Go

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. Go

    success := false

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

    rest := chilkat.NewRest()

    // Connect to the Azure Storage Blob Service
    bTls := true
    port := 443
    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 {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        return
    }

    // Provide Azure Cloud credentials for the REST call.
    azAuth := chilkat.NewAuthAzureStorage()
    azAuth.SetAccessKey("AZURE_ACCESS_KEY")
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    azAuth.SetAccount("chilkat")
    azAuth.SetScheme("SharedKey")
    azAuth.SetService("Blob")
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    azAuth.SetXMsVersion("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.
    sb := chilkat.NewStringBuilder()
    success = rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",sb)
    if success == false {
        // Examine the request/response to see what happened.
        fmt.Println("response status code = ", rest.ResponseStatusCode())
        fmt.Println("response status text = ", rest.ResponseStatusText())
        fmt.Println("response header: ", rest.ResponseHeader())
        fmt.Println("---")
        fmt.Println("LastRequestStartLine: ", rest.LastRequestStartLine())
        fmt.Println("LastRequestHeader: ", rest.LastRequestHeader())
        rest.DisposeRest()
        azAuth.DisposeAuthAzureStorage()
        sb.DisposeStringBuilder()
        return
    }

    // 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>

    fmt.Println(*sb.GetAsString())

    // To see if we got Tags or an Error, then examine the XML.
    xml := chilkat.NewXml()
    xml.LoadSb(sb,true)

    // Examine the tag..
    if xml.TagEquals("Tags") == true {
        fmt.Println("Blob exists!")
    } else {

        if xml.ChildContentMatches("Code","BlobNotFound",true) == true {
            fmt.Println("Blob does not exist.")
        } else {
            fmt.Println("Some other error...")
        }

    }

    fmt.Println("Success.")

    rest.DisposeRest()
    azAuth.DisposeAuthAzureStorage()
    sb.DisposeStringBuilder()
    xml.DisposeXml()