https://github.com/horazont/xmpp-echo-bot

XMPP/Jabber echo bot (written in sed)
https://github.com/horazont/xmpp-echo-bot

bash chatbot sed xmpp-bot

Last synced: about 2 months ago
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XMPP/Jabber echo bot (written in sed)

• Host: GitHub
• URL: https://github.com/horazont/xmpp-echo-bot
• Owner: horazont
• Created: 2018-04-20T10:43:04.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2020-07-25T17:55:51.000Z (about 4 years ago)
• Last Synced: 2024-07-05T12:29:33.108Z (3 months ago)
• Topics: bash, chatbot, sed, xmpp-bot
• Language: sed
• Size: 11.7 KB
• Stars: 148
• Watchers: 5
• Forks: 12
• Open Issues: 3
• Metadata Files:
  • Readme: README.rst

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README

        
XMPP Echo Bot

=============

Do you know that situation, you really really need an XMPP echo bot, but you don’t have access to high-level tools like `Python `_ to write one? All you have is `openssl`, `bash`, `dig`, `stdbuf` and `sed`? Then this tool is for you.

This is an XMPP echo bot written in (mostly) sed. Bash is used to do the pre-authentication setup (look up DNS records, establish TLS via ``openssl s_client``). sed processes the XML stream and handles all interaction with the server on the XMPP level. Yes, this kinda parses XML in sed.

Tested to work against Prosody 0.9.

Usage

-----

::

    ./echoz.sh user@domain password

Supported Features

------------------

* Off-the-Record messaging

* `XEP-0092 (Software Version) `_

* `XEP-0199 (XMPP Ping) `_

Testimonials

------------

* *This is crazy, I haven't crashed it yet!* — `Matthew Wild `_

* *I'm frightened. It's only two steps away from gaining consciousness.* — `Georg Lukas `_

* *I am simultaneously appalled and in awe. wow* — `Lance `_

* *With Echoz.sed, we were able to reduce our XMPP Echo server costs by 90% compared to our previous TeX-based solution.* — Leon

* *While simple and limited, sed is sufficiently powerful for a large number of purposes.* — `Wikipedia `_

* *oh my god this actually works* — `Test `_

Implementation Details

----------------------

* We use ``tr`` to convert ``>`` to ``\n`` -- since sed is line (or NUL) based, there’s not really another way to parse XMPP XML (which generally never contains newlines) with sed.

* TLS is handled outside of sed for similar reasons. And to keep my sanity (some people might question whether I still have any bit of sanity left).

* Likewise, SRV lookup and composition of the authentication data is entirely handled in bash. This also means that only PLAIN SASL authentication is supported -- SCRAM requires a level of interactivity which would be extremely hard to achieve in sed (not impossible though; we would "just" have to implement base64 and sha1-hmac in sed).

* Since XMPP is a protocol where the client speaks first, we need to hand sed some initial input to allow it to generate a "line" of output (the stream header). We do that with bash, and use that opportunity to pass some configuration to the sed program (namely JID and authentication string).

**Design Considerations**

* We considered using ``xml2`` to convert the XML stream into events; however, it turns out that ``2xm[`` doesn’t like stream resets. Also, using the ``tr`` approach also allows us to detect the end of elements, which is useful for various purposes.