Shredded Code

Before you start, you need to register at Microsoft Cognitive Services and ask for a free trial. Copy Face-Preview API key into an environment variable faceKEY as follows Sys.setenv(faceKEY = "***YOUR*KEY***"). Here, I will demonstrate Face API on my Twitter profile picture:

library(httr)
 
faceURL = "https://westus.api.cognitive.microsoft.com/face/v1.0/detect?returnFaceAttributes=age,gender,smile,facialHair"
img.url = "https://pbs.twimg.com/profile_images/420950459289833472/JtRoD1cw_400x400.jpeg"

faceKEY = Sys.getenv("faceKEY")
 
mybody = list(url = img.url)
 
faceResponse = POST(
  url = faceURL, 
  content_type('application/json'), add_headers(.headers = c('Ocp-Apim-Subscription-Key' = faceKEY)),
  body = mybody,
  encode = 'json'
)

# status ok = 200
faceResponse$status

## [1] 401

All information about a picture is now easily accesible by applying the function content.

content(faceResponse)

## $error
## $error$code
## [1] "Unspecified"
## 
## $error$message
## [1] "Access denied due to invalid subscription key. Make sure you are subscribed to an API you are trying to call and provide the right key."

For example happiness or beardiness can be extracted as follows.

content(faceResponse)[[1]]$faceAttributes$smile

## NULL

content(faceResponse)[[1]]$faceAttributes$facialHair$beard

## NULL

Adapted from Longhow Lam’s Blog by me, a crazy analyst with a little bit of beard.