emeto / resize-server

HTTP-accessible server for on-request image scaling

resize-server

This is a HTTP-accessible server for scaling images on request. Think of it as placeholder.com but for any image hosted on the internet.

Table of contents

1. How to use it?
2. Configuration
3. Misc. endpoints
4. Build

How to use it?

To use this server, you only need to send a GET request to the /v1/scale/do endpoint and specify these two query parameters :

Key	Value
path	The URL to the image
size	Output size in pixels with the following format 600x300 OR a preset name. Set the height portion to 0 to keep the aspect ratio of the image i.e.: 200x0

The scaled image will be directly output to the response. The response Content-Type header will be set the same as the source MIME type.

Configuration

Configuration is done in the ./config/config.json file, configuration is pretty basic.

Key	Value	Default
http.port	Port of the built-in HTTP server	80
logger.logLevel	Minimum level of logs that output to the console, accept the following values : info warn error debug	debug

Presets

You can add presets in your config file. They can be used for the size query parameter when making a request.

Key	Type	Description
name	string	The name of your preset, this will be used in the size query parameter
width	number	The output width in pixels
height	number	The output height in pixels
interFunc	string	The interpolation function name. One of NearestNeighbor, Bilinear, Bicubic, MitchellNetravali, Lanczos2, Lanczos3

Misc. Endpoints

Endpoint	Method	Description
/healthz	GET	Heartbeat function, just to tell you it's alive
/metrics	GET	Metrics endpoint for Prometheus

Build

Building from source requires Go 1.19 or later

go build -o ./app ./cmd/app