[rabbitmq-discuss] Bug? STOMP adaptor created queues with invalid UTF-8 characters

[Marek Majkowski]

On Mon, Feb 13, 2012 at 02:17, Toby Corkindale
<toby.corkindale at strategicdata.com.au> wrote:
> I *think* I've found symptoms of a bug in the RabbitMQ STOMP adaptor.
>
> We're using /topic/ subscriptions in our applications, and the STOMP adaptor
> creates some temporary queues in RabbitMQ.
> If you subscribe to /topic/foo.bar.123 it'll create a queue of the pattern
> stomp.dsub.foo.bar.123.XXXXXXXXXXXXXXXX
> where the Xs are random characters.
>
> It recently managed to create some with invalid UTF8 in the random section
> of the queue name. This broke the web management interface and the JSON REST
> API.
>
> =ERROR REPORT==== 13-Feb-2012::13:05:44 ===
> webmachine error: path="/api/queues//"
> {error,{exit,{ucs,{bad_utf8_character_code}},
>             [{xmerl_ucs,from_utf8,1},
>              {mochijson2,json_encode_string,2},
>              {mochijson2,'-json_encode_proplist/2-fun-0-',3},
>              {lists,foldl,3},
>              {mochijson2,json_encode_proplist,2},
>              {mochijson2,'-json_encode_array/2-fun-0-',3},
>              {lists,foldl,3},
>              {mochijson2,json_encode_array,2}]}}
>

When I think about it, it's actually quite likely to happen.

There are certain codepoints that mochiweb/mochijson refuses
to encode. (And mochijson is used by the mgmt plugin).

But under the hood RabbitMQ doesn't do any specific parsing for Unicode,
for Rabbit every string is a valid one.

I know about two character groups which are invalid:
 - D800–DFFF see:
    http://en.wikipedia.org/wiki/Mapping_of_Unicode_characters#Surrogates
 - and FFFE and FFFF, which mochijson just refuses to encode
    http://en.wikibooks.org/wiki/Unicode/Character_reference/F000-FFFF

I'm not aware of other invalid codepoints.
Do you know if in your case you used one of these?

> Is this intended behaviour? We've never seen this happen before.

Of course not, but it can be controversial to decide what actually
is an intended behaviour.

In the meantime please avoid using invalid Unicode codepoints :)

Cheers,
   Marek