FacialExpressionToEmoji.swift

import Foundation
import PlaygroundSupport

let apiKey = "[API KEY]"
let endPointUrl = "https://westus.api.cognitive.microsoft.com/emotion/v1.0"
let url = URL(string: "\(endPointUrl)/recognize")!
let testImageString = "https://pbs.twimg.com/profile_images/853106910861643776/tZh0rhmL.jpg"

struct Response: Decodable {
  let scores: Score
}

struct Score: Decodable {
  let anger: Float
  let contempt: Float
  let disgust: Float
  let fear: Float
  let happiness: Float
  let neutral: Float
  let sadness: Float
  let surprise: Float
}

enum ScoreEmoji: Int {
  case 😡, 🙄, 🤢, 😱, 😊, 😐, 😭, 😮

  init(_ index: Int) {
    self.init(rawValue: index)!
  }
}

// prepare json data
let json: [String: Any] = ["url": testImageString]
let jsonData = try? JSONSerialization.data(withJSONObject: json)

// create post request
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = jsonData
request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
request.setValue(apiKey, forHTTPHeaderField: "Ocp-Apim-Subscription-Key")

URLSession.shared.dataTask(with: request) { data, response, error in
  guard let data = data, error == nil else {
    print(error?.localizedDescription ?? "No data")
    return
  }

  do {
    let responses = try JSONDecoder().decode([Response].self, from: data)
    if let response = responses.first {
      let score = response.scores
      let values = [score.anger, score.contempt, score.disgust, score.fear, score.happiness, score.neutral, score.sadness, score.surprise]
      if let max = values.max(), let index = values.index(of: max) {
        let sentiment = ScoreEmoji(index)
        print(sentiment)
      }
    }
  } catch(let error) {
    print(error)
  }

  PlaygroundPage.current.finishExecution()
}.resume()

PlaygroundPage.current.needsIndefiniteExecution = true