fix(api): add ttl_seconds to QR challenge response and fix client-side countdown

The QR login page countdown timer compared the server's UTC expiration timestamp against the client's local clock, causing the QR code to appear immediately expired when the client clock was ahead of the server. Changes: - Add ttl_seconds field to CreateChallengeResponse (seconds until expiry) - Frontend countdown now uses relative elapsed time since response was received, eliminating clock-skew issues - Mobile app: replace alert-only QR button with actual camera-based QR code scanner using expo-camera - Add QRScannerScreen with barcode scanning, permission handling, and scan area overlay - Update camera permission description to mention QR code scanning - Add tests for ttl_seconds computation Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
2026-03-17 12:02:33 +00:00
parent 9fe50a87d1
commit 0f6a1ee1ec
8 changed files with 346 additions and 8 deletions
@@ -70,6 +70,7 @@ class CreateChallengeResponse(BaseModel):
    challenge_id: int
    challenge_token: str
    expires_at: datetime
+    ttl_seconds: int = Field(description="Seconds until the challenge expires (use for client-side countdown).")
    qr_payload: str = Field(description="The string to encode in the QR code.")


@@ -131,10 +132,16 @@ async def create_challenge(
    base_url = str(request.base_url).rstrip("/")
    qr_payload = f"docuelevate://qr-login?token={challenge.challenge_token}&server={base_url}"

+    # Compute the TTL in seconds so the client can run a countdown timer
+    # without comparing absolute timestamps (which breaks when client and
+    # server clocks are out of sync).
+    ttl_seconds = max(0, int((challenge.expires_at - challenge.created_at).total_seconds()))
+
    return {
        "challenge_id": challenge.id,
        "challenge_token": challenge.challenge_token,
        "expires_at": challenge.expires_at,
+        "ttl_seconds": ttl_seconds,
        "qr_payload": qr_payload,
    }

@@ -126,6 +126,8 @@ function qrLoginPage() {
    errorMsg: '',
    _pollTimer: null,
    _countdownTimer: null,
+    _ttlSeconds: 0,
+    _receivedAt: null,

    _csrfToken() {
      return document.cookie
@@ -156,6 +158,8 @@ function qrLoginPage() {
        this.challengeToken = data.challenge_token;
        this.qrPayload = data.qr_payload;
        this.expiresAt = new Date(data.expires_at);
+        this._ttlSeconds = data.ttl_seconds || 120;
+        this._receivedAt = Date.now();
        this.status = 'pending';
        this.deviceName = '';

@@ -214,8 +218,9 @@ function qrLoginPage() {
    },

    _updateCountdown() {
-      if (!this.expiresAt) { this.countdown = 0; return; }
-      const remaining = Math.max(0, Math.floor((this.expiresAt - new Date()) / 1000));
+      if (!this._receivedAt) { this.countdown = 0; return; }
+      const elapsed = (Date.now() - this._receivedAt) / 1000;
+      const remaining = Math.max(0, Math.floor(this._ttlSeconds - elapsed));
      this.countdown = remaining;
    },

