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use crate::{Client, Result}; use std::io::{Read, Write}; use std::net::TcpStream; #[cfg(feature = "tls")] use native_tls::{TlsConnector, TlsStream}; #[cfg(feature = "rustls-tls")] use rustls_connector::{RustlsConnector, TlsStream as RustlsStream}; /// A convenience builder for [`Client`] structs over various encrypted transports. /// /// Creating a [`Client`] using `native-tls` transport is straightforward: /// ```no_run /// # use imap::ClientBuilder; /// # {} #[cfg(feature = "tls")] /// # fn main() -> Result<(), imap::Error> { /// let client = ClientBuilder::new("imap.example.com", 993).native_tls()?; /// # Ok(()) /// # } /// ``` /// /// Similarly, if using the `rustls-tls` feature you can create a [`Client`] using rustls: /// ```no_run /// # use imap::ClientBuilder; /// # {} #[cfg(feature = "rustls-tls")] /// # fn main() -> Result<(), imap::Error> { /// let client = ClientBuilder::new("imap.example.com", 993).rustls()?; /// # Ok(()) /// # } /// ``` /// /// To use `STARTTLS`, just call `starttls()` before one of the [`Client`]-yielding /// functions: /// ```no_run /// # use imap::ClientBuilder; /// # {} #[cfg(feature = "rustls-tls")] /// # fn main() -> Result<(), imap::Error> { /// let client = ClientBuilder::new("imap.example.com", 993) /// .starttls() /// .rustls()?; /// # Ok(()) /// # } /// ``` /// The returned [`Client`] is unauthenticated; to access session-related methods (through /// [`Session`](crate::Session)), use [`Client::login`] or [`Client::authenticate`]. pub struct ClientBuilder<D> where D: AsRef<str>, { domain: D, port: u16, starttls: bool, } impl<D> ClientBuilder<D> where D: AsRef<str>, { /// Make a new `ClientBuilder` using the given domain and port. pub fn new(domain: D, port: u16) -> Self { ClientBuilder { domain, port, starttls: false, } } /// Use [`STARTTLS`](https://tools.ietf.org/html/rfc2595) for this connection. #[cfg(any(feature = "tls", feature = "rustls-tls"))] pub fn starttls(&mut self) -> &mut Self { self.starttls = true; self } /// Return a new [`Client`] using a `native-tls` transport. #[cfg(feature = "tls")] #[cfg_attr(docsrs, doc(cfg(feature = "tls")))] pub fn native_tls(&mut self) -> Result<Client<TlsStream<TcpStream>>> { self.connect(|domain, tcp| { let ssl_conn = TlsConnector::builder().build()?; Ok(TlsConnector::connect(&ssl_conn, domain, tcp)?) }) } /// Return a new [`Client`] using `rustls` transport. #[cfg(feature = "rustls-tls")] #[cfg_attr(docsrs, doc(cfg(feature = "rustls-tls")))] pub fn rustls(&mut self) -> Result<Client<RustlsStream<TcpStream>>> { self.connect(|domain, tcp| { let ssl_conn = RustlsConnector::new_with_native_certs()?; Ok(ssl_conn.connect(domain, tcp)?) }) } /// Make a [`Client`] using a custom TLS initialization. This function is intended /// to be used if your TLS setup requires custom work such as adding private CAs /// or other specific TLS parameters. /// /// The `handshake` argument should accept two parameters: /// /// - domain: [`&str`] /// - tcp: [`TcpStream`] /// /// and yield a `Result<C>` where `C` is `Read + Write`. It should only perform /// TLS initialization over the given `tcp` socket and return the encrypted stream /// object, such as a [`native_tls::TlsStream`] or a [`rustls_connector::TlsStream`]. /// /// If the caller is using `STARTTLS` and previously called [`starttls`](Self::starttls) /// then the `tcp` socket given to the `handshake` function will be connected and will /// have initiated the `STARTTLS` handshake. /// /// ```no_run /// # use imap::ClientBuilder; /// # use rustls_connector::RustlsConnector; /// # {} #[cfg(feature = "rustls-tls")] /// # fn main() -> Result<(), imap::Error> { /// let client = ClientBuilder::new("imap.example.com", 993) /// .starttls() /// .connect(|domain, tcp| { /// let ssl_conn = RustlsConnector::new_with_native_certs()?; /// Ok(ssl_conn.connect(domain, tcp)?) /// })?; /// # Ok(()) /// # } /// ``` pub fn connect<F, C>(&mut self, handshake: F) -> Result<Client<C>> where F: FnOnce(&str, TcpStream) -> Result<C>, C: Read + Write, { let tcp = if self.starttls { let tcp = TcpStream::connect((self.domain.as_ref(), self.port))?; let mut client = Client::new(tcp); client.read_greeting()?; client.run_command_and_check_ok("STARTTLS")?; client.into_inner()? } else { TcpStream::connect((self.domain.as_ref(), self.port))? }; let tls = handshake(self.domain.as_ref(), tcp)?; Ok(Client::new(tls)) } }