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import Foundation
enum HTTPSecurityGrade: String {
case a = "A"
case b = "B"
case c = "C"
case d = "D"
case f = "F"
static func grade(for headers: [HTTPHeader]) -> HTTPSecurityGrade {
let presentHeaderNames = Set(headers.map { $0.name.lowercased() })
let presentCount = HTTPHeader.securityHeaders.intersection(presentHeaderNames).count
switch presentCount {
case 5:
return .a
case 4:
return .b
case 3:
return .c
case 2:
return .d
default:
return .f
}
}
}
struct HTTPHeadersResult {
let headers: [HTTPHeader]
let statusCode: Int?
let responseTimeMs: Int?
let httpProtocol: String?
let http3Advertised: Bool
}
struct HTTPHeadersService {
static func fetch(domain: String) async -> ServiceResult<HTTPHeadersResult> {
let url = URL(string: "https://\(domain)")!
var request = URLRequest(url: url, timeoutInterval: 10)
request.httpMethod = "HEAD"
let metricsDelegate = TaskMetricsDelegate()
let startTime = Date()
do {
let (_, response) = try await URLSession.shared.data(for: request, delegate: metricsDelegate)
let responseTimeMs = max(0, Int(Date().timeIntervalSince(startTime) * 1000))
guard let httpResponse = response as? HTTPURLResponse else {
return .error(URLError(.badServerResponse).localizedDescription)
}
let headers = httpResponse.allHeaderFields.compactMap { entry -> HTTPHeader? in
guard let name = entry.key as? String,
let value = entry.value as? String else { return nil }
return HTTPHeader(name: name, value: value)
}
.sorted { $0.name.lowercased() < $1.name.lowercased() }
let networkProtocolName = metricsDelegate.metrics?.transactionMetrics
.compactMap { $0.networkProtocolName }
.last
let detectedProtocol = protocolLabel(for: networkProtocolName)
let altSvcValue = headerValue(named: "alt-svc", in: httpResponse)
let http3Advertised = altSvcValue?.localizedCaseInsensitiveContains("h3") == true
let result = HTTPHeadersResult(
headers: headers,
statusCode: httpResponse.statusCode,
responseTimeMs: responseTimeMs,
httpProtocol: detectedProtocol,
http3Advertised: http3Advertised
)
return headers.isEmpty ? .empty("No HTTP headers returned") : .success(result)
} catch {
return .error(error.localizedDescription)
}
}
private static func protocolLabel(for networkProtocolName: String?) -> String? {
guard let networkProtocolName else { return nil }
let normalized = networkProtocolName.lowercased()
if normalized == "h2" {
return "HTTP/2"
}
if normalized == "h3" || normalized.hasPrefix("quic") {
return "HTTP/3"
}
if normalized.hasPrefix("http/") {
return normalized.uppercased()
}
return networkProtocolName.uppercased()
}
private static func headerValue(named name: String, in response: HTTPURLResponse) -> String? {
response.allHeaderFields.first { key, _ in
guard let headerName = key as? String else { return false }
return headerName.caseInsensitiveCompare(name) == .orderedSame
}?.value as? String
}
}
private final class TaskMetricsDelegate: NSObject, URLSessionTaskDelegate {
private(set) var metrics: URLSessionTaskMetrics?
func urlSession(
_ _: URLSession,
task _: URLSessionTask,
didFinishCollecting metrics: URLSessionTaskMetrics
) {
self.metrics = metrics
}
}
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