Rust

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. Rust

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

let rest = chilkat::Rest::new();

// Connect to the Azure Storage Blob Service
let b_tls = true;
let port = 443;
let b_auto_reconnect = true;
// In this example, the storage account name is "chilkat".
if rest.connect("chilkat.blob.core.windows.net", port, b_tls, b_auto_reconnect).is_err() {
    println!("{}", rest.last_error_text());
    return;
}

// Provide Azure Cloud credentials for the REST call.
let az_auth = chilkat::AuthAzureStorage::new();
az_auth.set_access_key("AZURE_ACCESS_KEY");
// The account name used here should match the 1st part of the domain passed in the call to Connect (above).
az_auth.set_account("chilkat");
az_auth.set_scheme("SharedKey");
az_auth.set_service("Blob");
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
az_auth.set_x_ms_version("2021-08-06");
let _ = rest.set_auth_azure_storage(&az_auth).is_ok();

// 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.
let sb = chilkat::StringBuilder::new();
if rest.full_request_no_body_sb("GET", "/test/helloWorldajdfadf.txt?comp=tags", &sb).is_err() {
    // Examine the request/response to see what happened.
    println!("response status code = {}", rest.response_status_code());
    println!("response status text = {}", rest.response_status_text());
    println!("response header: {}", rest.response_header());
    println!("---");
    println!("LastRequestStartLine: {}", rest.last_request_start_line());
    println!("LastRequestHeader: {}", rest.last_request_header());
    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>

println!("{}", sb.get_as_string().unwrap_or_default());

// To see if we got Tags or an Error, then examine the XML.
let xml = chilkat::Xml::new();
let _ = xml.load_sb(&sb, true);

// Examine the tag..
if xml.tag_equals("Tags") {
    println!("Blob exists!");
} else {

    if xml.child_content_matches("Code", "BlobNotFound", true) {
        println!("Blob does not exist.");
    } else {
        println!("Some other error...");
    }

}

println!("Success.");