Add the backend app.

Better to split the main functions in it's separate application.
This will be used by all the other part of the dudeswave
experience.

dudeswave_backend/Makefile

@@ -0,0 +1,7 @@
+.PHONY:	all clean
+
+all:
+	${MAKE} -C src
+
+clean:
+	${MAKE} -C src clean

dudeswave_backend/ebin/dudeswave_backend.app

@@ -0,0 +1,10 @@
+{application,dudeswave_backend,
+             [{description,"The dudeswave core"},
+              {vsn,"1.0.0"},
+              {modules,[dudeswave_backend,dudeswave_backend_app,
+                  ,dudeswave_backend_supervisor,
+                  dudeswave_backend_auth,dudeswave_backend_user]},
+              {registered,[]},
+              {applications,[kernel,stdlib,erts,cowboy,ranch]},
+              {mod,{dudeswave_backend_app,[]}},
+              {start_phases,[]}]}.

dudeswave_backend/include/defines.hrl

@@ -0,0 +1,23 @@
+%
+% Copyright (c) 2024 Andrea Biscuola <a@abiscuola.com>
+%
+% Permission to use, copy, modify, and distribute this software for any
+% purpose with or without fee is hereby granted, provided that the above
+% copyright notice and this permission notice appear in all copies.
+%
+% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+%
+
+-define(APPBUCK, dudeswave).
+-define(USERSBUCK, dudes).
+-define(COOKIESBUCK, cookies).
+-define(RANDBYTES, 32).
+-define(DEFVALIDITY, 365).
+-define(DUDENAME, "dudename").
+-define(DUDEAUTH, "dudeauth").

dudeswave_backend/src/Makefile

@@ -0,0 +1,19 @@
+.PHONY:		all clean
+.SUFFIXES: 	.erl .beam
+
+ERLC?=	erlc -server
+
+ERLFLAGS=	-I ../../
+
+OBJS=	dudeswave_backend.beam dudeswave_backend_app.beam
+OBJS+=	dudeswave_backend_supervisor.beam
+OBJS+=	dudeswave_backend_auth.beam dudeswave_backend_user.beam
+
+all: ${OBJS}
+
+.erl.beam:
+	${ERLC} ${ERLOPTS} ${ERLFLAGS} $<
+
+clean:
+	rm -f *.beam
+

dudeswave_backend/src/dudeswave_backend.erl

@@ -0,0 +1,46 @@
+%
+% Copyright (c) 2024 Andrea Biscuola <a@abiscuola.com>
+%
+% Permission to use, copy, modify, and distribute this software for any
+% purpose with or without fee is hereby granted, provided that the above
+% copyright notice and this permission notice appear in all copies.
+%
+% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+%
+-module(dudeswave_backend).
+
+-behaviour(gen_server).
+
+% Server start function
+-export([start_link/0]).
+
+% Module callbacks
+-export([init/1, handle_call/3, handle_cast/2, terminate/2]).
+
+%
+% Startup functions
+%
+
+start_link() ->
+	gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+init([]) ->
+	process_flag(trap_exit, true),
+
+	{ok, 0}.
+
+%
+% Callbacks
+%
+
+handle_call(_Msg, _From, State) -> {noreply, State}.
+
+handle_cast(_Msg, State) -> {noreply, State}.
+
+terminate(_Reason, _N) -> ok.

dudeswave_backend/src/dudeswave_backend_app.erl

@@ -0,0 +1,31 @@
+%
+% Copyright (c) 2024 Andrea Biscuola <a@abiscuola.com>
+%
+% Permission to use, copy, modify, and distribute this software for any
+% purpose with or without fee is hereby granted, provided that the above
+% copyright notice and this permission notice appear in all copies.
+%
+% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+%
+-module(dudeswave_backend_app).
+-behaviour(application).
+
+-export([bootstrap/3, start/2, stop/1]).
+
+start(_Type, StartArgs) ->
+	crypto:rand_seed(),
+
+	dudeswave_backend_supervisor:start_link(StartArgs).
+
+stop(_State) -> ok.
+
+%
+% Bootstrap procedure to be completed
+%
+bootstrap(_Admin, _Password, _Nodes) -> ok.

dudeswave_backend/src/dudeswave_backend_auth.erl

@@ -0,0 +1,131 @@
+%
+% Copyright (c) 2024 Andrea Biscuola <a@abiscuola.com>
+%
+% Permission to use, copy, modify, and distribute this software for any
+% purpose with or without fee is hereby granted, provided that the above
+% copyright notice and this permission notice appear in all copies.
+%
+% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+%
+-module(dudeswave_backend_auth).
+-moduledoc """
+Dudes authentication module
+
+Here lives all the functions for the APIs needed to handle users authentication.
+""".
+
+-include_lib("dudeswave/include/defines.hrl").
+-include_lib("storage/include/storage.hrl").
+
+-export([authenticate/2, logout/2]).
+
+-doc """
+Verify a session with an existing cookie.
+
+Spec:
+
+```
+-spec authenticate(User, Auth) -> true | false | {true, Cookie, Validity} | {error, Reason} when
+	User :: binary(),
+	Auth :: {cookie, binary()} | {password, binary()},
+	Reason :: term().
+```
+
+Authenticate a user with either an existing `Cookie` or by issuing a new one
+after authenticating with `Password`.
+
+If `Cookie` is valid, the function returns `true`. If the authentication is denied
+returns `false`
+""".
+-spec authenticate(User, Auth) -> true | false | {true, Cookie, Validity} | {error, Reason} when
+	User :: binary(),
+	Auth :: {cookie, binary()} | {password, binary()},
+	Cookie :: binary(),
+	Validity :: pos_integer(),
+	Reason :: term().
+
+authenticate(User, {cookie, Cookie}) ->
+	case storage:read(?COOKIESBUCK, Cookie) of
+		{ok, [R]} ->
+			CurTime = calendar:now_to_universal_time(erlang:timestamp()),
+			CookieTime = R#object.value,
+			{user, CookieUser} = proplists:lookup(user, R#object.metadata),
+
+			if
+				CookieTime >= CurTime ->
+					if
+						User =:= CookieUser -> true;
+						true -> false
+					end;
+				true -> false
+			end;
+		{ok, []} -> false;
+		{error, _} -> {error, service_unavailable}
+	end;
+
+authenticate(User, {password, Password}) ->
+	case storage:read(?USERSBUCK, User) of
+		{ok, [R]} ->
+			Validity = case application:get_env(cookie_validity) of
+				{ok, Value} ->
+				    erlang:system_time(seconds) + Value * 86400;
+				undefined ->
+				    erlang:system_time(seconds) + ?DEFVALIDITY * 86400
+			end,
+
+			{hash, Hash} = proplists:lookup(hash, R#object.metadata),
+			{salt, Salt} = proplists:lookup(salt, R#object.metadata),
+			{approved, Appr} = proplists:lookup(approved, R#object.metadata),
+
+			Auth = crypto:hash(sha256, <<Password/binary, Salt/binary>>),
+
+			if
+				Appr =/= true -> false;
+				Auth =:= Hash ->
+					Cookie = base64:encode(rand:bytes(64)),
+					case storage:write(?COOKIESBUCK, <<Cookie/binary>>,
+					    Validity, [{user, User}]) of
+						ok -> {true, Cookie, Validity};
+						{error, Reason} -> {error, Reason}
+					end;
+				true -> false
+			end;
+		{ok, []} -> false;
+		{error, Reason} -> {error, Reason}
+	end.
+
+-doc """
+Close an existing session
+
+Spec:
+
+```
+-spec logout(User, Cookie) -> ok | {error, Reason} when
+	User :: binary(),
+	Cookie :: binary(),
+	Reason :: term().
+```
+
+Invalidate and delete `Cookie` associated with `User` from the system.
+""".
+-spec logout(User, Cookie) -> ok | {error, Reason} when
+	User :: binary(),
+	Cookie :: binary(),
+	Reason :: term().
+
+logout(User, Cookie) ->
+	case storage:read(?COOKIESBUCK, Cookie) of
+		{ok, [R]} ->
+			{user, User} = proplists:lookup(user, R#object.metadata),
+			storage:delete(?COOKIESBUCK, Cookie);
+		{ok, []} ->
+			{error, not_found};
+		{error, Reason} ->
+			{error, Reason}
+	end.

