(Swift 3,4,5...) Streaming Download Large File to the Local Filesystem

Downloads a large file in a streaming fashion to the local filesystem.

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

func chilkatTest() {
    // Azure File Service Example: Downloads a large file to the local filesystem using a Chilkat stream.
    // See:  https://docs.microsoft.com/en-us/rest/api/storageservices/get-file

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

    let rest = CkoRest()!

    // Connect to the Azure Storage Blob Service
    var bTls: Bool = true
    var port: Int = 443
    var bAutoReconnect: Bool = true
    // In this example, the storage account name is "chilkat".
    var success: Bool = rest.connect("chilkat.file.core.windows.net", port: port, tls: bTls, autoReconnect: bAutoReconnect)
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    // Provide Azure Cloud credentials for the REST calls.
    let azAuth = CkoAuthAzureStorage()!
    azAuth.accessKey = "AZURE_ACCESS_KEY"
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    azAuth.account = "chilkat"
    azAuth.scheme = "SharedKey"
    azAuth.service = "File"
    // This causes the "x-ms-version: 2020-08-04" header to be automatically added.
    azAuth.xMsVersion = "2020-08-04"
    success = rest.setAuthAzureStorage(azAuth)

    // Note: The application does not need to explicitly set the following
    // headers: x-ms-date, Authorization.  These headers
    // are automatically set by Chilkat.

    // When streaming a download to the local filesystem or directed elsewhere,
    // the complete HTTP GET operation must be broken into parts.
    // For example, an HTTP GET consists of sending the request, followed by reading the response header,
    // and then finally the response body.  We'll want to read the response header, and then based
    // on the information received (such as success or failure), either read the response body
    // as an error message, or as the file data.

    // Send the HTTP GET request to download the file.
    // The share is named "pip".
    success = rest.sendReqNoBody("GET", uriPath: "/pip/somethingBig.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 file 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/somethingBig.zip"

        // 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 large file.")

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

    }


}