From: Tim Vaughan <tgvaughan@gmail.com>
Date: Wed, 4 Sep 2019 15:52:46 +0000 (+0200)
Subject: Draft remote-delivery implementation.
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=commitdiff_plain;h=0000b11973ff2e22ae1a7183146c8e76f8197cc1;p=lambdamail.git

Draft remote-delivery implementation.
---

diff --git a/lambdamail.scm b/lambdamail.scm
index 48383e4..e66e4de 100644
--- a/lambdamail.scm
+++ b/lambdamail.scm
@@ -73,10 +73,10 @@
 (define (make-smtp-session in-port out-port config)
   (let ((user "")
         (password ""))
-    (lambda msg
-      (match msg
+    (lambda command
+      (match command
         (('get-line) (read-line in-port))
-        (('send-line strings ...) (write-line (conc (apply conc strings) "\r") out-port))
+        (('send strings ...) (write-line (conc (apply conc strings) "\r") out-port))
         (('set-user! u) (set! user u))
         (('set-password! p) (set! password p))
         (('user) user)
@@ -91,7 +91,7 @@
       ""))
 
 (define (process-smtp smtp-session config)
-  (smtp-session 'send-line "220 " (config-host config) lambdamail-version)
+  (smtp-session 'send "220 " (config-host config) lambdamail-version)
   (let loop ((msg (make-empty-message))
              (received-messages '()))
     (let ((line (smtp-session 'get-line)))
@@ -99,14 +99,14 @@
         (print "got " line)
         (cond
          ((smtp-command? "helo" line)
-          (smtp-session 'send-line "250 ok")
+          (smtp-session 'send "250 ok")
           (loop msg received-messages))
          ((smtp-command? "ehlo" line)
-          (smtp-session 'send-line
+          (smtp-session 'send
                         "250-" (config-host config)
                         " Hello " (smtp-command-args "ehlo" line))
-          (smtp-session 'send-line "250 AUTH PLAIN")
-          ;; (smtp-session 'send-line "250 STARTTLS")
+          (smtp-session 'send "250 AUTH PLAIN")
+          ;; (smtp-session 'send "250 STARTTLS")
           (loop msg received-messages))
          ((smtp-command? "auth plain" line)
           (let* ((auth-string (smtp-command-args "auth plain" line))
@@ -117,18 +117,18 @@
             (smtp-session 'set-user! user)
             (smtp-session 'set-password! password)
             (print "Attempted login, user: " user ", password: " password)
-            (smtp-session 'send-line "235 authentication successful")
+            (smtp-session 'send "235 authentication successful")
             (loop msg received-messages)))
          ((smtp-command? "mail from:" line)
           (message-from-set! msg (smtp-command-args "mail from:" line))
-          (smtp-session 'send-line "250 ok")
+          (smtp-session 'send "250 ok")
           (loop msg received-messages))
          ((smtp-command? "rcpt to:" line)
           (message-to-set! msg (smtp-command-args "rcpt to:" line))
-          (smtp-session 'send-line "250 ok")
+          (smtp-session 'send "250 ok")
           (loop msg received-messages))
          ((smtp-command? "data" line)
-          (smtp-session 'send-line "354 intermediate")
+          (smtp-session 'send "354 intermediate")
           (let text-loop ((text ""))
             (let ((text-line (smtp-session 'get-line)))
               (if (string=? "." text-line)
@@ -136,15 +136,15 @@
                   (text-loop (conc text text-line "\n")))))
           (message-user-set! msg (smtp-session 'user))
           (message-password-set! msg (smtp-session 'password))
-          (smtp-session 'send-line "250 ok")
+          (smtp-session 'send "250 ok")
           (loop (make-empty-message) (cons msg received-messages)))
          ((smtp-command? "quit" line)
-          (smtp-session 'send-line "221 closing transmission channel")
+          (smtp-session 'send "221 closing transmission channel")
           received-messages)
          ((string=? "" (string-trim line))
           (loop msg received-messages))
          (else
-          (smtp-session 'send-line "502 command not implemented")
+          (smtp-session 'send "502 command not implemented")
           (loop msg received-messages)))))))
 
 
@@ -157,30 +157,35 @@
           messages))
 
 (define (deliver-message msg config)
-  (let* ((local-addresses (get-local-addresses config))
-         (dest (assoc (message-to msg) local-addresses))
-         (orig (assoc (message-from msg) local-addresses)))
-    (cond
-     (dest
-      (let ((dest-dir (cadr dest)))
-        (deliver-message-local msg dest-file))
-      (print "Message DELIVERED (local):"))
-     (orig
-      (let ((password (caddr orig)))
-        (if (and
-             (string=? (conc "<" (message-user msg) "@" (config-host config) ">")
-                       (message-from msg))
-             password
-             (string=? (message-password msg) password))
-            (begin
-              (deliver-message-remote msg)
-              (print "Message DELIVERED (remote):"))
-            (print "Message DELIVERY REJECTED (auth failure):"))))
-     (else
-      (print "Message DELIVERY REJECTED (relay forbidden):"))))
-  (print " * From: " (message-from msg))
-  (print " * To: " (message-to msg))
-  #t)
+  (condition-case
+      (begin
+        (let* ((local-addresses (get-local-addresses config))
+               (dest (assoc (message-to msg) local-addresses))
+               (orig (assoc (message-from msg) local-addresses)))
+          (cond
+           (dest
+            (let ((dest-dir (cadr dest)))
+              (deliver-message-local msg dest-file))
+            (print "Message DELIVERED (local):"))
+           (orig
+            (let ((password (caddr orig)))
+              (if (and
+                   (string=? (conc "<" (message-user msg) "@" (config-host config) ">")
+                             (message-from msg))
+                   password
+                   (string=? (message-password msg) password))
+                  (begin
+                    (deliver-message-remote msg config)
+                    (print "Message DELIVERED (remote):"))
+                  (print "Message DELIVERY REJECTED (auth failure):"))))
+           (else
+            (print "Message DELIVERY REJECTED (relay forbidden):"))))
+        (print " * From: " (message-from msg))
+        (print " * To: " (message-to msg))
+        #t)
+    (o (exn)
+       (print "Message delivery failed.")
+       (print-error-message o))))
 
 ;; Local delivery
 
@@ -205,9 +210,38 @@
 
 ;; Remote delivery
 
-(define (deliver-message-remote msg)
-  (print "TODO"))
-
+(define (get-host-from-email email-string)
+  (car (string-split (cadr (string-split email-string "@")) ">")))
+
+(define (deliver-message-remote msg config)
+  (let ((host (get-host-from-email (message-to msg))))
+    (print "Attempting delivery to host " host)
+    (let-values (((tcp-in tcp-out) (tcp-connect host 25)))
+      (let ((smtp-session (make-outgoing-smtp-session tcp-in tcp-out)))
+        (let ((result (and
+                       (smtp-session 'expect "220")
+                       (smtp-session 'send "helo " (config-host config))
+                       (smtp-session 'expect "250")
+                       (smtp-session 'send "mail from:" (message-from msg))
+                       (smtp-session 'expect "250")
+                       (smtp-session 'send "rcpt to:" (message-to msg))
+                       (smtp-session 'expect "250")
+                       (smtp-session 'send "data")
+                       (smtp-session 'expect "354")
+                       (smtp-session 'send (message-text msg))
+                       (smtp-session 'expect "250")
+                       (smtp-session 'send "quit"))))
+          (close-input-port tcp-in)
+          (close-output-port tcp-out)
+          result)))))
+
+(define ((make-outgoing-smtp-session tcp-in tcp-out) command)
+  (match command
+    (('expect code)
+     (string-prefix? "220" (read-line tcp-in)))
+    (('send strings ...)
+     (write-string (string-translate (conc (apply conc strings) "\n") "\n" "\r\n")
+                   out-port))))
 
 ;;; Command line argument parsing
 ;;