C++ Requires Chilkat v11.5.0+

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.

C++

#include <CkJsonObject.h>
#include <CkPrivateKey.h>
#include <CkJwt.h>
#include <CkPrng.h>
#include <CkHttpCurl.h>

void ChilkatSample(void)
    {
    bool 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;

    CkJsonObject config;
    success = config.LoadFile("qa_data/tokens/box_jwt_config.json");
    if (success != true) {
        std::cout << config.lastErrorText() << "\r\n";
        return;
    }

    CkPrivateKey key;
    success = key.LoadEncryptedPem(config.stringOf("boxAppSettings.appAuth.privateKey"),config.stringOf("boxAppSettings.appAuth.passphrase"));
    if (success != true) {
        std::cout << key.lastErrorText() << "\r\n";
        return;
    }

    CkJsonObject header;
    header.UpdateString("alg","RS256");
    header.UpdateString("typ","JWT");
    header.UpdateString("kid",config.stringOf("boxAppSettings.appAuth.publicKeyID"));
    CkJwt jwt;
    CkPrng prng;
    const char *nonce = prng.genRandom(32,"hex");
    if (prng.get_LastMethodSuccess() != true) {
        std::cout << prng.lastErrorText() << "\r\n";
        return;
    }

    CkJsonObject claims;
    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));
    const char *assertion = jwt.createJwtPk(header.emit(),claims.emit(),key);
    if (jwt.get_LastMethodSuccess() != true) {
        std::cout << jwt.lastErrorText() << "\r\n";
        return;
    }

    CkHttpCurl curl;
    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.get_StatusCode() != 200)) {
        std::cout << "Box request failed. HTTP status: " << curl.get_StatusCode() << "\r\n";
        std::cout << "Failure reason: " << curl.get_FailReason() << "\r\n";
        return;
    }

    if (curl.VarDefined("!") != true) {
        std::cout << "Expected response fields are missing." << "\r\n";
        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.
    std::cout << "JWT access token obtained." << "\r\n";
    }