#smtp #dkim #mime #mail

mail-send

E-mail delivery library with SMTP and DKIM support

12 releases

new 0.4.2 Dec 1, 2023
0.4.1 Oct 3, 2023
0.4.0 Jun 2, 2023
0.3.2 Feb 17, 2023
0.2.0 May 31, 2022

#91 in Email

Download history 699/week @ 2023-08-16 620/week @ 2023-08-23 518/week @ 2023-08-30 420/week @ 2023-09-06 468/week @ 2023-09-13 446/week @ 2023-09-20 684/week @ 2023-09-27 747/week @ 2023-10-04 706/week @ 2023-10-11 864/week @ 2023-10-18 820/week @ 2023-10-25 988/week @ 2023-11-01 917/week @ 2023-11-08 746/week @ 2023-11-15 714/week @ 2023-11-22 815/week @ 2023-11-29

3,287 downloads per month
Used in 10 crates (6 directly)

Apache-2.0 OR MIT and AGPL-3.0-only

68KB
1.5K SLoC

mail-send

crates.io build docs.rs crates.io

mail-send is a Rust library to build, sign and send e-mail messages via SMTP. It includes the following features:

  • Generates e-mail messages conforming to the Internet Message Format standard (RFC 5322).
  • Full MIME support (RFC 2045 - 2049) with automatic selection of the most optimal encoding for each message body part.
  • DomainKeys Identified Mail (DKIM) Signatures (RFC 6376) with ED25519-SHA256, RSA-SHA256 and RSA-SHA1 support.
  • Simple Mail Transfer Protocol (SMTP; RFC 5321) delivery.
  • SMTP Service Extension for Secure SMTP over TLS (RFC 3207).
  • SMTP Service Extension for Authentication (RFC 4954) with automatic mechanism negotiation (from most secure to least secure):
    • CRAM-MD5 (RFC 2195)
    • DIGEST-MD5 (RFC 2831; obsolete but still supported)
    • XOAUTH2 (Google proprietary)
    • LOGIN
    • PLAIN
  • Full async (requires Tokio).

Usage Example

Send a message via an SMTP server that requires authentication:

    // Build a simple multipart message
    let message = MessageBuilder::new()
        .from(("John Doe", "john@example.com"))
        .to(vec![
            ("Jane Doe", "jane@example.com"),
            ("James Smith", "james@test.com"),
        ])
        .subject("Hi!")
        .html_body("<h1>Hello, world!</h1>")
        .text_body("Hello world!");

    // Connect to the SMTP submissions port, upgrade to TLS and
    // authenticate using the provided credentials.
    SmtpClientBuilder::new("smtp.gmail.com", 587)
        .implicit_tls(false)
        .credentials(("john", "p4ssw0rd"))
        .connect()
        .await
        .unwrap()
        .send(message)
        .await
        .unwrap();

Sign a message with DKIM and send it via an SMTP relay server:

    // Build a simple text message with a single attachment
    let message = MessageBuilder::new()
        .from(("John Doe", "john@example.com"))
        .to("jane@example.com")
        .subject("Howdy!")
        .text_body("These pretzels are making me thirsty.")
        .attachment("image/png", "pretzels.png", [1, 2, 3, 4].as_ref());

    // Sign an e-mail message using RSA-SHA256
    let pk_rsa = RsaKey::<Sha256>::from_rsa_pem(TEST_KEY).unwrap();
    let signer = DkimSigner::from_key(pk_rsa)
        .domain("example.com")
        .selector("default")
        .headers(["From", "To", "Subject"])
        .expiration(60 * 60 * 7); // Number of seconds before this signature expires (optional)

    // Connect to an SMTP relay server over TLS.
    // Signs each message with the configured DKIM signer.
    SmtpClientBuilder::new("smtp.gmail.com", 465)
        .connect()
        .await
        .unwrap()
        .send_signed(message, &signer)
        .await
        .unwrap();

More examples of how to build messages are available in the mail-builder crate. Please note that this library does not support parsing e-mail messages as this functionality is provided separately by the mail-parser crate.

Testing

To run the testsuite:

 $ cargo test --all-features

or, to run the testsuite with MIRI:

 $ cargo +nightly miri test --all-features

License

Licensed under either of

at your option.

Copyright (C) 2020-2022, Stalwart Labs Ltd.

Dependencies

~10–23MB
~395K SLoC