Swift

REST Read Response with Stream API

See more REST Examples

Demonstrates how to make a REST call that returns a binary body, and to receive the body through a stream API. Swift

func chilkatTest() {
    var success: Bool = false

    // 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
    success = rest.connect(hostname: "s3.amazonaws.com", port: port, tls: bTls, autoReconnect: bAutoReconnect)

    // ----------------------------------------------------------------------------
    // Important: For buckets created in regions outside us-east-1,
    // there are three important changes that need to be made.
    // See Working with S3 Buckets in Non-us-east-1 Regions for the details.
    // ----------------------------------------------------------------------------

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

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    rest.host = "chilkat100.s3.amazonaws.com"

    // Send the request to download the JPG.
    success = rest.sendReqNoBody(httpVerb: "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 {
        var errResponse: String? = rest.readRespBodyString()
        if rest.lastMethodSuccess != true {
            print("\(rest.lastErrorText!)")
        }
        else {
            print("\(errResponse!)")
        }

        return
    }

    let bodyStream = CkoStream()!
    // Set a 10 second read timeout for the stream. 
    // (Give up if no data arrives within 10 seconds after calling a read method.)
    bodyStream.readTimeoutMs = 10000

    // Create a background thread task to read the response body (which feeds
    // it to the bodyStream object.)
    var readResponseBodyTask: CkoTask? = rest.readRespBodyStreamAsync(stream: bodyStream, autoSetStreamCharset: true)

    // Start the task. 
    success = readResponseBodyTask!.run()

    // The application can now read the bodyStream...
    while (bodyStream.endOfStream != true) {

        // Read the next chunk of bytes (whatever is immediately available,
        // or wait for more data (up to 10 seconds because we set the stream's ReadTimeoutMs property)
        var nextChunk: NSData = bodyStream.readBytes()
        if bodyStream.lastMethodSuccess != true {
            print("Failed to receive more response data.")
            // Make sure the background task is aborted/cancelled.
            success = readResponseBodyTask!.cancel()
            readResponseBodyTask = nil
            return
        }

        // OK.. the app has the next chunk of the body, and may do whatever it wishes with it...
    }

    readResponseBodyTask = nil

    print("Successfully received the entire response body.")

}