feat: add new dispatch compose

index.js

@@ -14,7 +14,7 @@ const MockClient = require('./lib/mock/mock-client')
 const MockAgent = require('./lib/mock/mock-agent')
 const MockPool = require('./lib/mock/mock-pool')
 const mockErrors = require('./lib/mock/mock-errors')
-const ProxyAgent = require('./lib/proxy-agent')
+const Proxy = require('./lib/interceptor/proxy')
 const RetryAgent = require('./lib/retry-agent')
 const RetryHandler = require('./lib/handler/RetryHandler')
 const { getGlobalDispatcher, setGlobalDispatcher } = require('./lib/global')
@@ -29,13 +29,18 @@ module.exports.Client = Client
 module.exports.Pool = Pool
 module.exports.BalancedPool = BalancedPool
 module.exports.Agent = Agent
-module.exports.ProxyAgent = ProxyAgent
+module.exports.ProxyAgent = Proxy.ProxyAgent
 module.exports.RetryAgent = RetryAgent
 module.exports.RetryHandler = RetryHandler
 
 module.exports.DecoratorHandler = DecoratorHandler
 module.exports.RedirectHandler = RedirectHandler
 module.exports.createRedirectInterceptor = createRedirectInterceptor
+module.exports.interceptors = {
+  proxy: Proxy.interceptor,
+  redirect: require('./lib/interceptor/redirect'),
+  retry: require('./lib/interceptor/retry')
+}
 
 module.exports.buildConnector = buildConnector
 module.exports.errors = errors

lib/dispatcher.js

@@ -1,8 +1,11 @@
 'use strict'
-
 const EventEmitter = require('node:events')
 
+const kDispatcherVersion = Symbol.for('undici.dispatcher.version')
+
 class Dispatcher extends EventEmitter {
+  [kDispatcherVersion] = 1
+
   dispatch () {
     throw new Error('not implemented')
   }
@@ -14,6 +17,26 @@ class Dispatcher extends EventEmitter {
   destroy () {
     throw new Error('not implemented')
   }
+
+  compose (...interceptors) {
+    let dispatcher = this
+    for (const interceptor of interceptors) {
+      if (interceptor == null) {
+        continue
+      }
+
+      if (typeof interceptor !== 'function') {
+        throw new Error('invalid interceptor')
+      }
+
+      dispatcher = interceptor(dispatcher) ?? dispatcher
+
+      if (dispatcher[kDispatcherVersion] !== 1) {
+        throw new Error('invalid dispatcher')
+      }
+    }
+    return dispatcher
+  }
 }
 
 module.exports = Dispatcher

lib/proxy-agent.js → lib/interceptor/proxy.js

@@ -1,12 +1,12 @@
 'use strict'
 
-const { kProxy, kClose, kDestroy, kInterceptors } = require('./core/symbols')
 const { URL } = require('node:url')
-const Agent = require('./agent')
-const Pool = require('./pool')
-const DispatcherBase = require('./dispatcher-base')
-const { InvalidArgumentError, RequestAbortedError } = require('./core/errors')
-const buildConnector = require('./core/connect')
+const Agent = require('../agent')
+const Pool = require('../pool')
+const DispatcherBase = require('../dispatcher-base')
+const { kProxy, kClose, kDestroy, kInterceptors } = require('../core/symbols')
+const { InvalidArgumentError, RequestAbortedError } = require('../core/errors')
+const buildConnector = require('../core/connect')
 
 const kAgent = Symbol('proxy agent')
 const kClient = Symbol('proxy client')
@@ -27,36 +27,47 @@ class ProxyAgent extends DispatcherBase {
   constructor (opts) {
     super()
 
-    if (!opts || (typeof opts === 'object' && !(opts instanceof URL) && !opts.uri)) {
+    if (
+      !opts ||
+      (typeof opts === 'object' && !(opts instanceof URL) && !opts.uri)
+    ) {
       throw new InvalidArgumentError('Proxy uri is mandatory')
     }
 
     const { clientFactory = defaultFactory } = opts
     if (typeof clientFactory !== 'function') {
-      throw new InvalidArgumentError('Proxy opts.clientFactory must be a function.')
+      throw new InvalidArgumentError(
+        'Proxy opts.clientFactory must be a function.'
+      )
     }
 
     const url = this.#getUrl(opts)
     const { href, origin, port, protocol, username, password } = url
 
     this[kProxy] = { uri: href, protocol }
     this[kAgent] = new Agent(opts)
-    this[kInterceptors] = opts.interceptors?.ProxyAgent && Array.isArray(opts.interceptors.ProxyAgent)
-      ? opts.interceptors.ProxyAgent
-      : []
+    this[kInterceptors] =
+      opts.interceptors?.ProxyAgent &&
+      Array.isArray(opts.interceptors.ProxyAgent)
+        ? opts.interceptors.ProxyAgent
+        : []
     this[kRequestTls] = opts.requestTls
     this[kProxyTls] = opts.proxyTls
     this[kProxyHeaders] = opts.headers || {}
 
     if (opts.auth && opts.token) {
-      throw new InvalidArgumentError('opts.auth cannot be used in combination with opts.token')
+      throw new InvalidArgumentError(
+        'opts.auth cannot be used in combination with opts.token'
+      )
     } else if (opts.auth) {
       /* @deprecated in favour of opts.token */
       this[kProxyHeaders]['proxy-authorization'] = `Basic ${opts.auth}`
     } else if (opts.token) {
       this[kProxyHeaders]['proxy-authorization'] = opts.token
     } else if (username && password) {
-      this[kProxyHeaders]['proxy-authorization'] = `Basic ${Buffer.from(`${decodeURIComponent(username)}:${decodeURIComponent(password)}`).toString('base64')}`
+      this[kProxyHeaders]['proxy-authorization'] = `Basic ${Buffer.from(
+        `${decodeURIComponent(username)}:${decodeURIComponent(password)}`
+      ).toString('base64')}`
     }
 
