Message Archive Management (MAM) support for groupchats

- Groupchats now support XEP-0313 Message Archive Management (MAM)!
- This uses the history stored in the sqlite database, as implemented in the
  previous commits.
  - The QUERY-ARCHIVE megafunction builds up a SQL query to get stuff out of the
    database, in accordance with provided MAM + RSM parameters.
- Notably, various hacks are in here that need to be fixed.
  - IQ 'set's are now processed, which means we needed to add a stub impl of
    Schrödinger's Chat so people don't drop out of MUCs all of a sudden.
    (Well, it just responds to every ping indiscriminately...)
  - Oh also the new presence subscription stuff from earlier is borked.

component.lisp

@@ -247,6 +247,10 @@
               :disco-items)
              ((and (equal xmlns +vcard-temp-ns+) (equal tag-name "vCard"))
               :vcard-temp-get)
+             ((and (equal xmlns +mam-ns+) (equal tag-name "query"))
+              :mam-query)
+             ((and (equal xmlns +ping-ns+) (equal tag-name "ping"))
+              :ping)
              (t
               :generic-iq))))
     (call-component-iq-handler comp handler-type
@@ -261,7 +265,7 @@
     (let ((type (dom:get-attribute stanza "type"))
           (id (dom:get-attribute stanza "id"))
           (from (dom:get-attribute stanza "from")))
-      (if (equal type "get")
+      (if (or (equal type "get") (equal type "set"))
           (handle-iq-get comp id from stanza)
           (symbol-macrolet
               ((promise (gethash id (component-promises comp))))

db.lisp

@@ -35,6 +35,15 @@
       (with-bound-columns (id) get-stmt
         id))))
 
