web/client: update synology token from /api/auth call

When the /api/auth response indicates that synology auth is needed,
fetch the SynoToken and store it for future API calls.  This doesn't yet
update the server-side code to set the new SynoAuth field.

Updates tailscale/corp#14335

Signed-off-by: Will Norris <will@tailscale.com>

client/web/src/api.ts

@@ -1,4 +1,5 @@
 let csrfToken: string
+let synoToken: string | undefined // required for synology API requests
 let unraidCsrfToken: string | undefined // required for unraid POST requests (#8062)
 
 // apiFetch wraps the standard JS fetch function with csrf header
@@ -15,10 +16,14 @@ export function apiFetch(
 ): Promise<Response> {
   const urlParams = new URLSearchParams(window.location.search)
   const nextParams = new URLSearchParams(params)
+  if (synoToken) {
+    nextParams.set("SynoToken", synoToken)
+  } else {
     const token = urlParams.get("SynoToken")
     if (token) {
       nextParams.set("SynoToken", token)
     }
+  }
   const search = nextParams.toString()
   const url = `api${endpoint}${search ? `?${search}` : ""}`
 
@@ -62,6 +67,10 @@ function updateCsrfToken(r: Response) {
   }
 }
 
+export function setSynoToken(token?: string) {
+  synoToken = token
+}
+
 export function setUnraidCsrfToken(token?: string) {
   unraidCsrfToken = token
 }

client/web/src/hooks/auth.ts

@@ -1,9 +1,15 @@
 import { useCallback, useEffect, useState } from "react"
-import { apiFetch } from "src/api"
+import { apiFetch, setSynoToken } from "src/api"
+
+export enum AuthType {
+  synology = "synology",
+  tailscale = "tailscale",
+}
 
 export type AuthResponse = {
   ok: boolean
   authUrl?: string
+  authNeeded?: AuthType
 }
 
 // useAuth reports and refreshes Tailscale auth status
@@ -18,6 +24,14 @@ export default function useAuth() {
     return apiFetch(url, "GET")
       .then((r) => r.json())
       .then((d) => {
+        if ((d as AuthResponse).authNeeded == AuthType.synology) {
+          fetch("/webman/login.cgi")
+            .then((r) => r.json())
+            .then((data) => {
+              setSynoToken(data.SynoToken)
+            })
+        }
+
         setLoading(false)
         setData(d)
       })

client/web/web.go

@@ -269,9 +269,17 @@ func (s *Server) serveLoginAPI(w http.ResponseWriter, r *http.Request) {
 	return
 }
 
+type authType string
+
+var (
+	synoAuth      authType = "synology"  // user needs a SynoToken for subsequent API calls
+	tailscaleAuth authType = "tailscale" // user needs to complete Tailscale check mode
+)
+
 type authResponse struct {
 	OK         bool     `json:"ok"`                   // true when user has valid auth session
 	AuthURL    string   `json:"authUrl,omitempty"`    // filled when user has control auth action to take
+	AuthNeeded authType `json:"authNeeded,omitempty"` // filled when user needs to complete a specific type of auth
 }
 
 func (s *Server) serveTailscaleAuth(w http.ResponseWriter, r *http.Request) {