@ohos.file.hash (File Hash Processing)

The FileHash module implements hash processing on files.

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import { hash } from '@kit.CoreFileKit';

Guidelines

Before using the APIs provided by this module to perform operations on a file or directory, obtain the application sandbox path of the file or directory as follows:

  import { UIAbility } from '@kit.AbilityKit';
  import { window } from '@kit.ArkUI';

  export default class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      let context = this.context;
      let pathDir = context.filesDir;
    }
  }

For details about how to obtain the application sandbox path, see Obtaining Application File Paths.

hash.hash

hash(path: string, algorithm: string): Promise<string>

Calculates a hash value for a file. This API uses a promise to return the result.

Atomic service API: This API can be used in atomic services since API version 11.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Return value

Error codes

For details about the error codes, see Basic File IO Error Codes.

Example

  import { BusinessError } from '@kit.BasicServicesKit';
  let filePath = pathDir + "/test.txt";
  hash.hash(filePath, "sha256").then((str: string) => {
    console.info("calculate file hash succeed:" + str);
  }).catch((err: BusinessError) => {
    console.error("calculate file hash failed with error message: " + err.message + ", error code: " + err.code);
  });

hash.hash

hash(path: string, algorithm: string, callback: AsyncCallback<string>): void

Calculates a hash value for a file. This API uses an asynchronous callback to return the result.

Atomic service API: This API can be used in atomic services since API version 11.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Error codes

For details about the error codes, see Basic File IO Error Codes.

Example

  import { BusinessError } from '@kit.BasicServicesKit';
  let filePath = pathDir + "/test.txt";
  hash.hash(filePath, "sha256", (err: BusinessError, str: string) => {
    if (err) {
      console.error("calculate file hash failed with error message: " + err.message + ", error code: " + err.code);
    } else {
      console.info("calculate file hash succeed:" + str);
    }
  });

hash.createHash¹²⁺

createHash(algorithm: string): HashStream;

Creates a HashStream instance, which can be used to generate a message digest (a hash value) using the given algorithm.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Return value

Error codes

For details about the error codes, see Universal Error Codes and Basic File IO Error Codes.

Example

  // pages/xxx.ets
  import { fileIo as fs } from '@kit.CoreFileKit';

  function hashFileWithStream() {
    const filePath = pathDir + "/test.txt";
    // Create a readable stream.
    const rs = fs.createReadStream(filePath);
    // Create a hash stream.
    const hs = hash.createHash('sha256');
    rs.on('data', (emitData) => {
      const data = emitData?.data;
      hs.update(new Uint8Array(data?.split('').map((x: string) => x.charCodeAt(0))).buffer);
    });
    rs.on('close', async () => {
      const hashResult = hs.digest();
      const fileHash = await hash.hash(filePath, 'sha256');
      console.info(`hashResult: ${hashResult}, fileHash: ${fileHash}`);
    });
  }

HashStream¹²⁺

The HashStream class is a utility for creating a message digest of data. You can use createHash to create a HashStream instance.

update¹²⁺

update(data: ArrayBuffer): void

Updates the data for generating a message digest. This API can be called multiple times.

System capability: SystemCapability.FileManagement.File.FileIO

Error codes

For details about the error codes, see Universal Error Codes and Basic File IO Error Codes.

Example

  // Create a hash stream.
  const hs = hash.createHash('sha256');
  hs.update(new Uint8Array('1234567890'?.split('').map((x: string) => x.charCodeAt(0))).buffer);
  hs.update(new Uint8Array('abcdefg'?.split('').map((x: string) => x.charCodeAt(0))).buffer);
  const hashResult = hs.digest();
  // 88A00F46836CD629D0B79DE98532AFDE3AEAD79A5C53E4848102F433046D0106
  console.info(`hashResult: ${hashResult}`);

digest¹²⁺

digest(): string

Generates a message digest.

System capability: SystemCapability.FileManagement.File.FileIO

Error codes

For details about the error codes, see Universal Error Codes and Basic File IO Error Codes.

Example

  // Create a hash stream.
  const hs = hash.createHash('sha256');
  hs.update(new Uint8Array('1234567890'?.split('').map((x: string) => x.charCodeAt(0))).buffer);
  hs.update(new Uint8Array('abcdefg'?.split('').map((x: string) => x.charCodeAt(0))).buffer);
  const hashResult = hs.digest();
  // 88A00F46836CD629D0B79DE98532AFDE3AEAD79A5C53E4848102F433046D0106
  console.info(`hashResult: ${hashResult}`);

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