4768666030

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Commit Message

refactor: minor type improvements (#895)

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99.01

/src/http-proxy-middleware.ts

import type * as net from 'net';
import type * as http from 'http';
import type * as https from 'https';
import type { RequestHandler, Options, Filter } from './types';
import * as httpProxy from 'http-proxy';
import { verifyConfig } from './configuration';
import { getPlugins } from './get-plugins';
import { matchPathFilter } from './path-filter';
import * as PathRewriter from './path-rewriter';
import * as Router from './router';
import { Debug as debug } from './debug';
import { getFunctionName } from './utils/function';

export class HttpProxyMiddleware<TReq, TRes> {
  private wsInternalSubscribed = false;
  private serverOnCloseSubscribed = false;
  private proxyOptions: Options<TReq, TRes>;
  private proxy: httpProxy<TReq, TRes>;
  private pathRewriter;

  constructor(options: Options<TReq, TRes>) {
    verifyConfig<TReq, TRes>(options);
    this.proxyOptions = options;

    debug(`create proxy server`);
    this.proxy = httpProxy.createProxyServer({});

    this.registerPlugins(this.proxy, this.proxyOptions);

    this.pathRewriter = PathRewriter.createPathRewriter(this.proxyOptions.pathRewrite); // returns undefined when "pathRewrite" is not provided

    // https://github.com/chimurai/http-proxy-middleware/issues/19
    // expose function to upgrade externally
    this.middleware.upgrade = (req, socket, head) => {
      if (!this.wsInternalSubscribed) {
        this.handleUpgrade(req, socket, head);
      }
    };
  }

  // https://github.com/Microsoft/TypeScript/wiki/'this'-in-TypeScript#red-flags-for-this
  public middleware: RequestHandler = (async (req, res, next?) => {
    if (this.shouldProxy(this.proxyOptions.pathFilter, req)) {
      try {
        const activeProxyOptions = await this.prepareProxyRequest(req);
        debug(`proxy request to target: %O`, activeProxyOptions.target);
        this.proxy.web(req, res, activeProxyOptions);
      } catch (err) {
        next && next(err);
      }
    } else {
      next && next();
    }

    /**
     * Get the server object to subscribe to server events;
     * 'upgrade' for websocket and 'close' for graceful shutdown
     *
     * NOTE:
     * req.socket: node >= 13
     * req.connection: node < 13 (Remove this when node 12/13 support is dropped)
     */
    const server: https.Server = ((req.socket ?? req.connection) as any)?.server;

    if (server && !this.serverOnCloseSubscribed) {
      server.on('close', () => {
        debug('server close signal received: closing proxy server');
        this.proxy.close();
      });
      this.serverOnCloseSubscribed = true;
    }

    if (this.proxyOptions.ws === true) {
      // use initial request to access the server object to subscribe to http upgrade event
      this.catchUpgradeRequest(server);
    }
  }) as RequestHandler;

  private registerPlugins(proxy: httpProxy<TReq, TRes>, options: Options<TReq, TRes>) {
    const plugins = getPlugins<TReq, TRes>(options);
    plugins.forEach((plugin) => {
      debug(`register plugin: "${getFunctionName(plugin)}"`);
      plugin(proxy, options);
    });
  }

  private catchUpgradeRequest = (server: https.Server) => {
    if (!this.wsInternalSubscribed) {
      debug('subscribing to server upgrade event');
      server.on('upgrade', this.handleUpgrade);
      // prevent duplicate upgrade handling;
      // in case external upgrade is also configured
      this.wsInternalSubscribed = true;
    }
  };

  private handleUpgrade = async (req: http.IncomingMessage, socket: net.Socket, head: Buffer) => {
    if (this.shouldProxy(this.proxyOptions.pathFilter, req)) {
      const activeProxyOptions = await this.prepareProxyRequest(req);
      this.proxy.ws(req, socket, head, activeProxyOptions);
      debug('server upgrade event received. Proxying WebSocket');
    }
  };

  /**
   * Determine whether request should be proxied.
   */
  private shouldProxy = (
    pathFilter: Filter<TReq> | undefined,
    req: http.IncomingMessage
  ): boolean => {
    return matchPathFilter(pathFilter, req.url, req);
  };

