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image-hash

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

Supports JPG and PNG

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
});

API

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

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

Image-Hash Arguments

Argument Type Description Mandatory Example
location object or string A RequestJS Object 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

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.

Testing

npm test

Credit

The hard bit of this comes with thanks from commonsmachinery for blockhash-js

License

Distributed under an MIT license