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imagekit

3.0.2 • Public • Published

ImageKit SDK for Node.js

Node CI npm version License: MIT Twitter Follow

NodeJS SDK for ImageKit.io that implements the new APIs and interface for performing different file operations.

ImageKit is a complete image optimization and transformation solution that comes with an image CDN and media storage. It can be integrated with your existing infrastructure - storages like AWS S3, web servers, your CDN and custom domain names, allowing you to deliver optimized images in minutes with minimal code changes.

Table of contents

Installation

Use the following command to download this module. Use the optional --save parameter if you wish to save the dependency in your package.json file.

npm install imagekit

Initialization

var ImageKit = require("imagekit");

var imagekit = new ImageKit({
    publicKey : "your_public_api_key",
    privateKey : "your_private_api_key",
    urlEndpoint : "https://ik.imagekit.io/your_imagekit_id/"
});

Usage

You can use this NodeJS SDK for 3 different kinds of functions - URL generation, file uploads and file management. The usage of the SDK has been explained below

URL Generation

1. Using image path and image hostname or endpoint

This method allows you to create a URL using the path where the image exists and the URL endpoint (urlEndpoint) you want to use to access the image. You can refer to the documentation here to read more about URL endpoints in ImageKit and the section about image origins to understand about paths with different kinds of origins.

var imageURL = imagekit.url({
    path : "/default-image.jpg",
    urlEndpoint : "https://ik.imagekit.io/your_imagekit_id/endpoint/",
    transformation : [{
        "height" : "300",
        "width" : "400"
    }]
});

This results in a URL like

https://ik.imagekit.io/your_imagekit_id/endpoint/tr:h-300,w-400/default-image.jpg

2. Using full image URL

This method allows you to add transformation parameters to an existing, complete URL that is already mapped to ImageKit using the src parameter. This method should be used if you have the complete URL mapped to ImageKit stored in your database.

var imageURL = imagekit.url({
    src : "https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg",
    transformation : [{
        "height" : "300",
        "width" : "400"
    }]
});

This results in a URL like

https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=h-300%2Cw-400

The .url() method accepts the following parameters

Option Description
urlEndpoint Optional. The base URL to be appended before the path of the image. If not specified, the URL Endpoint specified at the time of SDK initialization is used. For example, https://ik.imagekit.io/your_imagekit_id/endpoint/
path Conditional. This is the path at which the image exists. For example, /path/to/image.jpg. Either the path or src parameter need to be specified for URL generation.
src Conditional. This is the complete URL of an image already mapped to ImageKit. For example, https://ik.imagekit.io/your_imagekit_id/endpoint/path/to/image.jpg. Either the path or src parameter need to be specified for URL generation.
transformation Optional. An array of objects specifying the transformation to be applied in the URL. The transformation name and the value should be specified as a key-value pair in the object. Different steps of a chained transformation can be specified as different objects of the array. The complete list of supported transformations in the SDK and some examples of using them are given later. If you use a transformation name that is not specified in the SDK, it gets applied as it is in the URL.
transformationPostion Optional. Default value is path that places the transformation string as a path parameter in the URL. Can also be specified as query which adds the transformation string as the query parameter tr in the URL. If you use src parameter to create the URL, then the transformation string is always added as a query parameter.
queryParameters Optional. These are the other query parameters that you want to add to the final URL. These can be any query parameters and not necessarily related to ImageKit. Especially useful, if you want to add some versioning parameter to your URLs.
signed Optional. Boolean. Default is false. If set to true, the SDK generates a signed image URL adding the image signature to the image URL. This can only be used if you are creating the URL with the urlEndpoint and path parameters, and not with the src parameter.
expireSeconds Optional. Integer. Meant to be used along with the signed parameter to specify the time in seconds from now when the URL should expire. If specified, the URL contains the expiry timestamp in the URL and the image signature is modified accordingly.

Examples of generating URLs

1. Chained Transformations as a query parameter

var imageURL = imagekit.url({
    path : "/default-image.jpg",
    urlEndpoint : "https://ik.imagekit.io/your_imagekit_id/endpoint/",
    transformation : [{
        "height" : "300",
        "width" : "400"
    }, {
        "rotation" : 90
    }],
    transformationPosition : "query"
});
https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=h-300%2Cw-400%3Art-90

2. Sharpening and contrast transforms and a progressive JPG image

There are some transforms like Sharpening that can be added to the URL with or without any other value. To use such transforms without specifying a value, specify the value as "-" in the transformation object, otherwise, specify the value that you want to be added to this transformation.

var imageURL = imagekit.url({
    src : "https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg",
    transformation : [{
        "format" : "jpg",
        "progressive" : "true",
        "effectSharpen" : "-",
        "effectContrast" : "1"
    }]
});
//Note that because `src` parameter was used, the transformation string gets added as a query parameter `tr`
https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=f-jpg%2Cpr-true%2Ce-sharpen%2Ce-contrast-1

3. Signed URL that expires in 300 seconds with the default URL endpoint and other query parameters

var imageURL = imagekit.url({
    path : "/default-image.jpg",
    queryParameters : {
        "v" : "123"
    },
    transformation : [{
        "height" : "300",
        "width" : "400"
    }],
    signed : true,
    expireSeconds : 300
});
https://ik.imagekit.io/your_imagekit_id/tr:h-300,w-400/default-image.jpg?v=123&ik-t=1567358667&ik-s=f2c7cdacbe7707b71a83d49cf1c6110e3d701054

List of supported transformations

The complete list of transformations supported and their usage in ImageKit can be found here. The SDK gives a name to each transformation parameter, making the code simpler and readable. If a transformation is supported in ImageKit, but a name for it cannot be found in the table below, then use the transformation code from ImageKit docs as the name when using in the url function.

