Node.js

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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Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    //  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.

    var imap = new chilkat.Imap();

    imap.Ssl = true;
    imap.Port = 993;

    success = imap.Connect("imap.example.com");
    if (success == false) {
        console.log(imap.LastErrorText);
        return;
    }

    success = imap.Login("user@example.com","myPassword");
    if (success == false) {
        console.log(imap.LastErrorText);
        return;
    }

    var numMessages = imap.SelectMailbox("Inbox");
    if (numMessages < 0) {
        console.log(imap.LastErrorText);
        return;
    }

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

    var failedSet = new chilkat.MessageSet();
    var fetchedSet = new chilkat.MessageSet();
    var bundle = new chilkat.EmailBundle();
    success = imap.FetchChunk2(1,count,failedSet,fetchedSet,bundle);
    if (success == false) {
        console.log(imap.LastErrorText);
        return;
    }

    console.log("Fetched: " + fetchedSet.Count);
    console.log("Failed:  " + failedSet.Count);

    success = imap.Disconnect();
    if (success == false) {
        console.log(imap.LastErrorText);
        return;
    }


}

chilkatExample();