1 files changed, 245 insertions, 0 deletions
diff --git a/util/pubsub.lua b/util/pubsub.lua
new file mode 100644
index 00000000..1363bcb5
--- /dev/null
+++ b/util/pubsub.lua
@@ -0,0 +1,245 @@
+module("pubsub", package.seeall);
+
+local service = {};
+local service_mt = { __index = service };
+
+local default_config = {
+	broadcaster = function () end;
+	get_affiliation = function () end;
+	capabilities = {};
+};
+
+function new(config)
+	config = config or {};
+	return setmetatable({
+		config = setmetatable(config, { __index = default_config });
+		affiliations = {};
+		nodes = {};
+	}, service_mt);
+end
+
+function service:may(node, actor, action)
+	if actor == true then return true; end
+	
+	
+	local node_obj = self.nodes[node];
+	local node_aff = node_obj and node_obj.affiliations[actor];
+	local service_aff = self.affiliations[actor]
+	                 or self.config.get_affiliation(actor, node, action)
+	                 or "none";
+	
+	local node_capabilities = node_obj and node_obj.capabilities;
+	local service_capabilities = self.config.capabilities;
+	
+	-- Check if node allows/forbids it	
+	if node_capabilities then
+		local caps = node_capabilities[node_aff or service_aff];
+		if caps then
+			local can = caps[action];
+			if can ~= nil then
+				return can;
+			end
+		end
+	end
+	-- Check service-wide capabilities instead
+	local caps = service_capabilities[node_aff or service_aff];
+	if caps then
+		local can = caps[action];
+		if can ~= nil then
+			return can;
+		end
+	end
+	
+	return false;
+end
+
+function service:set_affiliation(node, actor, jid, affiliation)
+	-- Access checking
+	if not self:may(node, actor, "set_affiliation") then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if not node_obj then
+		return false, "item-not-found";
+	end
+	node_obj.affiliations[jid] = affiliation;
+	local _, jid_sub = self:get_subscription(node, nil, jid);
+	if not jid_sub and not self:may(node, jid, "be_unsubscribed") then
+		local ok, err = self:add_subscription(node, nil, jid);
+		if not ok then
+			return ok, err;
+		end
+	elseif jid_sub and not self:may(node, jid, "be_subscribed") then
+		local ok, err = self:add_subscription(node, nil, jid);
+		if not ok then
+			return ok, err;
+		end
+	end
+	return true;
+end
+
+function service:add_subscription(node, actor, jid, options)
+	-- Access checking
+	local cap;
+	if jid == actor or self.config.jids_equal(actor, jid) then
+		cap = "subscribe";
+	else
+		cap = "subscribe_other";
+	end
+	if not self:may(node, actor, cap) then
+		return false, "forbidden";
+	end
+	if not self:may(node, jid, "be_subscribed") then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if not node_obj then
+		if not self.config.autocreate_on_subscribe then
+			return false, "item-not-found";
+		else
+			local ok, err = self:create(node, actor);
+			if not ok then
+				return ok, err;
+			end
+		end
+	end
+	node_obj.subscribers[jid] = options or true;
+	return true;
+end
+
+function service:remove_subscription(node, actor, jid)
+	-- Access checking
+	local cap;
+	if jid == actor or self.config.jids_equal(actor, jid) then
+		cap = "unsubscribe";
+	else
+		cap = "unsubscribe_other";
+	end
+	if not self:may(node, actor, cap) then
+		return false, "forbidden";
+	end
+	if not self:may(node, jid, "be_unsubscribed") then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if not node_obj then
+		return false, "item-not-found";
+	end
+	if not node_obj.subscribers[jid] then
+		return false, "not-subscribed";
+	end
+	node_obj.subscribers[jid] = nil;
+	return true;
+end
+
+function service:get_subscription(node, actor, jid)
+	-- Access checking
+	local cap;
+	if jid == actor or self.config.jids_equal(actor, jid) then
+		cap = "get_subscription";
+	else
+		cap = "get_subscription_other";
+	end
+	if not self:may(node, actor, cap) then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if node_obj then
+		return true, node_obj.subscribers[jid];
+	end
+end
+
+function service:create(node, actor)
+	-- Access checking
+	if not self:may(node, actor, "create") then
+		return false, "forbidden";
+	end
+	--
+	if self.nodes[node] then
+		return false, "conflict";
+	end
+	
+	self.nodes[node] = {
+		name = node;
+		subscribers = {};
+		config = {};
+		data = {};
+		affiliations = {};
+	};
+	local ok, err = self:set_affiliation(node, true, actor, "owner");
+	if not ok then
+		self.nodes[node] = nil;
+	end
+	return ok, err;
+end
+
+function service:publish(node, actor, id, item)
+	-- Access checking
+	if not self:may(node, actor, "publish") then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if not node_obj then
+		if not self.config.autocreate_on_publish then
+			return false, "item-not-found";
+		end
+		local ok, err = self:create(node, actor);
+		if not ok then
+			return ok, err;
+		end
+		node_obj = self.nodes[node];
+	end
+	node_obj.data[id] = item;
+	self.config.broadcaster(node, node_obj.subscribers, item);
+	return true;
+end
+
+function service:retract(node, actor, id, retract)
+	-- Access checking
+	if not self:may(node, actor, "retract") then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if (not node_obj) or (not node_obj.data[id]) then
+		return false, "item-not-found";
+	end
+	node_obj.data[id] = nil;
+	if retract then
+		self.config.broadcaster(node, node_obj.subscribers, retract);
+	end
+	return true
+end
+
+function service:get_items(node, actor, id)
+	-- Access checking
+	if not self:may(node, actor, "get_items") then
+		return false, "forbidden";
+	end
+	--
+	local node_obj = self.nodes[node];
+	if not node_obj then
+		return false, "item-not-found";
+	end
+	if id then -- Restrict results to a single specific item
+		return true, { node_obj.data[id] };
+	else
+		return true, node_obj.data;
+	end
+end
+
+function service:get_nodes(actor)
+	-- Access checking
+	if not self:may(nil, actor, "get_nodes") then
+		return false, "forbidden";
+	end
+	--
+	return true, self.nodes;
+end
+
+return _M;