--- a/sat/plugins/plugin_comp_ap_gateway.py	Tue Jan 25 17:27:39 2022 +0100
+++ b/sat/plugins/plugin_comp_ap_gateway.py	Tue Jan 25 17:54:06 2022 +0100
@@ -16,30 +16,40 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import time
-import json
 import base64
 import hashlib
-from urllib import parse
-from typing import Tuple
+import json
 from pathlib import Path
-import shortuuid
-from cryptography.hazmat.primitives.asymmetric import rsa
+import time
+from typing import Optional, Dict, Tuple, List, Union
+from urllib import parse
+import calendar
+import re
+import unicodedata
+
+import dateutil
 from cryptography.hazmat.primitives import serialization
 from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import rsa
 from cryptography.hazmat.primitives.asymmetric import padding
-from twisted.internet import reactor, threads, defer
-from twisted.web import server, resource as web_resource, http
-from twisted.words.protocols.jabber import jid
+import shortuuid
 import treq
 from treq.response import _Response as TReqResponse
-from sat.core.i18n import _
+from twisted.internet import defer, reactor, threads
+from twisted.web import http, resource as web_resource, server
+from twisted.words.protocols.jabber import jid, error
+from twisted.words.xish import domish
+from wokkel import pubsub, rsm
+
+from sat.core import exceptions
 from sat.core.constants import Const as C
-from sat.core import exceptions
+from sat.core.core_types import SatXMPPEntity
+from sat.core.i18n import _
 from sat.core.log import getLogger
-from sat.core.core_types import SatXMPPEntity
-from sat.tools.common import tls, data_format
 from sat.tools import utils
+from sat.tools.common import data_format, tls
+from sat.tools.common.async_utils import async_lru
+from sat.tools.utils import ensure_deferred
 
 
 log = getLogger(__name__)
@@ -52,21 +62,39 @@
     C.PI_MODES: [C.PLUG_MODE_COMPONENT],
     C.PI_TYPE: C.PLUG_TYPE_ENTRY_POINT,
     C.PI_PROTOCOLS: [],
-    C.PI_DEPENDENCIES: ["XEP-0106"],
+    C.PI_DEPENDENCIES: ["XEP-0106", "XEP-0277", "XEP-0060"],
     C.PI_RECOMMENDATIONS: [],
     C.PI_MAIN: "APGateway",
-    C.PI_HANDLER: C.BOOL_FALSE,
+    C.PI_HANDLER: C.BOOL_TRUE,
     C.PI_DESCRIPTION: _(
         "Gateway for bidirectional communication between XMPP and ActivityPub."
     ),
 }
 
+VERSION = unicodedata.normalize(
+    'NFKD',
+    f"{C.APP_NAME} ActivityPub Gateway {C.APP_VERSION}"
+)
+HEXA_ENC = r"(?P<hex>[0-9a-fA-f]{2})"
+RE_PERIOD_ENC = re.compile(f"\\.{HEXA_ENC}")
+RE_PERCENT_ENC = re.compile(f"%{HEXA_ENC}")
+RE_ALLOWED_UNQUOTED = re.compile(r"^[a-zA-Z0-9_-]+$")
 CONF_SECTION = f"component {IMPORT_NAME}"
 CONTENT_TYPE_AP = "application/activity+json; charset=utf-8"
 TYPE_ACTOR = "actor"
 TYPE_INBOX = "inbox"
+TYPE_OUTBOX = "outbox"
 TYPE_ITEM = "item"
 MEDIA_TYPE_AP = "application/activity+json"
+# mapping from AP metadata to microblog data
+AP_MB_MAP = {
+    "content": "content_xhtml",
+
+}
+AP_REQUEST_TYPES = {"actor", "outbox"}
+PAGE_SIZE = 10
+
+LRU_MAX_SIZE = 200
 
 
 class HTTPAPGServer(web_resource.Resource):
@@ -77,12 +105,11 @@
         self.apg = ap_gateway
         super().__init__()
 
-    def webfinger(self, request):
+    async def webfinger(self, request):
         url_parsed = parse.urlparse(request.uri.decode())
         query = parse.parse_qs(url_parsed.query)
         resource = query.get("resource", [""])[0]
         account = resource[5:].strip()
-        log.info(f"request pour {account}")
         if not resource.startswith("acct:") or not account:
             return web_resource.ErrorPage(
                 http.BAD_REQUEST, "Bad Request" , "Invalid webfinger resource"
@@ -101,18 +128,24 @@
             ]
         }
         request.setHeader("content-type", CONTENT_TYPE_AP)
-        return json.dumps(resp).encode()
+        request.write(json.dumps(resp).encode())
+        request.finish()
 
