Subscribing to #/#

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ನಾಗೇಶ್ ಸುಬ್ರಹ್ಮಣ್ಯ (Nagesh S)

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Jul 24, 2012, 2:34:43 AM7/24/12
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Is #/# a valid topic string ?

The subscription to the topic string #/# on the Eclipse Paho broker is accepted. As per the spec, the # should be the last character in a topic string. This is true when subscribing to #/#. However, as # is a multiple level wild card, specifying #/# sounds redundant. For sake of testing, I subscribed to # and see many multi level topics and their payloads flowing in. But, with #/#, nothing.

I think, if # is used in topic string, then, it should be the only # character and must appear at the end of the topic string.

ನಾಗೇಶ್

Nicholas O'Leary

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Jul 24, 2012, 3:19:52 AM7/24/12
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Hi Nagesh,

You are correct; there can be at most one # character and it must appear at the end.

#/# is not a valid subscription.

Regards,
N

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cogitoergosum

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Jul 24, 2012, 3:21:35 AM7/24/12
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Thanks, Nick.

Roger Light

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Jul 24, 2012, 5:52:09 AM7/24/12
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Hi Nagesh,

> The subscription to the topic string #/# on the Eclipse Paho broker is
> accepted.

...

> For sake of testing, I subscribed to # and see many multi level topics
> and their payloads flowing in. But, with #/#, nothing.

I believe that the broker is operating correctly here. The #/#
subscription is not being accepted internally, but there is currently
no mechanism to indicate a rejected subscription so the broker must
provide a positive response. That you are not seeing any messages to
that topic is an indication that you don't actually have a
subscription because the topic is invalid.

Cheers,

Roger

cogitoergosum

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Jul 24, 2012, 8:44:14 AM7/24/12
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Hi Roger,
Yes, I realised that. Thanks !

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