(Ruby) Download an IMAP Message Set

Demonstrates how to read a set of IMAP emails.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

success = false

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

imap = Chilkat::CkImap.new()

# Connect using TLS.
imap.put_Ssl(true)
imap.put_Port(993)
success = imap.Connect("imap.example.com")
if (success == false)
    print imap.lastErrorText() + "\n";
    exit
end

# Authenticate
success = imap.Login("email_account_login","email_account_password")
if (success == false)
    print imap.lastErrorText() + "\n";
    exit
end

# Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
if (success == false)
    print imap.lastErrorText() + "\n";
    exit
end

# Search for messages with the word "test" in the subject.
fetchUids = true

messageSet = Chilkat::CkMessageSet.new()
success = imap.QueryMbx("Subject test",fetchUids,messageSet)
if (success == false)
    print imap.lastErrorText() + "\n";
    exit
end

# Download the messages in a single call to FetchMsgSet.
# 
# This only makes sense if the number of emails to be downloaded is not too large.  
# For example, you wouldn't want to download 10000 emails in a single call to FetchMsgSet.
# Why? For two reasons:  (1) It could potentially cause an out-of-memory condition, and 
# (2) it would take an extremely large amount of time.  The longer the amount of time,
# the greater the likelihood of some kind of external networking or server problem occuring,
# and if it happens, then you would need to re-download everything from the beginning again.
# For large numbers of emails, it's better to loop over the emails in the message set
# and download/process one at a time as shown here: Download IMAP Messages One at a Time
# Downloading one message at a time makes it possible to resume the downloads rather than restart the entire operation all over again.

# If the message set is reasonable in size, you can download all at once using FetchMsgSet:

print "Number of messages = " + messageSet.get_Count().to_s() + "\n";

bundle = Chilkat::CkEmailBundle.new()
headersOnly = false
success = imap.FetchMsgSet(headersOnly,messageSet,bundle)
if (success == false)
    print imap.lastErrorText() + "\n";
    exit
end

# Display the Subject and From of each email.
email = Chilkat::CkEmail.new()
i = 0
numEmails = bundle.get_MessageCount()
while i < numEmails
    bundle.EmailAt(i,email)

    print email.getHeaderField("Date") + "\n";
    print email.subject() + "\n";
    print email.ck_from() + "\n";
    print "--" + "\n";
    i = i + 1
end