+(defun get-user-chat-localpart (chat-id)
+  "Get the user chat localpart for CHAT-ID, or NIL if none exists."
+  (with-prepared-statements
+      ((get-stmt "SELECT wa_jid FROM user_chats WHERE id = ?"))
+    (bind-parameters get-stmt chat-id)
+    (when (sqlite:step-statement get-stmt)
+      (with-bound-columns (localpart) get-stmt
+        localpart))))
+
 (defun get-user-chat-subject (uid localpart)
   "Get the user chat subject of LOCALPART for UID, or NIL if none exists."
   (with-prepared-statements
@@ -145,11 +154,13 @@
 (defun insert-xmpp-message (xm)
   "Inserts XM, a groupchat XMPP-MESSAGE, into the database."
   (assert (uiop:string-prefix-p "g" (conversation xm)) () "Tried to insert XMPP message for non-groupchat conversation ~A" (conversation xm))
-  (let ((chat-id (or
-                  (get-user-chat-id (uid xm) (conversation xm))
-                  (error "Couldn't find chat id for conversation ~A / uid ~A"
-                         (conversation xm) (uid xm))))
-        (ts-unix (local-time:timestamp-to-unix (timestamp xm))))
+  (let* ((chat-id (or
+                   (get-user-chat-id (uid xm) (conversation xm))
+                   (error "Couldn't find chat id for conversation ~A / uid ~A"
+                          (conversation xm) (uid xm))))
+
+         (local-time:*default-timezone* local-time:+utc-zone+)
+         (ts-unix (local-time:timestamp-to-unix (timestamp xm))))
     (with-prepared-statements
         ((insert-stmt "INSERT INTO user_chat_history (user_id, chat_id, user_from, ts_unix, xmpp_id, orig_id, body, oob_url) VALUES (?, ?, ?, ?, ?, ?, ?, ?)"))
       (bind-parameters insert-stmt (1 (uid xm)) (2 chat-id) (3 (from xm)) (4 ts-unix) (5 (xmpp-id xm)) (6 (orig-id xm)) (7 (body xm)) (8 (oob-url xm)))
@@ -163,3 +174,70 @@
     (when (sqlite:step-statement get-stmt)
       (with-bound-columns (xid) get-stmt
         xid))))
+
+(defun get-chat-history-ts (uid chat-id xmpp-id)
+  "Look up the UNIX timestamp for the given UID, CHAT-ID and XMPP-ID."
+  (with-prepared-statements
+      ((get-stmt "SELECT ts_unix FROM user_chat_history WHERE user_id = ? AND chat_id = ? AND xmpp_id = ?"))
+    (bind-parameters get-stmt uid chat-id xmpp-id)
+    (when (sqlite:step-statement get-stmt)
+      (with-bound-columns (tsu) get-stmt
+        tsu))))
+
+(defun query-archive (uid chat-id &key start end (limit 100) reference-stanza-id forward-page)
+  "Query the chat history archive for the chat identified by CHAT-ID and UID. Optionally narrow the query using START and END (UNIX timestamps), returning at most LIMIT items (which is clamped to 100).
+If an RSM REFERENCE-STANZA-ID is provided, narrow the query to be either after (T) or before (NIL) the history entry with that stanza ID, depending on the value of FORWARD-PAGE (see brackets)."
+  (let ((statement (make-string-output-stream))
+        (localpart (get-user-chat-localpart chat-id))
+        (local-time:*default-timezone* local-time:+utc-zone+)
+        (args (list chat-id uid)) ; WARNING this list is nreverse'd later!
+        (items-returned 0)
+        (sqlite-stmt))
+    (format statement "SELECT user_from, ts_unix, xmpp_id, orig_id, body, oob_url FROM user_chat_history WHERE user_id = ? AND chat_id = ?")
+    (when reference-stanza-id
+      (let ((reference-ts (or
+                           (get-chat-history-ts uid chat-id reference-stanza-id)
+                           (error "Couldn't locate reference stanza ID ~A" reference-stanza-id))))
+        (if forward-page
+            (setf start reference-ts)
+            (setf end reference-ts))))
+    (when start
+      (format statement " AND ts_unix > ?")
+      (push start args))
+    (when end
+      (format statement " AND ts_unix < ?")
+      (push end args))
+    (unless limit
+      (setf limit 100))
+    (when (> limit 100)
+      (setf limit 100)) ; clamp me owo
+    ;; We copy a trick from biboumi: in order to figure out whether there are
+    ;; more results if not for the limit existing, simply increment the limit
+    ;; by 1 and see if you get the extra element.
+    (format statement " ORDER BY ts_unix ~A LIMIT ~A" (if forward-page "ASC" "DESC") (1+ limit))
+    (setf args (nreverse args))
+    (bt:with-recursive-lock-held (*db-lock*)
+      (let ((stmt-text (get-output-stream-string statement)))
+        (setf sqlite-stmt (sqlite:prepare-statement *db* stmt-text)))
+      (loop
+        for param in args
+        for n from 1
+        do (sqlite:bind-parameter sqlite-stmt n param))
+      (values
+       (funcall
+        (if forward-page #'identity #'nreverse)
+        (loop
+          while (sqlite:step-statement sqlite-stmt)
+          do (incf items-returned)
+          while (<= items-returned limit)
+          collect (with-bound-columns (from ts-unix xmpp-id orig-id body oob-url) sqlite-stmt
+                    (make-instance 'xmpp-message
+                                   :uid uid
+                                   :conversation localpart
+                                   :from from
+                                   :timestamp (local-time:unix-to-timestamp ts-unix)
+                                   :xmpp-id xmpp-id
+                                   :orig-id orig-id
+                                   :body body
+                                   :oob-url oob-url))))
+       (<= items-returned limit)))))

default.nix

@@ -984,6 +984,7 @@ buildLisp.program {
     "xep-0030.lisp"
     "xep-0363.lisp"
     "xep-0115.lisp"
+    "xep-0313.lisp"
     "sqlite.lisp"
     "db.lisp"
     "media.lisp"

message.lisp

@@ -112,6 +112,39 @@ FIXME: the above behaviour is a bit meh."
       do (format oss "> ~A~%" item))
     (get-output-stream-string oss)))
 
+(defun deliver-mam-history-message (comp msg to-jid &optional query-id)
+  "Deliver MSG, an XMPP-MESSAGE, to TO-JID as a piece of MAM history, as part of the response to a MAM query with QUERY-ID."
+  (let* ((component-host (component-name comp))
+         (mam-from (concatenate 'string (conversation msg) "@" component-host))
+         (real-from (concatenate 'string mam-from "/" (from msg))))
+    (with-message (comp to-jid
+                   :from mam-from
+                   :type nil)
+      (cxml:with-element "result"
+        (cxml:attribute "xmlns" +mam-ns+)
+        (when query-id
+          (cxml:attribute "queryid" query-id))
+        (cxml:attribute "id" (xmpp-id msg))
+        (cxml:with-element "forwarded"
+          (cxml:attribute "xmlns" +forwarded-ns+)
+          (cxml:with-element "delay"
+            (cxml:attribute "xmlns" +delivery-delay-ns+)
+            (cxml:attribute "stamp" (local-time:format-timestring nil (timestamp msg))))
+          (cxml:with-element "message"
+            (cxml:attribute "from" real-from)
+            (cxml:attribute "xmlns" +client-ns+)
+            (cxml:attribute "type" "groupchat")
+            (cxml:with-element "body"
+              (cxml:text (body msg)))
+            (when (oob-url msg)
+              (cxml:with-element "x"
+                (cxml:attribute "xmlns" +oob-ns+)
+                (cxml:with-element "url"
+                  (cxml:text (oob-url msg)))))
+            (when (orig-id msg)
+              (cxml:with-element "origin-id"
+                (cxml:attribute "xmlns" +unique-stanzas-ns+)
+                (cxml:attribute "id" (orig-id msg))))))))))
 
 (defun deliver-xmpp-message (comp msg)
   "Deliver MSG, an XMPP-MESSAGE, to the intended destinations on COMP."

namespaces.lisp

@@ -22,3 +22,9 @@
 (defparameter +chat-states-ns+ "http://jabber.org/protocol/chatstates")
 (defparameter +hints-ns+ "urn:xmpp:hints")
 (defparameter +entity-caps-ns+ "http://jabber.org/protocol/caps")
+(defparameter +mam-ns+ "urn:xmpp:mam:2")
+(defparameter +rsm-ns+ "http://jabber.org/protocol/rsm")
+(defparameter +data-forms-ns+ "jabber:x:data")
+(defparameter +forwarded-ns+ "urn:xmpp:forward:0")
+(defparameter +client-ns+ "jabber:client")
+(defparameter +ping-ns+ "urn:xmpp:ping")

schema.sql

@@ -72,3 +72,5 @@ CREATE TABLE user_chat_history (
   body VARCHAR NOT NULL,
   oob_url VARCHAR
 );
+
+CREATE UNIQUE INDEX user_chat_history_unique ON user_chat_history (user_id, chat_id, xmpp_id);

stuff.lisp

@@ -59,6 +59,7 @@
                `((disco-identity ,chat-subject "text" "conference")
                  (disco-feature ,+disco-info-ns+)
                  (disco-feature ,+muc-ns+)
+                 (disco-feature ,+mam-ns+)
                  (disco-feature ,+muc-stable-id-ns+)
                  (disco-feature ,+unique-stanzas-ns+)
                  (disco-feature "muc_hidden")
@@ -272,6 +273,61 @@ WhatsXMPP represents users as u440123456789 and groups as g1234-5678."
     (admin-presence comp jid "Programming error" "xa")
     (remhash jid (component-whatsapps comp))))
 
