turn relayer into a server framework and put actual relay code into ./basic

basic/save.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/fiatjaf/go-nostr/event"
+)
+
+func (b *BasicRelay) SaveEvent(evt *event.Event) error {
+	// disallow large contents
+	if len(evt.Content) > 1000 {
+		return errors.New("event content too large")
+	}
+
+	// react to different kinds of events
+	switch evt.Kind {
+	case event.KindSetMetadata:
+		// delete past set_metadata events from this user
+		b.DB.Exec(`DELETE FROM event WHERE pubkey = $1 AND kind = 0`, evt.PubKey)
+	case event.KindRecommendServer:
+		// delete past recommend_server events equal to this one
+		b.DB.Exec(`DELETE FROM event WHERE pubkey = $1 AND kind = 2 AND content = $2`,
+			evt.PubKey, evt.Content)
+	case event.KindContactList:
+		// delete past contact lists from this same pubkey
+		b.DB.Exec(`DELETE FROM event WHERE pubkey = $1 AND kind = 3`, evt.PubKey)
+	default:
+		// delete all but the 10 most recent ones
+		b.DB.Exec(`DELETE FROM event WHERE pubkey = $1 AND kind = $2 AND created_at < (
+          SELECT created_at FROM event WHERE pubkey = $1
+          ORDER BY created_at DESC OFFSET 10 LIMIT 1
+        )`,
+			evt.PubKey, evt.Kind)
+	}
+
+	// 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, 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 from %s", evt.PubKey)
+	}
+
+	return nil
+}