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by tannhaeuser 2674 days ago
I can't see any advantage in using JSON and HTTP for a protocol. JSON shines for ad-hoc, untyped, structured message payloads rather than the strongly-typed semistructured text payloads possible with XML/SGML, and HTTP wasn't designed for federated protocols. It seems more like a fashion thing to me.
3 comments
forty 2674 days ago
I kind of agree with you, but I'll add that XMPP usage of XML is weird enough that it makes it hard it use a normal XML parser / producer. Honestly I really wanted to like XMPP. I read all the specs at the time, even started to write some code, but all I can say is that it really sucks. I haven't looked at matrix yet, I hope it's better
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olau 2674 days ago
Indeed! I was in the same boat - also started writing a client, but wasted too much time on the stupid XML stream idea.

Basically, chatting is message oriented, but the XMPP inventors thought it would be neat to start the connection with a tag like <beginconversation> which would then be dangling for the whole connection, preventing the use of a simple DOM XML parser (remember this is many years ago) for each message.

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edhelas 2673 days ago
Any XML parser that I know can parse XML in a stream, that's all you need to handle an incoming XMPP stream.

Just an example, here is the XML parser that I wrote in PHP https://github.com/movim/movim/blob/master/lib/moxl/src/Moxl... (127 lines), it basically handle the stream as an input and fire SimpleXML (can also be DOM XML) on the other hand.

This can handle thousands of XMPP messages (called stanza) per second :)

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forty 2673 days ago
Can it handle plaintext XML suddenly becoming TLS encrypted? Because that's also what happens on any XMPP connection. If it can, then great but I guess it's more an exception than the rule
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Arathorn 2673 days ago
fwiw, in Matrix, to send a message, it's:

  curl 'https://matrix.org/_matrix/client/r0/rooms/!RXNcERlITUVszBNIPW%3Amatrix.org/send/m.room.message/123?access_token='$TOKEN -X PUT --data '{"msgtype":"m.text","body":"hello world"}'
and to receive messages it's:

  curl 'https://matrix.org/_matrix/client/r0/sync?access_token='$TOKEN
Hopefully this ends up being quite easy to work with :)
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edhelas 2673 days ago
and for XMPP

    <message to="user@server.com"><body>Hello world</body></message>
No need for a token, the socket you're in is already authenticated :)
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eeZah7Ux 2674 days ago
Also flexibility can be good but XMPP is way too modular.
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edhelas 2673 days ago
You don't have to implement all the modules :p There is some basic ones that you need (see XEP-0412: XMPP Compliance Suites 2019 - https://xmpp.org/extensions/xep-0412.html) and you have already an up to date client and server. The rest if for specific use cases.
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Perceptes 2674 days ago
Part of their rationale is explained in their FAQ: https://matrix.org/docs/guides/faq#why-http%3F-doesn't-http-...
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zeveb 2673 days ago
I dislike JSON, but it's a step in the right direction from XML. XML is an inelegant, verbose, over-specified mess, a relic of 90s thinking. JSON is definitely an improvement.

HTPP's fine, I guess. It's certainly available everywhere, and saves one from writing a bunch of tiresome parsing code. But that's really an indictment of the current state of our technology. Popular languages should make it easy to read structured data out of a socket (with some sort of max length to prevent DDoSes) & write structured data to a socket. Since they don't, HTTP is an okay compromise. It's a bit heavyweight, but it gets the job done.

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