.org/methods/accounts/#lookup
+func (p *Processor) Lookup(
+	ctx context.Context,
+	requestingAccount *gtsmodel.Account,
+	query string,
+) (*apimodel.Account, gtserror.WithCode) {
+	// Validate query.
+	query = strings.TrimSpace(query)
+	if query == "" {
+		err := errors.New("search query was empty string after trimming space")
+		return nil, gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	// Be nice and normalize query by prepending '@'.
+	// This will make it easier for accountsByNamestring
+	// to pick this up as a valid namestring.
+	if query[0] != '@' {
+		query = "@" + query
+	}
+
+	log.
+		WithContext(ctx).
+		WithFields(kv.Fields{
+			{"query", query},
+		}...).
+		Debugf("beginning search")
+
+	// See if we have something that looks like a namestring.
+	username, domain, err := util.ExtractNamestringParts(query)
+	if err != nil {
+		err := errors.New("bad search query, must in the form '[username]' or '[username]@[domain]")
+		return nil, gtserror.NewErrorBadRequest(err, err.Error())
+	}
+
+	account, err := p.accountByUsernameDomain(
+		ctx,
+		requestingAccount,
+		username,
+		domain,
+		false, // never resolve!
+	)
+	if err != nil {
+		if errorsv2.Assignable(err, (*dereferencing.ErrNotRetrievable)(nil)) {
+			// ErrNotRetrievable is fine, just wrap it in
+			// a 404 to indicate we couldn't find anything.
+			err := fmt.Errorf("%s not found", query)
+			return nil, gtserror.NewErrorNotFound(err, err.Error())
+		}
+
+		// Real error has occurred.
+		err = gtserror.Newf("error looking up %s as account: %w", query, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	// If we reach this point, we found an account. Shortcut
+	// using the packageAccounts function to return it. This
+	// may cause the account to be filtered out if it's not
+	// visible to the caller, so anticipate this.
+	accounts, errWithCode := p.packageAccounts(ctx, requestingAccount, []*gtsmodel.Account{account})
+	if errWithCode != nil {
+		return nil, errWithCode
+	}
+
+	if len(accounts) == 0 {
+		// Account was not visible to the requesting account.
+		err := fmt.Errorf("%s not found", query)
+		return nil, gtserror.NewErrorNotFound(err, err.Error())
+	}
+
+	// We got a hit!
+	return accounts[0], nil
+}