Java

Streaming Download Large File to the Local Filesystem

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

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  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.

    CkRest rest = new CkRest();

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

    //  Provide Azure Cloud credentials for the REST calls.
    CkAuthAzureStorage azAuth = new CkAuthAzureStorage();
    azAuth.put_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.put_Account("chilkat");
    azAuth.put_Scheme("SharedKey");
    azAuth.put_Service("File");
    //  This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    azAuth.put_XMsVersion("2021-08-06");
    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) {
        System.out.println(rest.lastErrorText());
        return;
        }

    //  Read the response header.
    int responseStatusCode = rest.ReadResponseHeader();
    if (responseStatusCode < 0) {
        System.out.println(rest.lastErrorText());
        return;
        }

    System.out.println("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) {

        CkStream bodyStream = new CkStream();

        //  The stream's sink will be a file.
        bodyStream.put_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) {
            System.out.println(rest.lastErrorText());
            return;
            }

        System.out.println("Successfully received the large file.");

        }
    else {
        String errResponse = rest.readRespBodyString();
        if (rest.get_LastMethodSuccess() != true) {
            System.out.println(rest.lastErrorText());
            }
        else {
            System.out.println(errResponse);
            }

        }
  }
}