Visual Basic 6.0

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. Visual Basic 6.0

Dim success As Long
success = 0

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

Dim rest As New ChilkatRest

' Connect to the Azure Storage Blob Service
Dim bTls As Long
bTls = 1
Dim port As Long
port = 443
Dim bAutoReconnect As Long
bAutoReconnect = 1
' In this example, the storage account name is "chilkat".
success = rest.Connect("chilkat.blob.core.windows.net",port,bTls,bAutoReconnect)
If (success <> 1) Then
    Debug.Print rest.LastErrorText
    Exit Sub
End If

' Provide Azure Cloud credentials for the REST call.
Dim azAuth As New ChilkatAuthAzureStorage
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.

' 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.
Dim sb As New ChilkatStringBuilder
success = rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",sb)
If (success = 0) Then
    ' Examine the request/response to see what happened.
    Debug.Print "response status code = " & rest.ResponseStatusCode
    Debug.Print "response status text = " & rest.ResponseStatusText
    Debug.Print "response header: " & rest.ResponseHeader
    Debug.Print "---"
    Debug.Print "LastRequestStartLine: " & rest.LastRequestStartLine
    Debug.Print "LastRequestHeader: " & rest.LastRequestHeader
    Exit Sub
End If

' 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>

Debug.Print sb.GetAsString()

' To see if we got Tags or an Error, then examine the XML.
Dim xml As New ChilkatXml
success = xml.LoadSb(sb,1)

' Examine the tag..
If (xml.TagEquals("Tags") = 1) Then
    Debug.Print "Blob exists!"
Else

    If (xml.ChildContentMatches("Code","BlobNotFound",1) = 1) Then
        Debug.Print "Blob does not exist."
    Else
        Debug.Print "Some other error..."
    End If

End If

Debug.Print "Success."