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. Chilkat2 Java

import com.chilkatsoft.chilkat2.AuthAzureStorage;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Rest;
import com.chilkatsoft.chilkat2.Stream;

public class ChilkatExample {

    public static void main(String[] args) {
        // 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.

        Rest rest = new Rest();

        // 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".
        try {
            rest.connect("chilkat.file.core.windows.net", port, bTls, bAutoReconnect);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Provide Azure Cloud credentials for the REST calls.
        AuthAzureStorage azAuth = new AuthAzureStorage();
        azAuth.setAccessKey("AZURE_ACCESS_KEY");
        // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
        azAuth.setAccount("chilkat");
        azAuth.setScheme("SharedKey");
        azAuth.setService("File");
        // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
        azAuth.setXMsVersion("2021-08-06");
        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".
        try {
            rest.sendReqNoBody("GET", "/pip/somethingBig.zip");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Read the response header.
        int responseStatusCode = rest.readResponseHeader();
        if (responseStatusCode < 0) {
            System.out.println(rest.getLastErrorText());
            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) {
            Stream bodyStream = new Stream();

            // The stream's sink will be a file.
            bodyStream.setSinkFile("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.
            try {
                rest.readRespBodyStream(bodyStream, true);
            } catch (ChilkatException e) {
                System.out.println(e.getLastErrorText());
                return;
            }

            System.out.println("Successfully received the large file.");
        } else {
            String errResponse = null;
            try {
                errResponse = rest.readRespBodyString();
                System.out.println(errResponse);
            } catch (ChilkatException e) {
                System.out.println(e.getLastErrorText());
            }
        }
    }
}