[99s-extend] Rewriting URLs

[Paul Dickson]

Ok, here is all the code in bz_libmap.erl

execute(Req, Env) ->
    Path = cowboy_req:path(Req),
    Parts = filename:split(Path),

    case cowboy_req:method(Req) of
      <<"GET">> ->
         % Check for "/music/" requests
         rewrite( Parts, Req, Env );
      _Other ->
         {ok, Req, Env}
    end.

rewrite( [<<"/">>, <<"music">>, LibName | UrlParts], Req, Env ) ->
    % We want URLs of the form "/music/LIBNAME/everythingelse"
    % Get library definition.  If we do not know that name, then they
    % are asking for something that does not exist.
    case bz_db:get_library( LibName ) of
      [] ->
         io:format("No such library '~s'~n", [LibName] ),
         {stop, cowboy_req:reply(404, Req)};

      L when is_record(L,library) ->
          % Replace the library name with the library base.
          % This will be the head of an absolute file path.
          LibBase = L#library.base,
          NewPath = filename:join([LibBase | UrlParts]),
          NewInfo = filename:split(NewPath),
          Req2 = cowboy_req:set( [
            {path_info,[NewPath]},
            {path, [NewPath]}], Req),
          {ok, Req2, Env}
    end;
rewrite( _AnythingElse, Req, Env ) ->
    {ok, Req, Env}.