-    def APRequest(self, request):
-        path = request.path.decode()
-        actor_url = parse.urljoin(
-            f"https://{self.apg.public_url}",
-            path
-        )
-        __, account = self.apg.parseAPURL(actor_url)
-        inbox_url = self.apg.buildAPURL(TYPE_INBOX, account)
-        username = account.split("@", 1)[0]
-        actor = {
+    async def APActorRequest(
+        self,
+        request: "HTTPRequest",
+        account_jid: jid.JID,
+        node: Optional[str],
+        ap_account: str,
+        actor_url: str
+    ) -> dict:
+        inbox_url = self.apg.buildAPURL(TYPE_INBOX, ap_account)
+        outbox_url = self.apg.buildAPURL(TYPE_OUTBOX, ap_account)
+
+        # we have to use AP account as preferredUsername because it is used to retrieve
+        # actor handle (see https://socialhub.activitypub.rocks/t/how-to-retrieve-user-server-tld-handle-from-actors-url/2196)
+        preferred_username = ap_account.split("@", 1)[0]
+        return {
             "@context": [
                 "https://www.w3.org/ns/activitystreams",
                 "https://w3id.org/security/v1"
@@ -120,24 +153,191 @@
 
             "id": actor_url,
             "type": "Person",
-            "preferredUsername": username,
+            "preferredUsername": preferred_username,
             "inbox": inbox_url,
-
+            "outbox": outbox_url,
             "publicKey": {
                 "id": f"{actor_url}#main-key",
                 "owner": actor_url,
                 "publicKeyPem": self.apg.public_key_pem
             }
         }
+
+    def getCanonicalURL(self, request: "HTTPRequest") -> str:
+        return parse.urljoin(
+            f"https://{self.apg.public_url}",
+            request.path.decode().rstrip("/")
+        )
+
+    def queryData2RSMRequest(
+        self,
+        query_data: Dict[str, List[str]]
+    ) -> rsm.RSMRequest:
+        """Get RSM kwargs to use with RSMRequest from query data"""
+        page = query_data.get("page")
+
+        if page == ["first"]:
+            return rsm.RSMRequest(max_=PAGE_SIZE, before="")
+        elif page == ["last"]:
+            return rsm.RSMRequest(max_=PAGE_SIZE)
+        else:
+            for query_key in ("index", "before", "after"):
+                try:
+                    kwargs={query_key: query_data[query_key][0], "max_": PAGE_SIZE}
+                except (KeyError, IndexError, ValueError):
+                    pass
+                else:
+                    return rsm.RSMRequest(**kwargs)
+        raise ValueError(f"Invalid query data: {query_data!r}")
+
+    async def APOutboxPageRequest(
+        self,
+        request: "HTTPRequest",
+        account_jid: jid.JID,
+        node: Optional[str],
+        ap_account: str,
+        actor_url: str,
+        query_data: Dict[str, List[str]]
+    ) -> dict:
+        # we only keep useful keys, and sort to have consistent URL which can
+        # be used as ID
+        url_keys = sorted(set(query_data) & {"page", "index", "before", "after"})
+        query_data = {k: query_data[k] for k in url_keys}
+        rsm_kwargs = self.queryData2RSMRequest(query_data)
+        try:
+            items, metadata = await self.apg._p.getItems(
+                client=self.apg.client,
+                service=account_jid,
+                node=node,
+                rsm_request=self.queryData2RSMRequest(query_data),
+                extra = {C.KEY_USE_CACHE: False}
+            )
+        except error.StanzaError as e:
+            log.warning(f"Can't get data from pubsub node {node} at {account_jid}: {e}")
+            return {}
+
+        base_url = self.getCanonicalURL(request)
+        url = f"{base_url}?{parse.urlencode(query_data, True)}"
+        data = {
+            "@context": "https://www.w3.org/ns/activitystreams",
+            "id": url,
+            "type": "OrderedCollectionPage",
+            "partOf": base_url,
+            "orderedItems" : [
+                await self.apg.mbdata2APitem(
+                    self.apg.client,
+                    await self.apg._m.item2mbdata(
+                        self.apg.client,
+                        item,
+                        account_jid,
+                        node
+                    )
+                )
+                for item in reversed(items)
+            ]
+        }
+
+        # AP OrderedCollection must be in reversed chronological order, thus the opposite
+        # of what we get with RSM (at least with Libervia Pubsub)
+        if not metadata["complete"]:
+            try:
+                last= metadata["rsm"]["last"]
+            except KeyError:
+                last = None
+            data["prev"] = f"{base_url}?{parse.urlencode({'after': last})}"
+        if metadata["rsm"]["index"] != 0:
+            try:
+                first= metadata["rsm"]["first"]
+            except KeyError:
+                first = None
+            data["next"] = f"{base_url}?{parse.urlencode({'before': first})}"
+
+        return data
+
+    async def APOutboxRequest(
+        self,
+        request: "HTTPRequest",
+        account_jid: jid.JID,
+        node: Optional[str],
+        ap_account: str,
+        actor_url: str
+    ) -> dict:
+        if node is None:
+            node = self.apg._m.namespace
+
+        parsed_url = parse.urlparse(request.uri.decode())
+        query_data = parse.parse_qs(parsed_url.query)
+        if query_data:
+            return await self.APOutboxPageRequest(
+                request, account_jid, node, ap_account, actor_url, query_data
+            )
+
+        # XXX: we can't use disco#info here because this request won't work on a bare jid
+        # due to security considerations of XEP-0030 (we don't have presence
+        # subscription).
+        # The current workaround is to do a request as if RSM was available, and actually
+        # check its availability according to result.
+        try:
+            __, metadata = await self.apg._p.getItems(
+                client=self.apg.client,
+                service=account_jid,
+                node=node,
+                max_items=0,
+                rsm_request=rsm.RSMRequest(max_=0)
+            )
+        except error.StanzaError as e:
+            log.warning(f"Can't get data from pubsub node {node} at {account_jid}: {e}")
+            return {}
+        try:
+            items_count = metadata["rsm"]["count"]
+        except KeyError:
+            log.warning(
+                f"No RSM metadata found when requesting pubsub node {node} at "
+                f"{account_jid}, defaulting to items_count=20"
+            )
+            items_count = 20
+
+        url = self.getCanonicalURL(request)
+        url_first_page = f"{url}?{parse.urlencode({'page': 'first'})}"
+        url_last_page = f"{url}?{parse.urlencode({'page': 'last'})}"
+        return {
+            "@context": "https://www.w3.org/ns/activitystreams",
+            "id": url,
+            "totalItems": items_count,
+            "type": "OrderedCollection",
+            "first": url_first_page,
+            "last": url_last_page,
+        }
+
+    async def APRequest(self, request):
+        path = request.path.decode()
+        actor_url = parse.urljoin(
+            f"https://{self.apg.public_url}",
+            path
+        )
+        request_type, ap_account = self.apg.parseAPURL(actor_url)
+        account_jid, node = await self.apg.getJIDAndNode(ap_account)
+        if request_type not in AP_REQUEST_TYPES:
+            raise exceptions.DataError(f"Invalid request type: {request_type!r}")
+        method = getattr(self, f"AP{request_type.title()}Request")
+        ret_data = await method(request, account_jid, node, ap_account, actor_url)
         request.setHeader("content-type", CONTENT_TYPE_AP)
-        return json.dumps(actor).encode()
+        request.write(json.dumps(ret_data).encode())
+        request.finish()
+
+    def render(self, request):
+        request.setHeader("server", VERSION)
+        return super().render(request)
 
