Obtaining an Engage Access Token with a RingCentral Login

$ curl -XPOST https://engage.ringcentral.com/api/auth/login/rc/accesstoken \
      -d 'rcAccessToken=<rcAccessToken>' \
      -d 'rcTokenType=Bearer'

package main

import(
      "fmt"
      "encoding/json"
      "io/ioutil"
      "net/url"
    )

// EngageToken is an example and does not cover all the
// properties in the API response.
type EngageToken struct {
        AccessToken string `json:"accessToken"`
        TokenType   string `json:"tokenType"`
}

func RcToEvToken(rctoken string) (string, error) {
    res, err := http.PostForm(
            "https://engage.ringcentral.com/api/auth/login/rc/accesstoken",
            url.Values{"rcAccessToken": {rctoken}, "rcTokenType": {"Bearer"}})
    if err != nil {
            return "", err
    }
    if res.StatusCode >= 300 {
            return "", fmt.Errorf("Invalid Token Response [%v]", res.StatusCode)
    }
    engageToken := EngageToken{}
    bytes, err := ioutil.ReadAll(res.Body)
    if err != nil {
            return "", err
    }
    err = json.Unmarshal(bytes, &engageToken)
    return engageToken.AccessToken, err
}

func main() {
    rctoken := "myRcToken"

    evtoken, err := RcToEvToken(rctoken)
    if err != nil {
            log.Fatal(err)
    }
    fmt.Println(evtoken)
}

var https = require('https')

var RC_ACCESS_TOKEN = "VALID-RINGCENTRAL-ACCESS-TOKEN"

var url = "engage.ringcentral.com"
var path = '/api/auth/login/rc/accesstoken'
var body = 'rcAccessToken=' + RC_ACCESS_TOKEN + "&rcTokenType=Bearer"
var headers = { 'Content-Type': 'application/x-www-form-urlencoded' }

var options = {host: url, path: path, method: 'POST', headers: headers};
var post_req = https.request(options, function(res) {
      var response = ""
      res.on('data', function (chunk) {
          response += chunk
      }).on("end", function(){
          if (res.statusCode == 200){
              var tokensObj = JSON.parse(response)
              console.log(tokensObj.accessToken)
          }else{
              console.log(response)
          }
      });
    }).on('error', function (e) {
        console.log(e)
    })
post_req.write(body);
post_req.end();

import requests

RC_ACCESS_TOKEN = "VALID-RINGCENTRAL-ACCESS-TOKEN"
url = "https://engage.ringcentral.com/api/auth/login/rc/accesstoken"
body = "rcAccessToken=%s&rcTokenType=Bearer" % (RC_ACCESS_TOKEN)
headers = {
              'Content-Type': 'application/x-www-form-urlencoded'
          }
try:
    res = requests.post(url, headers=headers, data=body)
    if res.status_code == 200:
        jsonObj = json.loads(res._content)
        print (jsonObj['accessToken'])
    else:
        print (res._content)
except Exception as e:
    raise ValueError(e)

<?php
$RC_ACCESS_TOKEN = "VALID-RINGCENTRAL-ACCESS-TOKEN";

$url = "https://engage.ringcentral.com/api/auth/login/rc/accesstoken";
$body = 'rcAccessToken=' . $RC_ACCESS_TOKEN . "&rcTokenType=Bearer";
$headers = array ('Content-Type: application/x-www-form-urlencoded');

try{
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_POST, TRUE);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_TIMEOUT, 600);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
    $strResponse = curl_exec($ch);
    $curlErrno = curl_errno($ch);
    if ($curlErrno) {
        throw new Exception($curlErrno);
    } else {
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        if ($httpCode == 200) {
            $tokensObj = json_decode($strResponse);
            print ($tokensObj->accessToken);
        }else{
            print ($strResponse);
        }
    }
}catch (Exception $e) {
    throw $e;
}