(C#) Streaming Download Large File to the Local Filesystem

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

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// 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.

Chilkat.Rest rest = new Chilkat.Rest();

// Connect to the Azure Storage Blob Service
bool bTls = true;
int port = 443;
bool bAutoReconnect = true;
// In this example, the storage account name is "chilkat".
bool success = rest.Connect("chilkat.file.core.windows.net",port,bTls,bAutoReconnect);
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// Provide Azure Cloud credentials for the REST calls.
Chilkat.AuthAzureStorage azAuth = new Chilkat.AuthAzureStorage();
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","/pip/somethingBig.zip");
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// Read the response header.
int responseStatusCode = rest.ReadResponseHeader();
if (responseStatusCode < 0) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

Debug.WriteLine("Response status code = " + Convert.ToString(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) {

    Chilkat.Stream bodyStream = new Chilkat.Stream();

    // 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,true);
    if (success != true) {
        Debug.WriteLine(rest.LastErrorText);
        return;
    }

    Debug.WriteLine("Successfully received the large file.");

}
else {
    string errResponse = rest.ReadRespBodyString();
    if (rest.LastMethodSuccess != true) {
        Debug.WriteLine(rest.LastErrorText);
    }
    else {
        Debug.WriteLine(errResponse);
    }

}