parseDomainPattern parses a domain pattern like ":subdomain.example.com" into a domainMatcher. Parameter parts start with ":". Constant labels are lowercased per RFC 4343 (domain names are case-insensitive), but parameter names are preserved as-is so that DomainParam lookups work with the exact name
(pattern string)
| 53 | // but parameter names are preserved as-is so that DomainParam lookups work with |
| 54 | // the exact names the caller used (e.g., ":User" → param name "User"). |
| 55 | func parseDomainPattern(pattern string) domainMatcher { |
| 56 | pattern = utils.TrimSpace(pattern) |
| 57 | // Trim trailing dot of a fully-qualified domain name (RFC 3986), |
| 58 | // consistent with Fiber's own host normalization in Subdomains(). |
| 59 | pattern = utils.TrimRight(pattern, '.') |
| 60 | |
| 61 | // Validate pattern is not empty after trimming |
| 62 | if pattern == "" { |
| 63 | panic("Domain pattern cannot be empty") |
| 64 | } |
| 65 | |
| 66 | // Enforce RFC 1035 total length limit on patterns |
| 67 | if len(pattern) > 253 { |
| 68 | panic(fmt.Sprintf("Domain pattern '%s' exceeds RFC 1035 maximum of 253 characters (%d chars)", |
| 69 | pattern, len(pattern))) |
| 70 | } |
| 71 | |
| 72 | parts := strings.Split(pattern, ".") |
| 73 | |
| 74 | // Prevent DoS from patterns with excessive label counts |
| 75 | if len(parts) > maxDomainParts { |
| 76 | panic(fmt.Sprintf("Domain pattern '%s' has %d parts, which exceeds the maximum of %d", |
| 77 | pattern, len(parts), maxDomainParts)) |
| 78 | } |
| 79 | |
| 80 | m := domainMatcher{ |
| 81 | parts: make([]string, len(parts)), |
| 82 | numParts: len(parts), |
| 83 | } |
| 84 | |
| 85 | for i, part := range parts { |
| 86 | // Validate no empty labels (e.g., "example..com" is invalid) |
| 87 | if part == "" { |
| 88 | panic(fmt.Sprintf("Domain pattern '%s' contains empty label at position %d", pattern, i)) |
| 89 | } |
| 90 | |
| 91 | if part[0] == ':' { |
| 92 | // Validate parameter name is not empty |
| 93 | if len(part) == 1 { |
| 94 | panic(fmt.Sprintf("Domain pattern '%s' contains empty parameter name at position %d", pattern, i)) |
| 95 | } |
| 96 | paramName := part[1:] |
| 97 | // Validate parameter name contains only ASCII-safe characters (a-z, A-Z, 0-9, underscore, hyphen). |
| 98 | // Using explicit ASCII ranges rather than unicode.IsLetter/IsDigit to reject non-ASCII |
| 99 | // characters that are invalid in DNS names. |
| 100 | for _, ch := range paramName { |
| 101 | if !isASCIIAlphanumeric(ch) && ch != '_' && ch != '-' { |
| 102 | panic(fmt.Sprintf("Domain pattern '%s' contains invalid parameter name '%s' with character '%c'", pattern, paramName, ch)) |
| 103 | } |
| 104 | } |
| 105 | m.paramIdx = append(m.paramIdx, i) |
| 106 | m.paramNames = append(m.paramNames, paramName) // preserve original case |
| 107 | m.parts[i] = part // keep ":param" marker for matching |
| 108 | } else { |
| 109 | // Only lowercase constant labels (RFC 4343) |
| 110 | // Enforce RFC 1035 per-label length limit (63 characters) |
| 111 | if len(part) > 63 { |
| 112 | panic(fmt.Sprintf("Domain pattern '%s' has label '%s' exceeding RFC 1035 limit of 63 characters (%d chars)", |