Querying an Asset with User Authentication (ArkTS)

Available APIs

For details about the APIs, see:

preQuery(query: AssetMap): Promise<Uint8Array>

query(query: AssetMap): Promise<Array<AssetMap>>

postQuery(handle: AssetMap): Promise<void>

preQuery() parameters

query() parameters

postQuery() parameters

Example

Query asset demo_alias with user authentication.

import { asset } from '@kit.AssetStoreKit';
import { util } from '@kit.ArkTS';
import userAuth from '@ohos.userIAM.userAuth';
import { BusinessError } from '@kit.BasicServicesKit';

function stringToArray(str: string): Uint8Array {
  let textEncoder = new util.TextEncoder();
  return textEncoder.encodeInto(str);
}

function arrayToString(arr: Uint8Array): string {
  let textDecoder = util.TextDecoder.create("utf-8", { ignoreBOM: true });
  let str = textDecoder.decodeWithStream(arr, { stream: false })
  return str;
}

async function userAuthenticate(challenge: Uint8Array): Promise<Uint8Array> {
  return new Promise((resolve, reject) => {
    const authParam: userAuth.AuthParam = {
      challenge: challenge,
      authType: [userAuth.UserAuthType.PIN],
      authTrustLevel: userAuth.AuthTrustLevel.ATL1,
    };
    const widgetParam: userAuth.WidgetParam = { title:' Enter the lock screen password. '};
    try {
      let userAuthInstance = userAuth.getUserAuthInstance(authParam, widgetParam);
      userAuthInstance.on('result', {
        onResult(result) {
          if (result.result == userAuth.UserAuthResultCode.SUCCESS) {
            console.info(`User identity authentication succeeded.`);
            resolve(result.token);
          } else {
            console.error(`User identity authentication failed.`);
            reject();
          }
        }
      });
      userAuthInstance.start();
    } catch (error) {
      let err = error as BusinessError;
      console.error(`User identity authentication failed. Code is ${err.code}, message is ${err.message}`);
      reject();
    }
  })
}

function preQueryAsset(): Promise<Uint8Array> {
  return new Promise((resolve, reject) => {
    try {
      let query: asset.AssetMap = new Map();
      query.set(asset.Tag.ALIAS, stringToArray('demo_alias'));
      asset.preQuery(query).then((challenge: Uint8Array) => {
        resolve(challenge);
      }).catch(() => {
        reject();
      })
    } catch (error) {
      let err = error as BusinessError;
      console.error(`Failed to pre-query Asset. Code is ${err.code}, message is ${err.message}`);
      reject();
    }
  });
}

async function postQueryAsset(challenge: Uint8Array) {
  let handle: asset.AssetMap = new Map();
  handle.set(asset.Tag.AUTH_CHALLENGE, challenge);
  try {
    await asset.postQuery(handle);
    console.info(`Succeeded in post-querying Asset.`);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to post-query Asset. Code is ${err.code}, message is ${err.message}`);
  }
}

async function queryAsset() {
  // step1. Call asset.preQuery to obtain the challenge value.
  preQueryAsset().then(async (challenge: Uint8Array) => {
    try {
      // Step 2. Pass in the challenge value to start the user authentication dialog box.
      let authToken: Uint8Array = await userAuthenticate(challenge);
      // Step 3 After the user authentication is successful, pass in the challenge value and authorization token to query the plaintext of the asset.
      let query: asset.AssetMap = new Map();
      query.set(asset.Tag.ALIAS, stringToArray('demo_alias'));
      query.set(asset.Tag.RETURN_TYPE, asset.ReturnType.ALL);
      query.set(asset.Tag.AUTH_CHALLENGE, challenge);
      query.set(asset.Tag.AUTH_TOKEN, authToken);
      let res: Array<asset.AssetMap> = await asset.query(query);
      for (let i = 0; i < res.length; i++) {
        // parse the secret.
        let secret: Uint8Array = res[i].get(asset.Tag.SECRET) as Uint8Array;
        // parse uint8array to string
        let secretStr: string = arrayToString(secret);
      }
      // Step 4. After the plaintext is obtained, call asset.postQuery to perform postprocessing.
      postQueryAsset(challenge);
    } catch (error) {
      // Step 5. If the operation after preQuery() fails, call asset.postQuery to perform postprocessing.
      postQueryAsset(challenge);
    }
  }).catch ((err: BusinessError) => {
    console.error(`Failed to pre-query Asset. Code is ${err.code}, message is ${err.message}`);
  })
}

Constraints

N/A.