(Swift 3,4,5...) Streaming Decrypt HTTP Response

If the an encrypted file was previously uploaded, this example demonstrates how to download and decrypt in a streaming way.

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.

    let rest = CkoRest()!

    var bTls: Bool = true
    var port: Int = 443
    var bAutoReconnect: Bool = true
    var success: Bool = rest.connect("chilkatdownload.com", port: port, tls: bTls, autoReconnect: bAutoReconnect)

    // Send the request to download a file.
    success = rest.sendReqNoBody("GET", uriPath: "/9.5.0.83/chilkat-9.5.0-python-3.8-x64.zip")
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    // Read the response header.
    var responseStatusCode: Int = rest.readResponseHeader().intValue
    if responseStatusCode < 0 {
        print("\(rest.lastErrorText!)")
        return
    }

    print("Response status code = \(responseStatusCode)")

    // We expect a 200 response status if the JPG data is coming.
    // Otherwise, we'll get a string response body with an error message(or no response body).
    if responseStatusCode != 200 {
        var errResponse: String? = rest.readRespBodyString()
        if rest.lastMethodSuccess != true {
            print("\(rest.lastErrorText!)")
        }
        else {
            print("\(errResponse!)")
        }

        return
    }

    // Create an object for decrypting.
    // This example will use "none" for the encryption algorithm, which means it's just a pass-through.
    // Typically you would set the decrypt properties, such as secret key, IV, key length, padding scheme, cipher mode..
    let crypt = CkoCrypt2()!
    crypt.cryptAlgorithm = "none"

    // The following settings are ignored in this test because our CryptAlgorithm is "none".
    // However, if you were truly decrypting, you might set CryptAlgorithm = "aes".
    crypt.cipherMode = "cbc"
    crypt.keyLength = 128
    crypt.setEncodedKey("000102030405060708090A0B0C0D0E0F", encoding: "hex")
    crypt.setEncodedIV("000102030405060708090A0B0C0D0E0F", encoding: "hex")

    let receiveStream = CkoStream()!
    // The decryptStream's source will be the receiveStream.
    let decryptStream = CkoStream()!

    // The decrypt stream's sink will be a file.
    decryptStream.sinkFile = "qa_output/chilkat-9.5.0-python-3.8-x64.zip"
    decryptStream.setSourceStream(receiveStream)

    // Create and run a background async task to decrypt incoming data and write to a file.
    var decryptStreamTask: CkoTask? = crypt.decryptStreamAsync(decryptStream)
    success = decryptStreamTask!.run()

    success = rest.readRespBodyStream(receiveStream, autoSetStreamCharset: true)
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    print("Successfully received the .zip file.")

}