Supported Transformation Name Translates to parameter
height h
width w
aspectRatio ar
quality q
crop c
cropMode cm
x x
y y
focus fo
format f
radius r
background bg
border bo
rotation rt
blur bl
named n
overlayImage oi
overlayX ox
overlayY oy
overlayFocus ofo
overlayHeight oh
overlayWidth ow
overlayText ot
overlayTextFontSize ots
overlayTextFontFamily otf
overlayTextColor otc
overlayAlpha oa
overlayTextTypography ott
overlayBackground obg
overlayImageTrim oit
progressive pr
lossless lo
trim t
metadata md
colorProfile cp
defaultImage di
dpr dpr
effectSharpen e-sharpen
effectUSM e-usm
effectContrast e-contrast
effectGray e-grayscale
original orig

File Upload

The SDK provides a simple interface using the .upload() method to upload files to the ImageKit Media Library. It accepts all the parameters supported by the ImageKit Upload API.

The upload() method requires at least the file and the fileName parameter to upload a file and returns a callback with the error and result as arguments. You can pass other parameters supported by the ImageKit upload API using the same parameter name as specified in the upload API documentation. For example, to specify tags for a file at the time of upload use the tags parameter as specified in the documentation here.

Sample usage

imagekit.upload({
  file : <url|base_64|binary>, //required
  fileName : "my_file_name.jpg",   //required
}, function(error, result) {

});

If the upload succeed, error will be null and the result will be the same as what is received from ImageKit's servers. If the upload fails, error will be the same as what is received from ImageKit's servers and the result will be null.

File Management

The SDK provides a simple interface for all the media APIs mentioned here to manage your files. You can use a callback function with all API interfaces. The first argument of the callback function is the error and the second is the result of the API call. Error will be null if the API succeeds.

1. List & Search Files

Accepts an object specifying the parameters to be used to list and search files. All parameters specified in the documentation here can be passed as is with the correct values to get the results.

imagekit.listFiles({
    skip : 10,
    limit : 10
}, function(err, result) { 
    
});

2. Get File Details

Accepts the file ID and fetches the details as per the API documentation here.

imagekit.getFileDetails("file_id", function(err, result) {  

});

3. Get File Metadata

Accepts the file ID and fetches the metadata as per the API documentation here.

imagekit.getFileMetadata("file_id", function(err, result) {  

});

4. Update File Details

Update parameters associated with the file as per the API documentation here. The first argument to the updateFileDetails method is the file ID and the second argument is an object with the parameters to be updated.

imagekit.updateFileDetails("file_id", { 
    tags : ['image_tag'],
    customCoordinates : "10,10,100,100"
}, function(err, result) { 

});

5. Delete File

Delete a file as per the API documentation here. The method accepts the file ID of the file that has to be deleted.

imagekit.deleteFile("file_id", function(err, result) {
    
});

6. Purge Cache

Programmatically issue a cache clear request as per the API documentation here. Accepts the full URL of the file for which the cache has to be cleared.

imagekit.purgeCache("full_url", function(err, result) { 
    
});

7. Purge Cache Status

Get the purge cache request status using the request ID returned when a purge cache request gets submitted as per the API documentation here

imagekit.getPurgeCacheStatus("cache_request_id", function(err, result) {
    
});

Utility functions

We have included following commonly used utility functions in this package.

Authentication parameter generation

In case you are looking to implement client-side file upload, you are going to need a token, expiry timestamp and a valid signature for that upload. The SDK provides a simple method that you can use in your code to generate these authentication parameters for you.

Note: The Private API Key should never be exposed in any client-side code. You must always generate these authentication parameters on the server-side

var authenticationParameters = imagekit.getAuthenticationParameters(token, expire);

Returns

{
    token : "unique_token",
    expire : "valid_expiry_timestamp",
    signature : "generated_signature"
}

Both the token and expire parameters are optional. If not specified the SDK uses the uuid package to generate a random token and also generates a valid expiry timestamp internally. The value of the token and expire used to generate the signature are always returned in the response, no matter if they are provided as an input to this method or not.

Distance calculation between two pHash values

Perceptual hashing allows you to constructing a hash value that uniquely identifies an input image based on the contents of an image. ImageKit.io metadata API returns the pHash value of an image in the response. You can use this value to find a duplicate (or similar) image by calculating distance between pHash value of two images.

This SDK exposes pHashDistance function to calcualte distance between two pHash values. It accepts two pHash hexadecimal strings and returns a numeric value indicative of the level of difference between the two images.

const calculateDistance = () => {
    // asynchronously fetch metadata of two uploaded image files
    // ...
    // Extract pHash strings from both: say 'firstHash' and 'secondHash'
    // ...
    // Calculate the distance between them:
    const distance = imagekit.pHashDistance(firstHash, secondHash);
    return distance;
}

Distance calculation examples

imagekit.pHashDistance('f06830ca9f1e3e90', 'f06830ca9f1e3e90');
// output: 0 (same image)

imagekit.pHashDistance('2d5ad3936d2e015b', '2d6ed293db36a4fb');
// output: 17 (similar images)

imagekit.pHashDistance('a4a65595ac94518b', '7838873e791f8400');
// output: 37 (dissimilar images)

Support

For any feedback or to report any issues or general implementation support please reach out to support@imagekit.io

Links

License

Released under the MIT license.

Keywords

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Install

npm i imagekit

DownloadsWeekly Downloads

639

Version

3.0.2

License

MIT

Unpacked Size

47.8 kB

Total Files

41

Homepage

imagekit.io/

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