Rust

REST Receive Response in Chunks

See more REST Examples

Demonstrates how to receive a REST HTTP response in chunks.

Note: This example requires Chilkat 10.1.0 or greater.

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 web server
let b_tls = true;
let port = 443;
let b_auto_reconnect = true;
if rest.connect("chilkatsoft.com", port, b_tls, b_auto_reconnect).is_err() {
    println!("{}", rest.last_error_text());
    return;
}

// Send the request.
// This can be *any* kind of request: POST, GET, PUT, etc. using *any* of the Chilkat REST methods that send requests.
// For this example, we'll just GET a simple XML document that is about 274K in size.

if rest.send_req_no_body("GET", "/hamlet.xml").is_err() {
    println!("{}", rest.last_error_text());
    return;
}

// Get the response header.
let status_code = rest.read_response_header();
if status_code < 0 {
    println!("{}", rest.last_error_text());
    return;
}

println!("response status code = {}", status_code);

let output_file = "c:/temp/qa_output/hamlet.xml".to_string();

let fac = chilkat::FileAccess::new();
let _ = fac.open_for_write(&output_file).is_ok();
if status_code < 0 {
    println!("{}", fac.last_error_text());
    return;
}

// Get the response in chunks.
// (Note: There are more efficient ways to simply download a file from a web server, such as by calling Chilkat's Http.Download method.
// The purpose of this method is to show how to receive a response chunk-by-chunk.)
let bd = chilkat::BinData::new();
let mut status = 1;
while status == 1 {
    // Read a minimum of 16000 bytes.
    // Note: Because of TLS message lengths, or the possibility of the response being either compressed (gzip/deflate) or in the HTTP chunked encoding,
    // the amount of data received in each call can be greater than the specified min size.
    // Chilkat will return from the call as soon as it has received an amount equal to or more than the specified size,
    // except for the very last chunk, which can be less that the min size or even 0 bytes.

    // The status will be one of three values:
    // -1 = error
    // 0 = received the last chunk of the response.
    // 1 = received a chunk, and more chunks are coming..

    // The received data is *appended* to the contents of the BinData object.
    status = rest.read_resp_chunk_bd(16000, &bd);
    if status >= 0 {
        println!("Received chunk: {} bytes", bd.num_bytes());
        let _ = fac.file_write_bd(&bd, 0, 0);
        let _ = bd.clear();
    }

}

fac.file_close();

println!("Success.");