Add origin checks to web sockets (#6048)

* Move splitOnFirstEquals to util

I will be making use of this to parse the forwarded header.

* Type splitOnFirstEquals with two items

Also add some test cases.

* Check origin header on web sockets

* Update changelog with origin check

* Fix web sockets not closing with error code

test/unit/node/util.test.ts

@@ -601,3 +601,41 @@ describe("constructOpenOptions", () => {
     expect(urlSearch).toBe("?q=^&test")
   })
 })
+
+describe("splitOnFirstEquals", () => {
+  const tests = [
+    {
+      name: "empty",
+      key: "",
+      value: "",
+    },
+    {
+      name: "split on first equals",
+      key: "foo",
+      value: "bar",
+    },
+    {
+      name: "split on first equals even with multiple equals",
+      key: "foo",
+      value: "bar=baz",
+    },
+    {
+      name: "split with empty value",
+      key: "foo",
+      value: "",
+    },
+    {
+      name: "split with no value",
+      key: "foo",
+      value: undefined,
+    },
+  ]
+  tests.forEach((test) => {
+    it("should ${test.name}", () => {
+      const input = test.key && typeof test.value !== "undefined" ? `${test.key}=${test.value}` : test.key
+      const [key, value] = util.splitOnFirstEquals(input)
+      expect(key).toStrictEqual(test.key)
+      expect(value).toStrictEqual(test.value || undefined)
+    })
+  })
+})