local t_unpack = table.unpack; local time_now = os.time; local jid_prep = require "prosody.util.jid".prep; local set = require "prosody.util.set"; local st = require "prosody.util.stanza"; local it = require "prosody.util.iterators"; local uuid_generate = require "prosody.util.uuid".generate; local dataform = require"prosody.util.dataforms".new; local errors = require "prosody.util.error"; local xmlns_pubsub = "http://jabber.org/protocol/pubsub"; local xmlns_pubsub_errors = "http://jabber.org/protocol/pubsub#errors"; local xmlns_pubsub_owner = "http://jabber.org/protocol/pubsub#owner"; local _M = {}; local handlers = {}; _M.handlers = handlers; local pubsub_errors = { ["conflict"] = { "cancel", "conflict" }; ["invalid-jid"] = { "modify", "bad-request", nil, "invalid-jid" }; ["jid-required"] = { "modify", "bad-request", nil, "jid-required" }; ["nodeid-required"] = { "modify", "bad-request", nil, "nodeid-required" }; ["item-not-found"] = { "cancel", "item-not-found" }; ["not-subscribed"] = { "modify", "unexpected-request", nil, "not-subscribed" }; ["invalid-options"] = { "modify", "bad-request", nil, "invalid-options" }; ["forbidden"] = { "auth", "forbidden" }; ["not-allowed"] = { "cancel", "not-allowed" }; ["not-acceptable"] = { "modify", "not-acceptable" }; ["internal-server-error"] = { "wait", "internal-server-error" }; ["precondition-not-met"] = { "cancel", "conflict", nil, "precondition-not-met" }; ["invalid-item"] = { "modify", "bad-request", "invalid item" }; ["persistent-items-unsupported"] = { "cancel", "feature-not-implemented", nil, "persistent-items" }; }; local function pubsub_error_reply(stanza, error) local e = pubsub_errors[error]; if not e and errors.is_err(error) then e = { error.type, error.condition, error.text, error.pubsub_condition }; end local reply = st.error_reply(stanza, t_unpack(e, 1, 3)); if e[4] then reply:tag(e[4], { xmlns = xmlns_pubsub_errors }):up(); end return reply; end _M.pubsub_error_reply = pubsub_error_reply; local function dataform_error_message(err) -- ({ string : string }) -> string? local out = {}; for field, errmsg in pairs(err) do table.insert(out, ("%s: %s"):format(field, errmsg)) end return table.concat(out, "; "); end -- Note: If any config options are added that are of complex types, -- (not simply strings/numbers) then the publish-options code will -- need to be revisited local node_config_form = dataform { { type = "hidden"; var = "FORM_TYPE"; value = "http://jabber.org/protocol/pubsub#node_config"; }; { type = "text-single"; name = "title"; var = "pubsub#title"; label = "Title"; }; { type = "text-single"; name = "description"; var = "pubsub#description"; label = "Description"; }; { type = "text-single"; name = "payload_type"; var = "pubsub#type"; label = "The type of node data, usually specified by the namespace of the payload (if any)"; }; { type = "text-single"; datatype = "pubsub:integer-or-max"; name = "max_items"; range_min = 1; var = "pubsub#max_items"; label = "Max # of items to persist"; }; { type = "boolean"; name = "persist_items"; var = "pubsub#persist_items"; label = "Persist items to storage"; }; { type = "list-single"; name = "access_model"; var = "pubsub#access_model"; label = "Specify the subscriber model"; options = { "authorize", "open", "presence", "roster", "whitelist", }; }; { type = "list-multi"; -- TODO some way to inject options name = "roster_groups_allowed"; var = "pubsub#roster_groups_allowed"; label = "Roster groups allowed to subscribe"; }; { type = "list-single"; name = "publish_model"; var = "pubsub#publish_model"; label = "Specify the publisher model"; options = { "publishers"; "subscribers"; "open"; }; }; { type = "list-single"; var = "pubsub#send_last_published_item"; name = "send_last_published_item"; options = { "never"; "on_sub"; "on_sub_and_presence" }; }; { type = "boolean"; value = true; label = "Whether to deliver event notifications"; name = "notify_items"; var = "pubsub#deliver_notifications"; }; { type = "boolean"; value = true; label = "Whether to deliver payloads with event notifications"; name = "include_payload"; var = "pubsub#deliver_payloads"; }; { type = "list-single"; name = "notification_type"; var = "pubsub#notification_type"; label = "Specify the delivery style for notifications"; options = { { label = "Messages of type normal", value = "normal" }, { label = "Messages of type headline", value = "headline", default = true }, }; }; { type = "boolean"; label = "Whether to notify subscribers when the node is deleted"; name = "notify_delete"; var = "pubsub#notify_delete"; value = true; }; { type = "boolean"; label = "Whether to notify subscribers when items are removed from the node"; name = "notify_retract"; var = "pubsub#notify_retract"; value = true; }; { type = "list-single"; label = "Specify whose JID to include as the publisher of items"; name = "itemreply"; var = "pubsub#itemreply"; options = { { label = "Include the node owner's JID", value = "owner" }; { label = "Include the item publisher's JID", value = "publisher" }; { label = "Don't include any JID with items", value = "none", default = true }; }; }; }; _M.node_config_form = node_config_form; local subscribe_options_form = dataform { { type = "hidden"; var = "FORM_TYPE"; value = "http://jabber.org/protocol/pubsub#subscribe_options"; }; { type = "boolean"; name = "pubsub#include_body"; label = "Receive message body in addition to payload?"; }; }; _M.subscribe_options_form = subscribe_options_form; local node_metadata_form = dataform { { type = "hidden"; var = "FORM_TYPE"; value = "http://jabber.org/protocol/pubsub#meta-data"; }; { type = "text-single"; name = "pubsub#title"; }; { type = "text-single"; name = "pubsub#description"; }; { type = "text-single"; name = "pubsub#type"; }; { type = "text-single"; name = "pubsub#access_model"; }; { type = "text-single"; name = "pubsub#publish_model"; }; }; _M.node_metadata_form = node_metadata_form; local service_method_feature_map = { add_subscription = { "subscribe", "subscription-options" }; create = { "create-nodes", "instant-nodes", "item-ids", "create-and-configure" }; delete = { "delete-nodes" }; get_items = { "retrieve-items" }; get_subscriptions = { "retrieve-subscriptions" }; node_defaults = { "retrieve-default" }; publish = { "publish", "multi-items", "publish-options" }; purge = { "purge-nodes" }; retract = { "delete-items", "retract-items" }; set_node_config = { "config-node", "meta-data" }; set_affiliation = { "modify-affiliations" }; }; local service_config_feature_map = { autocreate_on_publish = { "auto-create" }; }; function _M.get_feature_set(service) local supported_features = set.new(); for method, features in pairs(service_method_feature_map) do if service[method] then for _, feature in ipairs(features) do if feature then supported_features:add(feature); end end end end for option, features in pairs(service_config_feature_map) do if service.config[option] then for _, feature in ipairs(features) do if feature then supported_features:add(feature); end end end end for affiliation in pairs(service.config.capabilities) do if affiliation ~= "none" and affiliation ~= "owner" then supported_features:add(affiliation.."-affiliation"); end end if service.node_defaults.access_model then supported_features:add("access-"..service.node_defaults.access_model); end if service.node_defaults.send_last_published_item ~= "never" then supported_features:add("last-published"); end if rawget(service.config, "itemstore") and rawget(service.config, "nodestore") then supported_features:add("persistent-items"); end if true --[[ node_metadata_form[max_items].datatype == "pubsub:integer-or-max" ]] then supported_features:add("config-node-max"); end return supported_features; end function _M.handle_disco_info_node(event, service) local stanza, reply, node = event.stanza, event.reply, event.node; local ok, ret = service:get_nodes(stanza.attr.from); if not ok then event.origin.send(pubsub_error_reply(stanza, ret)); return true; end local node_obj = ret[node]; if not node_obj then event.origin.send(pubsub_error_reply(stanza, "item-not-found")); return true; end event.exists = true; reply:tag("identity", { category = "pubsub", type = "leaf" }):up(); if node_obj.config then reply:add_child(node_metadata_form:form({ ["pubsub#title"] = node_obj.config.title; ["pubsub#description"] = node_obj.config.description; ["pubsub#type"] = node_obj.config.payload_type; ["pubsub#access_model"] = node_obj.config.access_model; ["pubsub#publish_model"] = node_obj.config.publish_model; }, "result")); end end function _M.handle_disco_items_node(event, service) local stanza, reply, node = event.stanza, event.reply, event.node; local ok, ret = service:get_items(node, stanza.attr.from); if not ok then event.origin.send(pubsub_error_reply(stanza, ret)); return true; end for _, id in ipairs(ret) do reply:tag("item", { jid = service.config.jid or module.host, name = id }):up(); end event.exists = true; end function _M.handle_pubsub_iq(event, service) local origin, stanza = event.origin, event.stanza; local pubsub_tag = stanza.tags[1]; local action = pubsub_tag.tags[1]; if not action then return origin.send(st.error_reply(stanza, "cancel", "bad-request")); end local prefix = ""; if pubsub_tag.attr.xmlns == xmlns_pubsub_owner then prefix = "owner_"; end local handler = handlers[prefix..stanza.attr.type.."_"..action.name]; if handler then handler(origin, stanza, action, service); return true; end end function handlers.get_items(origin, stanza, items, service) local node = items.attr.node; local requested_items = {}; for item in items:childtags("item") do table.insert(requested_items, item.attr.id); end if requested_items[1] == nil then requested_items = nil; end if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end local node_obj = service.nodes[node]; if not node_obj then origin.send(pubsub_error_reply(stanza, "item-not-found")); return true; end local resultspec; -- TODO rsm.get() if items.attr.max_items then resultspec = { max = tonumber(items.attr.max_items) }; end local ok, results = service:get_items(node, stanza.attr.from, requested_items, resultspec); if not ok then origin.send(pubsub_error_reply(stanza, results)); return true; end local expose_publisher = service.config.expose_publisher; if expose_publisher == nil and node_obj.config.itemreply == "publisher" then expose_publisher = true; end local data = st.stanza("items", { node = node }); local iter, v, i = ipairs(results); if not requested_items then -- XXX Hack to preserve order of explicitly requested items. iter, v, i = it.reverse(iter, v, i); end for _, id in iter, v, i do local item = results[id]; if not expose_publisher then item = st.clone(item); item.attr.publisher = nil; end data:add_child(item); end local reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :add_child(data); origin.send(reply); return true; end function handlers.get_subscriptions(origin, stanza, subscriptions, service) local node = subscriptions.attr.node; local ok, ret = service:get_subscriptions(node, stanza.attr.from, stanza.attr.from); if not ok then origin.send(pubsub_error_reply(stanza, ret)); return true; end local reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :tag("subscriptions"); for _, sub in ipairs(ret) do reply:tag("subscription", { node = sub.node, jid = sub.jid, subscription = 'subscribed' }):up(); end origin.send(reply); return true; end function handlers.owner_get_subscriptions(origin, stanza, subscriptions, service) local node = subscriptions.attr.node; local ok, ret = service:get_subscriptions(node, stanza.attr.from); if not ok then origin.send(pubsub_error_reply(stanza, ret)); return true; end local reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub_owner }) :tag("subscriptions"); for _, sub in ipairs(ret) do reply:tag("subscription", { node = sub.node, jid = sub.jid, subscription = 'subscribed' }):up(); end origin.send(reply); return true; end function handlers.owner_set_subscriptions(origin, stanza, subscriptions, service) local node = subscriptions.attr.node; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end if not service:may(node, stanza.attr.from, "subscribe_other") then origin.send(pubsub_error_reply(stanza, "forbidden")); return true; end local node_obj = service.nodes[node]; if not node_obj then origin.send(pubsub_error_reply(stanza, "item-not-found")); return true; end for subscription_tag in subscriptions:childtags("subscription") do if subscription_tag.attr.subscription == 'subscribed' then local ok, err = service:add_subscription(node, stanza.attr.from, subscription_tag.attr.jid); if not ok then origin.send(pubsub_error_reply(stanza, err)); return true; end elseif subscription_tag.attr.subscription == 'none' then local ok, err = service:remove_subscription(node, stanza.attr.from, subscription_tag.attr.jid); if not ok then origin.send(pubsub_error_reply(stanza, err)); return true; end end end local reply = st.reply(stanza); origin.send(reply); return true; end function handlers.set_create(origin, stanza, create, service) local node = create.attr.node; local ok, ret, reply; local config; local configure = stanza.tags[1]:get_child("configure"); if configure then local config_form = configure:get_child("x", "jabber:x:data"); if not config_form then origin.send(st.error_reply(stanza, "modify", "bad-request", "Missing dataform")); return true; end local form_data, err = node_config_form:data(config_form); if err then origin.send(st.error_reply(stanza, "modify", "bad-request", dataform_error_message(err))); return true; end config = form_data; end if node then ok, ret = service:create(node, stanza.attr.from, config); if ok then reply = st.reply(stanza); else reply = pubsub_error_reply(stanza, ret); end else repeat node = uuid_generate(); ok, ret = service:create(node, stanza.attr.from, config); until ok or ret ~= "conflict"; if ok then reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :tag("create", { node = node }); else reply = pubsub_error_reply(stanza, ret); end end origin.send(reply); return true; end function handlers.owner_set_delete(origin, stanza, delete, service) local node = delete.attr.node; local reply; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end local ok, ret = service:delete(node, stanza.attr.from); if ok then reply = st.reply(stanza); else reply = pubsub_error_reply(stanza, ret); end origin.send(reply); return true; end function handlers.set_subscribe(origin, stanza, subscribe, service) local node, jid = subscribe.attr.node, subscribe.attr.jid; jid = jid_prep(jid); if not (node and jid) then origin.send(pubsub_error_reply(stanza, jid and "nodeid-required" or "invalid-jid")); return true; end local options_tag, options = stanza.tags[1]:get_child("options"), nil; if options_tag then -- FIXME form parsing errors ignored here, why? local err options, err = subscribe_options_form:data(options_tag.tags[1]); if err then origin.send(st.error_reply(stanza, "modify", "bad-request", dataform_error_message(err))); return true end end local ok, ret = service:add_subscription(node, stanza.attr.from, jid, options); local reply; if ok then reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :tag("subscription", { node = node, jid = jid, subscription = "subscribed" }):up(); if options_tag then reply:add_child(options_tag); end else reply = pubsub_error_reply(stanza, ret); end origin.send(reply); local ok, config = service:get_node_config(node, true); if ok and config.send_last_published_item ~= "never" then local ok, id, item = service:get_last_item(node, jid); if not (ok and id) then return; end service.config.broadcaster("items", node, { [jid] = true }, item); end end function handlers.set_unsubscribe(origin, stanza, unsubscribe, service) local node, jid = unsubscribe.attr.node, unsubscribe.attr.jid; jid = jid_prep(jid); if not (node and jid) then origin.send(pubsub_error_reply(stanza, jid and "nodeid-required" or "invalid-jid")); return true; end local ok, ret = service:remove_subscription(node, stanza.attr.from, jid); local reply; if ok then reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :tag("subscription", { node = node, jid = jid, subscription = "none" }):up(); else reply = pubsub_error_reply(stanza, ret); end origin.send(reply); return true; end function handlers.get_options(origin, stanza, options, service) local node, jid = options.attr.node, options.attr.jid; jid = jid_prep(jid); if not (node and jid) then origin.send(pubsub_error_reply(stanza, jid and "nodeid-required" or "invalid-jid")); return true; end local ok, ret = service:get_subscription(node, stanza.attr.from, jid); if not ok then origin.send(pubsub_error_reply(stanza, "not-subscribed")); return true; end if ret == true then ret = {} end origin.send(st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :tag("options", { node = node, jid = jid }) :add_child(subscribe_options_form:form(ret))); return true; end function handlers.set_options(origin, stanza, options, service) local node, jid = options.attr.node, options.attr.jid; jid = jid_prep(jid); if not (node and jid) then origin.send(pubsub_error_reply(stanza, jid and "nodeid-required" or "invalid-jid")); return true; end local ok, ret = service:get_subscription(node, stanza.attr.from, jid); if not ok then origin.send(pubsub_error_reply(stanza, ret)); return true; elseif not ret then origin.send(pubsub_error_reply(stanza, "not-subscribed")); return true; end local old_subopts = ret; local new_subopts, err = subscribe_options_form:data(options.tags[1], old_subopts); if err then origin.send(st.error_reply(stanza, "modify", "bad-request", dataform_error_message(err))); return true; end local ok, err = service:add_subscription(node, stanza.attr.from, jid, new_subopts); if not ok then origin.send(pubsub_error_reply(stanza, err)); return true; end origin.send(st.reply(stanza)); return true; end function handlers.set_publish(origin, stanza, publish, service) local node = publish.attr.node; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end local required_config = nil; local publish_options = stanza.tags[1]:get_child("publish-options"); if publish_options then -- Ensure that the node configuration matches the values in publish-options local publish_options_form = publish_options:get_child("x", "jabber:x:data"); local err; required_config, err = node_config_form:data(publish_options_form); if err then origin.send(st.error_reply(stanza, "modify", "bad-request", dataform_error_message(err))); return true end end local item = publish:get_child("item"); local id = (item and item.attr.id); if not id then id = uuid_generate(); if item then item.attr.id = id; end end if item then item.attr.publisher = service.config.normalize_jid(stanza.attr.from); end local ok, ret = service:publish(node, stanza.attr.from, id, item, required_config); local reply; if ok then if type(ok) == "string" then id = ok; end reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub }) :tag("publish", { node = node }) :tag("item", { id = id }); else reply = pubsub_error_reply(stanza, ret); end origin.send(reply); return true; end function handlers.set_retract(origin, stanza, retract, service) local node, notify = retract.attr.node, retract.attr.notify; notify = (notify == "1") or (notify == "true"); local id = retract:get_child_attr("item", nil, "id"); if not (node and id) then origin.send(pubsub_error_reply(stanza, node and "item-not-found" or "nodeid-required")); return true; end local reply, notifier; if notify then notifier = st.stanza("retract", { id = id }); end local ok, ret = service:retract(node, stanza.attr.from, id, notifier); if ok then reply = st.reply(stanza); else reply = pubsub_error_reply(stanza, ret); end origin.send(reply); return true; end function handlers.owner_set_purge(origin, stanza, purge, service) local node = purge.attr.node; local reply; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end local ok, ret = service:purge(node, stanza.attr.from, true); if ok then reply = st.reply(stanza); else reply = pubsub_error_reply(stanza, ret); end origin.send(reply); return true; end function handlers.owner_get_configure(origin, stanza, config, service) local node = config.attr.node; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end local ok, node_config = service:get_node_config(node, stanza.attr.from); if not ok then origin.send(pubsub_error_reply(stanza, node_config)); return true; end local reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub_owner }) :tag("configure", { node = node }) :add_child(node_config_form:form(node_config)); origin.send(reply); return true; end function handlers.owner_set_configure(origin, stanza, config, service) local node = config.attr.node; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end if not service:may(node, stanza.attr.from, "configure") then origin.send(pubsub_error_reply(stanza, "forbidden")); return true; end local config_form = config:get_child("x", "jabber:x:data"); if not config_form then origin.send(st.error_reply(stanza, "modify", "bad-request", "Missing dataform")); return true; end local ok, old_config = service:get_node_config(node, stanza.attr.from); if not ok then origin.send(pubsub_error_reply(stanza, old_config)); return true; end local new_config, err = node_config_form:data(config_form, old_config); if err then origin.send(st.error_reply(stanza, "modify", "bad-request", dataform_error_message(err))); return true; end local ok, err = service:set_node_config(node, stanza.attr.from, new_config); if not ok then origin.send(pubsub_error_reply(stanza, err)); return true; end origin.send(st.reply(stanza)); return true; end function handlers.owner_get_default(origin, stanza, default, service) -- luacheck: