folder-hash

What is folder-hash?

The folder-hash npm package is used to generate hash values for the contents of a folder. This can be useful for verifying the integrity of files, detecting changes, and ensuring consistency across different environments.

What are folder-hash's main functionalities?

Generate Hash for a Folder

This feature allows you to generate a hash for the contents of a specified folder. The hash can be used to verify the integrity of the folder's contents.

const folderHash = require('folder-hash');
const options = { folders: { include: ['*'] } };
folderHash.hashElement('path/to/folder', options)
  .then(hash => console.log(hash))
  .catch(error => console.error('Error:', error));

Customizing Hash Options

This feature allows you to customize the hashing options, such as the algorithm, encoding, and which files or folders to include or exclude.

const folderHash = require('folder-hash');
const options = { 
  algo: 'sha256', 
  encoding: 'hex', 
  folders: { exclude: ['node_modules', 'test'] }, 
  files: { include: ['*.js', '*.json'] } 
};
folderHash.hashElement('path/to/folder', options)
  .then(hash => console.log(hash))
  .catch(error => console.error('Error:', error));

Other packages similar to folder-hash

hasha

The hasha package is a versatile hashing library that can hash strings, buffers, and streams. It supports multiple algorithms and is highly configurable. Unlike folder-hash, hasha does not specifically target folder contents but can be used in conjunction with other tools to achieve similar results.

crypto

The built-in Node.js crypto module provides cryptographic functionality, including hashing. While it does not directly support hashing entire folders, it can be used to hash individual files and combined with file system operations to hash folder contents. It offers more control but requires more manual setup compared to folder-hash.

checksum

The checksum package is designed to generate checksums for files and directories. It offers similar functionality to folder-hash but with a focus on simplicity and ease of use. It supports various algorithms and can be a good alternative for basic hashing needs.

README

Create a hash checksum over a folder or a file.
The hashes are propagated upwards, the hash that is returned for a folder is generated over all the hashes of its children.
The hashes are generated with the sha1 algorithm and returned in base64 encoding by default.

Each file returns a name and a hash, and each folder returns additionally an array of children (file or folder elements).

Usage

First, install folder-hash with npm install --save folder-hash or yarn add folder-hash.

Simple example

To see differences to the last version of this package, I would create hashes over all .js and .json files. But ignore everything inside folders starting with a dot, and also from the folders node_modules, test_coverage. The structure of the options object is documented below.
This example is also stored in ./examples/readme-example1.js.

const { hashElement } = require('folder-hash');

const options = {
  folders: { exclude: ['.*', 'node_modules', 'test_coverage'] },
  files: { include: ['*.js', '*.json'] },
};

console.log('Creating a hash over the current folder:');
hashElement('.', options)
  .then(hash => {
    console.log(hash.toString());
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

The returned information looks for example like this:

Creating a hash over the current folder:
{ name: '.', hash: 'YZOrKDx9LCLd8X39PoFTflXGpRU=,'
  children: [
    { name: 'examples', hash: 'aG8wg8np5SGddTnw1ex74PC9EnM=,'
      children: [
        { name: 'readme-example1.js', hash: 'Xlw8S2iomJWbxOJmmDBnKcauyQ8=' }
        { name: 'readme-with-callbacks.js', hash: 'ybvTHLCQBvWHeKZtGYZK7+6VPUw=' }
        { name: 'readme-with-promises.js', hash: '43i9tE0kSFyJYd9J2O0nkKC+tmI=' }
        { name: 'sample.js', hash: 'PRTD9nsZw3l73O/w5B2FH2qniFk=' }
      ]}
    { name: 'index.js', hash: 'kQQWXdgKuGfBf7ND3rxjThTLVNA=' }
    { name: 'package.json', hash: 'w7F0S11l6VefDknvmIy8jmKx+Ng=' }
    { name: 'test', hash: 'H5x0JDoV7dEGxI65e8IsencDZ1A=,'
      children: [
        { name: 'parameters.js', hash: '3gCEobqzHGzQiHmCDe5yX8weq7M=' }
        { name: 'test.js', hash: 'kg7p8lbaVf1CPtWLAIvkHkdu1oo=' }
      ]}
  ]}

And the structure may be traversed to e.g. create incremental backups.

It is also possible to only match the full path and not the basename. The same configuration could look like this:
You should be aware that *nix and Windows behave differently, so please use caution.

const options = {
  folders: {
    exclude: ['.*', '**.*', '**node_modules', '**test_coverage'],
    matchBasename: false,
    matchPath: true,
  },
  files: {
    //include: ['**.js', '**.json' ], // Windows
    include: ['*.js', '**/*.js', '*.json', '**/*.json'], // *nix
    matchBasename: false,
    matchPath: true,
  },
};

Parameters for the hashElement function

Name	Type	Attributes	Description
name	string		element name or an element's path
dir	string	<optional>	directory that contains the element (generated from name if omitted)
options	Object	<optional>	Options object (see below)
callback	fn	<optional>	Error-first callback function

Options

Default values

{
    algo: 'sha1',       // see crypto.getHashes() for options in your node.js REPL
    encoding: 'base64', // 'base64', 'hex' or 'binary'
    files: {
        exclude: [],
        include: [],
        matchBasename: true,
        matchPath: false,
        ignoreBasename: false,
        ignoreRootName: false
    },
    folders: {
        exclude: [],
        include: [],
        matchBasename: true,
        matchPath: false,
        ignoreRootName: false
    },
    symbolicLinks: {
        include: true,
        ignoreBasename: false,
        ignoreTargetPath: true,
        ignoreTargetContent: false,
        ignoreTargetContentAfterError: false,
    }
}