     def render_GET(self, request):
         path = request.path.decode().lstrip("/")
         if path.startswith(".well-known/webfinger"):
-            return self.webfinger(request)
+            defer.ensureDeferred(self.webfinger(request))
+            return server.NOT_DONE_YET
         elif path.startswith(self.apg.ap_path):
-            return self.APRequest(request)
+            defer.ensureDeferred(self.APRequest(request))
+            return server.NOT_DONE_YET
+
         return web_resource.NoResource().render(request)
 
 
@@ -157,6 +357,8 @@
     def __init__(self, host):
         self.host = host
         self.initialised = False
+        self._m = host.plugins["XEP-0277"]
+        self._p = host.plugins["XEP-0060"]
 
         host.bridge.addMethod(
             "APSend",
@@ -167,6 +369,9 @@
             async_=True,
         )
 
+    def getHandler(self, __):
+        return APPubsubService(self)
+
     async def init(self, client):
         if self.initialised:
             return
@@ -204,7 +409,8 @@
             format=serialization.PublicFormat.SubjectPublicKeyInfo
         ).decode()
 
-        # params (URL and port)
+        # params
+        # URL and port
         self.public_url = self.host.memory.getConfig(
             CONF_SECTION, "public_url"
         ) or self.host.memory.getConfig(
@@ -232,8 +438,16 @@
                 'bad ap-gateay http_connection_type, you must use one of "http" or '
                 '"https"'
             )
+        self.max_items = self.host.memory.getConfig(
+            CONF_SECTION, 'new_node_max_items', 50
+
+        )
         self.ap_path = self.host.memory.getConfig(CONF_SECTION, 'ap_path', '_ap')
         self.base_ap_url = parse.urljoin(f"https://{self.public_url}", f"{self.ap_path}/")
+        # True (default) if we provide gateway only to entities/services from our server
+        self.local_only = C.bool(
+            self.host.memory.getConfig(CONF_SECTION, 'local_only', C.BOOL_TRUE)
+        )
 
         # HTTP server launch
         self.server = HTTPServer(self)
@@ -247,8 +461,202 @@
             reactor.listenSSL(self.http_port, self.server, context_factory)
 
     async def profileConnecting(self, client):
+        self.client = client
         await self.init(client)
 