+(defun whatsxmpp-ping-handler (comp &key to from &allow-other-keys)
+  (declare (ignore comp to from))
+  ;; This is a stub!
+  nil)
+
+(defun whatsxmpp-mam-query-handler (comp &key to from stanza &allow-other-keys)
+  "Handles Message Archive Management (MAM) queries."
+  (with-component-data-lock (comp)
+    (let* ((stripped (strip-resource from))
+           (local-time:*default-timezone* local-time:+utc-zone+)
+           (uid (or
+                 (get-user-id stripped)
+                 (error 'stanza-error
+                        :defined-condition "registration-required"
+                        :text "You must be a bridge user to run MAM queries."
+                        :type "auth")))
+           (chat-id (or
+                     (get-user-chat-id uid (nth-value 1 (parse-jid to)))
+                     (error 'stanza-error
+                            :defined-condition "item-not-found"
+                            :text "Couldn't find a WhatsApp chat with that JID."
+                            :type "modify")))
+           (query-params (alist-from-mam-query (elt (child-elements stanza) 0))))
+      (format *debug-io* "~&MAM query for ~A from ~A:~%  params ~A~%" from to query-params)
+      (labels ((unix-from-mam (time-input)
+                 (alexandria:when-let ((time time-input))
+                   (local-time:timestamp-to-unix (local-time:parse-timestring time))))
+               (unix-from-mam-params (keyword params)
+                 (unix-from-mam (whatscl::cassoc keyword params))))
+        (multiple-value-bind (messages completep)
+            (query-archive uid chat-id
+                           :start (unix-from-mam-params :start query-params)
+                           :end (unix-from-mam-params :end query-params)
+                           :limit (alexandria:when-let
+                                      ((limit (whatscl::cassoc :max query-params)))
+                                    (parse-integer limit))
+                           :reference-stanza-id (or
+                                                 (whatscl::cassoc :after query-params)
+                                                 (whatscl::cassoc :before query-params))
+                           :forward-page (whatscl::cassoc :after query-params))
+          (format *debug-io* "~&MAM query for ~A returned ~A messages (complete: ~A)" from (length messages) completep)
+          (loop
+            for msg in messages
+            do (deliver-mam-history-message comp msg from (whatscl::cassoc :query-id query-params)))
+          `((cxml:with-element "fin"
+              (cxml:attribute "xmlns" ,+mam-ns+)
+              (cxml:attribute "complete" ,(if completep "true" "false"))
+              (cxml:with-element "set"
+                (cxml:attribute "xmlns" ,+rsm-ns+)
+                ,@(when (> (length messages) 0)
+                    `((cxml:with-element "first"
+                        (cxml:text ,(xmpp-id (first messages))))
+                      (cxml:with-element "last"
+                        (cxml:text ,(xmpp-id (car (last messages)))))))))))))))
+
 (defun do-chat-history-request (comp conn jid uid requested-jid)
   "Retrieves full chat history for the REQUESTED-JID, and inserts it into the database."
   (whatscl::get-full-chat-history
@@ -523,7 +579,8 @@ Returns three values: avatar data (as two values), and a generalized boolean spe
         (wx-localpart (wa-jid-to-whatsxmpp-localpart ct-jid)))
     (when (uiop:string-prefix-p "u" wx-localpart)
       ;; The user has an open chat with this other user, so they probably want a presence subscription.
-      (handle-wa-contact-presence-subscriptions comp jid wx-localpart)
+      (when (get-contact-name uid wx-localpart) ;; FIXME
+        (handle-wa-contact-presence-subscriptions comp jid wx-localpart))
       (return-from add-wa-chat))
     (unless (uiop:string-prefix-p "g" wx-localpart)
       (warn "Interesting localpart pased to ADD-WA-CHAT: ~A" wx-localpart)
@@ -601,6 +658,7 @@ Returns three values: avatar data (as two values), and a generalized boolean spe
               (let* ((new-from (concatenate 'string orig-to "/" muc-resource))
                      (group-localpart (nth-value 1 (parse-jid orig-to)))
                      (recipients (get-user-chat-joined (get-user-id jid) group-localpart)))
+                ;; FIXME: You can break the database's UNIQUE constraint here.
                 (insert-xmpp-message (make-instance 'xmpp-message
                                                     :conversation group-localpart
                                                     :uid (get-user-id jid)
@@ -905,7 +963,7 @@ Returns three values: avatar data (as two values), and a generalized boolean spe
          (let ((conn (gethash stripped (component-whatsapps comp))))
            (if conn
                (let ((chats (get-user-groupchats uid)))
-                 (reply (format nil "Fetching full chat history for ~A groupchats. This will probably take a long time.~%Note that even after completion is reported, some background media uploading may be in progress."
+                 (reply (format nil "Fetching full chat history for ~A groupchats. This will probably take a long time.~%Note that even after completion is reported, some background media uploading may be in progress.~%If the WhatsApp connection is interrupted midway through the fetch, you will need to retry the fetch."
                                 (length chats)))
                  (bt:make-thread
                   (lambda ()
@@ -1297,7 +1355,9 @@ Returns three values: avatar data (as two values), and a generalized boolean spe
 (defun register-whatsxmpp-handlers (comp)
   (register-component-iq-handler comp :disco-info #'disco-info-handler)
   (register-component-iq-handler comp :vcard-temp-get #'whatsxmpp-vcard-temp-handler)
-  (register-component-iq-handler comp :disco-items #'disco-items-handler))
+  (register-component-iq-handler comp :disco-items #'disco-items-handler)
+  (register-component-iq-handler comp :mam-query #'whatsxmpp-mam-query-handler)
+  (register-component-iq-handler comp :ping #'whatsxmpp-ping-handler))
 
