Unicode C

Azure Blob - Get Tags (Check if Blob Exists)

See more Azure Cloud Storage Examples

Gets the user-defined tags for a specified blob. This can also be used as a way to check to see if a blob exists. Unicode C

#include <C_CkRestW.h>
#include <C_CkAuthAzureStorageW.h>
#include <C_CkStringBuilderW.h>
#include <C_CkXmlW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkRestW rest;
    BOOL bTls;
    int port;
    BOOL bAutoReconnect;
    HCkAuthAzureStorageW azAuth;
    HCkStringBuilderW sb;
    HCkXmlW xml;

    success = FALSE;

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

    rest = CkRestW_Create();

    // Connect to the Azure Storage Blob Service
    bTls = TRUE;
    port = 443;
    bAutoReconnect = TRUE;
    // In this example, the storage account name is "chilkat".
    success = CkRestW_Connect(rest,L"chilkat.blob.core.windows.net",port,bTls,bAutoReconnect);
    if (success != TRUE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkRestW_Dispose(rest);
        return;
    }

    // Provide Azure Cloud credentials for the REST call.
    azAuth = CkAuthAzureStorageW_Create();
    CkAuthAzureStorageW_putAccessKey(azAuth,L"AZURE_ACCESS_KEY");
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    CkAuthAzureStorageW_putAccount(azAuth,L"chilkat");
    CkAuthAzureStorageW_putScheme(azAuth,L"SharedKey");
    CkAuthAzureStorageW_putService(azAuth,L"Blob");
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    CkAuthAzureStorageW_putXMsVersion(azAuth,L"2021-08-06");
    success = CkRestW_SetAuthAzureStorage(rest,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.

    // The Azure blob container is "test", the file is "helloWorld.txt"
    // Add "?comp=tags" to get the user-defined tags instead of the actual blob content.
    sb = CkStringBuilderW_Create();
    success = CkRestW_FullRequestNoBodySb(rest,L"GET",L"/test/helloWorldajdfadf.txt?comp=tags",sb);
    if (success == FALSE) {
        // Examine the request/response to see what happened.
        wprintf(L"response status code = %d\n",CkRestW_getResponseStatusCode(rest));
        wprintf(L"response status text = %s\n",CkRestW_responseStatusText(rest));
        wprintf(L"response header: %s\n",CkRestW_responseHeader(rest));
        wprintf(L"---\n");
        wprintf(L"LastRequestStartLine: %s\n",CkRestW_lastRequestStartLine(rest));
        wprintf(L"LastRequestHeader: %s\n",CkRestW_lastRequestHeader(rest));
        CkRestW_Dispose(rest);
        CkAuthAzureStorageW_Dispose(azAuth);
        CkStringBuilderW_Dispose(sb);
        return;
    }

    // A typical blob with no tags will return this:

    // <?xml version="1.0" encoding="utf-8"?>
    // <Tags><TagSet/></Tags>

    // If the blob does not exist, you get this:

    // <?xml version="1.0" encoding="utf-8"?>
    // <Error>
    //     <Code>BlobNotFound</Code>
    //     <Message>The specified blob does not exist.
    // 	RequestId:fcfefdd9-301e-001a-2135-3a23d2000000
    // 	Time:2023-02-06T14:17:00.7805577Z
    //     </Message>
    // </Error>

    wprintf(L"%s\n",CkStringBuilderW_getAsString(sb));

    // To see if we got Tags or an Error, then examine the XML.
    xml = CkXmlW_Create();
    CkXmlW_LoadSb(xml,sb,TRUE);

    // Examine the tag..
    if (CkXmlW_TagEquals(xml,L"Tags") == TRUE) {
        wprintf(L"Blob exists!\n");
    }
    else {

        if (CkXmlW_ChildContentMatches(xml,L"Code",L"BlobNotFound",TRUE) == TRUE) {
            wprintf(L"Blob does not exist.\n");
        }
        else {
            wprintf(L"Some other error...\n");
        }

    }

    wprintf(L"Success.\n");


    CkRestW_Dispose(rest);
    CkAuthAzureStorageW_Dispose(azAuth);
    CkStringBuilderW_Dispose(sb);
    CkXmlW_Dispose(xml);

    }