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Azure File Service: Upload Large File
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Sample code to upload a large file to a directory in a share in the Azure File Service. A file is uploaded by first creating the file in the Azure share and then writing ranges of bytes to the file. Azure imposes a 4MB limit for each PUT to write a range. Files larger than 4MB need to be uploaded by making multiple "Put Range" calls. This example uploads a large file requiring multiple "Put Range" calls.Chilkat B4X Downloads
Dim success As Boolean = False
' Azure File Service Example: Upload a large file.
' See: https://docs.microsoft.com/en-us/rest/api/storageservices/create-share
' also see: https://docs.microsoft.com/en-us/rest/api/storageservices/put-range
' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.
Dim rest As ChilkatRest
rest.Initialize("rest")
' Connect to the Azure Storage Blob Service
Dim bTls As Boolean = True
Dim port As Int = 443
Dim bAutoReconnect As Boolean = True
' In this example, the storage account name is "chilkat".
success = rest.Connect("chilkat.file.core.windows.net", port, bTls, bAutoReconnect)
If success <> True Then
Log(rest.LastErrorText)
Return
End If
' This example will upload a larger file.
Dim localFilePath As String = "qa_data/zips/somethingBig.zip"
Dim fac As ChilkatFileAccess
fac.Initialize
' Note: The FileSize method returns a signed 32-bit integer. If the file is potentially larger than 2GB, call FileSizeStr instead to return
' the size of the file as a string, then convert to an integer value.
Dim szLocalFile As Int = fac.FileSize(localFilePath)
If szLocalFile < 0 Then
Log(fac.LastErrorText)
Return
End If
' Provide Azure Cloud credentials for the REST calls.
Dim azAuth As ChilkatAuthAzureStorage
azAuth.Initialize
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 = "File"
' 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: x-ms-date, Authorization. These headers
' are automatically set by Chilkat.
' However, a few additional headers are required for the "Create File" operation:
rest.AddHeader("x-ms-type", "file")
' This required header specifies the final size of the file (or the maximum size it can be).
Dim sbFileSize As ChilkatStringBuilder
sbFileSize.Initialize
sbFileSize.AppendInt(szLocalFile)
rest.AddHeader("x-ms-content-length", sbFileSize.GetAsString)
' Send a PUT request to create the file (or replace the file if it already exists).
' This will initialize the file in the Azure file storage. To upload content, we'll need
' to do the "Put Range" operation one or more times.
' The following will create the file "somethingBig.zip" in the share "pip"
Dim responseStr As String = rest.FullRequestNoBody("PUT", "/pip/somethingBig.zip")
If rest.LastMethodSuccess <> True Then
Log(rest.LastErrorText)
Return
End If
' When successful, the Azure File Service will respond with a 201 (Created) response status code,
' with no XML response body. If an error response is returned, there will be an XML response body.
If rest.ResponseStatusCode <> 201 Then
' Examine the request/response to see what happened.
Log("response status code = " & rest.ResponseStatusCode)
Log("response status text = " & rest.ResponseStatusText)
Log("response header: " & rest.ResponseHeader)
Log("response body (if any): " & responseStr)
Log("---")
Log("LastRequestStartLine: " & rest.LastRequestStartLine)
Log("LastRequestHeader: " & rest.LastRequestHeader)
Return
End If
Log("Successfully created somethingBig.zip")
' --------------------------------------------------------------------------------
' Upload the file data...
' Make sure the headers from the "Create File" operation are removed.
rest.ClearAllHeaders
' The x-ms-write header is required for each "Put Range" request.
rest.AddHeader("x-ms-write", "update")
Dim sbRange As ChilkatStringBuilder
sbRange.Initialize
Dim sbResponseBody As ChilkatStringBuilder
sbResponseBody.Initialize
Dim bdFileData As ChilkatBinData
bdFileData.Initialize
' Open the file. We'll be reading and uploading in chunks..
success = fac.OpenForRead(localFilePath)
If success <> True Then
Log(fac.LastErrorText)
Return
End If
Dim numBytesLeft As Int = szLocalFile
Dim curIndex As Int = 0
Do While numBytesLeft > 0
Dim chunkSize As Int = numBytesLeft
' Azure allows for 4MB max chunks (4 x 1024 x 1024 = 4194304)
If chunkSize > 4194304 Then
chunkSize = 4194304
End If
' The only tricky part here is to correctly add the x-ms-range header.
' It will be formatted like this:
' x-ms-range: bytes=0-759623
sbRange.Clear
sbRange.Append("bytes=")
sbRange.AppendInt(curIndex)
sbRange.Append("-")
sbRange.AppendInt(curIndex + chunkSize - 1)
' This replaces the header if it already exists..
rest.AddHeader("x-ms-range", sbRange.GetAsString)
' Read the next chunk from the local file.
bdFileData.Clear
success = fac.FileReadBd(chunkSize, bdFileData)
success = rest.FullRequestBd("PUT", "/pip/somethingBig.zip?comp=range", bdFileData, sbResponseBody)
If success <> True Then
' This would indicate a failure where no response was received.
Log(rest.LastErrorText)
Return
End If
' A 201 response indicates the chunk was uploaded.
If rest.ResponseStatusCode <> 201 Then
' Examine the request/response to see what happened.
Log("response status code = " & rest.ResponseStatusCode)
Log("response status text = " & rest.ResponseStatusText)
Log("response header: " & rest.ResponseHeader)
Log("response body (if any): " & responseStr)
Log("---")
Log("LastRequestStartLine: " & rest.LastRequestStartLine)
Log("LastRequestHeader: " & rest.LastRequestHeader)
Return
End If
Log("Uploaded chunk from " & curIndex & " to " & (curIndex + chunkSize - 1))
curIndex = curIndex + chunkSize
numBytesLeft = numBytesLeft - chunkSize
Loop
fac.FileClose
Log("success.")