feat: A barebones SMTP server

This commit starts the fastn-mail crate. This will handle the SMTP/IMAP
and related email protcols. It'll also contain the bridge code so that
email clients can talk to this but the email get delivered over the iroh
network.

A simple SMTP impl is done, a lot of the things are left:
- support full SMTP proto
- upgrade to encrypted connection STARTTLS. Some client might depend on
  this.
- Actually deliver emails
- IMAP impl so that clients can fetch emails

The current impl is able to handle the tests/send-mail.py script. This
was just an experimentation to learn basics of SMTP protcol.

Author: siddhantk232

v0.5/Cargo.lock

@@ -86,6 +86,7 @@ ed25519-dalek = { version = "2.1.1", features = ["rand_core"] }
 data-encoding = "2"
 eyre = "0.6"
 ft-sys-shared = { version = "0.2.1", features = ["rusqlite", "host-only"] }
+futures = "0.3"
 futures-util = { version = "0.3", default-features = false, features = ["std"] }
 http = "1"
 http-body-util = "0.1"
@@ -102,6 +103,7 @@ magic-crypt = { version = "4", default-features = false }
 once_cell = "1"
 rand = "0.8.5"
 reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls"] }
+regex = "1"
 scc = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"

v0.5/Cargo.toml

@@ -6,6 +6,7 @@ authors.workspace = true
 license.workspace = true
 repository.workspace = true
 homepage.workspace = true
+description = "SMTP and IMAP implementation for fastn p2p email"
 
 [[bin]]
 name = "fastn-mail"
@@ -16,26 +17,23 @@ required-features = ["cli"]
 cli = ["clap", "tracing-subscriber"]
 
 [dependencies]
-# Core dependencies
-fastn-automerge.workspace = true
-autosurgeon.workspace = true
 automerge.workspace = true
+autosurgeon.workspace = true
+chrono.workspace = true
+eyre.workspace = true
+fastn-automerge.workspace = true
 fastn-id52 = { workspace = true, features = ["automerge"] }
+futures.workspace = true
+regex.workspace = true
+rusqlite.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 thiserror.workspace = true
-tracing.workspace = true
+tokio-util.workspace = true
 tokio.workspace = true
-
-# For database storage
-rusqlite.workspace = true
-
-# For timestamps
-chrono.workspace = true
-
-# For email parsing
+tracing.workspace = true
 mail-parser = "0.9"
 
 # CLI dependencies (optional)
 clap = { workspace = true, optional = true }
-tracing-subscriber = { workspace = true, optional = true }
+tracing-subscriber = { workspace = true, optional = true }

v0.5/fastn-mail/Cargo.toml

@@ -0,0 +1,5 @@
+import smtplib
+
+server = smtplib.SMTP('127.0.0.1', 9090)
+server.sendmail('siddhant@localhost', 'amitu@localhost', 'This is a test email')
+server.quit()