Password reset (#448)

* Password reset

* Various improvements and fixes for password reset

- Reorganize src/mail.rs to make it  cleaner
- add a build_mail function
- only make the requests invalid after 2 hours
- avoid infintely-growing list of requests by deleting them once completed, or after 24 hours
- avoid sending many requests for the same user
- validate the password reset form

* Avoid locking so many times

Fix durations

* Remove old requests even if the current one is not valid

* Remove unused feature

* Also remove the custom_derive and plugin features while we are at it

* Forgot a 0 è_é

* Avoid panicking while owning a request lock

* Use master branch of lettre so that we can build with the latest OpenSSL

* Fix the debug mailer

src/mail.rs

@@ -0,0 +1,80 @@
+use lettre_email::Email;
+use std::env;
+
+pub use self::mailer::*;
+
+#[cfg(feature = "debug-mailer")]
+mod mailer {
+    use lettre::{Transport, SendableEmail};
+    use std::{io::Read};
+
+    pub struct DebugTransport;
+
+    impl<'a> Transport<'a> for DebugTransport {
+        type Result = Result<(), ()>;
+
+        fn send(&mut self, email: SendableEmail) -> Self::Result {
+            println!(
+                "{}: from=<{}> to=<{:?}>\n{:#?}",
+                email.message_id().to_string(),
+                email.envelope().from().map(ToString::to_string).unwrap_or_default(),
+                email.envelope().to().to_vec(),
+                {
+                    let mut message = String::new();
+                    email.message().read_to_string(&mut message).map_err(|_| ())?;
+                    message
+                },
+            );
+            Ok(())
+        }
+    }
+
+    pub type Mailer = Option<DebugTransport>;
+
+    pub fn init() -> Mailer {
+        Some(DebugTransport)
+    }
+}
+
+#[cfg(not(feature = "debug-mailer"))]
+mod mailer {
+    use lettre::{
+        SmtpTransport,
+        SmtpClient,
+        smtp::{
+            authentication::{Credentials, Mechanism},
+            extension::ClientId,
+            ConnectionReuseParameters,
+        },
+    };
+    use std::env;
+
+    pub type Mailer = Option<SmtpTransport>;
+
+    pub fn init() -> Mailer {
+        let server = env::var("MAIL_SERVER").ok()?;
+        let helo_name = env::var("MAIL_HELO_NAME").unwrap_or_else(|_| "localhost".to_owned());
+        let username = env::var("MAIL_USER").ok()?;
+        let password = env::var("MAIL_PASSWORD").ok()?;
+        let mail = SmtpClient::new_simple(&server).unwrap()
+            .hello_name(ClientId::Domain(helo_name))
+            .credentials(Credentials::new(username, password))
+            .smtp_utf8(true)
+            .authentication_mechanism(Mechanism::Plain)
+            .connection_reuse(ConnectionReuseParameters::NoReuse)
+            .transport();
+        Some(mail)
+    }
+}
+
+pub fn build_mail(dest: String, subject: String, body: String) -> Option<Email> {
+    Email::builder()
+        .from(env::var("MAIL_ADDRESS")
+            .or_else(|_| Ok(format!("{}@{}", env::var("MAIL_USER")?, env::var("MAIL_SERVER")?)) as Result<_, env::VarError>)
+            .expect("Mail server is not correctly configured"))
+        .to(dest)
+        .subject(subject)
+        .text(body)
+        .build()
+        .ok()
+}