fix: return HTML for browser Accept headers on root route (#532) (#546)

Justxd22 · web-flow · commit faa7ed2ed652 · 2026-04-30T07:29:40.000-04:00
diff --git a/.changeset/dark-places-tickle.md b/.changeset/dark-places-tickle.md
@@ -0,0 +1,5 @@
+---
+"nostream": patch
+---
+
+Fix root HTML negotiation and subpath-aware template links behind trusted proxies.
diff --git a/package.json b/package.json
@@ -153,10 +153,9 @@
     "node": ">=24.14.1"
   },
   "dependencies": {
-    "@getalby/sdk": "^5.0.0",
     "@clack/prompts": "^1.2.0",
+    "@getalby/sdk": "^5.0.0",
     "@noble/secp256k1": "1.7.1",
-    "accepts": "^1.3.8",
     "axios": "^1.15.0",
     "cac": "^7.0.0",
     "colorette": "^2.0.20",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
diff --git a/resources/get-invoice.html b/resources/get-invoice.html
@@ -9,7 +9,7 @@
   </head>
   <body lang="en">
     <main class="container">
-      <form method="post" action="/invoices">
+      <form method="post" action="{{path_prefix}}/invoices">
         <div class="row">
           <div class="col">
             <h1 class="mt-4 mb-4 text-center text-nowrap">{{name}}</h1>
@@ -46,7 +46,7 @@ <h1 class="mt-4 mb-4 text-center text-nowrap">{{name}}</h1>
               <div class="form-check">
                 <input class="form-check-input" type="checkbox" id="tosAccepted" name="tosAccepted" value="yes" required>
                 <label class="form-check-label" for="tosAccepted">
-                  I have read and agree to the <a href="/terms" class="card-link" target="_blank" rel="noopener noreferrer">Terms of Service</a>
+                  I have read and agree to the <a href="{{path_prefix}}/terms" class="card-link" target="_blank" rel="noopener noreferrer">Terms of Service</a>
                 </label>
               </div>
             </div>
diff --git a/resources/index.html b/resources/index.html
@@ -46,7 +46,7 @@ <h5 class="card-title">Admission Required</h5>
                 This relay requires a one-time admission fee of <strong>{{amount}} sats</strong>
                 to publish events. Reading events is free.
               </p>
-              <a href="/invoices" class="btn btn-warning">Pay Admission Fee</a>
+              <a href="{{path_prefix}}/invoices" class="btn btn-warning">Pay Admission Fee</a>
             </div>
           </div>
 
@@ -62,9 +62,9 @@ <h5 class="card-title">Open Relay</h5>
 
           <!-- Legal links -->
           <div class="d-flex justify-content-center gap-3 mt-2 mb-5">
-            <a href="/terms" class="text-muted small">Terms of Service</a>
+            <a href="{{path_prefix}}/terms" class="text-muted small">Terms of Service</a>
             <span class="text-muted small">·</span>
-            <a href="/privacy" class="text-muted small">Privacy Policy</a>
+            <a href="{{path_prefix}}/privacy" class="text-muted small">Privacy Policy</a>
           </div>
 
         </div>
diff --git a/resources/invoices.html b/resources/invoices.html
@@ -14,7 +14,7 @@
   </head>
   <body lang="en">
     <main class="container">
-      <form method="post" action="/invoices">
+      <form method="post" action="{{path_prefix}}/invoices">
         <div class="row">
           <div class="col">
             <h1 class="mt-4 mb-4 text-center text-nowrap">{{name}}</h1>
@@ -106,6 +106,7 @@ <h2 class="text-danger">Invoice expired!</h2>
       var reference = "{{reference}}"
       var relayUrl = "{{relay_url}}"
       var relayPubkey = "{{relay_pubkey}}"
+      var pathPrefix = {{path_prefix_json}};
       var invoice = "{{invoice}}";
       var pubkey = "{{pubkey}}"
       var expiresAt = "{{expires_at}}"
@@ -124,7 +125,7 @@ <h2 class="text-danger">Invoice expired!</h2>
       }
 
