(MFC) Upload File in Blocks (with Content-MD5 header) and Commit the Block List

Demonstrates how to upload a file in blocks and then commit the block list. This example includes a Content-MD5 header for each block.

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

See Also: Using MFC CString in Chilkat

#include <CkRest.h>
#include <CkAuthAzureStorage.h>
#include <CkXml.h>
#include <CkFileAccess.h>
#include <CkCrypt2.h>
#include <CkStringBuilder.h>
#include <CkBinData.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // Azure Blob Service Example: Upload a file in blocks, and then commit the block list.
    // See also: https://msdn.microsoft.com/en-us/library/azure/dd135726.aspx

    // 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.

    // As the blocks are uploaded, we'll keep an XML block list for the subsequent commit..
    CkXml xml;
    xml.put_Tag("BlockList");

    // Any type of file can be uploaded in this way.  It can a text file, binary file, anything...
    // This example will upload an XML file that is approximately 275K in size.  It can be downloaded
    // at http://www.chilkatsoft.com/hamlet.xml
    CkFileAccess fac;
    success = fac.OpenForRead("qa_data/xml/hamlet.xml");
    // Assuming success for the example..

    // We'll upload in 16K blocks (normally a program would upload in larger block sizes than this,
    // but this is just an example...)
    int blockSize = 16384;

    // How many 16K blocks?  (Including 1 for the last partial block)
    int numBlocks = fac.GetNumBlocks(blockSize);

    CkCrypt2 crypt;
    crypt.put_HashAlgorithm("md5");

    CkStringBuilder sbResponseBody;
    CkStringBuilder uriPath;
    const char *blockId = 0;
    CkBinData dataBlock;
    const char *contentMd5 = 0;
    int i = 0;
    while (i < numBlocks) {

        dataBlock.Clear();
        success = fac.ReadBlockBd(i,blockSize,dataBlock);
        if (success == false) {
            strOut.append(fac.lastErrorText());
            strOut.append("\r\n");
            SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
            return;
        }

        // Generate a base64 block ID.  
        // (Chilkat provides a helper method named GenBlockId to make this easy)
        // A pre-base64 encoded block ID length of 4 is sufficient in this case because
        // this file certainly won't have more than 99,999 blocks..
        blockId = fac.genBlockId(i,4,"base64");

        // Add this blockId to the list of blocks to be committed.
        xml.NewChild2("Latest",blockId);

        // Build the URI path
        uriPath.Clear();
        success = uriPath.Append("/mycontainer/hamlet.xml?comp=block&blockId=");
        success = uriPath.Append(blockId);

        contentMd5 = crypt.hashBdENC(dataBlock);
        rest.AddHeader("Content-MD5",contentMd5);

        // Upload this block..
        sbResponseBody.Clear();
        success = rest.FullRequestBd("PUT",uriPath.getAsString(),dataBlock,sbResponseBody);
        if (success == false) {
            strOut.append(rest.lastErrorText());
            strOut.append("\r\n");
            SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
            return;
        }

        // Verify that we received a 201 status code.
        if (rest.get_ResponseStatusCode() != 201) {
            // 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("response body (if any): ");
            strOut.append(sbResponseBody.getAsString());
            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;
        }

        i = i + 1;
    }

    fac.FileClose();

    // Now commit the blocks.
    // Let's have a look at the XML that will commit the blocks:
    const char *xmlStr = xml.getXml();
    strOut.append(xmlStr);
    strOut.append("\r\n");

    // The XML will look like this:

    // <?xml version="1.0" encoding="utf-8" ?>
    // <BlockList>
    //     <Latest>MDAwMA==</Latest>
    //     <Latest>MDAwMQ==</Latest>
    //     <Latest>MDAwMg==</Latest>
    //     <Latest>MDAwMw==</Latest>
    //     <Latest>MDAwNA==</Latest>
    //     <Latest>MDAwNQ==</Latest>
    //     <Latest>MDAwNg==</Latest>
    //     <Latest>MDAwNw==</Latest>
    //     <Latest>MDAwOA==</Latest>
    //     <Latest>MDAwOQ==</Latest>
    //     <Latest>MDAxMA==</Latest>
    //     <Latest>MDAxMQ==</Latest>
    //     <Latest>MDAxMg==</Latest>
    //     <Latest>MDAxMw==</Latest>
    //     <Latest>MDAxNA==</Latest>
    //     <Latest>MDAxNQ==</Latest>
    //     <Latest>MDAxNg==</Latest>
    //     <Latest>MDAxNw==</Latest>
    // </BlockList>

    // --------------------------------------------------------------------------
    // IMPORTANT: Remove the Content-MD5 header previously set in the loop above.
    // --------------------------------------------------------------------------
    rest.RemoveHeader("Content-MD5");

    // Send the PUT Block List...
    const char *responseStr = rest.fullRequestString("PUT","/mycontainer/hamlet.xml?comp=blocklist",xmlStr);
    if (rest.get_LastMethodSuccess() != true) {
        strOut.append(rest.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // When successful, the Azure Storage service will respond with a 201 response status code,
    // with no response body.

    if (rest.get_ResponseStatusCode() != 201) {
        // 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("response body (if any): ");
        strOut.append(responseStr);
        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("Success.");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }