@inventivetalent/image-hash
v4.1.3
Published
Create a hash from an image
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Readme
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
});
//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)
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.
Testing
npm test
Credit
The hard bit of this comes with thanks from commonsmachinery for blockhash-js
License
Distributed under an MIT license