(MFC) Adding x-ms-range header to Azure Blob Download

See more Azure Cloud Storage Examples

Demonstrates how to add an x-ms-range header to an Azure blob download.

For more information, see https://docs.microsoft.com/en-us/rest/api/storageservices/get-blob

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkRest.h>
#include <CkAuthAzureStorage.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkRest 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.blob.core.windows.net",port,bTls,bAutoReconnect);
    if (success != true) {
        strOut.append(rest.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Provide Azure Cloud credentials for the REST call.
    CkAuthAzureStorage azAuth;
    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("Blob");
    // This causes the "x-ms-version: 2020-08-04" header to be automatically added.
    azAuth.put_XMsVersion("2020-08-04");
    success = rest.SetAuthAzureStorage(azAuth);

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

    // Add the x-ms-range header.
    // See x-ms-range Header Format
    // The file we're downloading contains "Hello World!", so we'll download just the "World!" part..
    rest.AddHeader("x-ms-range","bytes=6-");

    // The Azure blob container is "test", the file is "helloWorld.txt"
    CkStringBuilder sb;
    success = rest.FullRequestNoBodySb("GET","/test/helloWorld.txt",sb);
    if (success == false) {
        // Examine the request/response to see what happened.
        strOut.append("response status code = ");
        strOut.appendInt(rest.get_ResponseStatusCode());
        strOut.append("\r\n");
        strOut.append("response status text = ");
        strOut.append(rest.responseStatusText());
        strOut.append("\r\n");
        strOut.append("response header: ");
        strOut.append(rest.responseHeader());
        strOut.append("\r\n");
        strOut.append("---");
        strOut.append("\r\n");
        strOut.append("LastRequestStartLine: ");
        strOut.append(rest.lastRequestStartLine());
        strOut.append("\r\n");
        strOut.append("LastRequestHeader: ");
        strOut.append(rest.lastRequestHeader());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append(sb.getAsString());
    strOut.append("\r\n");

    strOut.append("Success.");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }