improved tls support

comm/xmpp.scm

@@ -1,6 +1,19 @@
 ;;; A basic XMPP library which should conform to RFCs 3920 and 3921
 ;;;
-;;; Copyright (C) 2009 FoAM vzw. LGPL.
+;;; Copyright (C) 2009 FoAM vzw. 
+;;;
+;;;  This package is free software: you can redistribute it and/or
+;;;  modify it under the terms of the GNU Lesser General Public
+;;;  License as published by the Free Software Foundation, either
+;;;  version 3 of the License, or (at your option) any later version.
+;;;
+;;;  This program is distributed in the hope that it will be useful,
+;;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;;;  Lesser General Public License for more details.
+;;;
+;;;  You can find a copy of the GNU Lesser General Public License at
+;;;  http://www.gnu.org/licenses/lgpl-3.0.html.
 ;;;
 ;;; Authors 
 ;;;
@@ -8,15 +21,15 @@
 ;;;
 ;;; Requirements
 ;;;
-;;;  PLT for now.
+;;;  PLT for now. TLS requires a version of PLT > 4.1.5.3
 ;;;
 ;;; Commentary
 ;;;
 ;;;  Still a long way from implementing even a minimal subset of XMPP
 ;;; 
 ;;;  features implemented
-;;;   - establish plaintext connections on port 5222
+;;;   - plaintext sessions on port 5222
-;;;   - partial "old sytle" ssl connections on port 5223
+;;;   - "old sytle" ssl sessions on port 5223
 ;;;   - authenticate using an existing account
 ;;;   - send messages (rfc 3921 sec.4)
 ;;;   - send presence (rfc 3921 sec.5)
@@ -25,9 +38,9 @@
 ;;;
 ;;;  features to implement
 ;;;   - account creation
-;;;   - managing subscription (rfc 3921 sec.6)
+;;;   - managing subscriptions (rfc 3921 sec.6)
 ;;;   - rosters (rfc 3921 sec.7)
-;;;   - plaintext/ssl/tls negotiation (rfc 3920 sec.5 & 6)
+;;;   - plaintext/tls/sasl negotiation (rfc 3920 sec.5 & 6) 
 ;;;   - encrypted connections using tls on port 5222
 ;;;   - correct namespaces in sxml
 ;;;   - message types
@@ -39,23 +52,21 @@
 ;;;   - rfc 3920 
 ;;;   - rfc 3921
 ;;;
-;;; bugs and/or improvements
+;;;  bugs and/or improvements
 ;;;   - read-async & repsonse-handler
 ;;;   - ssax:xml->sxml or lazy:xml->sxml
 ;;;   - default handlers
-;;;   - ssl read/write sequence
 ;;;   - chatbot exmples
 ;;;
 
 (module xmpp scheme
-
+  
   (provide (all-defined-out)
            ;open-connection
            ;open-ssl-connection
            ;with-xmpp-session
            )
   
- 
   (require (planet lizorkin/sxml:2:1/sxml))
   (require (planet lizorkin/ssax:2:0/ssax))
   (require mzlib/os)
@@ -72,11 +83,6 @@
   
   (define port 5222)
   (define ssl-port 5223)
-
-  (define ssl-write-flag #t) ;; semaphore for half-duplex ssl 
-
-  (define (ssl-write b)
-    (set! ssl-write-flag b))  
   
   (define (open-connection machine port handler)
     (let-values (((in out)
@@ -93,15 +99,13 @@
       (close-input-port in)))
   
   (define (read-async in)
-    (define bstr (make-bytes 0 0))
+    (bytes->string/utf-8 (list->bytes (read-async-bytes in))))
-    (when (byte-ready? in)
+  
-      (if (eq? (peek-byte in) eof)
+  (define (read-async-bytes in)
-          (break-thread (current-thread))
+    (let ((bstr '()))
-          (begin
+      (when (sync/timeout 0 in)
-            (set! bstr (bytes-append bstr 
+        (set! bstr (cons (read-byte in) (read-async-bytes in)))) bstr))
-                                     (make-bytes 1 (read-byte in)) 
+  
-                                     (read-async in)))))) bstr)
-
   (define ssxml srl:sxml->xml-noindent) 
   
   ;;;;;; ; ; ;      ;   ;; ;;;;;; ;
@@ -113,7 +117,7 @@
   ;; intialization
   (define (xmpp-stream host) 
     (string-append "<?xml version='1.0'?><stream:stream xmlns:stream='http://etherx.jabber.org/streams' to='" host "' xmlns='jabber:client'>"))
-
+  
   ;; authentication
   (define (xmpp-auth username password resource)
     (ssxml `(iq (@ (type "set") (id "auth")) 
@@ -121,17 +125,17 @@
                        (username ,username) 
                        (password ,password)
                        (resource ,resource)))))
-
+  
   (define (xmpp-session host)
     (ssxml `(iq (@ (to ,host) (type "set") (id "session")) 
                 (session (@ (xmlns "urn:ietf:params:xml:ns:xmpp-session")))))) 
   
   (define (starttls) "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>")
   
