dudeswave2/dudeswave/src/dudeswave_user_handler.erl

%
% 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_user_handler).
-moduledoc """
Register a new user.
""".

-behaviour(cowboy_handler).

-export([init/2, terminate/3]).

%
% Callbacks exports
%
-export([allowed_methods/2, content_types_accepted/2,
     known_methods/2, resource_exists/2, is_conflict/2,
     create_user/2]).


-include_lib("storage/include/storage.hrl").

-define(RANDBYTES, 32).

%
% Protocol functions
%

init(Req, State) ->
	{cowboy_rest, Req, State}.

allowed_methods(Req, State) ->
	{[<<"PUT">>], Req, State}.

content_types_accepted(Req, State) ->
	{[{{ <<"application">>, <<"json">>, '*'}, create_user}], Req, State}.

known_methods(Req, State) ->
	{[<<"PUT">>], Req, State}.

resource_exists(Req, State) ->
	{ok, Bucket} = maps:find(bucket, State),

	case cowboy:read_urlencoded_body(Req) of
		{ok, [{name, Name}, {username, User}, {password, Password}], NewReq} ->
			case storage:read(Bucket, User) of
				{ok, [_R]} ->
					{true, NewReq, user_exists};
				{ok, []} ->
					{false, NewReq, {Bucket, [{name, Name},
					    {username, User},{password, Password}]}}
			end
	end.

is_conflict(Req, user_exists) -> {true, Req, []};

is_conflict(Req, State) -> {false, Req, State}.

create_user(Req, {Bucket, [{name, Name}, {username, User}, {password, Pass}]}) ->
	crypto:rand_seed(),
	Salt = rand:bytes(32),
	Hash = crypto:hash(sha256, <<Pass/binary, Salt/binary>>),

	case storage:write(Bucket, User, Hash, [{salt, Salt}, {name, Name}]) of
		ok ->
			{true, Req, []};
		{error, Reason} ->
			{false, Req, Reason}
	end.

terminate(_Reason, _Req, _State) -> ok.