feat(connect): add preferH2 connector option to offer h2 first in ALPN#5327
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Antamansid wants to merge 1 commit into
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feat(connect): add preferH2 connector option to offer h2 first in ALPN#5327Antamansid wants to merge 1 commit into
preferH2 connector option to offer h2 first in ALPN#5327Antamansid wants to merge 1 commit into
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The built-in connector hardcodes `ALPNProtocols: ['http/1.1', 'h2']` (h1 first) after spreading user options, so the order cannot be overridden via the `connect` options. Servers that select the ALPN protocol by *client* preference — some load balancers do — then negotiate `http/1.1` even with `allowH2: true`, forcing the client onto HTTP/1.1. Add an opt-in `preferH2` option that, together with `allowH2`, offers ALPN as `['h2', 'http/1.1']` (h2 first) so HTTP/2 is negotiated whenever the server supports it. The default behaviour is unchanged. If the server does not support HTTP/2, ALPN transparently falls back to `http/1.1`. Signed-off-by: antamansid <antamansid@mail.ru>
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This relates to...
N/A — no existing issue. Affects clients talking to load balancers that select the ALPN protocol by client preference.
Rationale
The built-in connector hardcodes
ALPNProtocols: ['http/1.1', 'h2'](h1 first) after spreading user options (lib/core/connect.js), so the order cannot be overridden via theconnectoptions. Servers that select the ALPN protocol by client preference — some load balancers do (e.g. those relying on OpenSSL'sSSL_select_next_protosemantics) — then negotiatehttp/1.1even withallowH2: true, forcing the client onto HTTP/1.1.This adds an opt-in
preferH2connector option that, together withallowH2, offers ALPN as['h2', 'http/1.1'](h2 first), so HTTP/2 is negotiated whenever the server supports it. The default behaviour is unchanged (preferH2defaults tofalse). If the server does not support HTTP/2, ALPN transparently falls back tohttp/1.1.Changes
lib/core/connect.js: accept apreferH2build option; when set together withallowH2, offerALPNProtocols: ['h2', 'http/1.1']instead of the default['http/1.1', 'h2'].types/connector.d.ts: addpreferH2?: booleantoBuildOptions.docs/docs/api/Connector.md: document the new option.test/connect-h2-alpn-order.js: assert the offered ALPN order with and withoutpreferH2.test/types/connector.test-d.ts: type-level assertion forpreferH2.Features
preferH2(defaultfalse) to offer HTTP/2 first in ALPN, for servers that pick the protocol by client preference.Bug Fixes
N/A
Breaking Changes and Deprecations
N/A — the default ALPN order is unchanged;
preferH2is opt-in.Status