Image-hash NPM

image-hash

A wrapper around block-hash to easily hash a local or remote file with Node.

Supports JPG, PNG and WebP

Install

npm i -S image-hash

Use

const { imageHash }= require('image-hash');

// remote file simple
imageHash('https://ichef-1.bbci.co.uk/news/660/cpsprodpb/7F76/production/_95703623_mediaitem95703620.jpg', 16, true, (error, data) => {
  if (error) throw error;
  console.log(data);
  // 0773063f063f36070e070a070f378e7f1f000fff0fff020103f00ffb0f810ff0
});

// remote file with requestjs config object
const config = {
  uri: 'https://ichef-1.bbci.co.uk/news/660/cpsprodpb/7F76/production/_95703623_mediaitem95703620.jpg'
};

imageHash(config, 16, true, (error, data) => {
  if (error) throw error;
  console.log(data);
  // 0773063f063f36070e070a070f378e7f1f000fff0fff020103f00ffb0f810ff0
});

//local file
imageHash('./_95695590_tv039055678.jpg', 16, true, (error, data) => {
  if (error) throw error;
  console.log(data);
  // 0773063f063f36070e070a070f378e7f1f000fff0fff020103f00ffb0f810ff0
});

//Buffer
const fBuffer = fs.readFileSync(__dirname + '/example/_95695591_tv039055678.jpeg');
imageHash({
  ext: 'image/jpeg',
  data: fBuffer
}, 16, true, (error, data) => {
  if(error) throw error;
  console.log(data);
  // 0773063f063f36070e070a070f378e7f1f000fff0fff020103f00ffb0f810ff0
});

//Buffer, without ext arg
const fBuffer = fs.readFileSync(__dirname + '/example/_95695591_tv039055678.jpeg');
imageHash({
  data: fBuffer
}, 16, true, (error, data) => {
  if(error) throw error;
  console.log(data);
  // 0773063f063f36070e070a070f378e7f1f000fff0fff020103f00ffb0f810ff0
});

API

// name
imageHash(location, bits, precise, callback);

// types
imageHash(string|object, int, bool, function);

SETTINGS

Image hash will log out warnings if environment variable VERBOSE is set to true.

Image-Hash Arguments

Argument	Type	Description	Mandatory	Example
location	`object` or `string`	A RequestJS Object, `Buffer` object (See input types below for more details), or `String` with a valid url or file location	Yes	see above
bits	`int`	The number of bits in a row. The more bits, the more unique the hash.	Yes	8
precise	`bool`	Whether a precision algorithm is used. `true` Precise but slower, non-overlapping blocks. `false` Quick and crude, non-overlapping blocks. Method 2 is recommended as a good tradeoff between speed and good matches on any image size. The quick ones are only advisable when the image width and height are an even multiple of the number of blocks used.	Yes	`true`
callback	`function`	A function with `error` and `data` arguments - see below

Location Object Types

// Url Request Object
interface UrlRequestObject {
  encoding?: string | null,
  url: string | null,
};

// Buffer Object
interface BufferObject {
  ext?: string, // mime type of buffered file
  data: Buffer,
  name?: string // file name for buffered file
};

Callback Arguments

Argument	Type	Description
error	`Error Object` or `null`	If a run time error is detected this will be an `Error Object`, otherwise `null`
data	`string` or `null`	If there is no run time error, this be will be your hashed result, otherwise `null`

Development

I have made this with Typescript, ESLint, Jest, Babel and VSCode. All config files and global binaries are included. For developers using VS Code, make sure you have ESLint extension installed.