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cw-andrews / imagekit-dotnet

.NET SDK for ImageKit.io API

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ImageKit.io

DotNET (NET45/Standard/Core) SDK for ImageKit

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ImageKit DotNET SDK allows you to use image resizing, optimization, file uploading and other ImageKit APIs from applications written in server-side C#.

Table of contents

Installation

Package Manager

Install-Package Imagekit

PackageReference

<PackageReference Include="Imagekit" Version="3.1.5">
</PackageReference>

.Net CLI

dotnet add package Imagekit --version 3.1.5

Open up your project, navigate to the Nuget package manager console, and add the Imagekit package. Also, you can search for Imagekit in Nuget GUI.

Initialization

Add this reference where you want to use imagekit.io services:

using Imagekit;

ServerImagekit imagekit = new ServerImagekit(publicKey, privateKey, urlEndPoint, "path");

Note: You can get the apiKey, apiSecret, and ImagekitId from your Imagekit.io dashboard.

Demo application

The fastest way to get started is by running the demo application in the Sample folder.

Usage

You can use this DotNET SDK for three different 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 paths with different kinds of origins.

string imageURL = imagekit.Url(new Transformation().Width(400).Height(300))
    .Path("/default-image.jpg")
    .UrlEndpoint("https://ik.imagekit.io/your_imagekit_id/endpoint")
    .TransformationPosition("query")
    .Generate();

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.

string imageURL = imagekit.Url(new Transformation().Width(400).Height(300))
    .Src("https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg")
    .Generate();

This results in a URL like

https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=h-300,w-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 needs 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 needs 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 the array's different objects. 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.
transformationPosition Optional. The default value is path that places the transformation string as a URL path parameter. It can also be specified as query, which adds the transformation string as the URL's query parameter tr. If you use the 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 parameters 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 create the URL with the urlEndpoint and path parameters, 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

Transformation transformation = new Transformation()
    .Width(400).Height(300)
    .Chain()
    .Rotation(90);

string imageURL = imagekit.Url(transformation)
    .Path("/default-image.jpg")
    .UrlEndpoint("https://ik.imagekit.io/your_imagekit_id/endpoint")
    .TransformationPosition("query")
    .Generate();
https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=h-300,w-400:rt-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.

string src = "https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg";

Transformation trans = new Transformation()
    .Format("jpg")
    .Progressive(true)
    .EffectSharpen()
    .EffectContrast(1);

string imageURL = imagekit.Url(trans)
.Src(src)
.Generate();

Note: 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,pr-true,e-sharpen,e-contrast-1

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

Transformation trans = new Transformation()
    .Height(300).Width(400);
string[] queryParams = { "v=123" };

string imageURL = imagekit.Url(trans)
    .Path("/default-image.jpg")
    .QueryParameters(queryParams)
    .Signed(true).ExpireSeconds(300)
    .Generate();
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 b
rotation rt
blur bl
named n
overlayX ox
overlayY oy
overlayFocus ofo
overlayHeight oh
overlayWidth ow
overlayImage oi
overlayImageTrim oit
overlayImageAspectRatio oiar
overlayImageBackground oibg
overlayImageBorder oib
overlayImageDPR oidpr
overlayImageQuality oiq
overlayImageCropping oic
overlayImageTrim oit
overlayText ot
overlayTextFontSize ots
overlayTextFontFamily otf
overlayTextColor otc
overlayTextTransparency oa
overlayAlpha oa
overlayTextTypography ott
overlayBackground obg
overlayTextEncoded ote
overlayTextWidth otw
overlayTextBackground otbg
overlayTextPadding otp
overlayTextInnerAlignment otia
overlayRadius or
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. 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

ImagekitResponse resp = await imagekit
    .FileName("my_file_name.jpg")
    .UploadAsync(<fullPath|url|base_64|binary>);

Note: Upload argument can be a local fullPath or URL or byte array (byte[]) or Base64String of a file.

File Management

The SDK provides a simple interface for all the media APIs mentioned here to manage your files.

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 it is with the correct values to get the results.

List<ListAPIResponse> resp = await imagekit
    .Skip(0)
    .Limit(10)
    .ListFilesAsync();

You can also use advanced searching and sorting using SearchQuery and Sort function.

List<ListAPIResponse> resp = await imagekit
    .Skip(0)
    .Limit(3)
    .Sort("DESC_SIZE")
    .SearchQuery("tags IN [\"tag1\"]")
    .ListFilesAsync();

2. Get File Details

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

ListAPIResponse resp = await imagekit.GetFileDetailsAsync(fileId);

3. Get File Metadata

Accepts the fileId or URI and fetches the metadata as per the API documentation here.

MetadataResponse resp = await imagekit.GetFileMetadataAsync(<fileId|URI>);

4. Update File Details

Update parameters associated with the File as per the API documentation here.

string[] tags = { "one", "two" };
ListAPIResponse resp = await imagekit
    .Tags(tags)
    .CustomCoordinates("10,10,100,100")
    .UpdateFileDetailsAsync(fileId);

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.

string resp = await imagekit.DeleteFileAsync(fileId);

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.

PurgeAPIResponse resp = await imagekit.PurgeCacheAsync("full_url");

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

PurgeCacheStatusResponse resp = await imagekit.GetPurgeCacheStatusAsync("cache_request_id");

Utility functions

We have included the following commonly used utility functions in this library.

Authentication Parameter Generation

If you are looking to implement client-side file upload, you will 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

AuthParamResponse resp = imagekit.GetAuthenticationParameters();

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 is 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 construct a hash value that uniquely identifies an input image based on an image's contents. 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 the distance between the two images' pHash value.

This SDK exposes PHashDistance function to calculate the 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.

public static int CalculateDistance() {
    // asynchronously fetch metadata of two uploaded image files
    // ...
    // Extract pHash strings from both: say 'firstHash' and 'secondHash'
    // ...
    // Calculate the distance between them:
    int 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

This project is licensed under the MIT License - see the LICENSE File for details

About

.NET SDK for ImageKit.io API

https://imagekit.io

License:MIT License

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