  /**
   * Apply option.router and option.pathRewrite
   * Order matters:
   *    Router uses original path for routing;
   *    NOT the modified path, after it has been rewritten by pathRewrite
   * @param {Object} req
   * @return {Object} proxy options
   */
  private prepareProxyRequest = async (req: http.IncomingMessage) => {
    /**
     * Incorrect usage confirmed: https://github.com/expressjs/express/issues/4854#issuecomment-1066171160
     * Temporary restore req.url patch for {@link src/legacy/create-proxy-middleware.ts legacyCreateProxyMiddleware()}
     * FIXME: remove this patch in future release
     */
    if ((this.middleware as unknown as any).__LEGACY_HTTP_PROXY_MIDDLEWARE__) {
      req.url = (req as unknown as any).originalUrl || req.url;
    }

    const newProxyOptions = Object.assign({}, this.proxyOptions);

    // Apply in order:
    // 1. option.router
    // 2. option.pathRewrite
    await this.applyRouter(req, newProxyOptions);
    await this.applyPathRewrite(req, this.pathRewriter);

    return newProxyOptions;
  };

  // Modify option.target when router present.
  private applyRouter = async (req: http.IncomingMessage, options: Options<TReq, TRes>) => {
    let newTarget;

    if (options.router) {
      newTarget = await Router.getTarget(req, options);

      if (newTarget) {
        debug('router new target: "%s"', newTarget);
        options.target = newTarget;
      }
    }
  };

  // rewrite path
  private applyPathRewrite = async (req: http.IncomingMessage, pathRewriter) => {
    if (pathRewriter) {
      const path = await pathRewriter(req.url, req);

      if (typeof path === 'string') {
        debug('pathRewrite new path: %s', req.url);
        req.url = path;
      } else {
        debug('pathRewrite: no rewritten path found: %s', req.url);
      }
    }
  };
}

