add extend loader

package.json

@@ -28,7 +28,7 @@
   },
   "homepage": "https://github.com/eggjs/egg-core#readme",
   "dependencies": {
-    "@eggjs/koa": "^2.18.1",
+    "@eggjs/koa": "^2.18.2",
     "@eggjs/router": "^3.0.1",
     "egg-logger": "^3.5.0",
     "egg-path-matching": "^1.1.0",

src/egg.ts

@@ -35,6 +35,7 @@ export class EggCore extends KoaApplication {
   BaseContextClass: typeof BaseContextClass;
   Controller: typeof BaseContextClass;
   Service: typeof BaseContextClass;
+  Helper?: typeof BaseContextClass;
   lifecycle: Lifecycle;
   loader: EggLoader;
   #closePromise?: Promise<void>;

src/loader/egg_loader.ts

@@ -7,6 +7,7 @@ import homedir from 'node-homedir';
 import type { Logger } from 'egg-logger';
 import { readJSONSync } from 'utility';
 import { extend } from 'extend2';
+import { Request, Response, Context, Application } from '@eggjs/koa';
 import { FileLoader, FileLoaderOptions } from './file_loader.js';
 import { ContextLoader, ContextLoaderOptions } from './context_loader.js'
 import utils from '../utils/index.js';
@@ -16,6 +17,13 @@ import type { EggCore } from '../egg.js';
 
 const debug = debuglog('@eggjs/core:egg_loader');
 
+const originalPrototypes: Record<string, any> = {
+  request: Request.prototype,
+  response: Response.prototype,
+  context: Context.prototype,
+  application: Application.prototype,
+};
+
 export interface EggAppInfo {
   /** package.json */
   pkg: Record<string, any>;
@@ -932,6 +940,149 @@ export class EggLoader {
   }
   /** end Config loader */
 
+  /** start Extend loader */
+  /**
+   * mixin Agent.prototype
+   * @function EggLoader#loadAgentExtend
+   * @since 1.0.0
+   */
+  async loadAgentExtend() {
+    await this.loadExtend('agent', this.app);
+  }
+
+  /**
+   * mixin Application.prototype
+   * @function EggLoader#loadApplicationExtend
+   * @since 1.0.0
+   */
+  async loadApplicationExtend() {
+    await this.loadExtend('application', this.app);
+  }
+
+  /**
+   * mixin Request.prototype
+   * @function EggLoader#loadRequestExtend
+   * @since 1.0.0
+   */
+  async loadRequestExtend() {
+    await this.loadExtend('request', this.app.request);
+  }
+
+  /**
+   * mixin Response.prototype
+   * @function EggLoader#loadResponseExtend
+   * @since 1.0.0
+   */
+  async loadResponseExtend() {
+    await this.loadExtend('response', this.app.response);
+  }
+
+  /**
+   * mixin Context.prototype
+   * @function EggLoader#loadContextExtend
+   * @since 1.0.0
+   */
+  async loadContextExtend() {
+    await this.loadExtend('context', this.app.context);
+  }
+
+  /**
+   * mixin app.Helper.prototype
+   * @function EggLoader#loadHelperExtend
+   * @since 1.0.0
+   */
+  async loadHelperExtend() {
+    if (this.app.Helper) {
+      await this.loadExtend('helper', this.app.Helper.prototype);
+    }
+  }
+
+  /**
+   * Find all extend file paths by name
+   * can be override in top level framework to support load `app/extends/{name}.js`
+   *
+   * @param {String} name - filename which may be `app/extend/{name}.js`
+   * @return {Array} filepaths extend file paths
+   * @private
+   */
+  protected getExtendFilePaths(name: string): string[] {
+    return this.getLoadUnits().map(unit => path.join(unit.path, 'app/extend', name));
+  }
+
+  /**
+   * Loader app/extend/xx.js to `prototype`,
+   * @function loadExtend
+   * @param {String} name - filename which may be `app/extend/{name}.js`
+   * @param {Object} proto - prototype that mixed
+   * @since 1.0.0
+   */
+  async loadExtend(name: string, proto: object) {
+    this.timing.start(`Load extend/${name}.js`);
+    // All extend files
+    const filepaths = this.getExtendFilePaths(name);
+    // if use mm.env and serverEnv is not unittest
+    const needUnittest = 'EGG_MOCK_SERVER_ENV' in process.env && this.serverEnv !== 'unittest';
+    for (const filepath of filepaths) {
+      filepaths.push(filepath + `.${this.serverEnv}`);
+      if (needUnittest) {
+        filepaths.push(filepath + '.unittest');
+      }
+    }
+
+    const mergeRecord = new Map();
+    for (let filepath of filepaths) {
+      filepath = this.resolveModule(filepath)!;
+      if (!filepath) {
+        continue;
+      }
+      if (filepath.endsWith('/index.js')) {
+        this.app.deprecate(`app/extend/${name}/index.js is deprecated, use app/extend/${name}.js instead`);
+      } else if (filepath.endsWith('/index.ts')) {
+        this.app.deprecate(`app/extend/${name}/index.ts is deprecated, use app/extend/${name}.ts instead`);
+      }
+
+      const ext = await this.requireFile(filepath);
+
+      const properties = Object.getOwnPropertyNames(ext)
+        .concat(Object.getOwnPropertySymbols(ext) as any[]);
+
+      for (const property of properties) {
+        if (mergeRecord.has(property)) {
+          debug('Property: "%s" already exists in "%s"，it will be redefined by "%s"',
+            property, mergeRecord.get(property), filepath);
+        }
+
+        // Copy descriptor
+        let descriptor = Object.getOwnPropertyDescriptor(ext, property);
+        let originalDescriptor = Object.getOwnPropertyDescriptor(proto, property);
+        if (!originalDescriptor) {
+          // try to get descriptor from originalPrototypes
+          const originalProto = originalPrototypes[name];
+          if (originalProto) {
+            originalDescriptor = Object.getOwnPropertyDescriptor(originalProto, property);
+          }
+        }
+        if (originalDescriptor) {
+          // don't override descriptor
+          descriptor = {
+            ...descriptor,
+          };
+          if (!descriptor.set && originalDescriptor.set) {
+            descriptor.set = originalDescriptor.set;
+          }
+          if (!descriptor.get && originalDescriptor.get) {
+            descriptor.get = originalDescriptor.get;
+          }
+        }
+        Object.defineProperty(proto, property, descriptor!);
+        mergeRecord.set(property, filepath);
+      }
+      debug('merge %j to %s from %s', Object.keys(ext), name, filepath);
+    }
+    this.timing.end(`Load extend/${name}.js`);
+  }
+  /** end Extend loader */
+
   // Low Level API
 
   /**
@@ -1124,14 +1275,12 @@ function isValidatePackageName(name: string) {
   return true;
 }
 
-
 /**
  * Mixin methods to EggLoader
  * // ES6 Multiple Inheritance
  * https://medium.com/@leocavalcante/es6-multiple-inheritance-73a3c66d2b6b
  */
 // const loaders = [
-//   require('./mixin/config'),
 //   require('./mixin/extend'),
 //   require('./mixin/custom'),
 //   require('./mixin/service'),