(Swift 3,4,5...) Walmart Partner API Authentication (Generate a Signature for a Request)

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

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

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

    var success: Bool

    var consumerId: String? = "b68d2a72...."
    var baseUrl: String? = "https://marketplace.walmartapis.com/v2/feeds"
    // This is your Base64 encoded private key
    var privateEncodedStr: String? = "MIICeAIBADANBgkqhkiG9w0BAQEFAA......"
    var httpMethod: String? = "GET"

    // We need a timestamp in decimal string form representing the number of milliseconds since Jan 01 1970 UTC.
    let dt = CkoDateTime()!
    // Set bLocal = true for a timestamp in the local timezone.  Set bLocal = false for a UTC timestamp.
    var bLocal: Bool = false
    // This gets the timestamp in seconds, not milliseconds.
    var timeStampVal: Int = dt.getAsUnixTime(bLocal)

    // Build the string to sign.
    let sbStringToSign = CkoStringBuilder()!
    sbStringToSign.append(consumerId)
    sbStringToSign.append("\n")
    sbStringToSign.append(baseUrl)
    sbStringToSign.append("\n")
    sbStringToSign.append(httpMethod)
    sbStringToSign.append("\n")
    sbStringToSign.appendInt(timeStampVal)
    // 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).
    sbStringToSign.append("000\n")

    let privKey = CkoPrivateKey()!
    // 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.
    success = privKey.loadPem(privateEncodedStr)
    if success != true {
        print("\(privKey.lastErrorText!)")
        return
    }

    let rsa = CkoRsa()!
    success = rsa.importPrivateKeyObj(privKey)
    if success != true {
        print("\(rsa.lastErrorText!)")
        return
    }

    // We want a base64 signature string.
    rsa.encodingMode = "base64"

    var signatureString: String? = rsa.signStringENC(sbStringToSign.getAsString(), hashAlg: "SHA256")
    if rsa.lastMethodSuccess != true {
        print("\(rsa.lastErrorText!)")
        return
    }

    print("Signature String: \(signatureString!)")

}