sharp-resizer-server

an automatic node-based image resizer server, with frontend-friendly API

Install and Run

git clone git@github.com:scaccogatto/sharp-resizer-server.git
cd sharp-resizer-server
npm install
npm run start

Start resizing

After installation, everytime you add a new folder inside input, a watcher will be started, listening to any change
The folder's name should be a Number and it will be treated as a px value multiplied for 19.20 by default and scaled downwards the other folders inside input
Add images inside your preferred folder and the server will scale downwards automatically
Open a browser and call localhost:4080/images/json

Output

The API entry point (images/json) will output a JSON file ready for your frontend usage. The output format is:

{
  "bigImage.jpg": {
    "sizes": "100w",
    "srcset": "/images/output/100/bigImage.jpg 100w, /images/output/72/bigImage.jpg 72w, /images/output/37/bigImage.jpg 37w, /images/output/26/bigImage.jpg 26w, /images/output/16/bigImage.jpg 16w",
    "src": "/images/output/100/bigImage.jpg"
  },
  "mediumImage.jpg": {
    "sizes": "37w",
    "srcset": "/images/output/37/mediumImage.jpg 37w, /images/output/26/mediumImage.jpg 26w, /images/output/16/mediumImage.jpg 16w",
    "src": "/images/output/37/mediumImage.jpg"
  },
}

An Object containing images' names as keys and every key is an Object containing:

sizes: the greatest width found for that file
srcset: a string for <picture> TAGs, ready for use
src: for image fallback

Example

Tree:

input
--| 100
--| 72
--| 37
--| 26
--| 16

output
--| 100
--| 72
--| 37
--| 26
--| 16

Add an image into 100 folder

input
--| 100
  | -- bigImage.png
--| 72
--| 37
--| 26
--| 16

output
--| 100
  | -- bigImage.png
--| 72
  | -- bigImage.png
--| 37
  | -- bigImage.png
--| 26
  | -- bigImage.png
--| 16
  | -- bigImage.png

Add an image into 37 folder

input
--| 100
  | -- bigImage.png
--| 72
--| 37
  | -- mediumImage.png
--| 26
--| 16

output
--| 100
  | -- bigImage.png
--| 72
  | -- bigImage.png
--| 37
  | -- bigImage.png
  | -- mediumImage.png
--| 26
  | -- bigImage.png
  | -- mediumImage.png
--| 16
  | -- bigImage.png
  | -- mediumImage.png

Let's print the bigImage then, after reading things from API:

<picture>
  <source sizes="100w" srcset="/images/output/100/bigImage.jpg 100w, /images/output/72/bigImage.jpg 72w, /images/output/37/bigImage.jpg 37w, /images/output/26/bigImage.jpg 26w, /images/output/16/bigImage.jpg 16w",
    "src": "/images/output/100/bigImage.jpg" />
  <img src="/images/output/100/bigImage.jpg" />
</picture>

Advanced

Script parameters

You can also specify some script parameters such as:

-i input directory
-o output directory
-m pixel multipllier (when m = 1920 folder 100 -> 1920px)
-t maximum concurrent conversion threads
-p API local server port
-e API entry point

Defaults

node index.js -i input -o output -m 1920 -t 1 -p 4080 -e images

scaccogatto/sharp-resizer-server