resizr

A dead simple HTTP service developed in 1 hour for image resizing/cropping. Designed for easy integration from web apps and programmatic HTTP clients.

Behind the scenes it's powered by libvips and bimg.

resizr is currently used in production processing thoundands of images per day.

Rationale

I just created this to cover a very particular need. If you need more versatility, I would recommend you start building something custom by your own.

Features

• Fast: written in Go and uses libvips, a powerful image processing library in C.
• Simple (for now): just type the URL
• Supports image resize with crop calculus.
• Supports JPEG, PNG and WEBP formats and conversion between them.
• Automatic image rotation based on EXIF orientation metadata.
• Default image placeholder in case of processing error.
• Image fetching and resizing.
• No cache. Build your cache layer in front of it.

Upcoming features

• gzip responses
• CORS support
• Traffic throttle strategy

Installation

go get github.com/h2non/resizr

Usage

resizr 0.1.0

Usage:
  resizr -p 80
  resizr -placeholder image.jpg

Options:
  -a <addr>                 bind address [default: *]
  -p <port>                 bind port [default: 9000]
  -h, -help                 output help
  -v, -version              output version
  -placeholder <path>       placeholder image to use on error
  -cors                     Enable CORS support [default: false]
  -gzip                     Enable gzip compression [default: false]
  -key <key>                Define API key for authorization
  -http-read-timeout <num>  HTTP read timeout in seconds [default: 30]
  -http-write-timeout <num> HTTP write timeout in seconds [default: 30]
  -certfile <path>          TLS certificate file path
  -keyfile <path>           TLS private key file path
  -concurreny <num>         Throttle concurrency limit per second [default: disabled]
  -burst <num>              Throttle burst max cache size [default: 100]
  -mrelease <num>           OS memory release inverval in seconds [default: 30]
  -cpus <num>               Number of used cpu cores.
                            (default for current machine is 8 cores)

Start the server:

resizr -p 8080

Then, from a web browser, try opening the following URL:

http://localhost:8080/crop/200x200/http://imgsv.imaging.nikon.com/lineup/lens/zoom/normalzoom/af-s_dx_18-300mmf_35-56g_ed_vr/img/sample/sample4_l.jpg

Using it from HTML img tag is as simple as:

<img src="http://localhost:8080/crop/200x200/http://imgsv.imaging.nikon.com/lineup/lens/zoom/normalzoom/af-s_dx_18-300mmf_35-56g_ed_vr/img/sample/sample4_l.jpg" />

HTTP API

Handling errors

Since resizr has been designed to be used as public HTTP service, including web pages, the response MIME type must be respected in most scenarios, so the server will always reply with a placeholder image in case of error.

You can customize the placeholder image passing the -placeholder flag when starting resizr.

If image resizing fails for some reason, a 400 Bad Request will be used as response status, but the Content-Type will always image/*. If you want to see the error details, you have it in the Error header field.

GET /

Content-Type: application/json

Returns versions info.

GET /crop/{width}x{height?}/{imageUrl}

Content-Type: image/*

Performs an image resize with implicit crop calculus to automatically fit to the desired resolution.

height value is optional.

GET /resize/{width}x{height?}/{imageUrl}

Content-Type: image/*

Performs an image resize with implicit crop calculus and enlarge, if necessary, to the desired resolution.

height value is optional.

License

MIT