1 files changed, 80 insertions, 0 deletions
diff --git a/internal/filter/status/text.go b/internal/filter/status/text.go
new file mode 100644
index 000000000..347e1193c
--- /dev/null
+++ b/internal/filter/status/text.go
@@ -0,0 +1,80 @@
+// 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 status
+
+import (
+	"code.superseriousbusiness.org/gotosocial/internal/gtsmodel"
+	"code.superseriousbusiness.org/gotosocial/internal/text"
+)
+
+// getFilterableFields returns text fields from
+// a status that we might want to filter on:
+//
+//   - content warning
+//   - content (converted to plaintext from HTML)
+//   - media descriptions
+//   - poll options
+//
+// Each field should be filtered separately. This avoids
+// scenarios where false-positive multiple-word matches
+// can be made by matching the last word of one field
+// combined with the first word of the next field together.
+func getFilterableFields(status *gtsmodel.Status) []string {
+
+	// Estimate expected no of status fields.
+	fieldCount := 2 + len(status.Attachments)
+	if status.Poll != nil {
+		fieldCount += len(status.Poll.Options)
+	}
+	fields := make([]string, 0, fieldCount)
+
+	// Append content warning / title.
+	if status.ContentWarning != "" {
+		fields = append(fields, status.ContentWarning)
+	}
+
+	// Status content. Though we have raw text
+	// available for statuses created on our
+	// instance, use the plaintext version to
+	// remove markdown-formatting characters
+	// and ensure more consistent filtering.
+	if status.Content != "" {
+		text := text.ParseHTMLToPlain(status.Content)
+		if text != "" {
+			fields = append(fields, text)
+		}
+	}
+
+	// Media descriptions, only where they are set.
+	for _, attachment := range status.Attachments {
+		if attachment.Description != "" {
+			fields = append(fields, attachment.Description)
+		}
+	}
+
+	// Non-empty poll options.
+	if status.Poll != nil {
+		for _, opt := range status.Poll.Options {
+			if opt != "" {
+				fields = append(fields, opt)
+			}
+		}
+	}
+
+	return fields
+}