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

basic/query.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"database/sql"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/fiatjaf/go-nostr/event"
+	"github.com/fiatjaf/go-nostr/filter"
+	"github.com/rs/zerolog/log"
+)
+
+func (b *BasicRelay) QueryEvents(
+	filter *filter.EventFilter,
+) (events []event.Event, err error) {
+	var conditions []string
+	var params []interface{}
+
+	if filter == nil {
+		err = errors.New("filter cannot be null")
+		return
+	}
+
+	if filter.ID != "" {
+		conditions = append(conditions, "id = ?")
+		params = append(params, filter.ID)
+	}
+
+	if filter.Kind != nil && *filter.Kind != 0 {
+		conditions = append(conditions, "kind = ?")
+		params = append(params, filter.Kind)
+	}
+
+	if filter.Authors != nil {
+		if len(filter.Authors) == 0 {
+			// authors being [] means you won't get anything
+			return
+		} else {
+			inkeys := make([]string, 0, len(filter.Authors))
+			for _, key := range filter.Authors {
+				// to prevent sql attack here we will check if
+				// these keys are valid 32byte hex
+				parsed, err := hex.DecodeString(key)
+				if err != nil || len(parsed) != 32 {
+					continue
+				}
+				inkeys = append(inkeys, fmt.Sprintf("'%x'", parsed))
+			}
+			conditions = append(conditions, `pubkey IN (`+strings.Join(inkeys, ",")+`)`)
+		}
+	}
+
+	if filter.TagEvent != "" {
+		conditions = append(conditions, tagConditions)
+		params = append(params, filter.TagEvent)
+	}
+
+	if filter.TagProfile != "" {
+		conditions = append(conditions, tagConditions)
+		params = append(params, filter.TagProfile)
+	}
+
+	if filter.Since != 0 {
+		conditions = append(conditions, "created_at > ?")
+		params = append(params, filter.Since)
+	}
+
+	if len(conditions) == 0 {
+		// fallback
+		conditions = append(conditions, "true")
+	}
+
+	query := b.DB.Rebind("SELECT * FROM event WHERE " +
+		strings.Join(conditions, " AND ") +
+		" ORDER BY created_at LIMIT 100")
+
+	err = b.DB.Select(&events, query, params...)
+	if err != nil && err != sql.ErrNoRows {
+		log.Warn().Err(err).Interface("filter", filter).Msg("failed to fetch events")
+		err = fmt.Errorf("failed to fetch events: %w", err)
+	}
+
+	return
+}