(C++) Generate an E-way Bill

Demonstrates how to send an HTTP POST request to generate an e-way bill.

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#include <CkJsonObject.h>
#include <CkCrypt2.h>
#include <CkHttp.h>
#include <CkHttpResponse.h>
#include <CkStringBuilder.h>
#include <CkBinData.h>

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

    //  This example uses the previously obtained access token that was retrieved
    //  in this example:  Get EWAY Auth Token using Gstin, username, password, and app_key

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

    //  The jsonAuth contains something like this:
    //  {
    //    "authToken": "IBTeFtxNfVurg71LTzZ2r0xK7",
    //    "decryptedSek": "5g1TyTie7yoslU3DrbYATa7mWyPazlODE7cEh5Vy4Ho="
    //  }

    //  Generate the JSON data for the e-way bill.
    //  The following code can be generated by pasting representative JSON into this online tool:
    //  Generate JSON Code
    CkJsonObject jsonData;
    jsonData.UpdateString("supplyType","O");
    jsonData.UpdateString("subSupplyType","1");
    jsonData.UpdateString("docType","INV");
    jsonData.UpdateString("docNo","AW1234-2");
    jsonData.UpdateString("docDate","05/04/2018");
    jsonData.UpdateString("fromGstin","09ABDC24212B1FK");
    jsonData.UpdateString("fromTrdName","willy");
    jsonData.UpdateString("fromAddr1","3RD CROSS NO 200  19  A");
    jsonData.UpdateString("fromAddr2","GROUND FLOOR OZZY ROAD");
    jsonData.UpdateString("fromPlace","BUSY TOWN");
    jsonData.UpdateNumber("fromPincode","640033");
    jsonData.UpdateNumber("actFromStateCode","05");
    jsonData.UpdateNumber("fromStateCode","05");
    jsonData.UpdateString("toGstin","01AAAASCC10BBBB");
    jsonData.UpdateString("toTrdName","mthustra");
    jsonData.UpdateString("toAddr1","Shrek Ogre");
    jsonData.UpdateString("toAddr2","Basadronsil");
    jsonData.UpdateString("toPlace","Grifl Blagar");
    jsonData.UpdateNumber("toPincode","699988");
    jsonData.UpdateNumber("actToStateCode","29");
    jsonData.UpdateNumber("toStateCode","02");
    jsonData.UpdateNumber("totalValue","5609889");
    jsonData.UpdateNumber("cgstValue","0");
    jsonData.UpdateNumber("sgstValue","0");
    jsonData.UpdateNumber("igstValue","168296.67");
    jsonData.UpdateNumber("cessValue","224395.56");
    jsonData.UpdateString("transporterId","09ABDC24212B1FK");
    jsonData.UpdateString("transporterName","");
    jsonData.UpdateString("transDocNo","12332");
    jsonData.UpdateNumber("transMode","1");
    jsonData.UpdateString("transDistance","656");
    jsonData.UpdateString("transDocDate","10/04/2018");
    jsonData.UpdateString("vehicleNo","PBN4567");
    jsonData.UpdateString("vehicleType","R");
    jsonData.put_I(0);
    jsonData.UpdateString("itemList[i].productName","Wheat");
    jsonData.UpdateString("itemList[i].productDesc","Wheat");
    jsonData.UpdateNumber("itemList[i].hsnCode","1001");
    jsonData.UpdateNumber("itemList[i].quantity","4");
    jsonData.UpdateString("itemList[i].qtyUnit","BOX");
    jsonData.UpdateNumber("itemList[i].cgstRate","0");
    jsonData.UpdateNumber("itemList[i].sgstRate","0");
    jsonData.UpdateNumber("itemList[i].igstRate","3");
    jsonData.UpdateNumber("itemList[i].cessRate","4");
    jsonData.UpdateNumber("itemList[i].cessAdvol","0");
    jsonData.UpdateNumber("itemList[i].taxableAmount","5609889");

    //  The body of the HTTP POST will contain JSON that looks like this:
    //  	{
    //  	"action":"GENEWAYBILL",
    //  	"data": " iJiJGXq ... oUZp/25Y "
    //  	}

