57 lines
2.1 KiB
TypeScript
57 lines
2.1 KiB
TypeScript
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/**
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* `/plugins/events` SSE channel: the system-side push surface for the client
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* entry graph (connect → current graph frame; dev rebuild → rebuilt frame).
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* Presentation-only wire — frames never enter the session log (distinct from
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* the /api/* session SSE, which is api-contract territory). Connections are
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* plain node:http responses held in a set; the server's closeAllConnections
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* tears them down on shutdown.
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*/
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import type { ServerResponse } from 'node:http'
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import type { WebBootGraph } from './web-plugins.ts'
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/** One `/plugins/events` frame: the full graph on connect, or one rebuilt bundle notice. */
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export type PluginEventFrame =
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| { type: 'graph'; graph: WebBootGraph }
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| { type: 'rebuilt'; id: string; rev: string }
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/** Broadcast surface owned by the webserver routing layer. */
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export interface PluginEventChannel {
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/** Adopt one incoming SSE request: writes the SSE preamble and the current-graph frame, then keeps the response open. */
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connect(res: ServerResponse, graph: WebBootGraph): void
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/** Push one frame to every open connection. */
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broadcast(frame: PluginEventFrame): void
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}
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/** Serialize one frame as an SSE data line. */
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function sseData(frame: PluginEventFrame): string {
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return `data: ${JSON.stringify(frame)}\n\n`
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}
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/**
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* Create the channel (one per running server).
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* @returns the connect/broadcast surface.
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*/
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export function createPluginEventChannel(): PluginEventChannel {
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const connections = new Set<ServerResponse>()
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return {
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connect(res, graph) {
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res.writeHead(200, {
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'content-type': 'text/event-stream',
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'cache-control': 'no-cache',
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'connection': 'keep-alive',
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})
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// Comment line on open so clients/proxies see a live channel even when
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// no rebuild ever happens; EventSource frame parsing skips it naturally.
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res.write(': connected\n\n')
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res.write(sseData({ type: 'graph', graph }))
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connections.add(res)
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res.on('close', () => { connections.delete(res) })
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},
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broadcast(frame) {
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const line = sseData(frame)
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for (const res of connections) res.write(line)
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},
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}
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}
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