The acceptor (h2r-bwmsgsv2.php) will receive the messages from
Bandwidth via HTTP and put them in a Redis queue.  Then the translator
(r2s-bwmsgsv2.rb) will pick them up from the Redis queue and direct
them to the SGX (sgx-bwmsgsv2.rb), removing them from the pending
queue if the hand-off was successful.

The above components were added in order to improve resiliency of the
system, especially in situations where the SGX may become unavailable
for long periods of time.  Bandwidth will send the message again if it
is not received the first time, but it no longer stores the messages
itself in V2, so the consequences of missing an HTTP request are more
severe than in V1.

Analogous to fix for https://github.com/singpolyma/cheogram/issues/71 .

See merge request ossguy/sgx-catapult!18 for the discussion and details behind the merge.

https://xmpp.org/extensions/xep-0030.html#info-nodes requires that *if*
the query includes an optional node, it should be included in the
response.

Added a feature that allows the user to send a real MMS (e.g. picture
message) when using their server's HTTP Upload (XEP-0363).  With some
clients, like Conversations, the resulting file is sent via OOB, so we
use the presence of a URL in the OOB section to indicate a file is to
be sent.  Other ways of describing the URL are for now unsupported, as
we want to ensure that we only do this when the user implies that they
want to send a file.

For a number of reasons, this feature is gated on a per-user flag,
which is off by default.  The user may be used to the old behaviour
and not want a real MMS sent, or they may be confused if this feature
breaks when it didn't before (i.e. the carrier supports larger files
when sent via "internal" URL, as is done with Jingle File Transfer,
than it does when sent via "external" URL, as is done here).  A new
option will be added to jmp-acct_bot shortly to let the user set this
flag.

When the user tries to send a message to an "anonymous" JID (the type
of JID that jmp-fwdcalls will create when it gets a blocked caller ID,
as of https://gitlab.com/ossguy/jmp-fwdcalls/commit/e2032c8 anyway)
provide a more appropriate error message, as the JID does exist, it's
just that the user who left the voicemail isn't available at that JID.

Some clients expect <error/> first and we should always set the type
to :error regardless.

See merge request !17 for the discussion and details behind the merge.

Every error is of type error, and put the <error/> child first for
broken parsers that only get the first child.

This probably doesn't appear much in the wild, but good to have in
case we do see it.

See merge request !16 for the discussion and details behind the merge.

Empty and whitespace-only bodies are banned by catapult API, so return a
policy-violation error in those cases.

Closes #12

Works well in my tests and, from my understanding, will be helpful in
fixing https://gitlab.com/ossguy/jmp-fwdcalls/issues/7 .

See merge request !15 for the discussion and details behind the merge.

Mostly useful for extending the existing SGXcatapult application from
elsewhere.

I don't normally kill sgx-catapult from the command-line so my tests
just cover use via Monit, but it worked fine in those tests so seems
good to merge.

See merge request !14 for the discussion and details behind the merge.

The unused `subscription(:request?) do |s|` section became used when
we switched Blather to stop processing a stanza on the first matched
Ruby proc in 6d19b7f.  It was added way back in the first week of
sgx-catapult development and hadn't been touched (or likely thought
of) since.  So it's about time we deleted it anyway.

This does cause subscription requests to work again in my testing.

See merge request !13 for the discussion and details behind the merge.

Defer the stop to happen outside of the trap handler so that EM won't
freak out about it.

There were two handlers -- the more specific one was commented out? And
now that we only run the first matching handler, this caused all
subscriptions to be eaten.

Needed for https://gitlab.com/ossguy/jmp-fwdcalls/merge_requests/1 and
also adds optional subject and description parameters for filling in
the respective fields on the XMPP message (not used yet).

See merge request !10 for the discussion and details behind the merge.

Makes more sense there, and gives others who want to use it easier
access.

As mentioned in 889024e, 7729a26 had the side-effect of adding the
params values to the log.  In the spirit of 349d8b0, we are trying to
keep such values out of the log, so explicitly remove them to retain
the old (and desired) behaviour.

In 7729a26 the Redis parameters were moved such that the `REDIS_URL`
environment variable must now be used instead.

In 7729a26 a `use Goliath::Rack::Params` was added, which changes the
behaviour when printing the `env` in `response(env)`.  This will be
fixed in a later commit.

In 5f00e6d the XMPP features list advertised by sgx-catapult has been
fixed.  This is long overdue and good to have corrected at last.

See merge request !9 for the discussion and details behind the merge.

Also, remove advertisements of support for things we don't currently
support.

Defer executing the event loop until exit in case someone `require`s us
and wants to install extra stuff before we run.

Some small tweaks to the APIs to make the coming fwdcalls plugover
easier.

Also, normalise to use REDIS_URL environment variable instead of passing
host/port in args.

In particular, tested SMS send/receive (shouldn't have been impacted)
as well as the registration form display on an already-registered
account (using Cheogram's "Configure direct message route" ad-hoc
command).  Both appeared to work fine.  Since we don't currently use
much more than this in JMP (most registration is done behind the
scenes and Cheogram mainly uses registration for verification reasons)
that should be sufficient testing for now.

See merge request !8 for the discussion and details behind the merge.

Now everything uses EM and there's no blocking IO!

Also, fixes stalls caused by Blather mixing threads with EM by default:
https://github.com/adhearsion/blather/issues/130
https://github.com/eventmachine/eventmachine/issues/779

The last one (!11) wasn't quite right, but with this #8 is now fixed.

See merge request !12 for the discussion and details behind the merge.

By default, blather treats both false and nil returns from a handler as
a signal to pass control to the next handler.  That's counter-intuitive,
so let's over-ride that and always stop after the first handler (unless
throw(:pass) is explicitly called).

Catch everything that could happen in a handler, in every handler, and
panic if there's anything unhandled.

This reverts commit b5f8cc47d6eccf8214a653612527cbf76724385d.

Apparently blather is running the handlers for *all* iq, not just the
ones unhandled by others.

Thanks to @singpolyma for both reporting (#8) and fixing this.

See merge request !11 for the discussion and details behind the merge.

Closes #8

In the pre-refactor code, response.to_s looks something like this:
"#<Net::HTTPOK:0x00000002b8dad8>".  After the refactor in ff64421 the
chosen replacement value (http.response) outputs the entire body of
the response instead, which is more than we're looking to log.  So
remove it entirely ("#<EventMachine::HttpClient:0x00000001d6b810>",
the value of http.to_s, is even less useful than response.to_s was)
and just print the response code on its own in that line now.

This happens to fix an 80-column violation introduced in ff64421 as
well, which we should probably have checked by RuboCop at some point.