Thanks from India!

Hughes is off for a few days, but I am sure he will be able to answer you very soon.

Thank you for your patience.

Thank you for this demo. It has been very helpful getting me started with Erlang.

I wonder if you could offer some advice.

I am trying to split the stickyNotes app between two servers: one with the html, css, img and js, and one with the erlang server. However it’s not working.

The only change I’ve made to the code is in application.js I have changed the calls to post() from

post(json, “/notes”, null);

to

post(json, “http://localhost:8000/notes”, null);

The erlang server is receiving the requests, but instead of the POST requests it’s expecting, it’s receiving OPTIONS requests.

I need to figure out what stickyNotes_web.erl should do with an OPTIONS request, and how to get the browser to send POST requests.

I realise this is not really an Erlang question. It’s probably more to do with the change in the http handshake caused by the split between two servers. However, is this something MochiWeb and/or WebMachine can handle? Or is this the wrong way to split the app over two servers?

Any help appreciated. Once I’ve sorted it out I’ll post a summary.

Best wishes

Ivan

Thanks for pointing this out.

One way to fix that is to use the list_to_existing_atom/1 (@Lambder) BIF instead of the list_to_atom/1 one in the stickyNotes_web.erl file line 42 :

Action = list_to_existing_atom(binary_to_list(A)),

From the Erlang doc : “This function returns the atom whose text representation is String, but only if there already exists such atom”.

It seems that the tables required by the demo app have not been properly created.
The first time you launch the app with the ‘start-dev.sh’ script, be sure to launch stickydb:reset() in the Erlang console. This function is creating the initial Mnesia schema with 2 tables ‘counter’ and ‘note’.

=CRASH REPORT==== 18-Aug-2009::14:10:46 ===
crasher:
pid:
registered_name: []
exception exit: {aborted,{no_exists,counter}}
in function mnesia:abort/1
in call from mnesia_tm:dirty/2
in call from notes:create/1
in call from stickyNotes_web:loop/2
in call from mochiweb_http:headers/4
initial call: mochiweb_socket_server:acceptor_loop/1
ancestors: [stickyNotes_web,stickyNotes_sup,]
messages: []
links: [,#Port]
dictionary: [{mochiweb_request_body,
<>},
{mochiweb_request_recv,true},
{mochiweb_request_post,
[{"json",
"{"action":"create","doc":{"text":"","x":94,"y":99,"z":1,"color":"yellow"}}"}]},
{mochiweb_request_path,”/notes”}]
trap_exit: false
status: running
heap_size: 4181
stack_size: 23
reductions: 16707
neighbours:

=ERROR REPORT==== 18-Aug-2009::14:10:46 ===
{mochiweb_socket_server,235,{child_error,{aborted,{no_exists,counter}}}}