       async function getInvoiceStatus() {
-        fetch(`/invoices/${reference}/status`).then(async (response) => {
+        fetch(`${pathPrefix}/invoices/${reference}/status`).then(async (response) => {
           const data = await response.json()
           console.log('data', data)
           const { status } = data;
@@ -269,4 +270,4 @@ <h2 class="text-danger">Invoice expired!</h2>
       document.getElementById('sendPaymentBtn').addEventListener('click', sendPayment)
     </script>
   </body>
-</html>
+</html>
diff --git a/resources/post-invoice.html b/resources/post-invoice.html
@@ -14,7 +14,7 @@
   </head>
   <body lang="en">
     <main class="container">
-      <form method="post" action="/invoices">
+      <form method="post" action="{{path_prefix}}/invoices">
         <div class="row">
           <div class="col">
             <h1 class="mt-4 mb-4 text-center text-nowrap">{{name}}</h1>
@@ -106,6 +106,7 @@ <h2 class="text-danger">Invoice expired!</h2>
       var reference = {{reference_json}}
       var relayUrl = {{relay_url_json}}
       var relayPubkey = {{relay_pubkey_json}}
+      var pathPrefix = {{path_prefix_json}}
       var invoice = {{invoice_json}}
       var pubkey = {{pubkey_json}}
       var expiresAt = {{expires_at_json}}
@@ -124,7 +125,7 @@ <h2 class="text-danger">Invoice expired!</h2>
       }
 
       async function getInvoiceStatus() {
-        fetch(`/invoices/${reference}/status`).then(async (response) => {
+        fetch(`${pathPrefix}/invoices/${reference}/status`).then(async (response) => {
           if (!response.ok) {
             throw new Error(`unexpected status ${response.status}`)
           }
diff --git a/resources/privacy.html b/resources/privacy.html
@@ -61,9 +61,9 @@ <h5>Changes to this policy</h5>
           </p>
 
           <div class="mt-4">
-            <a href="/" class="text-muted small">← Back to home</a>
+            <a href="{{path_prefix}}/" class="text-muted small">← Back to home</a>
             <span class="text-muted small mx-2">·</span>
-            <a href="/terms" class="text-muted small">Terms of Service</a>
+            <a href="{{path_prefix}}/terms" class="text-muted small">Terms of Service</a>
           </div>
         </div>
       </div>
diff --git a/src/controllers/invoices/get-invoice-controller.ts b/src/controllers/invoices/get-invoice-controller.ts
@@ -8,9 +8,10 @@ import { FeeSchedule } from '../../@types/settings'
 import { IController } from '../../@types/controllers'
 
 import { getTemplate } from '../../utils/template-cache'
+import { getPublicPathPrefix } from '../../utils/http'
 
 export class GetInvoiceController implements IController {
-  public async handleRequest(_req: Request, res: Response): Promise<void> {
+  public async handleRequest(req: Request, res: Response): Promise<void> {
     const settings = createSettings()
 
     if (
@@ -21,6 +22,7 @@ export class GetInvoiceController implements IController {
       const feeSchedule = path<FeeSchedule>(['payments', 'feeSchedules', 'admission', '0'], settings)
       const page = getTemplate('./resources/get-invoice.html')
         .replaceAll('{{name}}', escapeHtml(name))
+        .replaceAll('{{path_prefix}}', escapeHtml(getPublicPathPrefix(req, settings)))
         .replaceAll('{{processor_json}}', safeJsonForScript(settings.payments.processor))
         .replaceAll('{{amount}}', (BigInt(feeSchedule.amount) / 1000n).toString())
         .replaceAll('{{nonce}}', res.locals.nonce)
diff --git a/src/controllers/invoices/post-invoice-controller.ts b/src/controllers/invoices/post-invoice-controller.ts
@@ -14,7 +14,7 @@ import { createLogger } from '../../factories/logger-factory'
 import { escapeHtml, safeJsonForScript } from '../../utils/html'
 import { fromBech32, toBech32 } from '../../utils/transform'
 import { getPublicKey, getRelayPrivateKey } from '../../utils/event'
-import { getRemoteAddress } from '../../utils/http'
+import { getPublicPathPrefix, getRemoteAddress } from '../../utils/http'
 import { getTemplate } from '../../utils/template-cache'
 