     const connect = buildConnector({ ...opts.proxyTls })
@@ -82,7 +93,11 @@ class ProxyAgent extends DispatcherBase {
           })
           if (statusCode !== 200) {
             socket.on('error', () => {}).destroy()
-            callback(new RequestAbortedError(`Proxy response (${statusCode}) !== 200 when HTTP Tunneling`))
+            callback(
+              new RequestAbortedError(
+                `Proxy response (${statusCode}) !== 200 when HTTP Tunneling`
+              )
+            )
           }
           if (opts.protocol !== 'https:') {
             callback(null, socket)
@@ -94,7 +109,10 @@ class ProxyAgent extends DispatcherBase {
           } else {
             servername = opts.servername
           }
-          this[kConnectEndpoint]({ ...opts, servername, httpSocket: socket }, callback)
+          this[kConnectEndpoint](
+            { ...opts, servername, httpSocket: socket },
+            callback
+          )
         } catch (err) {
           callback(err)
         }
@@ -173,11 +191,43 @@ function buildHeaders (headers) {
  * It should be removed in the next major version for performance reasons
  */
 function throwIfProxyAuthIsSent (headers) {
-  const existProxyAuth = headers && Object.keys(headers)
-    .find((key) => key.toLowerCase() === 'proxy-authorization')
+  const existProxyAuth =
+    headers &&
+    Object.keys(headers).find(
+      key => key.toLowerCase() === 'proxy-authorization'
+    )
   if (existProxyAuth) {
-    throw new InvalidArgumentError('Proxy-Authorization should be sent in ProxyAgent constructor')
+    throw new InvalidArgumentError(
+      'Proxy-Authorization should be sent in ProxyAgent constructor'
+    )
   }
 }
 
-module.exports = ProxyAgent
+module.exports = {
+  ProxyAgent,
+  interceptor: opts => {
+    if (typeof opts === 'string') {
+      opts = { uri: opts }
+    }
+
+    if (!opts || !opts.uri) {
+      throw new InvalidArgumentError('Proxy opts.uri is mandatory')
+    }
+
+    const { clientFactory = defaultFactory } = opts
+
+    if (typeof clientFactory !== 'function') {
+      throw new InvalidArgumentError(
+        'Proxy opts.clientFactory must be a function.'
+      )
+    }
+
+    if (opts.auth && opts.token) {
+      throw new InvalidArgumentError(
+        'opts.auth cannot be used in combination with opts.token'
+      )
+    }
+
+    return dispatcher => new ProxyAgent(dispatcher, opts)
+  }
+}

lib/interceptor/redirect.js

@@ -0,0 +1,54 @@
+const { InvalidArgumentError } = require('../core/errors')
+const Dispatcher = require('../dispatcher-base')
+const RedirectHandler = require('../handler/RedirectHandler')
+
+class RedirectDispatcher extends Dispatcher {
+  #opts
+  #dispatcher
+
+  constructor (dispatcher, opts) {
+    super()
+
+    this.#dispatcher = dispatcher
+    this.#opts = opts
+  }
+
+  dispatch (opts, handler) {
+    return this.#dispatcher.dispatch(
+      opts,
+      new RedirectHandler(this.#dispatcher, opts, this.#opts, handler)
+    )
+  }
+
+  close (...args) {
+    return this.#dispatcher.close(...args)
+  }
+
+  destroy (...args) {
+    return this.#dispatcher.destroy(...args)
+  }
+}
+
+module.exports = opts => {
+  if (opts?.maxRedirections == null || opts?.maxRedirections === 0) {
+    return null
+  }
+
+  if (!Number.isInteger(opts.maxRedirections) || opts.maxRedirections < 0) {
+    throw new InvalidArgumentError('maxRedirections must be a positive number')
+  }
+
+  return dispatcher => new RedirectDispatcher(dispatcher, opts)
+}
+
+module.exports = opts => {
+  if (opts?.maxRedirections == null || opts?.maxRedirections === 0) {
+    return null
+  }
+
+  if (!Number.isInteger(opts.maxRedirections) || opts.maxRedirections < 0) {
+    throw new InvalidArgumentError('maxRedirections must be a positive number')
+  }
+
+  return dispatcher => new RedirectDispatcher(dispatcher, opts)
+}

lib/interceptor/retry.js

@@ -0,0 +1,33 @@
+const Dispatcher = require('../dispatcher-base')
+const RetryHandler = require('../handler/RetryHandler')
+
+class RetryDispatcher extends Dispatcher {
+  #dispatcher
+  #opts
+
+  constructor (dispatcher, opts) {
+    super()
+
+    this.#dispatcher = dispatcher
+    this.#opts = opts
+  }
+
+  dispatch (opts, handler) {
+    return this.#dispatcher.dispatch(
+      opts,
+      new RetryHandler(this.#dispatcher, opts, this.#opts, handler)
+    )
+  }
+
+  close (...args) {
+    return this.#dispatcher.close(...args)
+  }
+
+  destroy (...args) {
+    return this.#dispatcher.destroy(...args)
+  }
+}
+
+module.exports = opts => {
+  return dispatcher => new RetryDispatcher(dispatcher, opts)
+}