+    async def apGet(self, url: str) -> dict:
+        """Retrieve AP JSON from given URL
+
+        @raise error.StanzaError: "service-unavailable" is sent when something went wrong
+            with AP server
+        """
+        try:
+            return await treq.json_content(await treq.get(
+                url,
+                headers = {
+                    "Accept": [MEDIA_TYPE_AP],
+                    "Content-Type": [MEDIA_TYPE_AP],
+                }
+            ))
+        except Exception as e:
+            raise error.StanzaError(
+                "service-unavailable",
+                text=f"Can't get AP data at {url}: {e}"
+            )
+
+    def mustEncode(self, text: str) -> bool:
+        """Indicate if a text must be period encoded"""
+        return (
+            not RE_ALLOWED_UNQUOTED.match(text)
+            or text.startswith("___")
+            or "---" in text
+        )
+
+    def periodEncode(self, text: str) -> str:
+        """Period encode a text
+
+        see [getJIDAndNode] for reasons of period encoding
+        """
+        return (
+            parse.quote(text, safe="")
+            .replace("---", "%2d%2d%2d")
+            .replace("___", "%5f%5f%5f")
+            .replace(".", "%2e")
+            .replace("~", "%7e")
+            .replace("%", ".")
+        )
+
+    async def getAPAccountFromJidAndNode(
+        self,
+        jid_: jid.JID,
+        node: Optional[str]
+    ) -> str:
+        """Construct AP account from JID and node
+
+        The account construction will use escaping when necessary
+        """
+        if not node or node == self._m.namespace:
+            node = None
+
+        if node and not jid_.user and not self.mustEncode(node):
+            is_pubsub = self.isPubsub(jid_)
+            # when we have a pubsub service, the user part can be used to set the node
+            # this produces more user-friendly AP accounts
+            if is_pubsub:
+                jid_.user = node
+                node = None
+
+        is_local = self.isLocal(jid_)
+        user = jid_.user if is_local else jid_.userhost()
+        if user is None:
+            user = ""
+        account_elts = []
+        if node and self.mustEncode(node) or self.mustEncode(user):
+            account_elts = ["___"]
+            if node:
+                node = self.periodEncode(node)
+            user = self.periodEncode(user)
+
+        if not user:
+            raise exceptions.InternalError("there should be a user part")
+
+        if node:
+            account_elts.extend((node, "---"))
+
+        account_elts.extend((
+            user, "@", jid_.host if is_local else self.client.jid.userhost()
+        ))
+        return "".join(account_elts)
+
+    def isLocal(self, jid_: jid.JID) -> bool:
+        """Returns True if jid_ use a domain or subdomain of gateway's host"""
+        local_host = self.client.host.split(".")
+        assert local_host
+        return jid_.host.split(".")[-len(local_host):] == local_host
+
+    async def isPubsub(self, jid_: jid.JID) -> bool:
+        """Indicate if a JID is a Pubsub service"""
+        host_disco = await self.host.getDiscoInfos(self.client, jid_)
+        return (
+            ("pubsub", "service") in host_disco.identities
+            and not ("pubsub", "pep") in host_disco.identities
+        )
+
+    async def getJIDAndNode(self, ap_account: str) -> Tuple[jid.JID, Optional[str]]:
+        """Decode raw AP account handle to get XMPP JID and Pubsub Node
+
+        Username are case insensitive.
+
+        By default, the username correspond to local username (i.e. username from
+        component's server).
+
+        If local name's domain is a pubsub service (and not PEP), the username is taken as
+        a pubsub node.
+
+        If ``---`` is present in username, the part before is used as pubsub node, and the
+        rest as a JID user part.
+
+        If username starts with ``___``, characters are encoded using period encoding
+        (i.e. percent encoding where a ``.`` is used instead of ``%``).
+
+        This horror is necessary due to limitation in some AP implementation (notably
+        Mastodon), cf. https://github.com/mastodon/mastodon/issues/17222
+
+        examples::
+
+        ``toto@example.org`` => JID = toto@example.org, node = None
+
+        ``___toto.40example.net@example.org`` => JID = toto@example.net (this one is a non-local JID, and will work only if setings ``local_only`` is False), node = None
+
+        ``toto@pubsub.example.org`` (with pubsub.example.org being a pubsub service) =>
+        JID = pubsub.example.org, node = toto
+
+        ``tata---toto@example.org`` => JID = toto@example.org, node = tata
+
+        ``___urn.3axmpp.3a.microblog.3a0@pubsub.example.org`` (with pubsub.example.org
+        being a pubsub service) ==> JID = pubsub.example.org, node = urn:xmpp:microblog:0
+
+        @param ap_account: ActivityPub account handle (``username@domain.tld``)
+        @return: service JID and pubsub node
+            if pubsub is None, default microblog pubsub node (and possibly other nodes
+            that plugins may hanlde) will be used
+        @raise ValueError: invalid account
+        @raise PermissionError: non local jid is used when gateway doesn't allow them
+        """
+        if ap_account.count("@") != 1:
+            raise ValueError("Invalid AP account")
+        if ap_account.startswith("___"):
+            encoded = True
+            ap_account = ap_account[3:]
+        else:
+            encoded = False
+
+        username, domain = ap_account.split("@")
+
+        if "---" in username:
+            node, username = username.rsplit("---", 1)
+        else:
+            node = None
+
+        if encoded:
+            username = parse.unquote(
+                RE_PERIOD_ENC.sub(r"%\g<hex>", username),
+                errors="strict"
+            )
+            if node:
+                node = parse.unquote(
+                    RE_PERIOD_ENC.sub(r"%\g<hex>", node),
+                    errors="strict"
+                )
+
+        if "@" in username:
+            username, domain = username.rsplit("@", 1)
+
+        if not node:
+            # we need to check host disco, because disco request to user may be
+            # blocked for privacy reason (see
+            # https://xmpp.org/extensions/xep-0030.html#security)
+            is_pubsub = await self.isPubsub(jid.JID(domain))
+
+            if is_pubsub:
+                # if the host is a pubsub service and not a PEP, we consider that username
+                # is in fact the node name
+                node = username
+                username = None
+
+        jid_s = f"{username}@{domain}" if username else domain
+        try:
+            jid_ = jid.JID(jid_s)
+        except RuntimeError:
+            raise ValueError(f"Invalid jid: {jid_s!r}")
+
+        if self.local_only and not self.isLocal(jid_):
+            raise exceptions.PermissionError(
+                "This gateway is configured to map only local entities and services"
+            )
+
+        return jid_, node
+
     def parseAPURL(self, url: str) -> Tuple[str, str]:
         """Parse an URL leading to an AP endpoint
 
@@ -313,10 +721,11 @@
         client = self.host.getClient(profile)
         return defer.ensureDeferred(self.publishMessage(client, mess_data, service))
 
-    async def getAPActorData(self, account: str) -> dict:
-        """Retrieve ActivityPub Actor data
+    async def getAPActorIdFromAccount(self, account: str) -> str:
+        """Retrieve account ID from it's handle using WebFinger
 
-        @param account: ActivityPub Actor identifier
+        @param account: AP handle (user@domain.tld)
+        @return: Actor ID (which is an URL)
         """
         if account.count("@") != 1 or "/" in account:
             raise ValueError("Invalid account: {account!r}")
@@ -343,18 +752,337 @@
             raise ValueError(
                 f"No ActivityPub link found for {account!r}"
             )
+        return href
+
+    async def getAPActorDataFromId(self, account: str) -> dict:
+        """Retrieve ActivityPub Actor data
+
+        @param account: ActivityPub Actor identifier
+        """
+        href = await self.getAPActorIdFromAccount(account)
+        return await self.apGet(href)
+
+    @async_lru(maxsize=LRU_MAX_SIZE)
+    async def getAPAccountFromId(self, actor_id: str):
+        """Retrieve AP account from the ID URL
+
+        @param actor_id: AP ID of the actor (URL to the actor data)
+        """
+        url_parsed = parse.urlparse(actor_id)
+        actor_data = await self.apGet(actor_id)
+        username = actor_data.get("preferredUsername")
+        if not username:
+            raise exceptions.DataError(
+                'No "preferredUsername" field found, can\'t retrieve actor account'
+            )
+        account = f"{username}@{url_parsed.hostname}"
+        # we try to retrieve the actor ID from the account to check it
+        found_id = await self.getAPActorIdFromAccount(account)
+        if found_id != actor_id:
+            # cf. https://socialhub.activitypub.rocks/t/how-to-retrieve-user-server-tld-handle-from-actors-url/2196
+            msg = (
+                f"Account ID found on WebFinger {found_id!r} doesn't match our actor ID "
+                f"({actor_id!r}). This AP instance doesn't seems to use "
+                '"preferredUsername" as we expect.'
+            )
+            log.warning(msg)
+            raise exceptions.DataError(msg)
+        return account
+
+    async def getAPItems(
+        self,
+        account: str,
+        max_items: Optional[int] = None,
+        chronological_pagination: bool = True,
+        after_id: Optional[str] = None,
+        start_index: Optional[int] = None,
+    ) -> Tuple[List[domish.Element], rsm.RSMResponse]:
+        """Retrieve AP items and convert them to XMPP items
+
+        @param account: AP account to get items from
+        @param max_items: maximum number of items to retrieve
+            retrieve all items by default
+        @param chronological_pagination: get pages in chronological order
+            AP use reversed chronological order for pagination, "first" page returns more
+            recent items. If "chronological_pagination" is True, "last" AP page will be
+            retrieved first.
+        @param after_id: if set, retrieve items starting from given ID
+            Due to ActivityStream Collection Paging limitations, this is inefficient and
+            if ``after_id`` is not already in cache, we have to retrieve every page until
+            we find it.
+            In most common cases, ``after_id`` should be in cache though (client usually
+            use known ID when in-order pagination is used).
+        @param start_index: start retrieving items from the one with given index
+            Due to ActivityStream Collection Paging limitations, this is inefficient and
+            all pages before the requested index will be retrieved to count items.
+        @return: XMPP Pubsub items and corresponding RSM Response
+            Items are always returned in chronological order in the result
+        """
+        actor_data = await self.getAPActorDataFromId(account)
+        outbox = actor_data.get("outbox")
+        rsm_resp: Dict[str, Union[bool, int]] = {}
+        if not outbox:
+            raise exceptions.DataError(f"No outbox found for actor {account}")
+        outbox_data = await self.apGet(outbox)
         try:
-            ap_actor_data = await treq.json_content(await treq.get(
-                href,
-                headers = {
-                    "Accept": [MEDIA_TYPE_AP],
-                    "Content-Type": [MEDIA_TYPE_AP],
-                }
-            ))
-        except Exception as e:
-            raise exceptions.DataError(f"Can't get ActivityPub actor data: {e}")
+            count = outbox_data["totalItems"]
+        except KeyError:
+            log.warning(
+                f'"totalItems" not found in outbox of {account}, defaulting to 20'
+            )
+            count = 20
+        else:
+            log.info(f"{account}'s outbox has {count} item(s)")
+            rsm_resp["count"] = count
+
+        if start_index is not None:
+            assert chronological_pagination and after_id is None
+            if start_index >= count:
+                return [], rsm_resp
+            elif start_index == 0:
+                # this is the default behaviour
+                pass
+            elif start_index > 5000:
+                raise error.StanzaError(
+                    "feature-not-implemented",
+                    text="Maximum limit for previous_index has been reached, this limit"
+                    "is set to avoid DoS"
+                )
+            else:
+                # we'll convert "start_index" to "after_id", thus we need the item just
+                # before "start_index"
+                previous_index = start_index - 1
+                retrieved_items = 0
+                current_page = outbox_data["last"]
+                while retrieved_items < count:
+                    page_data, items = await self.parseAPPage(current_page)
+                    if not items:
+                        log.warning(f"found an empty AP page at {current_page}")
+                        return [], rsm_resp
+                    page_start_idx = retrieved_items
+                    retrieved_items += len(items)
+                    if previous_index <= retrieved_items:
+                        after_id = items[previous_index - page_start_idx]["id"]
+                        break
+                    try:
+                        current_page = page_data["prev"]
+                    except KeyError:
+                        log.warning(
+                            f"missing previous page link at {current_page}: {page_data!r}"
+                        )
+                        raise error.StanzaError(
+                            "service-unavailable",
+                            "Error while retrieving previous page from AP service at "
+                            f"{current_page}"
+                        )
+
+        init_page = "last" if chronological_pagination else "first"
+        page = outbox_data.get(init_page)
+        if not page:
+            raise exceptions.DataError(
+                f"Initial page {init_page!r} not found for outbox {outbox}"
+            )
+        items = []
+        page_items = []
+        retrieved_items = 0
+        found_after_id = False
+
+        while retrieved_items < count:
+            __, page_items = await self.parseAPPage(page)
+            retrieved_items += len(page_items)
+            if after_id is not None and not found_after_id:
+                # if we have an after_id, we ignore all items until the requested one is
+                # found
+                limit_idx = [i["id"] for i in page_items].index(after_id)
+                if limit_idx == -1:
+                    # if "after_id" is not found, we don't add any item from this page
+                    log.debug(f"{after_id!r} not found at {page}, skipping")
+                else:
+                    found_after_id = True
+                    if chronological_pagination:
+                        page_items = page_items[limit_idx+1:]
+                        start_index = retrieved_items - len(page_items) + limit_idx + 1
+                    else:
+                        page_items = page_items[:limit_idx]
+                        start_index = count - (retrieved_items - len(page_items) +
+                                               limit_idx + 1)
+                    items.extend(page_items)
+            else:
+                items.extend(page_items)
+            if max_items is not None and len(items) >= max_items:
+                if chronological_pagination:
+                    items = items[:max_items]
+                else:
+                    items = items[-max_items:]
+                break
+            page = outbox_data.get("prev" if chronological_pagination else "next")
+            if not page:
+                break
+
+        if after_id is not None and not found_after_id:
+            raise error.StanzaError("item-not-found")
+
+        if after_id is None:
+            rsm_resp["index"] = 0 if chronological_pagination else count - len(items)
+
+        if start_index is not None:
+            rsm_resp["index"] = start_index
+        elif after_id is not None:
+            log.warning("Can't determine index of first element")
+        elif chronological_pagination:
+            rsm_resp["index"] = 0
+        else:
+            rsm_resp["index"] = count - len(items)
+        if items:
+            rsm_resp.update({
+                "first": items[0]["id"],
+                "last": items[-1]["id"]
+            })
+
+        return items, rsm.RSMResponse(**rsm_resp)
+
+    async def parseAPPage(self, url: str) -> Tuple[dict, List[domish.Element]]:
+        """Convert AP objects from an AP page to XMPP items
 
-        return ap_actor_data
+        @param url: url linking and AP page
+        @return: page data, pubsub items
+        """
+        page_data = await self.apGet(url)
+        ap_items = page_data.get("orderedItems")
+        if not ap_items:
+            log.warning('No "orderedItems" collection found')
+            return page_data, []
+        items = []
+        # AP Collections are in antichronological order, but we expect chronological in
+        # Pubsub, thus we reverse it
+        for ap_item in reversed(ap_items):
+            try:
+                ap_object, mb_data = await self.apItem2MBdata(ap_item)
+            except (exceptions.DataError, NotImplementedError, error.StanzaError):
+                continue
+
+            item_elt = await self._m.data2entry(
+                self.client, mb_data, ap_object["id"], None, self._m.namespace
+            )
+            item_elt["publisher"] = mb_data["author_jid"].full()
+            items.append(item_elt)
+
+        return page_data, items
+
+    async def apItem2MBdata(self, ap_item: dict) -> Tuple[dict, dict]:
+        """Convert AP item to microblog data
+
+        @return: AP Item's Object and microblog data
+        @raise exceptions.DataError: something is invalid in the AP item
+        @raise NotImplemented: some AP data is not handled yet
+        @raise error.StanzaError: error while contacting the AP server
+        """
+        ap_object = ap_item.get("object")
+        if not ap_object:
+            log.warning(f'No "object" found in AP item {ap_item!r}')
+            raise exceptions.DataError
+        if isinstance(ap_object, str):
+            ap_object = await self.apGet(ap_object)
+        obj_id = ap_object.get("id")
+        if not obj_id:
+            log.warning(f'No "id" found in AP object: {ap_object!r}')
+            raise exceptions.DataError
+        if ap_object.get("inReplyTo") is not None:
+            raise NotImplementedError
+        mb_data = {}
+        for ap_key, mb_key in AP_MB_MAP.items():
+            data = ap_object.get(ap_key)
+            if data is None:
+                continue
+            mb_data[mb_key] = data
+
+        # content
+        try:
+            language, content_xhtml = ap_object["contentMap"].popitem()
+        except (KeyError, AttributeError):
+            try:
+                mb_data["content_xhtml"] = mb_data["content"]
+            except KeyError:
+                log.warning(f"no content found:\n{ap_object!r}")
+                raise exceptions.DataError
+        else:
+            mb_data["language"] = language
+            mb_data["content_xhtml"] = content_xhtml
+
+        # author
+        actor = ap_item.get("actor")
+        if not actor:
+            log.warning(f"no actor associated to object id {obj_id!r}")
+            raise exceptions.DataError
+        elif isinstance(actor, list):
+            # we only keep first item of list as author
+            # TODO: handle multiple actors
+            if len(actor) > 1:
+                log.warning("multiple actors are not managed")
+            actor = actor[0]
+
+        if isinstance(actor, dict):
+            actor = actor.get("id")
+            if not actor:
+                log.warning(f"no actor id found: {actor!r}")
+                raise exceptions.DataError
+
+        if isinstance(actor, str):
+            account = await self.getAPAccountFromId(actor)
+            mb_data["author"] = account.split("@", 1)[0]
+            author_jid = mb_data["author_jid"] = jid.JID(
+                None,
+                (
+                    self.host.plugins["XEP-0106"].escape(account),
+                    self.client.jid.host,
+                    None
+                )
+            )
+        else:
+            log.warning(f"unknown actor type found: {actor!r}")
+            raise exceptions.DataError
+
+        # published/updated
+        for field in ("published", "updated"):
+            value = ap_object.get(field)
+            if not value and field == "updated":
+                value = ap_object.get("published")
+            if value:
+                try:
+                    mb_data[field] = calendar.timegm(
+                        dateutil.parser.parse(str(value)).utctimetuple()
+                    )
+                except dateutil.parser.ParserError as e:
+                    log.warning(f"Can't parse {field!r} field: {e}")
+        return ap_object, mb_data
+
+    async def mbdata2APitem(self, client: SatXMPPEntity, mb_data: dict) -> dict:
+        """Convert Libervia Microblog Data to ActivityPub item"""
+        if not mb_data.get("id"):
+            mb_data["id"] = shortuuid.uuid()
+        if not mb_data.get("author_jid"):
+            mb_data["author_jid"] = client.jid
+        ap_account = await self.getAPAccountFromJidAndNode(
+            jid.JID(mb_data["author_jid"]),
+            None
+        )
+        url_actor = self.buildAPURL(TYPE_ACTOR, ap_account)
+        url_item = self.buildAPURL(TYPE_ITEM, ap_account, mb_data["id"])
+        return {
+            "@context": "https://www.w3.org/ns/activitystreams",
+            "id": url_item,
+            "type": "Create",
+            "actor": url_actor,
+
+            "object": {
+                "id": url_item,
+                "type": "Note",
+                "published": utils.xmpp_date(mb_data["published"]),
+                "attributedTo": url_actor,
+                "content": mb_data.get("content_xhtml") or mb_data["content"],
+                "to": "https://www.w3.org/ns/activitystreams#Public"
+            }
+        }
 
     async def publishMessage(
         self,
@@ -382,34 +1110,114 @@
         if not service.user:
             raise ValueError("service must have a local part")
         account = self.host.plugins["XEP-0106"].unescape(service.user)
-        ap_actor_data = await self.getAPActorData(account)
+        ap_actor_data = await self.getAPActorDataFromId(account)
 
         try:
             inbox_url = ap_actor_data["endpoints"]["sharedInbox"]
         except KeyError:
             raise exceptions.DataError("Can't get ActivityPub actor inbox")
 