Name	Type	Attributes	Default	Description
algo	string	<optional>	'sha1'	checksum algorithm, see options in crypto.getHashes()
encoding	string	<optional>	'base64'	encoding of the resulting hash. One of 'base64', 'hex' or 'binary'
files	Object	<optional>	Rules object (see below)
folders	Object	<optional>	Rules object (see below)
symLinks	Object	<optional>	Symlink options (see below)

Rules object properties

Name	Type	Attributes	Default	Description
exclude	Array.<string> || Function	<optional>	[]	Array of optional exclude glob patterns, see minimatch doc. Can also be a function which returns true if the passed file is excluded.
include	Array.<string> || Function	<optional>	[]	Array of optional include glob patterns, see minimatch doc. Can also be a function which returns true if the passed file is included.
matchBasename	bool	<optional>	true	Match the glob patterns to the file/folder name
matchPath	bool	<optional>	false	Match the glob patterns to the file/folder path
ignoreBasename	bool	<optional>	false	Set to true to calculate the hash without the basename element
ignoreRootName	bool	<optional>	false	Set to true to calculate the hash without the basename of the root (first) element

Symlink options

Configure, how symbolic links should be hashed.
To understand how the options can be combined to create a specific behavior, look into test/symbolic-links.js.

Name	Type	Default	Description
include	bool	true	If false, symbolic links are not handled at all. A folder with three symbolic links inside will have no children entries.
ignoreBasename	bool	false	Set to true to calculate the hash without the basename element
ignoreTargetPath	bool	true	If false, the resolved link target is added to the hash (uses fs.readlink)
ignoreTargetContent	bool	false	If true, will only assess the basename and target path (as configured in the other options)
ignoreTargetContentAfterError	bool	false	If true, will ignore all errors while trying to hash symbolic links and only assess the basename and target path (as configured in other options). E.g. a missing target (ENOENT) or access permissions (EPERM).

Command line usage

After installing it globally via

$ npm install -g folder-hash

You can use it like this:

# local folder
$ folder-hash -c config.json .
# local folder
$ folder-hash
# global folder
$ folder-hash /user/bin

It also allows to pass an optional JSON configuration file with the -c or --config flag, which should contain the same configuration as when using the JavaScript API.

You can also use a local version of folder-hash like this:

$ npx folder-hash --help
Use folder-hash on cli like this:
  folder-hash [--config <json-file>] <file-or-folder>

Examples

Other examples using promises

See file ./examples/readme-with-promises.js

const path = require('path');
const { hashElement } = require('folder-hash');

// pass element name and folder path separately
hashElement('test', path.join(__dirname, '..'))
  .then(hash => {
    console.log('Result for folder "../test":', hash.toString(), '\n');
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

// pass element path directly
hashElement(__dirname)
  .then(hash => {
    console.log(`Result for folder "${__dirname}":`);
    console.log(hash.toString(), '\n');
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

// pass options (example: exclude dotFolders)
const options = { encoding: 'hex', folders: { exclude: ['.*'] } };
hashElement(__dirname, options)
  .then(hash => {
    console.log('Result for folder "' + __dirname + '" (with options):');
    console.log(hash.toString(), '\n');
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

Other examples using error-first callbacks

See ./examples/readme-with-callbacks.js

const path = require('path');
const { hashElement } = require('folder-hash');

// pass element name and folder path separately
hashElement('test', path.join(__dirname, '..'), (error, hash) => {
  if (error) {
    return console.error('hashing failed:', error);
  } else {
    console.log('Result for folder "../test":', hash.toString(), '\n');
  }
});

// pass element path directly
hashElement(__dirname, (error, hash) => {
  if (error) {
    return console.error('hashing failed:', error);
  } else {
    console.log('Result for folder "' + __dirname + '":');
    console.log(hash.toString(), '\n');
  }
});

// pass options (example: exclude dotFiles)
const options = { algo: 'md5', files: { exclude: ['.*'], matchBasename: true } };
hashElement(__dirname, options, (error, hash) => {
  if (error) {
    return console.error('hashing failed:', error);
  } else {
    console.log('Result for folder "' + __dirname + '":');
    console.log(hash.toString());
  }
});

Behavior

The behavior is documented and verified in the unit tests. Execute npm test or mocha test, and have a look at the test subfolder.
You can also have a look at the CircleCI report.

Creating hashes over files (with default options)

The hashes are the same if:

• A file is checked again
• Two files have the same name and content (but exist in different folders)

The hashes are different if:

• A file was renamed or its content was changed
• Two files have the same name but different content
• Two files have the same content but different names

Creating hashes over folders (with default options)

Content means in this case a folder's children - both the files and the subfolders with their children.

The hashes are the same if:

• A folder is checked again
• Two folders have the same name and content (but have different parent folders)

The hashes are different if:

• A file somewhere in the directory structure was renamed or its content was changed
• Two folders have the same name but different content
• Two folders have the same content but different names

License

MIT, see LICENSE.txt

Changelog

4.0.2 (2022-02-15)

• Update dependencies
• Minor changes to README