C

PRODA Get OAuth2 Access Token using JWT

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Demonstrates how to get an OAuth2 access token for the PRODA Australian Government Online Services using a JWT. C

#include <C_CkPrivateKey.h>
#include <C_CkJwt.h>
#include <C_CkJsonObject.h>
#include <C_CkHttp.h>
#include <C_CkHttpRequest.h>
#include <C_CkHttpResponse.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrivateKey privKey;
    HCkJwt jwt;
    HCkJsonObject jose;
    HCkJsonObject claims;
    int curDateTime;
    const char *jwtToken;
    HCkHttp http;
    HCkHttpRequest req;
    HCkHttpResponse resp;

    success = FALSE;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // First create a JWT to be sent in the POST to https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token

    privKey = CkPrivateKey_Create();

    // Load an RSA private key from a PEM file.
    // Chilkat provides alternative methods to load from other formats, or to load from a string or binary data.
    success = CkPrivateKey_LoadEncryptedPemFile(privKey,"qa_data/pem/rsa_passwd.pem","passwd");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkPrivateKey_Dispose(privKey);
        return;
    }

    jwt = CkJwt_Create();

    // Build the JOSE header
    jose = CkJsonObject_Create();
    // Use RS256.  Pass the string "RS384" or "RS512" to use RSA with SHA-384 or SHA-512.
    success = CkJsonObject_AppendString(jose,"alg","RS256");
    success = CkJsonObject_AppendString(jose,"typ","JWT");
    success = CkJsonObject_AppendString(jose,"kid","test-device");

    // Now build the JWT claims (also known as the payload)
    claims = CkJsonObject_Create();
    success = CkJsonObject_AppendString(claims,"iss","9646844092");
    success = CkJsonObject_AppendString(claims,"sub","test-device");
    success = CkJsonObject_AppendString(claims,"aud","https://proda.humanservices.gov.au");

    // Set the timestamp of when the JWT was created to now.
    curDateTime = CkJwt_GenNumericDate(jwt,0);
    success = CkJsonObject_AddIntAt(claims,-1,"iat",curDateTime);

    // Set the timestamp defining an expiration time (end time) for the token
    // to be now + 1 hour (3600 seconds)
    success = CkJsonObject_AddIntAt(claims,-1,"exp",curDateTime + 3600);

    // Produce the smallest possible JWT:
    CkJwt_putAutoCompact(jwt,TRUE);

    // Create the JWT token.  This is where the RSA signature is created.
    jwtToken = CkJwt_createJwtPk(jwt,CkJsonObject_emit(jose),CkJsonObject_emit(claims),privKey);

    // ---------------------------------------------------------------------
    // Build and send the POST, which should look something like this:

    // POST https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token HTTP/1.1
    // Content-Type: application/x-www-form-urlencoded
    // Content-Length: 666
    // Host: vnd.proda.humanservices.gov.au
    // 
    // grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&assertion=<jwt>&client_id=VendorClient03

    http = CkHttp_Create();

    req = CkHttpRequest_Create();
    CkHttpRequest_putHttpVerb(req,"POST");
    CkHttpRequest_putContentType(req,"application/x-www-form-urlencoded");

    // Add the request params.
    CkHttpRequest_AddParam(req,"grant_type","urn:ietf:params:oauth:grant-type:jwt-bearer");
    CkHttpRequest_AddParam(req,"assertion",jwtToken);
    CkHttpRequest_AddParam(req,"client_id","VendorClient03");

    resp = CkHttpResponse_Create();
    success = CkHttp_HttpReq(http,"https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token",req,resp);
    if (success == FALSE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        CkPrivateKey_Dispose(privKey);
        CkJwt_Dispose(jwt);
        CkJsonObject_Dispose(jose);
        CkJsonObject_Dispose(claims);
        CkHttp_Dispose(http);
        CkHttpRequest_Dispose(req);
        CkHttpResponse_Dispose(resp);
        return;
    }

    printf("Response status code = %d\n",CkHttpResponse_getStatusCode(resp));
    printf("Response body:\n");
    printf("%s\n",CkHttpResponse_bodyStr(resp));


    CkPrivateKey_Dispose(privKey);
    CkJwt_Dispose(jwt);
    CkJsonObject_Dispose(jose);
    CkJsonObject_Dispose(claims);
    CkHttp_Dispose(http);
    CkHttpRequest_Dispose(req);
    CkHttpResponse_Dispose(resp);

    }