Remove Dgraph, check hex field case, reject if any uppercase

pkg/neo4j/hex_utils.go

@@ -0,0 +1,103 @@
+// Package neo4j provides hex utilities for normalizing pubkeys and event IDs.
+//
+// The nostr library applies binary optimization to e/p tags, storing 64-character
+// hex strings as 33-byte binary (32 bytes + null terminator). This file provides
+// utilities to ensure all pubkeys and event IDs stored in Neo4j are in consistent
+// lowercase hex format.
+package neo4j
+
+import (
+	"strings"
+
+	"git.mleku.dev/mleku/nostr/encoders/hex"
+	"git.mleku.dev/mleku/nostr/encoders/tag"
+)
+
+// Tag binary encoding constants (matching the nostr library)
+const (
+	// BinaryEncodedLen is the length of a binary-encoded 32-byte hash with null terminator
+	BinaryEncodedLen = 33
+	// HexEncodedLen is the length of a hex-encoded 32-byte hash (pubkey or event ID)
+	HexEncodedLen = 64
+	// HashLen is the raw length of a hash (pubkey/event ID)
+	HashLen = 32
+)
+
+// IsBinaryEncoded checks if a value is stored in the nostr library's binary-optimized format
+func IsBinaryEncoded(val []byte) bool {
+	return len(val) == BinaryEncodedLen && val[HashLen] == 0
+}
+
+// NormalizePubkeyHex ensures a pubkey/event ID is in lowercase hex format.
+// It handles:
+// - Binary-encoded values (33 bytes with null terminator) -> converts to lowercase hex
+// - Uppercase hex strings -> converts to lowercase
+// - Already lowercase hex -> returns as-is
+//
+// This should be used for all pubkeys and event IDs before storing in Neo4j
+// to prevent duplicate nodes due to case differences.
+func NormalizePubkeyHex(val []byte) string {
+	// Handle binary-encoded values from the nostr library
+	if IsBinaryEncoded(val) {
+		// Convert binary to lowercase hex
+		return hex.Enc(val[:HashLen])
+	}
+
+	// Handle hex strings (may be uppercase from external sources)
+	if len(val) == HexEncodedLen {
+		return strings.ToLower(string(val))
+	}
+
+	// For other lengths (possibly prefixes), lowercase the hex
+	return strings.ToLower(string(val))
+}
+
+// ExtractPTagValue extracts a pubkey from a p-tag, handling binary encoding.
+// Returns lowercase hex string suitable for Neo4j storage.
+// Returns empty string if the tag doesn't have a valid value.
+func ExtractPTagValue(t *tag.T) string {
+	if t == nil || len(t.T) < 2 {
+		return ""
+	}
+
+	// Use ValueHex() which properly handles both binary and hex formats
+	hexVal := t.ValueHex()
+	if len(hexVal) == 0 {
+		return ""
+	}
+
+	// Ensure lowercase (ValueHex returns the library's encoding which is lowercase,
+	// but we normalize anyway for safety with external data)
+	return strings.ToLower(string(hexVal))
+}
+
+// ExtractETagValue extracts an event ID from an e-tag, handling binary encoding.
+// Returns lowercase hex string suitable for Neo4j storage.
+// Returns empty string if the tag doesn't have a valid value.
+func ExtractETagValue(t *tag.T) string {
+	if t == nil || len(t.T) < 2 {
+		return ""
+	}
+
+	// Use ValueHex() which properly handles both binary and hex formats
+	hexVal := t.ValueHex()
+	if len(hexVal) == 0 {
+		return ""
+	}
+
+	// Ensure lowercase
+	return strings.ToLower(string(hexVal))
+}
+
+// IsValidHexPubkey checks if a string is a valid 64-character hex pubkey
+func IsValidHexPubkey(s string) bool {
+	if len(s) != HexEncodedLen {
+		return false
+	}
+	for _, c := range s {
+		if !((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F')) {
+			return false
+		}
+	}
+	return true
+}