Module melib::mbox

source ·
Expand description

§Mbox formats

§Resources

§mbox format

mbox describes a family of incompatible legacy formats.

“All of the ‘mbox’ formats store all of the messages in the mailbox in a single file. Delivery appends new messages to the end of the file.” 1

“Each message is preceded by a From_ line and followed by a blank line. A From_ line is a line that begins with the five characters ‘F’, ‘r’, ‘o’, ‘m’, and ’ ’.” 1

§From / postmark line

“An mbox is a text file containing an arbitrary number of e-mail messages. Each message consists of a postmark, followed by an e-mail message formatted according to RFC822, RFC2822. The file format is line-oriented. Lines are separated by line feed characters (ASCII 10).

“A postmark line consists of the four characters ‘From’, followed by a space character, followed by the message’s envelope sender address, followed by whitespace, and followed by a time stamp. This line is often called From_ line.

“The sender address is expected to be addr-spec as defined in RFC2822 3.4.1. The date is expected to be date-time as output by asctime(3). For compatibility reasons with legacy software, two-digit years greater than or equal to 70 should be interpreted as the years 1970+, while two-digit years less than 70 should be interpreted as the years 2000-2069. Software reading files in this format should also be prepared to accept non-numeric timezone information such as ‘CET DST’ for Central European Time, daylight saving time.

“Example:

 From example@example.com Fri Jun 23 02:56:55 2000

“In order to avoid misinterpretation of lines in message bodies which begin with the four characters ‘From’, followed by a space character, the mail delivery agent must quote any occurrence of ’From ’ at the start of a body line.” 2

§Metadata

melib recognizes the CClient (a Pine client API) convention for metadata in mbox format:

  • Status: R (Seen) and O (non-Recent) flags
  • X-Status: A (Answered), F (Flagged), T (Draft) and D (Deleted) flags
  • X-Keywords: Message’s keywords

§Parsing an mbox file

let file_contents = vec![]; // Replace with actual mbox file contents
let index: Arc<Mutex<HashMap<EnvelopeHash, (Offset, Length)>>> =
    Arc::new(Mutex::new(HashMap::default()));
let mut message_iter = MessageIterator {
    index: index.clone(),
    input: &file_contents.as_slice(),
    offset: 0,
    file_offset: 0,
    format: Some(MboxFormat::MboxCl2),
};
let envelopes: Result<Vec<Envelope>> = message_iter.collect();

§Writing / Appending an mbox file

let mbox_1: &[u8] = br#"From: <a@b.c>\n\nHello World"#;
let mbox_2: &[u8] = br#"From: <d@e.f>\n\nHello World #2"#;
let mut file = std::io::BufWriter::new(std::fs::File::create(&"out.mbox")?);
let format = MboxFormat::MboxCl2;
format.append(
    &mut file,
    mbox_1,
    None,                                // Envelope From
    Some(melib::utils::datetime::now()), // Delivered date
    Default::default(),                  // Flags and tags
    MboxMetadata::None,
    true,
    false,
)?;
format.append(
    &mut file,
    mbox_2,
    None,
    Some(melib::utils::datetime::now()),
    Default::default(), // Flags and tags
    MboxMetadata::None,
    false,
    false,
)?;
file.flush()?;
  1.  ↩
  2.  ↩

Modules§

Structs§

Enums§

  • MboxFormat
    Choose between “mboxo”, “mboxrd”, “mboxcl”, “mboxcl2”. For new mailboxes, prefer “mboxcl2” which does not alter the mail body.
  • MboxMetadata

Functions§

Type Aliases§