Merge pull request #493 from kenr707/postgres-sessions

merged, thanks

src/boss/session_adapters/boss_session_adapter_pgsql.erl

@@ -0,0 +1,114 @@
+-module(boss_session_adapter_pgsql).
+-behaviour(boss_session_adapter).
+-export([start/0, start/1, stop/1, init/1]).
+
+-export([session_exists/2, create_session/3, lookup_session/2]).
+-export([lookup_session_value/3, set_session_value/4, delete_session/2, delete_session_value/3]).
+
+-record(conn, {
+        prefix,
+        exp_time
+    }).
+
+start() ->
+    start([]).
+
+start(_Options) ->
+    {ok, #conn{ prefix = sess }}.
+
+stop(_Conn) ->
+    ok.
+
+init(_Options) ->
+    error_logger:info_msg("Starting distributed session Postgresql storage~n"),
+
+    %% Do we have a session table?  If not, create it.
+    case boss_db:table_exists(boss_session) of
+        false ->
+	    {ok, _, _} = boss_db:execute("CREATE TABLE boss_session (id VARCHAR NOT NULL PRIMARY KEY,"
+					 " data HSTORE);");
+        _ ->
+            noop
+    end.
+
+session_exists(_, SessionID) ->
+    {ok, _, Result} = boss_db:execute("SELECT * FROM boss_session WHERE id=$1;",[SessionID]),
+    Result =/= [].
+
+create_session(_, SessionID, []) ->
+    {ok,_} = boss_db:execute("INSERT INTO boss_session (id) VALUES ($1);",[SessionID]),
+%%% This never gets called with actual data.  If that changes, do something appropriate here
+%%%    ok;
+%%%create_session(_, SessionID, Data) ->
+%%%    {ok,_,_} = boss_db:execute("INSERT INTO boss_session(id,data) VALUES ($1,$2);",[SessionID, encode(Data)]),
+    ok.
+
+lookup_session(_, SessionID) ->
+    recover_data(SessionID).	
+
+lookup_session_value(Conn, SessionID, Key) when is_atom(Key) ->
+    lookup_session_value(Conn, SessionID, atom_to_list(Key));
+lookup_session_value(_, SessionID, Key) when is_list(Key) ->
+    Data = recover_data(SessionID),
+    case proplists:get_value(Key, Data) of
+	undefined -> [];
+	V -> V
+    end.
+
+set_session_value(Conn, Sid, Key, Value) when is_atom(Key) ->
+    set_session_value(Conn, Sid, atom_to_list(Key), Value);
+set_session_value(Conn, Sid, Key, Value) when is_list(Key) ->
+    F = fun(Data) ->
+		Data1 = term_to_binary(Data),
+		Data2 = base64:encode(Data1),
+		Data3 = binary_to_list(Data2),
+		Data3
+	end,
+    delete_session_value(Conn, Sid, Key),
+    case lookup_session(Conn,Sid) of
+	[] ->
+	    {ok,_} = boss_db:execute("UPDATE boss_session SET data='"
+			    ++ Key ++ "=>" ++ F(Value) ++ "'::hstore WHERE id=$1;", [Sid]);
+	_ ->
+	    {ok,_} = boss_db:execute("UPDATE boss_session SET data=data || '"
+			    ++ Key ++ "=>" ++ F(Value) ++ "'::hstore WHERE id=$1;", [Sid])
+    end,
+    ok.
+
+delete_session(_, Sid) ->
+    {ok,_} = boss_db:execute("DELETE FROM boss_session WHERE id=$1;",[Sid]),
+    ok.
+
+delete_session_value(Conn, Sid, Key) when is_atom(Key) ->
+    delete_session_value(Conn, Sid, atom_to_list(Key));
+delete_session_value(Conn, Sid, Key) when is_list(Key) ->
+    case lookup_session_value(Conn,Sid, Key) of
+	undefined -> ok;
+	[] -> ok;
+	_ ->
+	    {ok,_} = boss_db:execute("UPDATE boss_session SET data=delete(data,$1) where id=$2;",[Key,Sid]),
+	    ok
+    end.
+
+%%--------------------------------------------------------------------
+%%% Internal functions
+%%--------------------------------------------------------------------
+recover_data(Sid)->
+    F = fun(X) -> [C || C <- binary_to_list(X), ((C =/= 32) and (C =/= $\\) and (C =/= $\"))] end,
+    F2 = fun(Data) ->
+                Data1 = [C || C <- binary_to_list(Data), (C =/= $\")],
+		Data2 = base64:decode(Data1),
+		Data3 = binary_to_term(Data2),
+		Data3
+	end,
+    case boss_db:execute("SELECT data FROM boss_session WHERE id=$1;",[Sid]) of
+        {ok,_,[{null}]} -> [];
+        {ok,_,[{<<>>}]} -> [];
+	{ok,_,[{Data}]} ->
+	    Data1 = binary:split(Data, <<",">>),
+	    Data2 = lists:map(fun(X) -> binary:split(X,<<"=>">>) end, Data1),
+	    Data3 = lists:map(fun([X,Y]) -> {F(X),F2(Y)} end, Data2),
+            Data3;
+	_ -> []
+    end.
+