 (defun whatsxmpp-init ()
   "Initialise the whatsxmpp bridge."

utils.lisp

@@ -17,6 +17,10 @@
   "Returns the child elements (excluding text nodes) of the CXML DOM node NODE."
   (remove-if-not #'dom:element-p (dom:child-nodes node)))
 
+(defun nil-empty (seq)
+  "If SEQ (a sequence) is empty, returns NIL; otherwise, returns SEQ."
+  (unless (eql (length seq) 0) seq))
+
 (defmacro with-promise-from-thread (() &body forms)
   "Return a promise that executes FORMS in a new thread, resolving the promise with the return value of (PROGN ,@FORMS) or rejecting it if an ERROR condition is thrown (with said condition)."
   (let ((resolve (gensym))

whatsxmpp.asd

@@ -13,6 +13,7 @@
    (:file "xep-0030")
    (:file "xep-0363")
    (:file "xep-0115")
+   (:file "xep-0313")
    (:file "sqlite")
    (:file "db")
    (:file "media")

xep-0313.lisp

@@ -0,0 +1,31 @@
+;;;; XEP-0313: Message Archive Management
+
+(in-package :whatsxmpp)
+
+(defun whitelisted-mam-keywordize (thing)
+  "Interns THING, but only after making sure it's a string from XEP-0313."
+  (if (member thing '("start" "end" "with" "first" "last" "count" "max" "FORM_TYPE" "after" "before")
+              :test #'string=)
+      (intern (string-upcase thing) :keyword)
+      thing))
+
+(defun alist-from-mam-query (query-elt)
+  "Parses the QUERY-ELT, a MAM <query> element, and returns an alist."
+  (labels ((consify-df (field-elt)
+             (cons (whitelisted-mam-keywordize
+                    (dom:get-attribute field-elt "var"))
+                   (nil-empty
+                    (get-node-text
+                     (get-node-named (child-elements field-elt) "value")))))
+           (consify-rsm (rsm-elt)
+             (cons (whitelisted-mam-keywordize
+                    (dom:node-name rsm-elt))
+                   (nil-empty (get-node-text rsm-elt)))))
+    (let* ((x-elt (get-node-with-xmlns (child-elements query-elt) +data-forms-ns+))
+           (rsm-elt (get-node-with-xmlns (child-elements query-elt) +rsm-ns+))
+           (query-id (dom:get-attribute query-elt "queryid"))
+           (form-fields (map 'list #'consify-df (child-elements x-elt)))
+           (rsm-fields (when rsm-elt
+                         (map 'list #'consify-rsm (child-elements rsm-elt)))))
+      (append form-fields rsm-fields (when query-id
+                                       `((:query-id . ,query-id)))))))