feat: upgrade dnscache_httpclient and enable dnscache_fetch

app/extend/context.js

@@ -11,6 +11,7 @@ const LOCALS_LIST = Symbol('Context#localsList');
 const COOKIES = Symbol('Context#cookies');
 const CONTEXT_LOGGERS = Symbol('Context#logger');
 const CONTEXT_HTTPCLIENT = Symbol('Context#httpclient');
+const CONTEXT_FETCH = Symbol('Context#fetch');
 const CONTEXT_ROUTER = Symbol('Context#router');
 
 const proto = module.exports = {
@@ -49,6 +50,51 @@ const proto = module.exports = {
     return this.httpclient.curl(url, options);
   },
 
+  /**
+   * Get a wrapper fetch instance with context
+   *
+   * @return {ContextFetch} the wrapper fetch instance
+   */
+  get fetchClient() {
+    if (!this.app.fetch) return null;
+    if (!this[CONTEXT_FETCH]) {
+      this[CONTEXT_FETCH] = new this.app.ContextFetch(this);
+    }
+    return this[CONTEXT_FETCH];
+  },
+
+  /**
+   * Shortcut for fetchClient.fetch
+   *
+   * @function Context#fetch
+   * @param {String|URL} url - request url address.
+   * @param {Object} [init] - fetch init options.
+   * @return {Promise<Response>} see {@link ContextFetch#fetch}
+   */
+  fetch(url, init) {
+    const client = this.fetchClient;
+    if (!client) {
+      throw new Error('fetch is not available, please upgrade to Node.js >= 20 and install urllib4');
+    }
+    return client.fetch(url, init);
+  },
+
+  /**
+   * Shortcut for fetchClient.safeFetch with SSRF protection
+   *
+   * @function Context#safeFetch
+   * @param {String|URL} url - request url address.
+   * @param {Object} [init] - fetch init options.
+   * @return {Promise<Response>} see {@link ContextFetch#safeFetch}
+   */
+  safeFetch(url, init) {
+    const client = this.fetchClient;
+    if (!client) {
+      throw new Error('safeFetch is not available, please upgrade to Node.js >= 20 and install urllib4');
+    }
+    return client.safeFetch(url, init);
+  },
+
   /**
    * Alias to {@link Application#router}
    *

config/config.default.js

@@ -289,8 +289,14 @@ module.exports = appInfo => {
   /**
    * The option for httpclient
    * @member Config#httpclient
-   * @property {Boolean} enableDNSCache - Enable DNS lookup from local cache or not, default is false.
-   * @property {Boolean} dnsCacheLookupInterval - minimum interval of DNS query on the same hostname (default 10s).
+   * @property {Boolean} enableDNSCache - Enable DNS lookup cache using dns.lookup (old behavior), default is false.
+   * @property {Number} dnsCacheLookupInterval - DNS cache lookup interval in ms for old dns.lookup mode, default is 10000 ms.
+   *
+   * @property {Boolean} useDNSResolver - Enable DNS resolve cache using dns.resolve (new feature), default is false.
+   * @property {Array<String>} dnsServers - Custom DNS nameservers for DNS resolver cache, e.g. ['8.8.8.8', '1.1.1.1']. If not set, use system default.
+   *
+   * @property {Number} dnsCacheMaxLength - DNS cache max size, default is 1000.
+   * @property {Boolean} dnsAddressRotation - Enable address rotation for both lookup and resolve modes, default is true.
    *
    * @property {Number} request.timeout - httpclient request default timeout, default is 5000 ms.
    *
@@ -307,12 +313,21 @@ module.exports = appInfo => {
    * @property {Boolean} allowH2 - use urllib@4 HttpClient and enable H2, default is false. Only works on Node.js >= 18
    */
   config.httpclient = {
+    // Enable DNS cache mode using dns.lookup
     enableDNSCache: false,
-    dnsCacheLookupInterval: 10000,
+    dnsCacheLookupInterval: 10000, // will not work if useDNSResolver is true
+
+    // DNS resolver mode using dns.resolve (new feature)
+    useDNSResolver: false, // will not work if enableDNSCache IS NOT true
+    dnsServers: undefined, // Use system default if not set
+
+    // Common dns options
     dnsCacheMaxLength: 1000,
+    dnsAddressRotation: true,
 
     request: {
       timeout: 5000,
+      reset: false, // only works when useHttpClientNext is true
     },
     httpAgent: {
       keepAlive: true,

index.d.ts

@@ -89,6 +89,19 @@ declare module 'egg' {
     new(ctx: Context): EggContextHttpClient;
   }
 
+  export interface EggContextFetch {
+    ctx: Context;
+    app: Application;
+    fetch(url: string | URL, init?: RequestInit): Promise<Response>;
+    /**
+     * safeFetch request helper with SSRF protection
+     */
+    safeFetch(url: string | URL, init?: RequestInit): Promise<Response>;
+  }
+  interface EggContextFetchConstructor {
+    new (ctx: Context): EggContextFetch;
+  }
+
   /**
    * BaseContextClass is a base class that can be extended,
    * it's instantiated in context level,

lib/core/context_fetch.js

@@ -0,0 +1,36 @@
+class ContextFetch {
+  constructor(ctx) {
+    this.ctx = ctx;
+    this.app = ctx.app;
+  }
+
+  /**
+   * fetch request helper based on native fetch API or urllib4's FetchFactory
+   * Keep the same api with {@link Application#fetch}.
+   *
+   * @param {String|URL} url - request url address.
+   * @param {Object} [init] - fetch init options.
+   * @return {Promise<Response>} fetch response
+   */
+  async fetch(url, init) {
+    init = init || {};
+    init.ctx = this.ctx;
+    return await this.app.fetch(url, init);
+  }
+
+  /**
+   * safeFetch request helper with SSRF protection
+   * Keep the same api with {@link Application#safeFetch}.
+   *
+   * @param {String|URL} url - request url address.
+   * @param {Object} [init] - fetch init options.
+   * @return {Promise<Response>} fetch response
+   */
+  async safeFetch(url, init) {
+    init = init || {};
+    init.ctx = this.ctx;
+    return await this.app.safeFetch(url, init);
+  }
+}
+
+module.exports = ContextFetch;