(Swift 3,4,5...) (using AWS Signature Version 2) Streaming Download to File

The main purpose of this example is to demonstrate how to use the older Signature Version 2 authentication w/ S3. It uses V2 authentication to download a file.

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()!

    // Connect to the Amazon AWS REST server.
    var bTls: Bool = true
    var port: Int = 443
    var bAutoReconnect: Bool = true
    // The file is located in the bucket named "chilkat100", which becomes part of the domain:
    var success: Bool = rest.connect("chilkat100.s3.amazonaws.com", port: port, tls: bTls, autoReconnect: bAutoReconnect)

    // Provide AWS credentials for the REST call.
    let authAws = CkoAuthAws()!
    authAws.accessKey = "AWS_ACCESS_KEY"
    authAws.secretKey = "AWS_SECRET_KEY"
    authAws.serviceName = "s3"

    // For AWS Signature Version 2, the following two properties need to be set:
    authAws.signatureVersion = 2
    // See http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement
    authAws.canonicalizedResourceV2 = "/chilkat100/starfish.jpg"

    success = rest.setAuthAws(authAws)

    // Send the request to download the JPG.
    success = rest.sendReqNoBody("GET", uriPath: "/starfish.jpg")
    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 {

        let bodyStream = CkoStream()!

        // The stream's sink will be a file.
        bodyStream.sinkFile = "qa_output/starfish.jpg"

        // Read the response body to the stream.  Given that we've
        // set the stream's sink to a file, it will stream directly
        // to the file.
        success = rest.readRespBodyStream(bodyStream, autoSetStreamCharset: true)
        if success != true {
            print("\(rest.lastErrorText!)")
            return
        }

        print("Successfully received the JPG file.")

    }
    else {
        var errResponse: String? = rest.readRespBodyString()
        if rest.lastMethodSuccess != true {
            print("\(rest.lastErrorText!)")
        }
        else {
            print("\(errResponse!)")
        }

    }


}