Merge branch 'master' into xtr/react-loop-simplification

packages/client/connection/src/api-request-trust.ts

@@ -14,6 +14,7 @@
  */
 
 import type { IncomingHttpHeaders } from 'node:http'
+import { isLoopbackHostname } from './loopback-hostname.ts'
 
 /** The request facts the fence reads (structural subset of IncomingMessage). */
 interface ApiTrustRequest {
@@ -25,14 +26,6 @@ function header(headers: IncomingHttpHeaders, name: string): string | undefined
   return typeof value === 'string' ? value : undefined
 }
 
-function isLoopbackHostname(hostname: string): boolean {
-  if (hostname === 'localhost' || hostname === '[::1]') return true
-  const parts = hostname.split('.')
-  return parts.length === 4
-    && parts[0] === '127'
-    && parts.every(part => /^\d{1,3}$/.test(part) && Number(part) <= 255)
-}
-
 /** Normalized URL of a Host-header authority (hostname lowercased, default port stripped, IPv6 bracketed), or undefined when unparsable. */
 function parseAuthority(authority: string): URL | undefined {
   try {

packages/client/connection/src/client/index.ts

@@ -8,6 +8,7 @@ import type { IApiClient } from './api.ts'
 import { ConnectionController, type ConnectionConfig, type ConnectionSinks, type ConnectionState } from './connection.ts'
 import { FixtureApiClient } from './fixture.ts'
 import { WebApiClient } from './web-api-client.ts'
+import { isLoopbackHostname } from '../loopback-hostname.ts'
 
 // ---- Contract re-exports (browser-safe apiproxy channels + core types) ----
 export type {
@@ -48,6 +49,8 @@ export const inject: string[] = []
 export interface ConnectionHandle {
   /** Shared api client (fixture or real, decided at boot from the page URL). */
   readonly api: IApiClient
+  /** Whether the current page authority is loopback; non-browser contexts default to true. */
+  readonly isLoopback: boolean
   /**
    * Start the connect/pump/reconnect loop with the consumer's frame sinks.
    * One consumer owns the streams (the runtime object layer); a second call
@@ -64,11 +67,13 @@ export interface ConnectionHandle {
  * @param ctx - client cordis context.
  */
 export function apply(ctx: Context): void {
-  const fixture = typeof location !== 'undefined' && new URLSearchParams(location.search).has('fixture')
+  const pageLocation = typeof location === 'undefined' ? undefined : location
+  const fixture = pageLocation !== undefined && new URLSearchParams(pageLocation.search).has('fixture')
   const api: IApiClient = fixture ? new FixtureApiClient() : new WebApiClient()
   let started = false
   const handle: ConnectionHandle = {
     api,
+    isLoopback: pageLocation === undefined || isLoopbackHostname(pageLocation.hostname),
     start(sinks, config) {
       if (started) throw new Error('connection: the stream loop is already owned by another consumer')
       started = true

packages/client/connection/src/loopback-hostname.ts

@@ -0,0 +1,18 @@
+/**
+ * Browser-safe, zero-dependency loopback classification shared by the `/api`
+ * Host fence and the package's `ctx.connection` state. The predicate stays
+ * package-internal; client plugins consume the derived state through Cordis.
+ */
+
+/**
+ * Whether a normalized URL hostname names the local loopback authority.
+ * @param hostname - WHATWG URL hostname (IPv6 literals retain brackets).
+ * @returns true for localhost, IPv6 loopback, or any IPv4 address in 127/8.
+ */
+export function isLoopbackHostname(hostname: string): boolean {
+  if (hostname === 'localhost' || hostname === '[::1]') return true
+  const parts = hostname.split('.')
+  return parts.length === 4
+    && parts[0] === '127'
+    && parts.every(part => /^\d{1,3}$/.test(part) && Number(part) <= 255)
+}