Xojo Plugin

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

See more Azure Cloud Storage Examples

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

Dim success As Boolean
success = False

// 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.

Dim rest As New Chilkat.Rest

// Connect to the Azure Storage Blob Service
Dim bTls As Boolean
bTls = True
Dim port As Int32
port = 443
Dim bAutoReconnect As Boolean
bAutoReconnect = True
// In this example, the storage account name is "chilkat".
success = rest.Connect("chilkat.blob.core.windows.net",port,bTls,bAutoReconnect)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// Provide Azure Cloud credentials for the REST call.
Dim azAuth As New Chilkat.AuthAzureStorage
azAuth.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.Account = "chilkat"
azAuth.Scheme = "SharedKey"
azAuth.Service = "Blob"
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
azAuth.XMsVersion = "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.

// As the blocks are uploaded, we'll keep an XML block list for the subsequent commit..
Dim xml As New Chilkat.Xml
xml.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
Dim fac As New Chilkat.FileAccess
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...)
Dim blockSize As Int32
blockSize = 16384

// How many 16K blocks?  (Including 1 for the last partial block)
Dim numBlocks As Int32
numBlocks = fac.GetNumBlocks(blockSize)

Dim crypt As New Chilkat.Crypt2
crypt.HashAlgorithm = "md5"

Dim sbResponseBody As New Chilkat.StringBuilder
Dim uriPath As New Chilkat.StringBuilder
Dim blockId As String
Dim dataBlock As New Chilkat.BinData
Dim contentMd5 As String
Dim i As Int32
i = 0
While i < numBlocks

    success = dataBlock.Clear()
    success = fac.ReadBlockBd(i,blockSize,dataBlock)
    If (success = False) Then
        System.DebugLog(fac.LastErrorText)
        Return
    End If

    // 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)
    success = rest.AddHeader("Content-MD5",contentMd5)

    // Upload this block..
    sbResponseBody.Clear 
    success = rest.FullRequestBd("PUT",uriPath.GetAsString(),dataBlock,sbResponseBody)
    If (success = False) Then
        System.DebugLog(rest.LastErrorText)
        Return
    End If

    // Verify that we received a 201 status code.
    If (rest.ResponseStatusCode <> 201) Then
        // Examine the request/response to see what happened.
        System.DebugLog("response status code = " + Str(rest.ResponseStatusCode))
        System.DebugLog("response status text = " + rest.ResponseStatusText)
        System.DebugLog("response header: " + rest.ResponseHeader)
        System.DebugLog("response body (if any): " + sbResponseBody.GetAsString())
        System.DebugLog("---")
        System.DebugLog("LastRequestStartLine: " + rest.LastRequestStartLine)
        System.DebugLog("LastRequestHeader: " + rest.LastRequestHeader)
        Return
    End If

    i = i + 1
Wend

fac.FileClose 

// Now commit the blocks.
// Let's have a look at the XML that will commit the blocks:
Dim xmlStr As String
xmlStr = xml.GetXml()
System.DebugLog(xmlStr)

// 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.
// --------------------------------------------------------------------------
success = rest.RemoveHeader("Content-MD5")

// Send the PUT Block List...
Dim responseStr As String
responseStr = rest.FullRequestString("PUT","/mycontainer/hamlet.xml?comp=blocklist",xmlStr)
If (rest.LastMethodSuccess <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

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

If (rest.ResponseStatusCode <> 201) Then
    // Examine the request/response to see what happened.
    System.DebugLog("response status code = " + Str(rest.ResponseStatusCode))
    System.DebugLog("response status text = " + rest.ResponseStatusText)
    System.DebugLog("response header: " + rest.ResponseHeader)
    System.DebugLog("response body (if any): " + responseStr)
    System.DebugLog("---")
    System.DebugLog("LastRequestStartLine: " + rest.LastRequestStartLine)
    System.DebugLog("LastRequestHeader: " + rest.LastRequestHeader)
    Return
End If

System.DebugLog("Success.")