lemmy/crates/utils/src/email.rs

use crate::{error::LemmyError, settings::structs::Settings};
use html2text;
use lettre::{
  message::{Mailbox, MultiPart},
  transport::smtp::{authentication::Credentials, extension::ClientId},
  Address,
  Message,
  SmtpTransport,
  Transport,
};
use std::str::FromStr;
use uuid::Uuid;

pub mod translations {
  rosetta_i18n::include_translations!();
}

pub fn send_email(
  subject: &str,
  to_email: &str,
  to_username: &str,
  html: &str,
  settings: &Settings,
) -> Result<(), LemmyError> {
  let email_config = settings
    .email
    .clone()
    .ok_or_else(|| LemmyError::from_message("no_email_setup"))?;
  let domain = settings.hostname.clone();

  let (smtp_server, smtp_port) = {
    let email_and_port = email_config.smtp_server.split(':').collect::<Vec<&str>>();
    let email = *email_and_port
      .first()
      .ok_or_else(|| LemmyError::from_message("missing an email"))?;
    let port = email_and_port
      .get(1)
      .ok_or_else(|| {
        LemmyError::from_message("email.smtp_server needs a port, IE smtp.xxx.com:465")
      })?
      .parse::<u16>()?;

    (email, port)
  };

  // use usize::MAX as the line wrap length, since lettre handles the wrapping for us
  let plain_text = html2text::from_read(html.as_bytes(), usize::MAX);

  let email = Message::builder()
    .from(
      email_config
        .smtp_from_address
        .parse()
        .expect("email from address isn't valid"),
    )
    .to(Mailbox::new(
      Some(to_username.to_string()),
      Address::from_str(to_email).expect("email to address isn't valid"),
    ))
    .message_id(Some(format!("<{}@{}>", Uuid::new_v4(), settings.hostname)))
    .subject(subject)
    .multipart(MultiPart::alternative_plain_html(
      plain_text,
      html.to_string(),
    ))
    .expect("email built incorrectly");

  // don't worry about 'dangeous'. it's just that leaving it at the default configuration
  // is bad.

  // Set the TLS
  let builder_dangerous = SmtpTransport::builder_dangerous(smtp_server).port(smtp_port);

  let mut builder = match email_config.tls_type.as_str() {
    "starttls" => SmtpTransport::starttls_relay(smtp_server)?,
    "tls" => SmtpTransport::relay(smtp_server)?,
    _ => builder_dangerous,
  };

  // Set the creds if they exist
  if let (Some(username), Some(password)) = (email_config.smtp_login, email_config.smtp_password) {
    builder = builder.credentials(Credentials::new(username, password));
  }

  let mailer = builder.hello_name(ClientId::Domain(domain)).build();

  let result = mailer.send(&email);

  match result {
    Ok(_) => Ok(()),
    Err(e) => Err(LemmyError::from_error_message(e, "email_send_failed")),
  }
}