refactor: node tools and canvas host url

src/infra/canvas-host-url.ts

@@ -0,0 +1,64 @@
+type HostSource = string | null | undefined;
+
+type CanvasHostUrlParams = {
+  canvasPort?: number;
+  hostOverride?: HostSource;
+  requestHost?: HostSource;
+  forwardedProto?: HostSource | HostSource[];
+  localAddress?: HostSource;
+  scheme?: "http" | "https";
+};
+
+const isLoopbackHost = (value: string) => {
+  const normalized = value.trim().toLowerCase();
+  if (!normalized) return false;
+  if (normalized === "localhost") return true;
+  if (normalized === "::1") return true;
+  if (normalized === "0.0.0.0" || normalized === "::") return true;
+  return normalized.startsWith("127.");
+};
+
+const normalizeHost = (value: HostSource, rejectLoopback: boolean) => {
+  if (!value) return "";
+  const trimmed = value.trim();
+  if (!trimmed) return "";
+  if (rejectLoopback && isLoopbackHost(trimmed)) return "";
+  return trimmed;
+};
+
+const parseHostHeader = (value: HostSource) => {
+  if (!value) return "";
+  try {
+    return new URL(`http://${String(value).trim()}`).hostname;
+  } catch {
+    return "";
+  }
+};
+
+const parseForwardedProto = (value: HostSource | HostSource[]) => {
+  if (Array.isArray(value)) return value[0];
+  return value;
+};
+
+export function resolveCanvasHostUrl(params: CanvasHostUrlParams) {
+  const port = params.canvasPort;
+  if (!port) return undefined;
+
+  const scheme =
+    params.scheme ??
+    (parseForwardedProto(params.forwardedProto)?.trim() === "https"
+      ? "https"
+      : "http");
+
+  const override = normalizeHost(params.hostOverride, true);
+  const requestHost = normalizeHost(parseHostHeader(params.requestHost), !!override);
+  const localAddress = normalizeHost(
+    params.localAddress,
+    Boolean(override || requestHost),
+  );
+
+  const host = override || requestHost || localAddress;
+  if (!host) return undefined;
+  const formatted = host.includes(":") ? `[${host}]` : host;
+  return `${scheme}://${formatted}:${port}`;
+}