fix: tolerate SSE-buffering reverse proxies in the composer - #631
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Deployments behind a reverse proxy or WAF that buffers text/event-stream responses break two client paths, since SSE frames may never reach the browser: 1. ensureEventsConnected() before sendAgentCommand waits for a connected event that never arrives — the composer silently swallows the message (input cleared, no POST, no error). Race it against a 3s timeout so the prompt is sent regardless; a missed stream then only costs event-based niceties, not the prompt itself. 2. Prompt settlement relies on SSE events; with the stream buffered the UI settles only on the next reconcile poll (15s default). Keep the default but allow NEXT_PUBLIC_AGENT_STATE_RECONCILE_MS to lower it (e.g. 2000) so a finished prompt settles the UI within ~2s on such deployments. Verified behind an Nginx reverse proxy with SSE buffering enabled: prompts send, complete, and render within ~2s with the env override; without the fix the message never POSTs and the UI hangs until a manual refresh.
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What does this PR do?
Deployments behind a reverse proxy / WAF that buffers
text/event-streamresponses break two client paths, because SSE frames never reach the browser:ensureEventsConnected()beforesendAgentCommandwaits for a connected event that never arrives — the composer silently swallows the message (input clears, no POST, no error). This PR races it against a 3s timeout (SSE_CONNECT_RACE_TIMEOUT_MS), so the prompt always goes out; a missed stream only costs event-based niceties, not the prompt itself.NEXT_PUBLIC_AGENT_STATE_RECONCILE_MSso buffering-proxy deployments can lower it (e.g. 2000 → UI settles ~2s after completion).Design note
Defaults are unchanged — direct-connection users see zero behavior difference. The env override is opt-in for non-ideal proxies where the correct server-side fix (disabling SSE buffering) isn't available.
Related Issue
No existing issue found for the silent-swallow symptom.
Changes Made
hooks/useAgentSession.ts:await ensureEventsConnected(...)call sites → raced againstSSE_CONNECT_RACE_TIMEOUT_MS(3s)AGENT_STATE_RECONCILE_MSnow overridable viaNEXT_PUBLIC_AGENT_STATE_RECONCILE_MS(default unchanged at 15s)Verification
Running behind Nginx with SSE buffering on (cannot change the upstream WAF config): without the fix, prompts never POST and the UI hangs; with it, prompts send, complete, and render within ~2s using the env override. Full vitest suite passes (844 tests),
tsc --noEmitclean.中文摘要：反代/WAF 缓冲 SSE 时，
ensureEventsConnected永远等不到 connected 事件，输入框会静默吞掉消息（不 POST 不报错）。改为 3s 竞速保底必发；reconcile 轮询保持 15s 默认、新增NEXT_PUBLIC_AGENT_STATE_RECONCILE_MS供缓冲代理部署降到 2s。默认行为零变化。