    //  The "data" is the encrypted jsonData using our previously agreed-upon symmetric encryption key.
    //  Let's begin build the JSON request body..
    CkJsonObject jsonRequestBody;
    jsonRequestBody.UpdateString("action","GENEWAYBILL");

    //  Setup the encryptor using the decryptedSek from the jsonAuth
    CkCrypt2 crypt;
    crypt.put_CryptAlgorithm("aes");
    crypt.put_CipherMode("ecb");
    crypt.put_KeyLength(256);
    crypt.SetEncodedKey(jsonAuth.stringOf("decryptedSek"),"base64");
    crypt.put_EncodingMode("base64");

    //  Encrypt the jsonData and add it to our JSON request body
    jsonRequestBody.UpdateString("data",crypt.encryptStringENC(jsonData.emit()));

    CkHttp http;

    //  Add the authtoken to the request header.
    //  Be careful to be precise with uppercase/lowercase ("authtoken" vs "authToken")
    http.SetRequestHeader("authtoken",jsonAuth.stringOf("authToken"));
    http.SetRequestHeader("Gstin","09ABDC24212B1FK");
    http.put_Accept("application/json");

    //  POST the request to generate an e-way bill:
    CkHttpResponse *resp = http.PostJson2("http://ewb.wepgst.com/api/EWayBill","application/json",jsonRequestBody.emit());
    if (http.get_LastMethodSuccess() != true) {
        std::cout << http.lastErrorText() << "\r\n";
        return;
    }

    int respStatusCode = resp->get_StatusCode();
    std::cout << "response status code =" << respStatusCode << "\r\n";
    std::cout << "response body:" << "\r\n";
    std::cout << resp->bodyStr() << "\r\n";

    if (respStatusCode != 200) {
        delete resp;
        std::cout << "Failed in some unknown way." << "\r\n";
        return;
    }

    //  When the response status code = 200, we'll have either
    //  success response like this:
    //   {"status":"1","data":"..."}
    // 
    //  or a failed response like this:
    // 
    //  {"status":"0","error":"eyJlcnJvckNvZGVzIjoiMTA4In0="}

    //  Load the response body into a JSON object.
    CkJsonObject json;
    json.Load(resp->bodyStr());
    delete resp;

    int status = json.IntOf("status");
    std::cout << "status = " << status << "\r\n";

    if (status != 1) {
        //  Failed.  Base64 decode the error
        // {"status":"0","error":"eyJlcnJvckNvZGVzIjoiMTA4In0="}
        //  For an invalid password, the error is: {"errorCodes":"108"}
        CkStringBuilder sbError;
        json.StringOfSb("error",sbError);
        sbError.Decode("base64","utf-8");
        std::cout << "error: " << sbError.getAsString() << "\r\n";
        return;
    }

    json.put_EmitCompact(false);
    std::cout << "JSON response:" << "\r\n";
    std::cout << json.emit() << "\r\n";

    CkBinData bdData;
    bdData.AppendEncoded(json.stringOf("data"),"base64");
    crypt.DecryptBd(bdData);

    //  Decrypts to
    //  {"ewayBillNo":331001121234,"ewayBillDate":"24/05/2018 04:38:00 PM","validUpto":"31/05/2018 11:59:00 PM"}

    CkJsonObject jsonBill;
    jsonBill.Load(bdData.getString("utf-8"));

    int ewayBillNo = jsonBill.IntOf("ewayBillNo");
    std::cout << "ewayBillNo = " << ewayBillNo << "\r\n";

    const char *ewayBillDate = jsonBill.stringOf("ewayBillDate");
    std::cout << "ewayBillDate = " << ewayBillDate << "\r\n";

    const char *validUpto = jsonBill.stringOf("validUpto");
    std::cout << "validUpto = " << validUpto << "\r\n";

    //  Sample output:

    //  ewayBillNo = 331001121234
    //  ewayBillDate = 24/05/2018 04:55:00 PM
    //  validUpto = 31/05/2018 11:59:00 PM
    }