diff options
| -rw-r--r-- | client/client.erl | 82 | ||||
| -rw-r--r-- | server/client.erl | 11 | ||||
| -rw-r--r-- | server/dispatcher.erl | 12 |
3 files changed, 60 insertions, 45 deletions
diff --git a/client/client.erl b/client/client.erl index b72b5ee..43dbfc6 100644 --- a/client/client.erl +++ b/client/client.erl @@ -12,49 +12,53 @@ checkLogin(Value) -> end. buildNode(Server) -> + %% build the node string of the server by using the hostname list_to_atom("distributed_music_system_main_node@" ++ Server). rpc(Server, Function, Params) -> - rpc:call(buildNode(Server), client, Function, Params). + %% shortcut for calling a function from the server + rpc:call(buildNode(Server), dispatcher, Function, Params). -wait_for_reply() -> - receive - {_, Msg} -> - Msg; - Why -> Why - after 3000 -> - {error, timeout} - end. - -register(Name, Password) -> - try checkLogin(true) of - _ -> - server:rpc(cli, {register, Name, Password}) - catch - {error, login_state} -> - {error, not_logged_in} - end. - -%register the client with the server register(Server, Name, Password) -> + %% check if client is not logged in (if client is logged in, + %% register/2 should be used) try checkLogin(false) of _ -> + %% register a new user account on the server rpc(Server, register, [self(), {Name, Password}]) catch {error, login_state} -> {error, logged_in} end, - wait_for_reply(). -%login to the server + %% wait for response + receive + {_, Msg} -> + Msg; + Why -> Why + after 3000 -> + %% protect from waiting endless for server response (maybe + %% if used wrong hostname or something like that) + {error, timeout} + end. + login(Server, Name, Password) -> + %% load common/server (used by server and client) code:purge(server), code:load_abs("../common/server"), + %% check if client is not logged in (if client is logged in, it + %% would make no sense to login again) try checkLogin(false) of _ -> + %% login to the server rpc(Server, login, [self(), {node(), Name, Password}]), receive + %% the server returns the Pid of the process on the + %% client, that should handle the communication + %% between server and client, the process is started + %% by the server on the client node and registered + %% here as cli process {ok, {ok, {logged_in, Pid}}} -> erlang:register(cli, Pid), {ok, logged_in}; @@ -63,6 +67,9 @@ login(Server, Name, Password) -> Msg -> Msg after 3000 -> + %% protect from waiting endless for server + %% response (maybe if used wrong hostname or + %% something like that) {error, timeout} end catch @@ -70,17 +77,10 @@ login(Server, Name, Password) -> {error, logged_in} end. -%request the playlist from the server -list() -> - try checkLogin(true) of - _ -> - server:rpc(cli, list) - catch - {error, login_state} -> - {error, not_logged_in} - end. - send_to_server(Cmd, Server) -> + %% generic helper function for sending a message to the given + %% server and wait for a response from the server (the function + %% returns a tupel of the reponse and the server) Server ! Cmd, receive {ok, Msg} -> @@ -89,6 +89,8 @@ send_to_server(Cmd, Server) -> {Msg, Server} end. +%% the handle functions are called from the process started by the +%% process started by the server on login and registered as cli handle(list, Server) -> send_to_server(list, Server); handle(get_votes, Server) -> @@ -99,15 +101,20 @@ handle({devote, Artist, Title}, Server) -> send_to_server({devote, Artist, Title}, Server); handle({register, Name, Password}, Server) -> send_to_server({register, Name, Password}, Server); + handle({change_state, NewState}, _) -> + %% change the state of the server (used from the client process on + %% the server to set the process id, so that the client could send + %% messages directly to the server {{ok}, NewState}; handle(Cmd, Server) -> + %% fallback to return a error message for not existing commands {{error, {unknown_command, Cmd}}, Server}. try_logged_in_rpc(Rpc) -> - %% tries to execute an rpc for logged in user and returns error - %% message if user is not logged in + %% helper function that tries to execute an rpc for logged in user + %% and returns error message if user is not logged in try checkLogin(true) of _ -> server:rpc(cli, Rpc) @@ -116,6 +123,10 @@ try_logged_in_rpc(Rpc) -> {error, not_logged_in} end. +list() -> + %% request the playlist from the server + try_logged_in_rpc(list). + getVotes() -> %% queries the server for the current votes this client possesses try_logged_in_rpc(get_votes). @@ -128,3 +139,6 @@ devote(Artist, Title) -> %% negative vote, decrements the votes for {Artist, Title} by one try_logged_in_rpc({devote, Artist, Title}). +register(Name, Password) -> + %% register a new user (used by the admin) + try_logged_in_rpc({register, Name, Password}). diff --git a/server/client.erl b/server/client.erl index 6c81349..03f6276 100644 --- a/server/client.erl +++ b/server/client.erl @@ -1,5 +1,5 @@ -module(client). --export([start/2, loop/2, register/2, login/2]). +-export([start/2, loop/2]). start(Node, User) -> %% start linked processes on client and server to get notice if @@ -68,12 +68,3 @@ loop(Client, User) -> Client ! {error, {unknown_command, Cmd}} end, loop(Client, User). - -register(Client, {Name, Password}) -> - %% forward the register messages to the dispatcher (if user is not - %% logged in) - dis ! {Client, {register, {Name, Password}}}. - -login(Client, {Node, Name, Password}) -> - %% forward the login messages to the dispatcher - dis ! {Client, {login, {Node, Name, Password}}}. diff --git a/server/dispatcher.erl b/server/dispatcher.erl index 08b19ec..a0a0459 100644 --- a/server/dispatcher.erl +++ b/server/dispatcher.erl @@ -1,5 +1,5 @@ -module(dispatcher). --export([start/0, handle/2]). +-export([start/0, handle/2, register/2, login/2]). checkUserExists([_|_]) -> %% helper function to check if given array contains at least one element @@ -74,3 +74,13 @@ handle({'EXIT', From, _}, State) -> handle(Cmd, State) -> %% standard command to find invalid commands and emit an error {{error, {unknown_command, Cmd}}, State}. + +register(Client, {Name, Password}) -> + %% forward the register messages to the dispatcher (called form + %% the client) + dis ! {Client, {register, {Name, Password}}}. + +login(Client, {Node, Name, Password}) -> + %% forward the login messages to the dispatcher (called form the + %% client) + dis ! {Client, {login, {Node, Name, Password}}}. |