(Lianja) Walmart Partner API Authentication (Generate a Signature for a Request)

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

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// 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("CkDateTime")
// Set bLocal = .T. for a timestamp in the local timezone.  Set bLocal = .F. for a UTC timestamp.
llBLocal = .F.
// This gets the timestamp in seconds, not milliseconds.
lnTimeStampVal = loDt.GetAsUnixTime(llBLocal)

// Build the string to sign.
loSbStringToSign = createobject("CkStringBuilder")
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("CkPrivateKey")
// 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.
llSuccess = loPrivKey.LoadPem(lcPrivateEncodedStr)
if (llSuccess <> .T.) then
    ? loPrivKey.LastErrorText
    release loDt
    release loSbStringToSign
    release loPrivKey
    return
endif

loRsa = createobject("CkRsa")
llSuccess = loRsa.ImportPrivateKeyObj(loPrivKey)
if (llSuccess <> .T.) then
    ? loRsa.LastErrorText
    release loDt
    release loSbStringToSign
    release loPrivKey
    release loRsa
    return
endif

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

lcSignatureString = loRsa.SignStringENC(loSbStringToSign.GetAsString(),"SHA256")
if (loRsa.LastMethodSuccess <> .T.) then
    ? loRsa.LastErrorText
    release loDt
    release loSbStringToSign
    release loPrivKey
    release loRsa
    return
endif

? "Signature String: " + lcSignatureString


release loDt
release loSbStringToSign
release loPrivKey
release loRsa