-        if not mess_data.get("id"):
-            mess_data["id"] = shortuuid.uuid()
-        url_actor = self.buildAPURL(TYPE_ACTOR, client.jid.userhost())
-        url_item = self.buildAPURL(TYPE_ITEM, client.jid.userhost(), mess_data["id"])
-        now = time.time()
-        item_data = {
-            "@context": "https://www.w3.org/ns/activitystreams",
-            "id": url_item,
-            "type": "Create",
-            "actor": url_actor,
-
-            "object": {
-                "id": url_item,
-                "type": "Note",
-                "published": utils.xmpp_date(now),
-                "attributedTo": url_actor,
-                "inReplyTo": mess_data["node"],
-                "content": mess_data.get("content_xhtml") or mess_data["content"],
-                "to": "https://www.w3.org/ns/activitystreams#Public"
-            }
-        }
+        item_data = await self.mbdata2APitem(client, mess_data)
+        url_actor = item_data["object"]["attributedTo"]
         resp = await self.signAndPost(inbox_url, url_actor, item_data)
         if resp.code != 202:
             raise exceptions.NetworkError(f"unexpected return code: {resp.code}")
+
+
+class APPubsubService(rsm.PubSubService):
+    """Pubsub service for XMPP requests"""
+
+    def __init__(self, apg):
+        super(APPubsubService, self).__init__()
+        self.host = apg.host
+        self.apg = apg
+        self.discoIdentity = {
+            "category": "pubsub",
+            "type": "service",
+            "name": "Libervia ActivityPub Gateway",
+        }
+
+    @ensure_deferred
+    async def publish(self, requestor, service, nodeIdentifier, items):
+        raise NotImplementedError
+
+    @ensure_deferred
+    async def items(
+        self,
+        requestor: jid.JID,
+        service: jid.JID,
+        node: str,
+        maxItems: Optional[int],
+        itemIdentifiers: Optional[List[str]],
+        rsm_req: Optional[rsm.RSMRequest]
+    ) -> List[domish.Element]:
+        if not service.user:
+            return []
+        ap_account = self.host.plugins["XEP-0106"].unescape(service.user)
+        if ap_account.count("@") != 1:
+            log.warning(f"Invalid AP account used by {requestor}: {ap_account!r}")
+            return []
+        if node != self.apg._m.namespace:
+            raise error.StanzaError(
+                "feature-not-implemented",
+                text=f"{VERSION} only supports {self.apg._m.namespace} "
+                "node for now"
+            )
+        if rsm_req is None:
+            if maxItems is None:
+                maxItems = 20
+            kwargs = {
+                "max_items": maxItems,
+                "chronological_pagination": False,
+            }
+        else:
+            if len(
+                [v for v in (rsm_req.after, rsm_req.before, rsm_req.index)
+                 if v is not None]
+            ) > 1:
+                raise error.StanzaError(
+                    "bad-request",
+                    text="You can't use after, before and index at the same time"
+                )
+            kwargs = {"max_items": rsm_req.max}
+            if rsm_req.after is not None:
+                kwargs["after_id"] = rsm_req.after
+            elif rsm_req.before is not None:
+                kwargs["chronological_pagination"] = False
+                if rsm_req.before != "":
+                    kwargs["after_id"] = rsm_req.before
+            elif rsm_req.index is not None:
+                kwargs["start_index"] = rsm_req.index
+
+        log.info(
+            f"No cache found for node {node} at {service} (AP account {ap_account}), "
+            "using Collection Paging to RSM translation"
+        )
+        return await self.apg.getAPItems(ap_account, **kwargs)
+
+    @ensure_deferred
+    async def retract(self, requestor, service, nodeIdentifier, itemIdentifiers):
+        raise NotImplementedError
+
+    def getNodeInfo(
+        self,
+        requestor: jid.JID,
+        service: jid.JID,
+        nodeIdentifier: str,
+        pep: bool = False,
+        recipient: Optional[jid.JID] = None
+    ) -> Optional[dict]:
+        if not nodeIdentifier:
+            return None
+        info = {
+            "type": "leaf",
+            "meta-data": [
+                {"var": "pubsub#persist_items", "type": "boolean", "value": True},
+                {"var": "pubsub#max_items", "value": "max"},
+                {"var": "pubsub#access_model", "type": "list-single", "value": "open"},
+                {"var": "pubsub#publish_model", "type": "list-single", "value": "open"},
+
+            ]
+
+        }
+        return info