(Unicode C++) Azure Storage: Download Blob to File

See more Azure Cloud Storage Examples

Sample code to download an Azure blob to a file.

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

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#include <CkRestW.h>
#include <CkAuthAzureStorageW.h>
#include <CkStreamW.h>

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

    CkRestW 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(L"chilkat.blob.core.windows.net",port,bTls,bAutoReconnect);
    if (success != true) {
        wprintf(L"%s\n",rest.lastErrorText());
        return;
    }

    // Provide Azure Cloud credentials for the REST call.
    CkAuthAzureStorageW azAuth;
    azAuth.put_AccessKey(L"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(L"chilkat");
    azAuth.put_Scheme(L"SharedKey");
    azAuth.put_Service(L"Blob");
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    azAuth.put_XMsVersion(L"2021-08-06");
    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.

    // Setup a file stream for the download
    CkStreamW fileStream;
    fileStream.put_SinkFile(L"qa_output/starfish.jpg");

    // Indicate that the call to FullRequestNoBody should send the response body
    // to fileStream if the response status code is 200.
    // If a non-success response status code is received, then nothing
    // is streamed to the output file and the error response is returned by FullRequestNoBody.
    int expectedStatus = 200;
    rest.SetResponseBodyStream(expectedStatus,true,fileStream);

    // The Azure blob container is "test", the file is "starfish.jpg"
    const wchar_t *responseStr = rest.fullRequestNoBody(L"GET",L"/test/starfish.jpg");
    if (rest.get_LastMethodSuccess() != true) {
        // Examine the request/response to see what happened.
        wprintf(L"response status code = %d\n",rest.get_ResponseStatusCode());
        wprintf(L"response status text = %s\n",rest.responseStatusText());
        wprintf(L"response header: %s\n",rest.responseHeader());
        wprintf(L"response body (if any): %s\n",responseStr);
        wprintf(L"---\n");
        wprintf(L"LastRequestStartLine: %s\n",rest.lastRequestStartLine());
        wprintf(L"LastRequestHeader: %s\n",rest.lastRequestHeader());
        return;
    }

    wprintf(L"Success.\n");
    }