Cookie Session

Library for managing a moderately sized sessions inside secure signed encrypted cookies.

Typical usage

Take a look at examples.

A typical use case for Cowboy Web server:

handle(Req, State) ->

  % session params
  SessionOpts = {
      <<"s">>,    % cookie name
      <<"FOO">>,  % cipher secret
      1000,       % session time-to-live in seconds, older sessions are expired
      <<"/">>     % cookie path
    },

  % get previous session
  {Session, Req2} = cowboy_cookie_session:get_session(SessionOpts, Req),

  % do the job
  % ...
  {Status, Headers, Body, Req3} = {200, [], <<"OK">>, Req2},

  % set new session
  Req4 = case KeepSession of
      true ->
        Session2 = {foo, bar},
        cowboy_cookie_session:set_session(Session2, SessionOpts, Req3);
      false ->
        cowboy_cookie_session:set_session(undefined, SessionOpts, Req3)
    end,

  % respond
  {ok, Req5} = cowboy_req:reply(Status, Headers, Body, Req4),
  {ok, Req5, State}.

Cowboy middleware

A Cowboy middleware is also provided here.

Protocol options passed to cowboy:start_http/4 should contain:

  ...

  % middleware
  {middlewares, [
      cowboy_router,
      cowboy_cookie_session,
      cowboy_handler]},

  % environment
  {env, [

    % session parameters
    {session_opts, {
        <<"sid">>,       % cookie name
        <<"tOpcekpet">>, % encryption secret
        1000,            % cookie time-to-live in seconds
        <<"/">>}},       % cookie path
    ...

Then in the handler:

init(_Transport, Req, Opts) ->

  % get previous session
  {session, Session, SessionOpts} = lists:keyfind(session, 1, Opts),
  {ok, Req, {Session, SessionOpts}}.

handle(Req, {Session, SessionOpts} = State) ->

  % do the job
  % ...
  {Status, Headers, Body, Req2} = {200, [], <<"OK">>, Req},

  % mangle the session
  Session2 = [{foo, bar} | Session],

  % set new session
  Req3 = cowboy_cookie_session:set_session(Session2, SessionOpts, Req2},

  % respond
  {ok, Req4} = cowboy_req:reply(Status, Headers, Body, Req3),
  {ok, Req4, State}.

Elli middleware

An Elli middleware is also provided here. Note, that Elli doesn't provide cookie management means per se, and you'll need to depend on elli_cookie.

% session params
SessionOpts = {
    <<"s">>,    % cookie name
    <<"FOO">>,  % cipher secret
    1000,       % session time-to-live in seconds, older sessions are expired
    <<"/">>     % cookie path
  },

% specify middleware layers
Middleware = [{mods, [
  % cookie session
  {elli_cookie_session, SessionOpts},
  ...
]}],

% start server
elli:start_link([
  {callback, elli_middleware},
  {callback_args, Middleware},
  ...
]).

Then in the handler:

handle(Req = #req{args = Args}, _Args) ->

  % get previous session
  {session, Session} = lists:keyfind(session, 1, Args),

  % do the job
  % ...
  {Status, Headers, Body} = {200, [], <<"OK">>},

  % mangle the session
  Session2 = [{foo, bar} | Session],

  % set new session
  % NB: special return for honoring session
  {with_session, Status, Headers, Body, Session2}.

License

Copyright (c) 2013 Vladimir Dronnikov dronnikov@gmail.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.