Question

I have some problem.

I want to associate process with one user (all requests from user receive one process, in HTTP 1.1 default keep-alive is on, and all requests send through one socket.)

I have following code:

loop(Sock, Reg_pid) ->

    {ok, Conn} = gen_tcp:accept(Sock),

    Pid = spawn(fun () -> client_socket(Conn,Reg_pid) end),
    gen_tcp:controlling_process(Conn, Pid),

    Pid ! {take, Conn}, %% race condition 

loop(Sock, Reg_pid).

client_socket(S,Reg_pid) ->

    io:format("in~n"),

receive

    {take, So} ->
        inet:setopts(So, [{active, once}]),
        client_socket(So, Reg_pid);

    {http, Socket, {http_request, _Method, {abs_path, _Path}, _Vers}} ->

        case http_uri2:parse_path_query(_Path) of

            {"/",[]} -> 

                io:format("Main pid - ~p ~n", [self()]),                
                gen_tcp:send(Socket, response("<a href='http://127.0.0.1:8080/register?name=Max'>Click</a>"));              

            {"/register",[{"name", Player_name}]} ->

                io:format("Register pid - ~p ~n", [self()]);



            _-> ok

        end,

        inet:setopts(Socket, [{active, once}]),

        client_socket(Socket, Reg_pid);

     {tcp_closed, Socket} ->

        io:format("Socket ~w closed [~w]~n",[Socket,self()]);
    %   gen_tcp:close(Socket);

      {tcp_error, Socket, Reason} ->
            io:format("Error ~w closed [~w]~n",[Socket,self()]);


    _-> ok


end.

When i connect through browser to server(index page) and then click link that return server, i have next result:

3> server:start(8080).
<0.43.0>
in 
Main pid - <0.45.0> 
in 
in 
Register pid - <0.46.0> 
in 

I can’t understand why my next request(click to link) receive other process(Register pid – <0.46.0>) ?

In this way, All requests from one user spawn new process, i want that all requsts from one users handle one process, how i can implament this ?

Thank you!

Answer 1

The browser may choose to not adhere to the Keep-Alive and instead create a new socket. Instead of trusting the Keep-Alive, you may consider sending a session cookie to the browser, associating the current session with a certain process. The session cookie will be sent by the browser for each request. Before you create a new process for new requests, check for the session cookie and see if there is a process associated with that session already.