Box: Get a Service Account Token with JWT

See more Box Examples

Use the encrypted private key in a Box application configuration file to sign a short-lived assertion and exchange it for an access token. Configure and authorize a JWT Server app first. The enterprise subject obtains the service-account token.

See the Box API guide for setup and the complete workflow.

var success = false;

//  Requires Chilkat 11.5.0 or later and a previously unlocked Chilkat bundle.
//  See Global Unlock Sample.
//  Guide: Box API Guide.

success = false;

var config = new CkJsonObject();
success = config.LoadFile("qa_data/tokens/box_jwt_config.json");
if (success !== true) {
    console.log(config.LastErrorText);
    return;
}

var key = new CkPrivateKey();
success = key.LoadEncryptedPem(config.StringOf("boxAppSettings.appAuth.privateKey"),config.StringOf("boxAppSettings.appAuth.passphrase"));
if (success !== true) {
    console.log(key.LastErrorText);
    return;
}

var header = new CkJsonObject();
header.UpdateString("alg","RS256");
header.UpdateString("typ","JWT");
header.UpdateString("kid",config.StringOf("boxAppSettings.appAuth.publicKeyID"));
var jwt = new CkJwt();
var prng = new CkPrng();
var nonce = prng.GenRandom(32,"hex");
if (prng.LastMethodSuccess !== true) {
    console.log(prng.LastErrorText);
    return;
}

var claims = new CkJsonObject();
claims.UpdateString("iss",config.StringOf("boxAppSettings.clientID"));
claims.UpdateString("sub",config.StringOf("enterpriseID"));
claims.UpdateString("box_sub_type","enterprise");
claims.UpdateString("aud","https://api.box.com/oauth2/token");
claims.UpdateString("jti",nonce);
claims.UpdateInt("exp",jwt.GenNumericDate(45));
var assertion = jwt.CreateJwtPk(header.Emit(),claims.Emit(),key);
if (jwt.LastMethodSuccess !== true) {
    console.log(jwt.LastErrorText);
    return;
}

var curl = new CkHttpCurl();
curl.SetVar("client_id",config.StringOf("boxAppSettings.clientID"));
curl.SetVar("client_secret",config.StringOf("boxAppSettings.clientSecret"));
curl.SetVar("assertion",assertion);
curl.ClearTargetOutput("*");
curl.ClearVar("access_token");
curl.AddTargetOutput("access_token","access_token");
success = curl.DoYourThing("curl -X POST \"https://api.box.com/oauth2/token\" --data-urlencode \"grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer\" --data-urlencode \"client_id={{client_id}}\" --data-urlencode \"client_secret={{client_secret}}\" --data-urlencode \"assertion={{assertion}}\"");
if ((success !== true) || (curl.StatusCode !== 200)) {
    console.log("Box request failed. HTTP status: " + curl.StatusCode);
    console.log("Failure reason: " + curl.FailReason);
    return;
}

if (curl.VarDefined("!") !== true) {
    console.log("Expected response fields are missing.");
    return;
}

//  Reuse the token in this HttpCurl instance. JWT tokens are renewed by making
//  a new assertion/token request, not by using a refresh token.
console.log("JWT access token obtained.");