refactor framework interface, simplify basic and whitelisted, bring expensive on and rewrite it.

storage/postgresql/save.go

@@ -0,0 +1,45 @@
+package postgresql
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/fiatjaf/go-nostr"
+)
+
+func (b *PostgresBackend) SaveEvent(evt *nostr.Event) error {
+	// react to different kinds of events
+	if evt.Kind == nostr.KindSetMetadata || evt.Kind == nostr.KindContactList || (10000 <= evt.Kind && evt.Kind < 20000) {
+		// delete past events from this user
+		b.DB.Exec(`DELETE FROM event WHERE pubkey = $1 AND kind = $2`, evt.PubKey, evt.Kind)
+	} else if evt.Kind == nostr.KindRecommendServer {
+		// delete past recommend_server events equal to this one
+		b.DB.Exec(`DELETE FROM event WHERE pubkey = $1 AND kind = $2 AND content = $3`,
+			evt.PubKey, evt.Kind, evt.Content)
+	}
+
+	// insert
+	tagsj, _ := json.Marshal(evt.Tags)
+	_, err := b.DB.Exec(`
+        INSERT INTO event (id, pubkey, created_at, kind, tags, content, sig)
+        VALUES ($1, $2, $3, $4, $5, $6, $7)
+    `, evt.ID, evt.PubKey, evt.CreatedAt.Unix(), evt.Kind, tagsj, evt.Content, evt.Sig)
+	if err != nil {
+		if strings.Index(err.Error(), "UNIQUE") != -1 {
+			// already exists
+			return nil
+		}
+
+		return fmt.Errorf("failed to save event %s: %w", evt.ID, err)
+	}
+
+	// delete ephemeral events after a minute
+	go func() {
+		time.Sleep(75 * time.Second)
+		b.DB.Exec("DELETE FROM event WHERE id = $1", evt.ID)
+	}()
+
+	return nil
+}