 const logger = createLogger('post-invoice-controller')
@@ -125,6 +125,7 @@ export class PostInvoiceController implements IController {
     const relayPubkey = getPublicKey(relayPrivkey)
 
     const expiresAt = invoice.expiresAt?.toISOString() ?? ''
+    const pathPrefix = getPublicPathPrefix(request, currentSettings)
 
     const pageContent = getTemplate('./resources/post-invoice.html')
     const body = pageContent
@@ -133,6 +134,7 @@ export class PostInvoiceController implements IController {
       .replaceAll('{{relay_url_html}}', escapeHtml(relayUrl))
       .replaceAll('{{invoice_html}}', escapeHtml(invoice.bolt11))
       .replaceAll('{{pubkey_html}}', escapeHtml(pubkey))
+      .replaceAll('{{path_prefix}}', escapeHtml(pathPrefix))
       .replaceAll('{{amount}}', (amount / 1000n).toString())
       // JS contexts — safeJsonForScript serializes and escapes < to prevent </script> injection
       .replaceAll('{{reference_json}}', safeJsonForScript(invoice.id))
@@ -141,6 +143,7 @@ export class PostInvoiceController implements IController {
       .replaceAll('{{invoice_json}}', safeJsonForScript(invoice.bolt11))
       .replaceAll('{{pubkey_json}}', safeJsonForScript(pubkey))
       .replaceAll('{{expires_at_json}}', safeJsonForScript(expiresAt))
+      .replaceAll('{{path_prefix_json}}', safeJsonForScript(pathPrefix))
       .replaceAll('{{processor_json}}', safeJsonForScript(currentSettings.payments.processor))
       // nonce is crypto-random base64 — safe in both attribute and script contexts
       .replaceAll('{{nonce}}', response.locals.nonce)
diff --git a/src/handlers/request-handlers/get-privacy-request-handler.ts b/src/handlers/request-handlers/get-privacy-request-handler.ts
@@ -3,18 +3,21 @@ import { NextFunction, Request, Response } from 'express'
 import { createSettings as settings } from '../../factories/settings-factory'
 
 import { escapeHtml } from '../../utils/html'
+import { getPublicPathPrefix } from '../../utils/http'
 
 import { getTemplate } from '../../utils/template-cache'
 
-export const getPrivacyRequestHandler = (_req: Request, res: Response, next: NextFunction) => {
+export const getPrivacyRequestHandler = (req: Request, res: Response, next: NextFunction) => {
+  const currentSettings = settings()
   const {
     info: { name },
-  } = settings()
+  } = currentSettings
 
   let page: string
   try {
     page = getTemplate('./resources/privacy.html')
       .replaceAll('{{name}}', escapeHtml(name))
+      .replaceAll('{{path_prefix}}', escapeHtml(getPublicPathPrefix(req, currentSettings)))
       .replaceAll('{{nonce}}', res.locals.nonce)
   } catch (err) {
     next(err)
diff --git a/src/handlers/request-handlers/get-terms-request-handler.ts b/src/handlers/request-handlers/get-terms-request-handler.ts
@@ -1,17 +1,20 @@
 import { NextFunction, Request, Response } from 'express'
 import { escapeHtml } from '../../utils/html'
+import { getPublicPathPrefix } from '../../utils/http'
 import { getTemplate } from '../../utils/template-cache'
 import { createSettings as settings } from '../../factories/settings-factory'
 
-export const getTermsRequestHandler = (_req: Request, res: Response, next: NextFunction) => {
+export const getTermsRequestHandler = (req: Request, res: Response, next: NextFunction) => {
+  const currentSettings = settings()
   const {
     info: { name },
-  } = settings()
+  } = currentSettings
 
