Xbase++ Requires Chilkat v11.0.0+

Get E-way Bill System Access Token

See more HTTP Misc Examples

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

LOCAL nSuccess
LOCAL oPubkey
LOCAL cPassword
LOCAL oRsa
LOCAL cEncPassword
LOCAL oPrng
LOCAL cApp_key
LOCAL cEncAppKey
LOCAL oJsonBody
LOCAL oHttp
LOCAL oResp
LOCAL nRespStatusCode
LOCAL oJson
LOCAL nStatus
LOCAL oSbError
LOCAL cAuthToken
LOCAL oCrypt
LOCAL oBdSek
LOCAL oJsonEwayAuth
LOCAL oFac

nSuccess := 0

//  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
oPubkey := CreateObject("Chilkat.PublicKey")
nSuccess := oPubkey:LoadFromFile("qa_data/pem/eway_publickey.pem")
IF (nSuccess == 0)
    ? oPubkey:LastErrorText
    oPubkey:destroy()
    RETURN
ENDIF

//  Encrypt the password using the RSA public key provided by eway..
cPassword := "my_wepgst_password"
oRsa := CreateObject("Chilkat.Rsa")
oRsa:Charset := "utf-8"
oRsa:EncodingMode := "base64"

nSuccess := oRsa:UsePublicKey(oPubkey)
IF (nSuccess == 0)
    ? oRsa:LastErrorText
    oPubkey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  Returns the encrypted password as base64 (because the EncodingMode = "base64")
cEncPassword := oRsa:EncryptStringENC(cPassword, 0)
IF (oRsa:LastMethodSuccess == 0)
    ? oRsa:LastErrorText
    oPubkey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  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.
oPrng := CreateObject("Chilkat.Prng")
//  Generate a random string containing some numbers, uppercase, and lowercase.
cApp_key := oPrng:RandomString(32, 1, 1, 1)

? "app_key = " + cApp_key

//  RSA encrypt the app_key.
cEncAppKey := oRsa:EncryptStringENC(cApp_key, 0)
IF (oRsa:LastMethodSuccess == 0)
    ? oRsa:LastErrorText
    oPubkey:destroy()
    oRsa:destroy()
    oPrng:destroy()
    RETURN
ENDIF

//  Prepare the JSON body for the HTTP POST that gets the access token.
oJsonBody := CreateObject("Chilkat.JsonObject")
oJsonBody:UpdateString("action", "ACCESSTOKEN")
//  Use your username instead of "09ABDC24212B1FK".
oJsonBody:UpdateString("username", "09ABDC24212B1FK")
oJsonBody:UpdateString("password", cEncPassword)
oJsonBody:UpdateString("app_key", cEncAppKey)

oHttp := CreateObject("Chilkat.Http")

//  Add required headers.
//  Use your ewb-user-id instead of "03AEXPR16A9M010"
oHttp:SetRequestHeader("ewb-user-id", "03AEXPR16A9M010")
//  The Gstin should be the same as the username in the jsonBody above.
oHttp:SetRequestHeader("Gstin", "09ABDC24212B1FK")
oHttp:Accept := "application/json"

//  POST the JSON...
oResp := CreateObject("Chilkat.HttpResponse")
nSuccess := oHttp:HttpJson("POST", "http://ewb.wepgst.com/api/Authenticate", oJsonBody, "application/json", oResp)
IF (nSuccess == 0)
    ? oHttp:LastErrorText
    oPubkey:destroy()
    oRsa:destroy()
    oPrng:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    RETURN
ENDIF

nRespStatusCode := oResp:StatusCode
? "response status code =" + Str(nRespStatusCode)
? "response body:"
? oResp:BodyStr

IF (nRespStatusCode != 200)
    ? "Failed in some unknown way."
    oPubkey:destroy()
    oRsa:destroy()
    oPrng:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    RETURN
ENDIF

//  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.
oJson := CreateObject("Chilkat.JsonObject")
oJson:Load(oResp:BodyStr)

nStatus := oJson:IntOf("status")
? "status = " + Str(nStatus)

IF (nStatus != 1)
    //  Failed.  Base64 decode the error
    //  {"status":"0","error":"eyJlcnJvckNvZGVzIjoiMTA4In0="}
    //  For an invalid password, the error is: {"errorCodes":"108"}
    oSbError := CreateObject("Chilkat.StringBuilder")
    oJson:StringOfSb("error", oSbError)
    oSbError:Decode("base64", "utf-8")
    ? "error: " + oSbError:GetAsString()
    oPubkey:destroy()
    oRsa:destroy()
    oPrng:destroy()
    oJsonBody:destroy()
    oHttp:destroy()
    oResp:destroy()
    oJson:destroy()
    oSbError:destroy()
    RETURN
ENDIF

//  At this point, we know the request was entirely successful.
cAuthToken := oJson:StringOf("authtoken")

//  Decrypt the sek key using our app_key.
oCrypt := CreateObject("Chilkat.Crypt2")
oCrypt:CryptAlgorithm := "aes"
oCrypt:CipherMode := "ecb"
oCrypt:KeyLength := 256
oCrypt:SetEncodedKey(cApp_key, "us-ascii")
oCrypt:EncodingMode := "base64"

oBdSek := CreateObject("Chilkat.BinData")
oBdSek:AppendEncoded(oJson:StringOf("sek"), "base64")
oCrypt:DecryptBd(oBdSek)

//  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.
oJsonEwayAuth := CreateObject("Chilkat.JsonObject")
oJsonEwayAuth:UpdateString("authToken", cAuthToken)
oJsonEwayAuth:UpdateString("decryptedSek", oBdSek:GetEncoded("base64"))
oJsonEwayAuth:EmitCompact := 0

oFac := CreateObject("Chilkat.FileAccess")
oFac:WriteEntireTextFile("qa_data/tokens/ewayAuth.json", oJsonEwayAuth:Emit(), "utf-8", 0)

? "Saved:"
? oJsonEwayAuth:Emit()

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

oPubkey:destroy()
oRsa:destroy()
oPrng:destroy()
oJsonBody:destroy()
oHttp:destroy()
oResp:destroy()
oJson:destroy()
oSbError:destroy()
oCrypt:destroy()
oBdSek:destroy()
oJsonEwayAuth:destroy()
oFac:destroy()