Explain how we speak before the server

1 files changed, 1 insertions, 0 deletions

diff --git a/README.rst b/README.rst
index 17eea4a..c0d72bf 100644
--- a/README.rst
+++ b/README.rst
@@ -11,6 +11,7 @@ Tricks and shortcuts
 * 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).
 
 Usage
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