ignore 212/default local reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub_owner }) :tag("default") :add_child(node_config_form:form(service.node_defaults)); origin.send(reply); return true; end function handlers.owner_get_affiliations(origin, stanza, affiliations, service) local node = affiliations.attr.node; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end if not service:may(node, stanza.attr.from, "set_affiliation") then origin.send(pubsub_error_reply(stanza, "forbidden")); return true; end local node_obj = service.nodes[node]; if not node_obj then origin.send(pubsub_error_reply(stanza, "item-not-found")); return true; end local reply = st.reply(stanza) :tag("pubsub", { xmlns = xmlns_pubsub_owner }) :tag("affiliations", { node = node }); for jid, affiliation in pairs(node_obj.affiliations) do reply:tag("affiliation", { jid = jid, affiliation = affiliation }):up(); end origin.send(reply); return true; end function handlers.owner_set_affiliations(origin, stanza, affiliations, service) local node = affiliations.attr.node; if not node then origin.send(pubsub_error_reply(stanza, "nodeid-required")); return true; end if not service:may(node, stanza.attr.from, "set_affiliation") then origin.send(pubsub_error_reply(stanza, "forbidden")); return true; end local node_obj = service.nodes[node]; if not node_obj then origin.send(pubsub_error_reply(stanza, "item-not-found")); return true; end for affiliation_tag in affiliations:childtags("affiliation") do local jid = affiliation_tag.attr.jid; local affiliation = affiliation_tag.attr.affiliation; jid = jid_prep(jid); if affiliation == "none" then affiliation = nil; end local ok, err = service:set_affiliation(node, stanza.attr.from, jid, affiliation); if not ok then -- FIXME Incomplete error handling, -- see XEP 60 8.9.2.4 Multiple Simultaneous Modifications origin.send(pubsub_error_reply(stanza, err)); return true; end end local reply = st.reply(stanza); origin.send(reply); return true; end local function create_encapsulating_item(id, payload, publisher) local item = st.stanza("item", { id = id, publisher = publisher, xmlns = xmlns_pubsub }); item:add_child(payload); return item; end local function archive_itemstore(archive, max_items, user, node) module:log("debug", "Creation of archive itemstore for node %s with limit %d", node, max_items); local get_set = {}; function get_set:items() -- luacheck: ignore 212/self local data, err = archive:find(user, { limit = tonumber(max_items); reverse = true; }); if not data then module:log("error", "Unable to get items: %s", err); return true; end module:log("debug", "Listed items %s", data); return function() -- luacheck: ignore 211/when local id, payload, when, publisher = data(); if id == nil then return; end local item = create_encapsulating_item(id, payload, publisher); return id, item; end; end function get_set:get(key) -- luacheck: ignore 212/self local data, err = archive:find(user, { key = key; -- Get the last item with that key, if the archive doesn't deduplicate reverse = true, limit = 1; }); if not data then module:log("error", "Unable to get item: %s", err); return nil, err; end local id, payload, when, publisher = data(); module:log("debug", "Get item %s (published at %s by %s)", id, when, publisher); if id == nil then return nil; end return create_encapsulating_item(id, payload, publisher); end function get_set:set(key, value) -- luacheck: ignore 212/self local data, err; if value ~= nil then local publisher = value.attr.publisher; local payload = value.tags[1]; data, err = archive:append(user, key, payload, time_now(), publisher); else data, err = archive:delete(user, { key = key; }); end -- TODO archive support for maintaining maximum items archive:delete(user, { truncate = max_items; }); if not data then module:log("error", "Unable to set item: %s", err); return nil, err; end return data; end function get_set:clear() -- luacheck: ignore 212/self return archive:delete(user); end function get_set:resize(size) -- luacheck: ignore 212/self max_items = size; return archive:delete(user, { truncate = size; }); end function get_set:head() -- This should conveniently return the most recent item local item = self:get(nil); if item then return item.attr.id, item; end end return get_set; end _M.archive_itemstore = archive_itemstore; return _M;