From 2c38b5edee339e5fe9060a835d9772a71606dc85 Mon Sep 17 00:00:00 2001
From: Christian Cleberg <hello@cleberg.net>
Date: Fri, 3 Apr 2026 17:14:00 -0500
Subject: Add HTTP header grading and protocol metadata

---
 DomainDig/HTTPHeadersService.swift | 100 ++++++++++++++++++++++++++++++++++---
 1 file changed, 94 insertions(+), 6 deletions(-)

(limited to 'DomainDig/HTTPHeadersService.swift')

diff --git a/DomainDig/HTTPHeadersService.swift b/DomainDig/HTTPHeadersService.swift
index a297165..04efce6 100644
--- a/DomainDig/HTTPHeadersService.swift
+++ b/DomainDig/HTTPHeadersService.swift
@@ -1,22 +1,110 @@
 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 throws -> [HTTPHeader] {
+    static func fetch(domain: String) async throws -> HTTPHeadersResult {
         let url = URL(string: "https://\(domain)")!
         var request = URLRequest(url: url, timeoutInterval: 10)
         request.httpMethod = "HEAD"
+        let metricsDelegate = TaskMetricsDelegate()
+        let startTime = Date()
 
-        let (_, response) = try await URLSession.shared.data(for: request)
+        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 {
             throw URLError(.badServerResponse)
         }
 
-        return httpResponse.allHeaderFields.compactMap { key, value in
-            guard let name = key as? String,
-                  let val = value as? String else { return nil }
-            return HTTPHeader(name: name, value: val)
+        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
+
+        return HTTPHeadersResult(
+            headers: headers,
+            statusCode: httpResponse.statusCode,
+            responseTimeMs: responseTimeMs,
+            httpProtocol: detectedProtocol,
+            http3Advertised: http3Advertised
+        )
+    }
+
+    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(
+        _ session: URLSession,
+        task: URLSessionTask,
+        didFinishCollecting metrics: URLSessionTaskMetrics
+    ) {
+        self.metrics = metrics
     }
 }
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