(Lianja) 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.

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// 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.

loRest = createobject("CkRest")

// Connect to the Azure Storage Blob Service
llBTls = .T.
lnPort = 443
llBAutoReconnect = .T.
// In this example, the storage account name is "chilkat".
llSuccess = loRest.Connect("chilkat.blob.core.windows.net",lnPort,llBTls,llBAutoReconnect)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

// Provide Azure Cloud credentials for the REST call.
loAzAuth = createobject("CkAuthAzureStorage")
loAzAuth.AccessKey = "AZURE_ACCESS_KEY"
// The account name used here should match the 1st part of the domain passed in the call to Connect (above).
loAzAuth.Account = "chilkat"
loAzAuth.Scheme = "SharedKey"
loAzAuth.Service = "Blob"
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
loAzAuth.XMsVersion = "2021-08-06"
llSuccess = loRest.SetAuthAzureStorage(loAzAuth)

// 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..
loXml = createobject("CkXml")
loXml.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
loFac = createobject("CkFileAccess")
llSuccess = loFac.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...)
lnBlockSize = 16384

// How many 16K blocks?  (Including 1 for the last partial block)
lnNumBlocks = loFac.GetNumBlocks(lnBlockSize)

loCrypt = createobject("CkCrypt2")
loCrypt.HashAlgorithm = "md5"

loSbResponseBody = createobject("CkStringBuilder")
loUriPath = createobject("CkStringBuilder")

loDataBlock = createobject("CkBinData")

i = 0
do while i < lnNumBlocks

    loDataBlock.Clear()
    llSuccess = loFac.ReadBlockBd(i,lnBlockSize,loDataBlock)
    if (llSuccess = .F.) then
        ? loFac.LastErrorText
        release loRest
        release loAzAuth
        release loXml
        release loFac
        release loCrypt
        release loSbResponseBody
        release loUriPath
        release loDataBlock
        return
    endif

    // 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..
    lcBlockId = loFac.GenBlockId(i,4,"base64")

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

    // Build the URI path
    loUriPath.Clear()
    llSuccess = loUriPath.Append("/mycontainer/hamlet.xml?comp=block&blockId=")
    llSuccess = loUriPath.Append(lcBlockId)

    lcContentMd5 = loCrypt.HashBdENC(loDataBlock)
    loRest.AddHeader("Content-MD5",lcContentMd5)

    // Upload this block..
    loSbResponseBody.Clear()
    llSuccess = loRest.FullRequestBd("PUT",loUriPath.GetAsString(),loDataBlock,loSbResponseBody)
    if (llSuccess = .F.) then
        ? loRest.LastErrorText
        release loRest
        release loAzAuth
        release loXml
        release loFac
        release loCrypt
        release loSbResponseBody
        release loUriPath
        release loDataBlock
        return
    endif

    // Verify that we received a 201 status code.
    if (loRest.ResponseStatusCode <> 201) then
        // Examine the request/response to see what happened.
        ? "response status code = " + str(loRest.ResponseStatusCode)
        ? "response status text = " + loRest.ResponseStatusText
        ? "response header: " + loRest.ResponseHeader
        ? "response body (if any): " + loSbResponseBody.GetAsString()
        ? "---"
        ? "LastRequestStartLine: " + loRest.LastRequestStartLine
        ? "LastRequestHeader: " + loRest.LastRequestHeader
        release loRest
        release loAzAuth
        release loXml
        release loFac
        release loCrypt
        release loSbResponseBody
        release loUriPath
        release loDataBlock
        return
    endif

    i = i + 1
enddo

loFac.FileClose()

// Now commit the blocks.
// Let's have a look at the XML that will commit the blocks:
lcXmlStr = loXml.GetXml()
? lcXmlStr

// 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.
// --------------------------------------------------------------------------
loRest.RemoveHeader("Content-MD5")

// Send the PUT Block List...
lcResponseStr = loRest.FullRequestString("PUT","/mycontainer/hamlet.xml?comp=blocklist",lcXmlStr)
if (loRest.LastMethodSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    release loAzAuth
    release loXml
    release loFac
    release loCrypt
    release loSbResponseBody
    release loUriPath
    release loDataBlock
    return
endif

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

if (loRest.ResponseStatusCode <> 201) then
    // Examine the request/response to see what happened.
    ? "response status code = " + str(loRest.ResponseStatusCode)
    ? "response status text = " + loRest.ResponseStatusText
    ? "response header: " + loRest.ResponseHeader
    ? "response body (if any): " + lcResponseStr
    ? "---"
    ? "LastRequestStartLine: " + loRest.LastRequestStartLine
    ? "LastRequestHeader: " + loRest.LastRequestHeader
    release loRest
    release loAzAuth
    release loXml
    release loFac
    release loCrypt
    release loSbResponseBody
    release loUriPath
    release loDataBlock
    return
endif

? "Success."


release loRest
release loAzAuth
release loXml
release loFac
release loCrypt
release loSbResponseBody
release loUriPath
release loDataBlock