@@ -19,7 +19,7 @@
      "bundleIdentifier": "org.docuelevate.mobile",
      "appleTeamId": "975U2ZESBM",
      "infoPlist": {
-        "NSCameraUsageDescription": "DocuElevate uses the camera to capture documents for upload.",
+        "NSCameraUsageDescription": "DocuElevate uses the camera to scan QR codes for login and to capture documents for upload.",
        "NSPhotoLibraryUsageDescription": "DocuElevate accesses your photo library to select documents for upload.",
        "NSPhotoLibraryAddUsageDescription": "DocuElevate saves scanned documents to your photo library.",
        "UIBackgroundModes": ["fetch", "remote-notification"],
@@ -101,7 +101,7 @@
      [
        "expo-camera",
        {
-          "cameraPermission": "DocuElevate uses the camera to capture documents for upload."
+          "cameraPermission": "DocuElevate uses the camera to scan QR codes for login and to capture documents for upload."
        }
      ],
      "expo-document-picker",
@@ -12,6 +12,7 @@ export default function AuthLayout() {
    <Stack screenOptions={{ headerShown: false }}>
      <Stack.Screen name="index" />
      <Stack.Screen name="login" />
+      <Stack.Screen name="qr-scanner" />
    </Stack>
  );
 }
@@ -0,0 +1,4 @@
+/**
+ * QR scanner route – camera-based QR code scanning for mobile login.
+ */
+export { default } from "../../src/screens/QRScannerScreen";
@@ -144,10 +144,7 @@ export default function LoginScreen() {
        <Pressable
          style={[styles.qrButton, qrLoading && styles.buttonDisabled]}
          onPress={() => {
-            Alert.alert(
-              "Scan QR Code",
-              "Open the DocuElevate web app on your computer, go to Profile → Security & Sessions → \"Log in on mobile via QR code\", and scan the QR code shown there.\n\nThe app will automatically detect the QR code when scanned with your device camera."
-            );
+            router.push("/(auth)/qr-scanner");
          }}
          disabled={loading || qrLoading}
          accessibilityRole="button"
@@ -0,0 +1,295 @@
+/**
+ * QRScannerScreen – camera-based QR code scanner for mobile login.
+ *
+ * Opens the device camera and scans for QR codes containing a
+ * `docuelevate://qr-login?token=...&server=...` payload.  On successful
+ * scan the token is claimed via the API and the user is signed in.
+ */
+
+import { CameraView, useCameraPermissions } from "expo-camera";
+import { useRouter } from "expo-router";
+import React, { useCallback, useRef, useState } from "react";
+import {
+  ActivityIndicator,
+  Alert,
+  Pressable,
+  StyleSheet,
+  Text,
+  View,
+} from "react-native";
+import { useAuth } from "../context/AuthContext";
+
+export default function QRScannerScreen() {
+  const { signInWithQR } = useAuth();
+  const router = useRouter();
+  const [permission, requestPermission] = useCameraPermissions();
+  const [scanned, setScanned] = useState(false);
+  const [processing, setProcessing] = useState(false);
+  const processingRef = useRef(false);
+
+  const handleBarCodeScanned = useCallback(
+    async (result: { data: string }) => {
+      // Prevent duplicate scans while processing
+      if (processingRef.current) return;
+
+      const { data } = result;
+
+      // Only accept docuelevate:// QR codes
+      if (!data.startsWith("docuelevate://qr-login")) return;
+
+      processingRef.current = true;
+      setScanned(true);
+      setProcessing(true);
+
+      try {
+        const url = new URL(data);
+        const token = url.searchParams.get("token");
+        const server = url.searchParams.get("server");
+
+        if (!token || !server) {
+          Alert.alert("Invalid QR Code", "This QR code does not contain valid login information.");
+          setScanned(false);
+          processingRef.current = false;
+          setProcessing(false);
+          return;
+        }
+
+        await signInWithQR(server, token);
+        // signInWithQR updates AuthContext → AuthGuard redirects to main app
+      } catch (err: unknown) {
+        const message = err instanceof Error ? err.message : "QR login failed";
+        Alert.alert("QR Login Failed", message);
+        setScanned(false);
+        processingRef.current = false;
+        setProcessing(false);
+      }
+    },
+    [signInWithQR]
+  );
+
+  // Permissions not yet determined
+  if (!permission) {
+    return (
+      <View style={styles.centered}>
+        <ActivityIndicator size="large" color="#1e40af" />
+      </View>
+    );
+  }
+
+  // Permission denied
+  if (!permission.granted) {
+    return (
+      <View style={styles.centered}>
+        <Text style={styles.permissionText}>
+          Camera access is required to scan QR codes.
+        </Text>
+        <Pressable
+          style={styles.permissionButton}
+          onPress={requestPermission}
+          accessibilityRole="button"
+          accessibilityLabel="Grant camera access"
+        >
+          <Text style={styles.permissionButtonText}>Grant Camera Access</Text>
