Introduction

"PicAPI" is an HTTP-server which implements a method to download a JPEG image and resize it.

API

GET /resize

GET-parameter	description	required?
url	An URL to download the image	Y
width	resulting width (in pixels)	Y
height	resulting height (in pixels)	Y

Response

A JPEG image will be returned as the body.

If the response is returned from a cache then a header X-Cached-Response will also be returned.

cURL example:

curl -s --output /tmp/resized.jpg 'http://localhost:8486/resize?width=1230&height=200&url=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fc%2Fc7%2FJPS-sample.jpg'

Quick start

Install build dependencies (Debian/Ubuntu)

sudo apt-get install libgraphicsmagick1-dev

If you're unable to use external libraries (like graphicsmagick) then you can switch to a native implementation (imageprocessorimaging or imageprocessornfntresize instead of imageprocessorgraphicsmagick) in file imageprocessor/image_processor.go.

Install

go get github.com/xaionaro-go/picapi/cmd/picapid

Run

PICAPI_LOGGING_LEVEL=debug $(go env GOPATH)/bin/picapid

Performance test

$(go env GOPATH)/bin/picapid &
$(go env GOPATH)/bin/gobench -u 'http://localhost:8486/resize?width=10&height=10&url=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fc%2Fc7%2FJPS-sample.jpg' -t 10

Dispatching 100 clients
Waiting for results...

Requests:                          1077603 hits
Successful requests:               1077603 hits
Network failed:                          0 hits
Bad requests failed (!2xx):              0 hits
Successful requests rate:           107760 hits/sec
Read throughput:                  57007156 bytes/sec
Write throughput:                 21339232 bytes/sec
Test time:                              10 sec

cpufreq-info  | grep 'current policy' | head -1; echo; grep 'model name' /proc/cpuinfo  | head -1

  current policy: frequency should be within 800 MHz and 3.70 GHz.
  
model name      : Intel(R) Core(TM) i7-4800MQ CPU @ 2.70GHz

Packages

• imageprocessor is a wrapper around different image manipulation tools (like imagemagick). Currently we use graphicsmagick as the backend.
• httpserver is a wrapper around an http router (currently we use fasthttprouter) and imageprocessor to serve incoming HTTP requests.
• main (cmd/picapid) is the entry-point/executable package.
• config is just a structure to configure the main.

Image Processors

You mean switch it to another image processor in file imageprocessor/image_processor.go. See benchmarks.