1	import type * as net from 'net';
2	import type * as http from 'http';
3	import type * as https from 'https';
4	import type { RequestHandler, Options, Filter } from './types';
5	import * as httpProxy from 'http-proxy';	12✔
6	import { verifyConfig } from './configuration';	12✔
7	import { getPlugins } from './get-plugins';	12✔
8	import { matchPathFilter } from './path-filter';	12✔
9	import * as PathRewriter from './path-rewriter';	12✔
10	import * as Router from './router';	12✔
11	import { Debug as debug } from './debug';	12✔
12	import { getFunctionName } from './utils/function';	12✔
13
14	export class HttpProxyMiddleware<TReq, TRes> {	12✔
15	private wsInternalSubscribed = false;	71✔
16	private serverOnCloseSubscribed = false;	71✔
17	private proxyOptions: Options<TReq, TRes>;
18	private proxy: httpProxy<TReq, TRes>;
19	private pathRewriter;
20
21	constructor(options: Options<TReq, TRes>) {
22	verifyConfig<TReq, TRes>(options);	71✔
23	this.proxyOptions = options;	71✔
24
25	debug(`create proxy server`);	71✔
26	this.proxy = httpProxy.createProxyServer({});	71✔
27
28	this.registerPlugins(this.proxy, this.proxyOptions);	71✔
29
30	this.pathRewriter = PathRewriter.createPathRewriter(this.proxyOptions.pathRewrite); // returns undefined when "pathRewrite" is not provided	71✔
31
32	// https://github.com/chimurai/http-proxy-middleware/issues/19
33	// expose function to upgrade externally
34	this.middleware.upgrade = (req, socket, head) => {	71✔
35	if (!this.wsInternalSubscribed) {	2✔
36	this.handleUpgrade(req, socket, head);	2✔
37	}
38	};
39	}
40
41	// https://github.com/Microsoft/TypeScript/wiki/'this'-in-TypeScript#red-flags-for-this
42	public middleware: RequestHandler = (async (req, res, next?) => {	71✔
43	if (this.shouldProxy(this.proxyOptions.pathFilter, req)) {	54✔
44	try {	49✔
45	const activeProxyOptions = await this.prepareProxyRequest(req);	49✔
46	debug(`proxy request to target: %O`, activeProxyOptions.target);	48✔
47	this.proxy.web(req, res, activeProxyOptions);	48✔
48	} catch (err) {
49	next && next(err);	2✔
50	}
51	} else {
52	next && next();	5✔
53	}
54
55	/**
56	* Get the server object to subscribe to server events;
57	* 'upgrade' for websocket and 'close' for graceful shutdown
58	*
59	* NOTE:
60	* req.socket: node >= 13
61	* req.connection: node < 13 (Remove this when node 12/13 support is dropped)
62	*/
63	const server: https.Server = ((req.socket ?? req.connection) as any)?.server;	54✔
64
65	if (server && !this.serverOnCloseSubscribed) {	54✔
66	server.on('close', () => {	52✔
67	debug('server close signal received: closing proxy server');	52✔
68	this.proxy.close();	52✔
69	});
70	this.serverOnCloseSubscribed = true;	52✔
71	}
72
73	if (this.proxyOptions.ws === true) {	54✔
74	// use initial request to access the server object to subscribe to http upgrade event
75	this.catchUpgradeRequest(server);	2✔
76	}
77	}) as RequestHandler;
78
79	private registerPlugins(proxy: httpProxy<TReq, TRes>, options: Options<TReq, TRes>) {
80	const plugins = getPlugins<TReq, TRes>(options);	71✔
81	plugins.forEach((plugin) => {	71✔
82	debug(`register plugin: "${getFunctionName(plugin)}"`);	281✔
83	plugin(proxy, options);	281✔
84	});
85	}
86
87	private catchUpgradeRequest = (server: https.Server) => {	71✔
88	if (!this.wsInternalSubscribed) {	2✔
89	debug('subscribing to server upgrade event');	1✔
90	server.on('upgrade', this.handleUpgrade);	1✔
91	// prevent duplicate upgrade handling;
92	// in case external upgrade is also configured
93	this.wsInternalSubscribed = true;	1✔
94	}
95	};
96
97	private handleUpgrade = async (req: http.IncomingMessage, socket: net.Socket, head: Buffer) => {	71✔
98	if (this.shouldProxy(this.proxyOptions.pathFilter, req)) {	3✔
99	const activeProxyOptions = await this.prepareProxyRequest(req);	3✔
100	this.proxy.ws(req, socket, head, activeProxyOptions);	3✔
101	debug('server upgrade event received. Proxying WebSocket');	3✔
102	}
103	};
104
105	/**
106	* Determine whether request should be proxied.
107	*/
108	private shouldProxy = (	71✔
109	pathFilter: Filter<TReq> \| undefined,
110	req: http.IncomingMessage
111	): boolean => {
112	return matchPathFilter(pathFilter, req.url, req);	57✔
113	};
114
115	/**
116	* Apply option.router and option.pathRewrite
117	* Order matters:
118	* Router uses original path for routing;
119	* NOT the modified path, after it has been rewritten by pathRewrite
120	* @param {Object} req
121	* @return {Object} proxy options
122	*/
123	private prepareProxyRequest = async (req: http.IncomingMessage) => {	71✔
124	/**
125	* Incorrect usage confirmed: https://github.com/expressjs/express/issues/4854#issuecomment-1066171160
126	* Temporary restore req.url patch for {@link src/legacy/create-proxy-middleware.ts legacyCreateProxyMiddleware()}
127	* FIXME: remove this patch in future release
128	*/
129	if ((this.middleware as unknown as any).__LEGACY_HTTP_PROXY_MIDDLEWARE__) {	52✔
130	req.url = (req as unknown as any).originalUrl \|\| req.url;	5!
131	}
132
133	const newProxyOptions = Object.assign({}, this.proxyOptions);	52✔
134
135	// Apply in order:
136	// 1. option.router
137	// 2. option.pathRewrite
138	await this.applyRouter(req, newProxyOptions);	52✔
139	await this.applyPathRewrite(req, this.pathRewriter);	51✔
140
141	return newProxyOptions;	51✔
142	};
143
144	// Modify option.target when router present.
145	private applyRouter = async (req: http.IncomingMessage, options: Options<TReq, TRes>) => {	71✔
146	let newTarget;
147
148	if (options.router) {	52✔
149	newTarget = await Router.getTarget(req, options);	10✔
150
151	if (newTarget) {	9✔
152	debug('router new target: "%s"', newTarget);	7✔
153	options.target = newTarget;	7✔
154	}
155	}
156	};
157
158	// rewrite path
159	private applyPathRewrite = async (req: http.IncomingMessage, pathRewriter) => {	71✔
160	if (pathRewriter) {	51✔
161	const path = await pathRewriter(req.url, req);	10✔
162
163	if (typeof path === 'string') {	10✔
164	debug('pathRewrite new path: %s', req.url);	9✔
165	req.url = path;	9✔
166	} else {
167	debug('pathRewrite: no rewritten path found: %s', req.url);	1✔
168	}
169	}
170	};
171	}

chimurai / http-proxy-middleware / 4768666030

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