Rust

Fetch a Chunk of Messages, Tracking Failures

Demonstrates the Chilkat Imap.FetchChunk2 method, which downloads a run of messages by sequence number and reports which succeeded and which failed. The arguments are the starting sequence number, the count, a MessageSet that receives the failed IDs, a MessageSet that receives the successfully-fetched IDs, and the EmailBundle. This example fetches the first chunk of messages and reports the success and failure counts.

Background: When bulk-downloading a large mailbox, individual messages can occasionally fail to fetch (a corrupt message on the server, a transient error) without failing the whole operation. FetchChunk2 is designed for that reality: it returns a partial EmailBundle plus two MessageSet objects so your code can log or retry exactly the messages that did not come through, rather than aborting the entire sync.

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Rust


// Demonstrates the Imap.FetchChunk2 method, which downloads a run of messages by sequence
// number and reports which succeeded and which failed.  The 1st argument is the starting
// sequence number, the 2nd is the count, the 3rd receives the failed IDs, the 4th receives
// the successfully-fetched IDs, and the 5th is the EmailBundle.

let imap = chilkat::Imap::new();

imap.set_ssl(true);
imap.set_port(993);

if imap.connect("imap.example.com").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

if imap.login("user@example.com", "myPassword").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

if imap.select_mailbox("Inbox").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

let num_messages = imap.num_messages();

// Fetch messages 1..25 (or fewer if the mailbox is smaller).
let mut count = 25;
if count > num_messages {
    count = num_messages;
}

let failed_set = chilkat::MessageSet::new();
let fetched_set = chilkat::MessageSet::new();
let bundle = chilkat::EmailBundle::new();
if imap.fetch_chunk2(1, count, &failed_set, &fetched_set, &bundle).is_err() {
    println!("{}", imap.last_error_text());
    return;
}

println!("Fetched: {}", fetched_set.count());
println!("Failed:  {}", failed_set.count());

if imap.disconnect().is_err() {
    println!("{}", imap.last_error_text());
    return;
}