def check

bend-kit-websocket@0.4.0.0 · websocket.bend:208

import Base

208# Does a server's head (up to its blank line) accept the upgrade? want is accept(key).
209# Upgrade and Sec-WebSocket-Accept must each come once. No extension or subprotocol
210# was asked for, so the server may name none (§4.1).
211def check(+head: String, +want: String) -> Result<&1, &1, U32 & String, Unit>:
212  verdict(Unit,
213    first(reject(Bool.not(status(String.split(head, '\n'))), 1002, "status line is not HTTP/1.1 101"),
214    first(reject(Bool.not(lines.ok(headers(head))), 1002, "malformed header line"),
215    first(reject(Bool.not(value.is(value.lower(field(head, "upgrade")), "websocket")), 1002, "Upgrade is not one websocket"),
216    first(reject(Bool.not(tokens(fields(head, "connection"), "upgrade")), 1002, "Connection lacks Upgrade"),
217    first(reject(Bool.not(value.is(field(head, "sec-websocket-accept"), want)), 1002, "Sec-WebSocket-Accept is not one match for the key"),
218    first(reject(Bool.not(none(fields(head, "sec-websocket-extensions"))), 1002, "unrequested extension"),
219      reject(Bool.not(none(fields(head, "sec-websocket-protocol"))), 1002, "unrequested subprotocol"))))))),
220    Unit{})