-   ;; messages
+  ;; messages
   (define (message to body)
     (ssxml `(message (@ (to ,to)) (body ,body))))
-
+  
   ;; presence
   (define (presence #:from (from "") 
                     #:to (to "") 
@@ -156,19 +160,19 @@
   (define message-type (sxpath-element "message/@type/text()"))
   (define message-body (sxpath-element "message/body/text()"))
   (define message-subject (sxpath-element "message/subject/text()"))
-
+  
   ;; info/query
   (define iq-type (sxpath-element "iq/@type/text()"))
   (define iq-id (sxpath-element "iq/@id/text()"))
   (define iq-error-type (sxpath-element "iq/error/@type/text()"))
   (define iq-error-text (sxpath-element "iq/error/text()"))
   (define iq-error (sxpath-element "iq/error"))
-
+  
   ;; presence
   (define presence-show (sxpath-element "presence/show/text()"))
   (define presence-from (sxpath-element "presence/@from/text()"))
   (define presence-status (sxpath-element "presence/status/text()"))
-
+  
   
   ;;;;;;;;; ; ;; ; ; ;;  ;;    ;  ;
   ;;
@@ -180,7 +184,7 @@
   ;;;;;; ;;  ; ; ;;  ;
   
   (define xmpp-handlers (make-hash)) ;; a hash of tags and functions (possibly extend to using sxpaths)
-    
+  
   (define (set-xmpp-handler type fcn)
     (dict-set! xmpp-handlers type fcn))
   
@@ -189,12 +193,11 @@
       (when fcn (begin
                   (display (format "attempting to run handler ~a.~%" fcn))
                   (fcn sz)))))
-    
+  
   ;; no real parsing yet. dispatches any received xml stanzas as sxml
   
   (define (parse-xmpp-response str)
     (when (> (string-length str) 0)
-      (newline)
       (let ((sz (ssax:xml->sxml (open-input-string (clean str)) '())))
         ;;(let ((sz (lazy:xml->sxml (open-input-string str) '())))
         (cond
@@ -211,10 +214,10 @@
   ;; example handlers to print stanzas or their contents
   (define (print-message sz)
     (display (format "a ~a message from ~a which says '~a.'~%" (message-type sz) (message-from sz) (message-body sz))))
-    
+  
   (define (print-iq sz)
-   (display (format "an iq response of type '~a' with id '~a.'~%" (iq-type sz) (iq-id sz))))
+    (display (format "an iq response of type '~a' with id '~a.'~%" (iq-type sz) (iq-id sz))))
-
+  
   (define (print-presence sz)
     (display (format " p-r-e-s-e-n-e-c--> ~a is ~a" (presence-from sz) (presence-status))))
   
@@ -224,55 +227,52 @@
   ;; QND hack to filter out anything not a message, iq or presence
   (define (clean str)
     (let ((test (substring str 0 3)))
-    (cond ((string-ci=? test "<me") str)
+      (cond ((string-ci=? test "<me") str)
-          ((string-ci=? test "<iq") str)
+            ((string-ci=? test "<iq") str)
-          ((string-ci=? test "<pr") str)
+            ((string-ci=? test "<pr") str)
-          (else "<null/>"))))
+            (else "<null/>"))))
-
+  
-  ;; repsonse handler
+  
+  ;; response handler
   (define (xmpp-response-handler in)
     (thread (lambda () 
               (let loop () 
-                (when ssl-write-flag
+                (parse-xmpp-response (read-async in))
-                  (parse-xmpp-response (bytes->string/utf-8 (read-async in))))
+                (sleep 0.1) ;; slight delay to avoid a tight loop
-                (sleep 0.1)
                 (loop)))))
-
-  ;; ideally something like this would work.. . 
-  (define (xmmp-read-stanza in)
-    (parse-xmpp-response (read-line in)))
   
   ;; jid splicing (assuming the jid is in the format user@host/resource)
   (define (jid-user jid)
     (string-take jid (string-index jid #\@)))
- 
+  
   (define (jid-host jid)
     (let* ((s (string-take-right jid (- (string-length jid) (string-index jid #\@) 1)))
            (v (string-index s #\/)))
       (if v (string-take s v) s )))
-    
+  
   (define (jid-resource jid)
     (let ((r (jid-resource-0 jid)))
       (if (void? r) (gethostname) r)))
-
+  
   (define (jid-resource-0 jid)
     (let ((v (string-index jid #\/)))
       (when v (string-take-right jid (- (string-length jid) v 1)))))    
+
   
   ;;;;  ;; ; ; ;; ;;   ;;;; ;
   ;;
   ;; interfaces
   ;;
   ;;;;; ;; ;;;;   ;   ;;  ;
-
+  
   (defmacro with-xmpp-session (jid pass . body)
     `(let ((host (jid-host ,jid))
            (user (jid-user ,jid))
            (resource (jid-resource ,jid)))
        (let-values (((in out)
-                     ;;(ssl-connect host ssl-port 'tls)))
+                     (ssl-connect host ssl-port 'tls)))
-                     (tcp-connect host port)))
+         ;;(tcp-connect host port)))
-         (define (send str) (fprintf out "~A~%" str))
+         (define (send str) (fprintf out "~A~%" str) (flush-output out))
          (file-stream-buffer-mode out 'line)
          (xmpp-response-handler in) 
          (send (xmpp-stream host))
@@ -280,11 +280,11 @@
          ;(send starttls)
          (send (xmpp-auth user ,pass resource))
          (send (presence))
-         (send (presence #:status "Available"))                    
+         (send (presence #:status "Available"))
          ,@body
          (close-output-port out)
          (close-input-port in))))
-
+  
-
+  
-) ;; end module
+  ) ;; end module