   let page: string
   try {
     page = getTemplate('./resources/terms.html')
       .replaceAll('{{name}}', escapeHtml(name))
+      .replaceAll('{{path_prefix}}', escapeHtml(getPublicPathPrefix(req, currentSettings)))
       .replaceAll('{{nonce}}', res.locals.nonce)
   } catch (err) {
     next(err)
diff --git a/src/handlers/request-handlers/root-request-handler.ts b/src/handlers/request-handlers/root-request-handler.ts
@@ -1,4 +1,3 @@
-import accepts from 'accepts'
 import { NextFunction, Request, Response } from 'express'
 import { path, pathEq } from 'ramda'
 import { createSettings } from '../../factories/settings-factory'
@@ -7,19 +6,51 @@ import { FeeSchedule } from '../../@types/settings'
 import { DEFAULT_FILTER_LIMIT } from '../../constants/base'
 import { fromBech32 } from '../../utils/transform'
 import { getTemplate } from '../../utils/template-cache'
+import { getPublicPathPrefix, joinPathPrefix } from '../../utils/http'
 import packageJson from '../../../package.json'
 
+export const hasExplicitNostrJsonAcceptHeader = (request: Request): boolean => {
+  const acceptHeader = request.headers.accept
+
+  if (!acceptHeader) {
+    return false
+  }
+
+  const acceptHeaderValue = Array.isArray(acceptHeader) ? acceptHeader.join(',') : acceptHeader
+
+  return acceptHeaderValue.split(',').some((token) => {
+    const [mediaType, ...params] = token
+      .split(';')
+      .map((value) => value.trim().toLowerCase())
+
+    if (mediaType !== 'application/nostr+json') {
+      return false
+    }
+
+    const quality = params.find((param) => param.startsWith('q='))
+
+    if (!quality) {
+      return true
+    }
+
+    const qValue = Number.parseFloat(quality.slice(2))
+
+    return !Number.isNaN(qValue) && qValue > 0
+  })
+}
+
 export const rootRequestHandler = (request: Request, response: Response, next: NextFunction) => {
   const settings = createSettings()
+  const pathPrefix = getPublicPathPrefix(request, settings)
 
-  if (accepts(request).type(['application/nostr+json'])) {
+  if (hasExplicitNostrJsonAcceptHeader(request)) {
     const {
       info: { name, description, banner, icon, pubkey: rawPubkey, self: rawSelf, contact, relay_url, terms_of_service },
     } = settings
 
     const paymentsUrl = new URL(relay_url)
     paymentsUrl.protocol = paymentsUrl.protocol === 'wss:' ? 'https:' : 'http:'
-    paymentsUrl.pathname = '/invoices'
+    paymentsUrl.pathname = joinPathPrefix(pathPrefix, '/invoices')
 
     const content = settings.limits?.event?.content
     const eventLimits = settings.limits?.event
@@ -112,6 +143,7 @@ export const rootRequestHandler = (request: Request, response: Response, next: N
       .replaceAll('{{description}}', escapeHtml(settings.info.description ?? ''))
       .replaceAll('{{relay_url}}', escapeHtml(settings.info.relay_url))
       .replaceAll('{{amount}}', amount)
+      .replaceAll('{{path_prefix}}', escapeHtml(pathPrefix))
       .replaceAll('{{payments_section_class}}', admissionFeeEnabled ? '' : 'd-none')
       .replaceAll('{{no_payments_section_class}}', admissionFeeEnabled ? 'd-none' : '')
       .replaceAll('{{nonce}}', response.locals.nonce)
diff --git a/src/routes/index.ts b/src/routes/index.ts
@@ -1,4 +1,3 @@
-import accepts from 'accepts'
 import express, { Router } from 'express'
 
 import { nodeinfo21Handler, nodeinfoHandler } from '../handlers/request-handlers/nodeinfo-handler'
@@ -9,12 +8,12 @@ import { getPrivacyRequestHandler } from '../handlers/request-handlers/get-priva
 import { getTermsRequestHandler } from '../handlers/request-handlers/get-terms-request-handler'
 import invoiceRouter from './invoices'
 import { rateLimiterMiddleware } from '../handlers/request-handlers/rate-limiter-middleware'
-import { rootRequestHandler } from '../handlers/request-handlers/root-request-handler'
+import { hasExplicitNostrJsonAcceptHeader, rootRequestHandler } from '../handlers/request-handlers/root-request-handler'
 
