CDN Documentation

Sign URLs with key and salt, so an attacker won’t be able to cause a denial-of-service attack by requesting multiple different image resizes.

Features

• Generate URL to image proxy
• Generate s3 URL

Quickstart

Using s3 path

import (
"fmt"
"github.com/forkyid/go-utils/v1/cdn"
)

  

func ExampleClient() {
	c, _ := cdn.New("http://example.com", "key", "saltkey")
	
	url := c.GetUrl(&cdn.Image{
						Url: c.GetS3Url(&cdn.S3{
							BucketName: "bucket.example.com",
							Path: "users/example/post/photos/5ee87fad6b12c90001cf41ab.jpg",}),
						Width: 800,
						})
	fmt.Println(url)
	// Output: http://example.com/Gc3qJZz3REIrYcZxqY1oXiTNSAplq8fhLxgrIqybLlA/fill/800/0/no/1/czM6Ly9pbWcuZm9ya3kuaWQvdXNlcnMvYWd1c2R3aS9wb3N0L3Bob3Rvcy81ZWU4N2ZhZDZiMTJjOTAwMDFjZjQxYWIuanBn.webp
}

Using URL

import (
"fmt"
"github.com/forkyid/go-utils/v1/cdn"
)

  

func ExampleClient() {
	c, _ := cdn.New("http://example.com", "key", "saltkey")
	
	url := c.GetUrl(&cdn.Image{
						Url: "https://example.com/5ee87fad6b12c90001cf41ab.jpg",
						Width: 800,
						})
	fmt.Println(url)
	// Output: http://example.com/Gc3qJZz3REIrYcZxqY1oXiTNSAplq8fhLxgrIqybLlA/fill/800/0/no/1/czM6Ly9pbWcuZm9ya3kuaWQvdXNlcnMvYWd1c2R3aS9wb3N0L3Bob3Rvcy81ZWU4N2ZhZDZiMTJjOTAwMDFjZjQxYWIuanBn.webp
}

Image Configuration

type  Image  struct {
	Url string
	Resize string
	Width int
	Height int
	X int
	Y int
	Gravity string
	Enlarge int
	Extension string
}

Information:

• Resizing types Supports the following resizing types:

  • fit: resizes the image while keeping aspect ratio to fit given size;
  • fill: resizes the image while keeping aspect ratio to fill given size and cropping projecting parts;
  • auto: if both source and resulting dimensions have the same orientation (portrait or landscape), imgproxy will use fill. Otherwise, it will use fit.

• Width and height : Width and height parameters define the size of the resulting image in pixels. Depending on the resizing type applied, the dimensions may differ from the requested ones.

• Gravity When imgproxy needs to cut some parts of the image, it is guided by the gravity. The following values are supported:

  • no: north (top edge);
  • so: south (bottom edge);
  • ea: east (right edge);
  • we: west (left edge);
  • noea: north-east (top-right corner);
  • nowe: north-west (top-left corner);
  • soea: south-east (bottom-right corner);
  • sowe: south-west (bottom-left corner);
  • ce: center;
  • sm: smart. libvips detects the most “interesting” section of the image and considers it as the center of the resulting image;
  • fp:%x:%y - focus point. x and y are floating point numbers between 0 and 1 that describe the coordinates of the center of the resulting image. Treat 0 and 1 as right/left for x and top/bottom for y.

• Enlarge When set to 1, t or true, imgproxy will enlarge the image if it is smaller than the given size.

• URL There are two ways to specify source url:

  • S3

    c.GetUrl(&cdn.Image{
    	Url: c.GetS3Url(&cdn.S3{
    			BucketName: "bucket.example.com",
    			Path: "users/example/post/photos/5ee87fad6b12c90001cf41ab.jpg",
    		}),
    	Width:  800,
    })
    

  • Image URL

    c.GetUrl(&cdn.Image{
       Url: "https://example.com/5ee87fad6b12c90001cf41ab.jpg",
       Width:  800,
    })
    

• Extension Extension specifies the format of the resulting image. At the moment, imgproxy supports only jpg, png, webp, gif, ico, and tiff, them being the most popular and useful image formats.