server.sse_lifecycle

SSE lifecycle bridge — connection status for[sse-connect]elements.

htmx's SSE extension creates anEventSourceinternally but doesn't surface connection lifecycle to the DOM in a way that's easy to style or hook into. This script bridges that gap.

On everyhtmx:sseOpen and htmx:sseErrorevent, it updates a data-sse-state attribute on the [sse-connect]element:

• "connected"— EventSource is open
• "disconnected"— EventSource errored or closed

This enables pure-CSS connection indicators::

[data-sse-state="disconnected"] .sse-indicator { display: block; }
[data-sse-state="connected"] .sse-indicator { display: none; }

It also dispatcheschirp:sse:connected and chirp:sse:disconnected custom events on the element for JS hooks.

Injected into full-page HTML responses viaHTMLInjectmiddleware. Controlled byAppConfig(sse_lifecycle=True) (default: True).