Native SASL support

Cargo.toml

@@ -27,6 +27,7 @@ bufstream = "0.1.3"
 imap-proto = "0.16.1"
 nom = { version = "7.1.0", default-features = false }
 base64 = "0.21"
+rsasl = { version = "2.0.0", default-features = false, features = ["std", "provider_base64"], optional = true }
 chrono = { version = "0.4", default-features = false, features = ["std"]}
 lazy_static = "1.4"
 ouroboros = "0.15.0"
@@ -42,6 +43,8 @@ failure = "0.1.8"
 mime = "0.3.4"
 openssl = "0.10.35"
 
+rsasl = { version = "2.0.0", default-features = false, features = ["config_builder"] }
+
 [[example]]
 name = "basic"
 required-features = ["default"]
@@ -69,3 +72,11 @@ required-features = ["default"]
 [[test]]
 name = "imap_integration"
 required-features = ["default"]
+
+[[example]]
+name = "rustls_sasl"
+required-features = ["rustls-tls", "rsasl", "rsasl/registry_static"]
+
+[[example]]
+name = "rustls_sasl_gss"
+required-features = ["rustls-tls", "rsasl", "rsasl/registry_static", "rsasl/gssapi"]

examples/rustls_sasl.rs

@@ -0,0 +1,85 @@
+extern crate imap;
+
+use std::{env, error::Error};
+use rsasl::callback::{Context, Request, SessionData};
+use rsasl::config::SASLConfig;
+use rsasl::prelude::{Mechname, SessionError};
+use rsasl::property::{AuthId, AuthzId, Hostname, Password};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    // Read config from environment or .env file
+    let host = env::var("HOST").expect("missing envvar host");
+    let user = env::var("MAILUSER").ok();
+    let password = env::var("PASSWORD").ok();
+    let port = 993;
+
+    if let Some(email) = fetch_inbox_top(host, user, password, port)? {
+        println!("{}", &email);
+    }
+
+    Ok(())
+}
+
+struct MyCb {
+    authid: Option<String>,
+    authzid: Option<String>,
+    passwd: Option<String>,
+    host: String,
+}
+impl rsasl::callback::SessionCallback for MyCb {
+    fn callback(&self, _session_data: &SessionData, _context: &Context, request: &mut Request) -> Result<(), SessionError> {
+        if let Some(authid) = self.authid.as_deref() { request.satisfy::<AuthId>(authid)?; }
+        if let Some(authzid) = self.authzid.as_deref() { request.satisfy::<AuthzId>(authzid)?; }
+        if let Some(passwd) = self.passwd.as_deref() { request.satisfy::<Password>(passwd.as_bytes())?; }
+        if let Some(authid) = self.authid.as_ref() { request.satisfy::<AuthId>(authid)?; }
+        request.satisfy::<Hostname>(&self.host)?;
+        Ok(())
+    }
+}
+
+fn fetch_inbox_top(
+    host: String,
+    user: Option<String>,
+    password: Option<String>,
+    port: u16,
+) -> Result<Option<String>, Box<dyn Error>> {
+    let client = imap::ClientBuilder::new(&host, port).rustls()?;
+
+    let cb = MyCb {
+        authid: user,
+        authzid: None,
+        passwd: password,
+        host,
+    };
+    let saslconfig = SASLConfig::builder().with_defaults().with_callback(cb)?;
+
+    println!("SASL configuration options — enable features like 'rsasl/plain' or 'rsasl/sha2' to add available mechanisms:");
+    println!("{saslconfig:?}");
+
+    // the client we have here is unauthenticated.
+    // to do anything useful with the e-mails, we need to log in
+    let mut imap_session = client.sasl_auth(saslconfig).map_err(|e| e.0)?;
+
+    // we want to fetch the first email in the INBOX mailbox
+    imap_session.select("INBOX")?;
+
+    // fetch message number 1 in this mailbox, along with its RFC822 field.
+    // RFC 822 dictates the format of the body of e-mails
+    let messages = imap_session.fetch("1", "RFC822")?;
+    let message = if let Some(m) = messages.iter().next() {
+        m
+    } else {
+        return Ok(None);
+    };
+
+    // extract the message's body
+    let body = message.body().expect("message did not have a body!");
+    let body = std::str::from_utf8(body)
+        .expect("message was not valid utf-8")
+        .to_string();
+
+    // be nice to the server and log out
+    imap_session.logout()?;
+
+    Ok(Some(body))
+}