refactor(ext/http): extract 02_websocket.ts from 01_http.js (#23460)

Landing part of https://github.com/denoland/deno/pull/21903

This will allow us to more easily refactor `serveHttp` to live on top of
`serve` by splitting the websocket code out. There's probably a lot more
we could do here but this helps.

1 files changed, 185 insertions, 0 deletions

diff --git a/ext/http/02_websocket.ts b/ext/http/02_websocket.ts
new file mode 100644
index 000000000..073929961
--- /dev/null
+++ b/ext/http/02_websocket.ts
@@ -0,0 +1,185 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+import { internals, primordials } from "ext:core/mod.js";
+import { op_http_websocket_accept_header } from "ext:core/ops";
+const {
+  ArrayPrototypeIncludes,
+  ArrayPrototypeMap,
+  ArrayPrototypePush,
+  StringPrototypeCharCodeAt,
+  StringPrototypeSplit,
+  StringPrototypeToLowerCase,
+  StringPrototypeToUpperCase,
+  TypeError,
+  Symbol,
+} = primordials;
+import { toInnerRequest } from "ext:deno_fetch/23_request.js";
+import {
+  fromInnerResponse,
+  newInnerResponse,
+} from "ext:deno_fetch/23_response.js";
+import { setEventTargetData } from "ext:deno_web/02_event.js";
+import {
+  _eventLoop,
+  _idleTimeoutDuration,
+  _idleTimeoutTimeout,
+  _protocol,
+  _readyState,
+  _rid,
+  _role,
+  _server,
+  _serverHandleIdleTimeout,
+  createWebSocketBranded,
+  WebSocket,
+} from "ext:deno_websocket/01_websocket.js";
+
+const _ws = Symbol("[[associated_ws]]");
+
+const websocketCvf = buildCaseInsensitiveCommaValueFinder("websocket");
+const upgradeCvf = buildCaseInsensitiveCommaValueFinder("upgrade");
+
+function upgradeWebSocket(request, options = {}) {
+  const inner = toInnerRequest(request);
+  const upgrade = request.headers.get("upgrade");
+  const upgradeHasWebSocketOption = upgrade !== null &&
+    websocketCvf(upgrade);
+  if (!upgradeHasWebSocketOption) {
+    throw new TypeError(
+      "Invalid Header: 'upgrade' header must contain 'websocket'",
+    );
+  }
+
+  const connection = request.headers.get("connection");
+  const connectionHasUpgradeOption = connection !== null &&
+    upgradeCvf(connection);
+  if (!connectionHasUpgradeOption) {
+    throw new TypeError(
+      "Invalid Header: 'connection' header must contain 'Upgrade'",
+    );
+  }
+
+  const websocketKey = request.headers.get("sec-websocket-key");
+  if (websocketKey === null) {
+    throw new TypeError(
+      "Invalid Header: 'sec-websocket-key' header must be set",
+    );
+  }
+
+  const accept = op_http_websocket_accept_header(websocketKey);
+
+  const r = newInnerResponse(101);
+  r.headerList = [
+    ["upgrade", "websocket"],
+    ["connection", "Upgrade"],
+    ["sec-websocket-accept", accept],
+  ];
+
+  const protocolsStr = request.headers.get("sec-websocket-protocol") || "";
+  const protocols = StringPrototypeSplit(protocolsStr, ", ");
+  if (protocols && options.protocol) {
+    if (ArrayPrototypeIncludes(protocols, options.protocol)) {
+      ArrayPrototypePush(r.headerList, [
+        "sec-websocket-protocol",
+        options.protocol,
+      ]);
+    } else {
+      throw new TypeError(
+        `Protocol '${options.protocol}' not in the request's protocol list (non negotiable)`,
+      );
+    }
+  }
+
+  const socket = createWebSocketBranded(WebSocket);
+  setEventTargetData(socket);
+  socket[_server] = true;
+  socket[_idleTimeoutDuration] = options.idleTimeout ?? 120;
+  socket[_idleTimeoutTimeout] = null;
+
+  if (inner._wantsUpgrade) {
+    return inner._wantsUpgrade("upgradeWebSocket", r, socket);
+  }
+
+  const response = fromInnerResponse(r, "immutable");
+
+  response[_ws] = socket;
+
+  return { response, socket };
+}
+
+const spaceCharCode = StringPrototypeCharCodeAt(" ", 0);
+const tabCharCode = StringPrototypeCharCodeAt("\t", 0);
+const commaCharCode = StringPrototypeCharCodeAt(",", 0);
+
+/** Builds a case function that can be used to find a case insensitive
+ * value in some text that's separated by commas.
+ *
+ * This is done because it doesn't require any allocations.
+ * @param checkText {string} - The text to find. (ex. "websocket")
+ */
+function buildCaseInsensitiveCommaValueFinder(checkText) {
+  const charCodes = ArrayPrototypeMap(
+    StringPrototypeSplit(
+      StringPrototypeToLowerCase(checkText),
+      "",
+    ),
+    (c) => [
+      StringPrototypeCharCodeAt(c, 0),
+      StringPrototypeCharCodeAt(StringPrototypeToUpperCase(c), 0),
+    ],
+  );
+  /** @type {number} */
+  let i;
+  /** @type {number} */
+  let char;
+
+  /** @param {string} value */
+  return function (value) {
+    for (i = 0; i < value.length; i++) {
+      char = StringPrototypeCharCodeAt(value, i);
+      skipWhitespace(value);
+
+      if (hasWord(value)) {
+        skipWhitespace(value);
+        if (i === value.length || char === commaCharCode) {
+          return true;
+        }
+      } else {
+        skipUntilComma(value);
+      }
+    }
+
+    return false;
+  };
+
+  /** @param value {string} */
+  function hasWord(value) {
+    for (let j = 0; j < charCodes.length; ++j) {
+      const { 0: cLower, 1: cUpper } = charCodes[j];
+      if (cLower === char || cUpper === char) {
+        char = StringPrototypeCharCodeAt(value, ++i);
+      } else {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /** @param value {string} */
+  function skipWhitespace(value) {
+    while (char === spaceCharCode || char === tabCharCode) {
+      char = StringPrototypeCharCodeAt(value, ++i);
+    }
+  }
+
+  /** @param value {string} */
+  function skipUntilComma(value) {
+    while (char !== commaCharCode && i < value.length) {
+      char = StringPrototypeCharCodeAt(value, ++i);
+    }
+  }
+}
+
+// Expose this function for unit tests
+internals.buildCaseInsensitiveCommaValueFinder =
+  buildCaseInsensitiveCommaValueFinder;
+
+export { _ws, upgradeWebSocket };