 const router: Router = express.Router()
 
 router.use((req, res, next) => {
-  if (req.method === 'GET' && accepts(req).type(['application/nostr+json'])) {
+  if (req.method === 'GET' && req.path === '/' && hasExplicitNostrJsonAcceptHeader(req)) {
     return rootRequestHandler(req, res, next)
   }
   next()
diff --git a/src/utils/http.ts b/src/utils/http.ts
@@ -56,3 +56,59 @@ export const getRemoteAddress = (request: IncomingMessage, settings: Settings):
 
   return (result as string).split(',')[0].trim()
 }
+
+const normalizePathPrefix = (pathPrefix: string | undefined): string => {
+  if (typeof pathPrefix !== 'string') {
+    return ''
+  }
+
+  const prefix = pathPrefix.split(',')[0].trim()
+
+  if (!prefix.startsWith('/') || prefix.startsWith('//')) {
+    return ''
+  }
+
+  try {
+    const { pathname } = new URL(prefix, 'http://nostream.local')
+    const normalized = pathname.replace(/\/+$/, '')
+
+    return normalized === '/' ? '' : normalized
+  } catch {
+    return ''
+  }
+}
+
+const getRelayUrlPathPrefix = (relayUrl: string | undefined): string => {
+  if (typeof relayUrl !== 'string') {
+    return ''
+  }
+
+  try {
+    return normalizePathPrefix(new URL(relayUrl).pathname)
+  } catch {
+    return ''
+  }
+}
+
+const getTrustedForwardedPathPrefix = (request: IncomingMessage, settings: Settings): string => {
+  const socketAddress = request.socket?.remoteAddress
+  if (typeof socketAddress !== 'string' || !isTrustedProxy(socketAddress, settings)) {
+    return ''
+  }
+
+  const rawHeader = request.headers?.['x-forwarded-prefix']
+  const rawPrefix = Array.isArray(rawHeader) ? rawHeader[0] : rawHeader
+
+  return normalizePathPrefix(rawPrefix)
+}
+
+export const getPublicPathPrefix = (request: IncomingMessage, settings: Settings): string => {
+  return getTrustedForwardedPathPrefix(request, settings) || getRelayUrlPathPrefix(settings.info?.relay_url)
+}
+
+export const joinPathPrefix = (prefix: string, path: string): string => {
+  const normalizedPrefix = prefix.replace(/\/+$/, '')
+  const normalizedPath = path.startsWith('/') ? path : `/${path}`
+
+  return `${normalizedPrefix}${normalizedPath}`
+}
diff --git a/test/integration/features/nip-11/nip-11.feature b/test/integration/features/nip-11/nip-11.feature
@@ -22,6 +22,11 @@ Feature: NIP-11
     Then the response Content-Type does not include "application/nostr+json"
     And the response body is not a relay information document
 
+  Scenario: Relay serves HTML for typical browser Accept header
+    When a browser requests the root path
+    Then the response Content-Type includes "text/html"
+    And the response body is not a relay information document
+
   Scenario: Relay information document reports max_filters from settings
     When a client requests the relay information document
     Then the limitation object contains a max_filters field
diff --git a/test/integration/features/nip-11/nip-11.feature.ts b/test/integration/features/nip-11/nip-11.feature.ts
diff --git a/test/unit/controllers/invoices/get-invoice-controller.spec.ts b/test/unit/controllers/invoices/get-invoice-controller.spec.ts
diff --git a/test/unit/controllers/invoices/post-invoice-controller.spec.ts b/test/unit/controllers/invoices/post-invoice-controller.spec.ts
diff --git a/test/unit/handlers/request-handlers/get-privacy-request-handler.spec.ts b/test/unit/handlers/request-handlers/get-privacy-request-handler.spec.ts
diff --git a/test/unit/handlers/request-handlers/root-request-handler.spec.ts b/test/unit/handlers/request-handlers/root-request-handler.spec.ts
diff --git a/test/unit/utils/http.spec.ts b/test/unit/utils/http.spec.ts

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +"nostream": patch
 +---
++
 +Fix root HTML negotiation and subpath-aware template links behind trusted proxies.