(Visual FoxPro) Walmart Partner API Authentication (Generate a Signature for a Request)

Demonstrates how to generate a signature for a Walmart Partner REST API call.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL lnSuccess
LOCAL lcConsumerId
LOCAL lcBaseUrl
LOCAL lcPrivateEncodedStr
LOCAL lcHttpMethod
LOCAL loDt
LOCAL lnBLocal
LOCAL lnTimeStampVal
LOCAL loSbStringToSign
LOCAL loPrivKey
LOCAL loRsa
LOCAL lcSignatureString

lnSuccess = 0

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

lcConsumerId = "b68d2a72...."
lcBaseUrl = "https://marketplace.walmartapis.com/v2/feeds"
* This is your Base64 encoded private key
lcPrivateEncodedStr = "MIICeAIBADANBgkqhkiG9w0BAQEFAA......"
lcHttpMethod = "GET"

* We need a timestamp in decimal string form representing the number of milliseconds since Jan 01 1970 UTC.
loDt = CreateObject('Chilkat.CkDateTime')
* Set bLocal = 1 for a timestamp in the local timezone.  Set bLocal = 0 for a UTC timestamp.
lnBLocal = 0
* This gets the timestamp in seconds, not milliseconds.
lnTimeStampVal = loDt.GetAsUnixTime(lnBLocal)

* Build the string to sign.
loSbStringToSign = CreateObject('Chilkat.StringBuilder')
loSbStringToSign.Append(lcConsumerId)
loSbStringToSign.Append(CHR(10))
loSbStringToSign.Append(lcBaseUrl)
loSbStringToSign.Append(CHR(10))
loSbStringToSign.Append(lcHttpMethod)
loSbStringToSign.Append(CHR(10))
loSbStringToSign.AppendInt(lnTimeStampVal)
* We add three zero's so that the timestamp value is in milliseconds.
* We don't care about accuracy down to less than a second.
* All the server cares about is that the request was signed at the current date/time
* within some reasonable margin of error (to account for systems having clocks
* that may be slightly different).
loSbStringToSign.Append("000" + CHR(10))

loPrivKey = CreateObject('Chilkat.PrivateKey')
* Load the private key into a private key object.
* Note: Technically the private key is not PEM because it lacks the header/footer strings
* used for PEM.  However, the LoadPem method will still accept it and load it correctly.
lnSuccess = loPrivKey.LoadPem(lcPrivateEncodedStr)
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loDt
    RELEASE loSbStringToSign
    RELEASE loPrivKey
    CANCEL
ENDIF

loRsa = CreateObject('Chilkat.Rsa')
lnSuccess = loRsa.UsePrivateKey(loPrivKey)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loDt
    RELEASE loSbStringToSign
    RELEASE loPrivKey
    RELEASE loRsa
    CANCEL
ENDIF

* We want a base64 signature string.
loRsa.EncodingMode = "base64"

lcSignatureString = loRsa.SignStringENC(loSbStringToSign.GetAsString(),"SHA256")
IF (loRsa.LastMethodSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loDt
    RELEASE loSbStringToSign
    RELEASE loPrivKey
    RELEASE loRsa
    CANCEL
ENDIF

? "Signature String: " + lcSignatureString

RELEASE loDt
RELEASE loSbStringToSign
RELEASE loPrivKey
RELEASE loRsa