(PHP Extension) Get E-way Bill System Access Token

Sends a request to get an E-way bill system access token.

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

//  First load the public key provided by the E-way bill System
$pubkey = new CkPublicKey();
$success = $pubkey->LoadFromFile('qa_data/pem/eway_publickey.pem');
if ($success != true) {
    print $pubkey->lastErrorText() . "\n";
    exit;
}

//  Encrypt the password using the RSA public key provided by eway..
$password = 'my_wepgst_password';
$rsa = new CkRsa();
$rsa->put_Charset('utf-8');
$rsa->put_EncodingMode('base64');

$success = $rsa->ImportPublicKeyObj($pubkey);
if ($success != true) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

//  Returns the encrypted password as base64 (because the EncodingMode = "base64")
$encPassword = $rsa->encryptStringENC($password,false);
if ($rsa->get_LastMethodSuccess() != true) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

//  Generate a random app_key.  This should be 32 bytes (us-ascii chars)
//  We need 32 bytes because we'll be doing 256-bit AES ECB encryption, and 32 bytes = 256 bits.
$prng = new CkPrng();
//  Generate a random string containing some numbers, uppercase, and lowercase.
$app_key = $prng->randomString(32,true,true,true);

print 'app_key = ' . $app_key . "\n";

//  RSA encrypt the app_key.
$encAppKey = $rsa->encryptStringENC($app_key,false);
if ($rsa->get_LastMethodSuccess() != true) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

//  Prepare the JSON body for the HTTP POST that gets the access token.
$jsonBody = new CkJsonObject();
$jsonBody->UpdateString('action','ACCESSTOKEN');
//  Use your username instead of "09ABDC24212B1FK".
$jsonBody->UpdateString('username','09ABDC24212B1FK');
$jsonBody->UpdateString('password',$encPassword);
$jsonBody->UpdateString('app_key',$encAppKey);

$http = new CkHttp();

//  Add required headers.
//  Use your ewb-user-id instead of "03AEXPR16A9M010"
$http->SetRequestHeader('ewb-user-id','03AEXPR16A9M010');
//  The Gstin should be the same as the username in the jsonBody above.
$http->SetRequestHeader('Gstin','09ABDC24212B1FK');
$http->put_Accept('application/json');

//  POST the JSON...
// resp is a CkHttpResponse
$resp = $http->PostJson2('http://ewb.wepgst.com/api/Authenticate','application/json',$jsonBody->emit());
if ($http->get_LastMethodSuccess() != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

$respStatusCode = $resp->get_StatusCode();
print 'response status code =' . $respStatusCode . "\n";
print 'response body:' . "\n";
print $resp->bodyStr() . "\n";

if ($respStatusCode != 200) {

    print 'Failed in some unknown way.' . "\n";
    exit;
}

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

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

$status = $json->IntOf('status');
print 'status = ' . $status . "\n";

if ($status != 1) {
    //  Failed.  Base64 decode the error
    // {"status":"0","error":"eyJlcnJvckNvZGVzIjoiMTA4In0="}
    //  For an invalid password, the error is: {"errorCodes":"108"}
    $sbError = new CkStringBuilder();
    $json->StringOfSb('error',$sbError);
    $sbError->Decode('base64','utf-8');
    print 'error: ' . $sbError->getAsString() . "\n";
    exit;
}

//  At this point, we know the request was entirely successful.
$authToken = $json->stringOf('authtoken');

//  Decrypt the sek key using our app_key.
$crypt = new CkCrypt2();
$crypt->put_CryptAlgorithm('aes');
$crypt->put_CipherMode('ecb');
$crypt->put_KeyLength(256);
$crypt->SetEncodedKey($app_key,'us-ascii');
$crypt->put_EncodingMode('base64');

$bdSek = new CkBinData();
$bdSek->AppendEncoded($json->stringOf('sek'),'base64');
$crypt->DecryptBd($bdSek);

//  bdSek now contains the decrypted symmetric encryption key...
//  We'll use it to encrypt the JSON payloads we send.

//  Let's persist our authtoken and decrypted sek (symmetric encryption key).
//  To send EWAY requests (such as to create an e-way bill), we'll just load
//  and use these pre-obtained credentials.
$jsonEwayAuth = new CkJsonObject();
$jsonEwayAuth->UpdateString('authToken',$authToken);
$jsonEwayAuth->UpdateString('decryptedSek',$bdSek->getEncoded('base64'));
$jsonEwayAuth->put_EmitCompact(false);

$fac = new CkFileAccess();
$fac->WriteEntireTextFile('qa_data/tokens/ewayAuth.json',$jsonEwayAuth->emit(),'utf-8',false);

print 'Saved:' . "\n";
print $jsonEwayAuth->emit() . "\n";

//  Sample output:
//  {
//    "authToken": "IBTeFtxNfVurg71LTzZ2r0xK7",
//    "decryptedSek": "5g1TyTie7yoslU3DrbYATa7mWyPazlODE7cEh5Vy4Ho="
//  }

?>