jpeginator.R

### THE JPEGINATOR
### Openwhisk bmp->jpeg conversion using OpenWhisk
### Author: Frederico Munoz <frederico.munoz@pt.ibm.com>
### Date: APR 2017
### License: Eclipse Public License v1.0

## Load the image-related libraries
library(bmp)
library(pixmap)
library(base64enc)
library(httr)
library(jsonlite)

## Read and encode
read_filename <- file("lisboa_arco.png", "rb")
b64 <- base64encode(read_filename)

## Set the REST endpoint - change for your own
url <- "https://openwhisk.ng.bluemix.net/api/v1/web/frederico.munoz%40pt.ibm.com_Default/default/jpeginator.json"

## The POST request itself, passing the image as a JSON argument
req <- POST(url, body = list(image = b64), encode = "json")

## Parsing the request
j <- fromJSON(content(req, "text"))

## Let's see what we have here
str(j)

## Write file (which is now a JPEG, courtesy of the JPEGINATOR!!!1!
## ... 
writeBin(base64decode(j$body), "lisboa2.jpg")