feat: http2settings implementation

lib/http2client.js

@@ -0,0 +1,51 @@
+const FRAME_TYPES = [
+	"DATA", // standard request / response payloads
+	"HEADERS", // starts stream, carries request headers
+	"PRIORITY", // advises the priority of a stream
+	"RST_STREAM", // immediately terminates a stream
+	"SETTINGS", // inform other end of endpoint config
+	"PUSH_PROMISE", // pre-warns peer of wanted streams
+	"PING",
+	"GOAWAY", // graceful version of RST_STREAM
+	"WINDOW_UPDATE", // defines flow-control
+	"CONTINUATION" // continue a sequence of headers
+];
+
+function parseHttp2Settings(settings) {
+
+	/* under RFC7540 section 3.2.1, the settings must be a base64url encoded
+	   SETTINGS frame. 16 bit identifiers, 32 bit values. */
+	let parsed = "";
+	for (let i = 0; i < Object.keys(settings).length; i += 2) {
+		parsed += `${settings[i]}${settings[i + 1]}\r\n`;
+	}
+
+	// base64url polyfill, courtesy of @panva
+	let encoded;
+	if (Buffer.isEncoding("base64url")) {
+		encoded = Buffer.from(settings)
+			.toString("base64url")
+			.replace(/[=]+$/g, "");
+	} else {
+		encoded = Buffer.from(settings)
+			.toString("base64")
+			.replace(/\+/g, "-")
+			.replace(/\//g, "_")
+			.replace(/[=]+$/g, "");
+	}
+	return encoded;
+}
+
+function http2Connect(url, options) {
+	if (url.protocol === "https:") {
+		throw new Error("Invalid protocol - httpConnect upgrades http streams");
+	}
+	throw new Error("UNIMPLEMENTED");
+}
+
+function https2Connect(url, options) {
+	if (url.protocol === "http:") {
+		throw new Error("Invalid protocol - https2Connect upgrades https streams");
+	}
+	throw new Error("UNIMPLEMENTED");
+}