If you upload a file to a page that gets redirected by the 404 handler, you get a function clause error in boss_web_controller_handle_request:process_result

[RobertSwirsky]

Here's what happens:

• Do an http file upload to a URL that doesn't exist and gets handled by the 404 mechanism
• add a POST handler to the 404 controller (though this will happen without it)

Here's my route

% 404 File Not Found handler
{404, [{controller, "unlogged"}, {action, "error404"}]}.

And this is the unlogged controller.

error404('GET', []) ->
    { ok, [] };
error404('POST', []) ->
    [{_, _FileName, TempLocation, _Size, _Name, _}|_] = Req:post_files(),
    file:delete(TempLocation),
    {output, "Go Away"}.

There will be a crash in boss_web_controller_handle_request:process_result because there's no matching function clause.

I added a catch-all at the end to see what we're getting:

% [ ... lots of clauses before this one ... ]
process_result(_, _, {StatusCode, Payload, Headers}) when is_integer(StatusCode) ->
    {StatusCode, boss_web_controller:merge_headers(Headers, [{"Content-Type", "text/html"}]), Payload};
process_result(_, _, X) ->
    lager:info("process_result! I have no idea: ~p", [X]).

And we got this output:

18:40:43.814 [info] process_result! I have no idea: {{ok,"Go Away",[]},undefined,[]}

The problem is those two extra params after the 3-element tuple aren't matched by any existing function header.

You'll have the same problem if the POST handler returned {json, []} or {ok, []} too.