dudeswave_backend/src/dudeswave_backend_supervisor.erl

@@ -0,0 +1,31 @@
+%
+% Copyright (c) 2024 Andrea Biscuola <a@abiscuola.com>
+%
+% Permission to use, copy, modify, and distribute this software for any
+% purpose with or without fee is hereby granted, provided that the above
+% copyright notice and this permission notice appear in all copies.
+%
+% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+%
+-module(dudeswave_backend_supervisor).
+-behaviour(supervisor).
+
+-export([start/0,
+    start_link/1,
+    init/1]).
+
+start() ->
+	spawn(fun() -> supervisor:start_link({local, ?MODULE}, ?MODULE, _Arg = []) end).
+
+start_link(Args) ->
+	supervisor:start_link({local, ?MODULE}, ?MODULE, Args).
+
+init([]) ->
+	{ok, {{one_for_one, 3, 10}, [{tag1, {dudeswave_backend, start_link, []}, permanent,
+	    10000, worker, [dudeswave_backend]}]}}.

dudeswave_backend/src/dudeswave_backend_user.erl

@@ -0,0 +1,134 @@
+%
+% Copyright (c) 2024 Andrea Biscuola <a@abiscuola.com>
+%
+% Permission to use, copy, modify, and distribute this software for any
+% purpose with or without fee is hereby granted, provided that the above
+% copyright notice and this permission notice appear in all copies.
+%
+% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+%
+-module(dudeswave_backend_user).
+
+-include_lib("dudeswave/include/defines.hrl").
+-include_lib("storage/include/storage.hrl").
+
+-export([details/1, new/3, update/4, delete/1]).
+
+-doc """
+Return user details.
+
+Spec:
+
+```
+-spec details(User) -> Value | {error, Reason} when
+	User :: binary(),
+	Value :: term(),
+	Reason :: term().
+```
+""".
+-spec details(User) -> Value | {error, Reason} when
+	User :: binary(),
+	Value :: term(),
+	Reason :: term().
+
+details(User) ->
+	case storage:read(?USERSBUCK, User) of
+		{ok, [R]} -> R#object.value;
+		{error, Reason} -> {error, Reason};
+		{ok, []} -> {error, not_found}
+	end.
+
+-doc """
+Create a new user.
+
+Spec:
+
+```
+-spec new(User, Password, Email) -> ok | {error, Reason} when
+	User :: binary(),
+	Password :: binary(),
+	Email :: binary(),
+	Reason :: term().
+```
+
+The `User` is created, and stored in the application's users bucket
+`Password` is salted and hashed with SHA256 before being stored.
+
+The new user is saved with a metadata `approved` of `false`,
+""".
+-spec new(User, Password, Email) -> ok | {error, Reason} when
+	User :: binary(),
+	Password :: binary(),
+	Email :: binary(),
+	Reason :: term().
+
+new(User, Password, Email) ->
+	Salt = rand:bytes(?RANDBYTES),
+	Hash = crypto:hash(sha256, <<Password/binary, Salt/binary>>),
+
+	Data = #{<<"email">> => Email},
+	Metadata = [{salt, Salt}, {hash, Hash}, {approved, false}],
+
+	storage:write(?USERSBUCK, User, Data, Metadata).
+
+-doc """
+Update user's details
+
+Spec:
+
+```
+-spec update(User, Name, Email, Desc) -> ok | {error, Reason} when
+	User :: binary(),
+	Name :: binary(),
+	Email :: binary(),
+	Desc :: binary(),
+	Reason :: term().
+```
+
+The details apart from `User` are updated. The username itself is immutable
+and cannot be modified. All the other fields, excluding the e-mail, are the
+ones that can be seen in the public page.
+""".
+-spec update(User, Name, Email, Desc) -> ok | {error, Reason} when
+	User :: binary(),
+	Name :: binary(),
+	Email :: binary(),
+	Desc :: binary(),
+	Reason :: term().
+
+update(User, Name, Email, Desc) ->
+	{ok, CurData, Metadata} = case storage:read(?USERSBUCK, User) of
+		{ok, [R]} ->
+			{ok, R#object.value, R#object.metadata};
+		{error, Reason} -> {error, Reason}
+	end,
+
+	Data = CurData#{<<"email">> => Email, <<"name">> => Name,
+	    <<"description">> => Desc},
+
+	storage:write(?USERSBUCK, User, Data, Metadata).
+
+-doc """
+Delete an existing user from the database.
+
+```
+-spec delete(User) -> ok | {error, Reason} when
+	User :: binary(),
+	Reason :: term().
+```
+""".
+-spec delete(User) -> ok | {error, Reason} when
+	User :: binary(),
+	Reason :: term().
+
+delete(User) ->
+	% We are missing the cleanup of the cookies
+	% here. For that, we need to add at least another
+	% API to the storage layer.
+	storage:delete(?USERSBUCK, User).