+        </Pressable>
+        <Pressable
+          onPress={() => router.back()}
+          style={styles.backLink}
+          accessibilityRole="button"
+          accessibilityLabel="Go back"
+        >
+          <Text style={styles.backLinkText}>← Back</Text>
+        </Pressable>
+      </View>
+    );
+  }
+
+  return (
+    <View style={styles.container}>
+      <CameraView
+        style={styles.camera}
+        facing="back"
+        barcodeScannerSettings={{
+          barcodeTypes: ["qr"],
+        }}
+        onBarcodeScanned={scanned ? undefined : handleBarCodeScanned}
+      />
+
+      {/* Overlay with scan area indicator */}
+      <View style={styles.overlay}>
+        <View style={styles.overlayTop} />
+        <View style={styles.overlayMiddle}>
+          <View style={styles.overlaySide} />
+          <View style={styles.scanArea}>
+            <View style={[styles.corner, styles.cornerTopLeft]} />
+            <View style={[styles.corner, styles.cornerTopRight]} />
+            <View style={[styles.corner, styles.cornerBottomLeft]} />
+            <View style={[styles.corner, styles.cornerBottomRight]} />
+          </View>
+          <View style={styles.overlaySide} />
+        </View>
+        <View style={styles.overlayBottom}>
+          {processing ? (
+            <View style={styles.statusContainer}>
+              <ActivityIndicator color="#fff" />
+              <Text style={styles.statusText}>Signing in…</Text>
+            </View>
+          ) : (
+            <Text style={styles.instructionText}>
+              Point your camera at the QR code{"\n"}shown on the DocuElevate web app
+            </Text>
+          )}
+
+          <Pressable
+            onPress={() => router.back()}
+            style={styles.cancelButton}
+            accessibilityRole="button"
+            accessibilityLabel="Cancel QR scan"
+          >
+            <Text style={styles.cancelButtonText}>Cancel</Text>
+          </Pressable>
+        </View>
+      </View>
+    </View>
+  );
+}
+
+const SCAN_AREA_SIZE = 250;
+const CORNER_SIZE = 24;
+const CORNER_WIDTH = 3;
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: "#000",
+  },
+  camera: {
+    flex: 1,
+  },
+  centered: {
+    flex: 1,
+    justifyContent: "center",
+    alignItems: "center",
+    backgroundColor: "#f3f4f6",
+    padding: 24,
+  },
+  permissionText: {
+    fontSize: 16,
+    color: "#374151",
+    textAlign: "center",
+    marginBottom: 20,
+  },
+  permissionButton: {
+    backgroundColor: "#1e40af",
+    borderRadius: 8,
+    paddingVertical: 14,
+    paddingHorizontal: 24,
+    minHeight: 48,
+    alignItems: "center",
+    justifyContent: "center",
+  },
+  permissionButtonText: {
+    color: "#fff",
+    fontSize: 16,
+    fontWeight: "600",
+  },
+  backLink: {
+    marginTop: 20,
+    minHeight: 44,
+    alignItems: "center",
+    justifyContent: "center",
+  },
+  backLinkText: {
+    fontSize: 14,
+    color: "#6b7280",
+  },
+  overlay: {
+    ...StyleSheet.absoluteFillObject,
+  },
+  overlayTop: {
+    flex: 1,
+    backgroundColor: "rgba(0,0,0,0.5)",
+  },
+  overlayMiddle: {
+    flexDirection: "row",
+    height: SCAN_AREA_SIZE,
+  },
+  overlaySide: {
+    flex: 1,
+    backgroundColor: "rgba(0,0,0,0.5)",
+  },
+  scanArea: {
+    width: SCAN_AREA_SIZE,
+    height: SCAN_AREA_SIZE,
+  },
+  corner: {
+    position: "absolute",
+    width: CORNER_SIZE,
+    height: CORNER_SIZE,
+  },
+  cornerTopLeft: {
+    top: 0,
+    left: 0,
+    borderTopWidth: CORNER_WIDTH,
+    borderLeftWidth: CORNER_WIDTH,
+    borderColor: "#fff",
+  },
+  cornerTopRight: {
+    top: 0,
+    right: 0,
+    borderTopWidth: CORNER_WIDTH,
+    borderRightWidth: CORNER_WIDTH,
+    borderColor: "#fff",
+  },
+  cornerBottomLeft: {
+    bottom: 0,
+    left: 0,
+    borderBottomWidth: CORNER_WIDTH,
+    borderLeftWidth: CORNER_WIDTH,
+    borderColor: "#fff",
+  },
+  cornerBottomRight: {
+    bottom: 0,
+    right: 0,
+    borderBottomWidth: CORNER_WIDTH,
+    borderRightWidth: CORNER_WIDTH,
+    borderColor: "#fff",
+  },
+  overlayBottom: {
+    flex: 1,
+    backgroundColor: "rgba(0,0,0,0.5)",
+    alignItems: "center",
+    paddingTop: 32,
+  },
+  statusContainer: {
+    flexDirection: "row",
+    alignItems: "center",
+    gap: 10,
+  },
+  statusText: {
+    color: "#fff",
+    fontSize: 16,
+    fontWeight: "600",
+  },
+  instructionText: {
+    color: "#fff",
+    fontSize: 15,
+    textAlign: "center",
+    lineHeight: 22,
+  },
+  cancelButton: {
+    marginTop: 24,
+    paddingVertical: 12,
+    paddingHorizontal: 32,
+    borderRadius: 8,
+    borderWidth: 1,
+    borderColor: "rgba(255,255,255,0.5)",
+    minHeight: 44,
+    alignItems: "center",
+    justifyContent: "center",
+  },
+  cancelButtonText: {
+    color: "#fff",
+    fontSize: 15,
+    fontWeight: "500",
+  },
+});
@@ -401,6 +401,35 @@ class TestQRLogin:
            expires = expires.replace(tzinfo=timezone.utc)
        assert expires > datetime.now(timezone.utc)

+    @patch("app.utils.session_manager.settings")
+    def test_create_qr_challenge_ttl_seconds(self, mock_settings, db_session: Session, sample_user_id: str):
+        """Test that ttl_seconds can be derived from created_at and expires_at.
+
+        The API endpoint computes ttl_seconds = (expires_at - created_at) to
+        allow the client to run a countdown timer without comparing absolute
+        timestamps (avoiding clock-skew issues).
+        """
+        from app.utils.session_manager import create_qr_challenge
+
+        mock_settings.qr_login_challenge_ttl_seconds = 120
+
+        challenge = create_qr_challenge(db_session, sample_user_id)
+
+        ttl_seconds = max(0, int((challenge.expires_at - challenge.created_at).total_seconds()))
+        assert ttl_seconds == 120
+
+    @patch("app.utils.session_manager.settings")
+    def test_create_qr_challenge_custom_ttl(self, mock_settings, db_session: Session, sample_user_id: str):
+        """Test that a custom TTL is correctly reflected in the challenge timestamps."""
+        from app.utils.session_manager import create_qr_challenge
+
+        mock_settings.qr_login_challenge_ttl_seconds = 300
+
+        challenge = create_qr_challenge(db_session, sample_user_id)
+
+        ttl_seconds = max(0, int((challenge.expires_at - challenge.created_at).total_seconds()))
+        assert ttl_seconds == 300
+
    @patch("app.utils.session_manager.settings")
    def test_validate_qr_challenge_valid(self, mock_settings, db_session: Session, sample_user_id: str):
        """Test validating a valid QR challenge."""