1. Use a finite-state-machine REST framework like webmachine or cowboy_rest. This will help you in the long run once you grok how they work.
2. Your intention here is that the user might have done something silly. Write a helper which can load arguments from the request and fail if some of them are missing. The best approach is to shuffle as much as possible into a routing layer and then let the routing layer return the 4xx responses. This only leaves up optional arguments, where an undefined option is what you want to handle. Look at how, e.g., cowboy is doing this.
You can essentially avoid all of this boilerplate, if you construct your HTTP RESTful API correctly.
db:find/3 should probably return either {ok, UserRec} or not_found. Something along the lines of
case db:find(my_db, users, #{<<"username">> => Username}) of
{ok, #{<<"password">> := Password} = UserRec}} -> respond(200, ...);
{ok, UserRec} -> respond(401, ...);
not_found -> respond(404) % or something more appropriate
end.
1. Use a finite-state-machine REST framework like webmachine or cowboy_rest. This will help you in the long run once you grok how they work.
2. Your intention here is that the user might have done something silly. Write a helper which can load arguments from the request and fail if some of them are missing. The best approach is to shuffle as much as possible into a routing layer and then let the routing layer return the 4xx responses. This only leaves up optional arguments, where an undefined option is what you want to handle. Look at how, e.g., cowboy is doing this.
You can essentially avoid all of this boilerplate, if you construct your HTTP RESTful API correctly.
db:find/3 should probably return either {ok, UserRec} or not_found. Something along the lines of