在 Android 上自訂 Firebase 電話號碼驗證流程

// This instance does not require an Activity context.
val fpnv = FirebasePhoneNumberVerification.getInstance()

// Your request should include a nonce, which will propagate through the flow
// and be present in the final response from FPNV. See the section "Verifying
// the Firebase PNV token" for details on generating and verifying this.
val nonce = fetchNonceFromYourServer()

fpnv.getDigitalCredentialPayload(nonce, "https://example.com/privacy-policy")
  .addOnSuccessListener { fpnvDigitalCredentialPayload ->
    // Use the payload in the next step.
    // ...
  }
  .addOnFailureListener { e -> /* Handle payload fetch failure */ }

// This example uses string interpolation for clarity, but you should use some kind of type-safe
// serialization method.
fun buildDigitalCredentialRequestJson(nonce: String, fpnvDigitalCredentialPayload: String) = """
    {
      "requests": [
        {
          "protocol": "openid4vp-v1-unsigned",
          "data": {
            "response_type": "vp_token",
            "response_mode": "dc_api",
            "nonce": "$nonce",
            "dcql_query": { "credentials": [$fpnvDigitalCredentialPayload] }
          }
        }
      ]
    }
""".trimIndent()

suspend fun makeFpnvRequest(
  context: Activity, nonce: String, fpnvDigitalCredentialPayload: String): GetCredentialResponse {
  // Helper function to build the digital credential request (defined above).
  // Pass the same nonce you passed to getDigitalCredentialPayload().
  val digitalCredentialRequestJson =
    buildDigitalCredentialRequestJson(nonce, fpnvDigitalCredentialPayload)

  // CredentialManager requires an Activity context.
  val credentialManager = CredentialManager.create(context)

  // Build a Credential Manager request that includes the Firebase PNV option. Note that
  // you can't combine the digital credential option with other options.
  val request = GetCredentialRequest.Builder()
    .addCredentialOption(GetDigitalCredentialOption(digitalCredentialRequestJson))
    .build()

  // getCredential is a suspend function, so it must run in a coroutine scope,
  val cmResponse: GetCredentialResponse = try {
    credentialManager.getCredential(context, request)
  } catch (e: GetCredentialException) {
    // If the user cancels the operation, the feature isn't available, or the
    // SIM doesn't support the feature, a GetCredentialCancellationException
    // will be returned. Otherwise, a GetCredentialUnsupportedException will
    // be returned with details in the exception message.
    throw e
  }
  return cmResponse
}

val dcApiResponse = extractApiResponse(cmResponse)

fun extractApiResponse(response: GetCredentialResponse): String {
  val credential = response.credential
  when (credential) {
    is DigitalCredential -> {
      val json = JSONObject(credential.credentialJson)
      val firebaseJwtArray =
          json.getJSONObject("data").getJSONObject("vp_token").getJSONArray("firebase")
      return firebaseJwtArray.getString(0)

    }
    else -> {
      // Handle any unrecognized credential type here.
      Log.e(TAG, "Unexpected type of credential ${credential.type}")
    }
  }
}

fpnv.exchangeCredentialResponseForPhoneNumber(dcApiResponse)
  .addOnSuccessListener { result ->
    val phoneNumber = result.getPhoneNumber()
    // Verification successful
  }
  .addOnFailureListener { e -> /* Handle exchange failure */ }

app.get('/fpnvNonce', async (req, res) => {
    const nonce = crypto.randomUUID();

    // TODO: Save the nonce to a database, key store, etc.
    // You should also assign the nonce an expiration time and periodically
    // clear expired nonces from your database.
    await persistNonce({
        nonce,
        expiresAt: Date.now() + 180000, // Give it a short duration.
    });

    // Return the nonce to the caller.
    res.send({ nonce });
});

import { JwtVerifier } from "aws-jwt-verify";

// Find your Firebase project number in the Firebase console.
const FIREBASE_PROJECT_NUMBER = "123456789";

// The issuer and audience claims of the FPNV token are specific to your
// project.
const issuer = `https://fpnv.googleapis.com/projects/${FIREBASE_PROJECT_NUMBER}`;
const audience = `https://fpnv.googleapis.com/projects/${FIREBASE_PROJECT_NUMBER}`;

// The JWKS URL contains the current public signing keys for FPNV tokens.
const jwksUri = "https://fpnv.googleapis.com/v1beta/jwks";

// Configure a JWT verifier to check the following:
// - The token is signed by Google
// - The issuer and audience claims match your project
// - The token has not yet expired (default begavior)
const fpnvVerifier = JwtVerifier.create({ issuer, audience, jwksUri });

app.post('/verifiedPhoneNumber', async (req, res) => {
    if (!req.body) return res.sendStatus(400);
    // Get the token from the body of the request.
    const fpnvToken = req.body;
    try {
        // Attempt to verify the token using the verifier configured above.
        const verifiedPayload = await fpnvVerifier.verify(fpnvToken);

        // Now that you've verified the signature and claims, verify the nonce.
        // TODO: Try to look up the nonce in your database and remove it if it's
        // found; if it's not found or it's expired, throw an error.
        await testAndRemoveNonce(verifiedPayload.nonce);

        // Only after verifying the JWT signature, claims, and nonce, get the
        // verified phone number from the subject claim.
        // You can use this value however it's needed by your app.
        const verifiedPhoneNumber = verifiedPayload.sub;
        // (Do something with it...)

        return res.sendStatus(200);
    } catch {
        // If verification fails, reject the token.
        return res.sendStatus(400);
    }
});