perf: lazy require dependencies (#8025)

lib/middleware/cache.js

@@ -1,9 +1,10 @@
-const Redis = require('ioredis');
 const Lru = require('lru-cache');
 const md5 = require('@/utils/md5');
 const config = require('@/config').value;
 const logger = require('@/utils/logger');
 
+let Redis;
+
 module.exports = function (app) {
     let available = false;
     const globalCache = {
@@ -12,6 +13,7 @@ module.exports = function (app) {
     };
 
     if (config.cache.type === 'redis') {
+        Redis = Redis || require('ioredis');
         const redisClient = new Redis(config.redis.url);
 
         redisClient.on('error', (error) => {

lib/middleware/parameter.js

@@ -1,10 +1,11 @@
 const entities = require('entities');
-const mercury_parser = require('@postlight/mercury-parser');
 const cheerio = require('cheerio');
 const { simplecc } = require('simplecc-wasm');
 const got = require('@/utils/got');
 const config = require('@/config').value;
 
+let mercury_parser;
+
 module.exports = async (ctx, next) => {
     await next();
 
@@ -204,6 +205,8 @@ module.exports = async (ctx, next) => {
                     const parsed_result = await ctx.cache.tryGet(`mercury-cache-${link}`, async () => {
                         // if parser failed, return default description and not report error
                         try {
+                            mercury_parser = mercury_parser || require('@postlight/mercury-parser');
+
                             const res = await got(link);
                             const $ = cheerio.load(res.data);
                             const result = await mercury_parser.parse(link, {

lib/utils/request-wrapper.js

@@ -1,17 +1,20 @@
 const config = require('@/config').value;
-const HttpsProxyAgent = require('https-proxy-agent');
-const SocksProxyAgent = require('socks-proxy-agent');
-const tunnel = require('tunnel');
 const logger = require('./logger');
 const http = require('http');
 const https = require('https');
 
+let tunnel;
+let HttpsProxyAgent;
+let SocksProxyAgent;
+
 let agent = null;
 if (config.proxyUri && typeof config.proxyUri === 'string') {
     let proxy = null;
     if (config.proxyUri.startsWith('http')) {
+        HttpsProxyAgent = HttpsProxyAgent || require('https-proxy-agent');
         proxy = new HttpsProxyAgent(config.proxyUri);
     } else if (config.proxyUri.startsWith('socks')) {
+        SocksProxyAgent = SocksProxyAgent || require('socks-proxy-agent');
         proxy = new SocksProxyAgent(config.proxyUri);
     } else {
         throw 'Unknown proxy-uri format';
@@ -27,10 +30,12 @@ if (config.proxyUri && typeof config.proxyUri === 'string') {
 
     switch (config.proxy.protocol) {
         case 'socks':
+            SocksProxyAgent = SocksProxyAgent || require('socks-proxy-agent');
             agent.http = new SocksProxyAgent(proxyUrl);
             agent.https = new SocksProxyAgent(proxyUrl);
             break;
         case 'http':
+            tunnel = tunnel || require('tunnel');
             process.env.NODE_TLS_REJECT_UNAUTHORIZED = 0;
             agent.http = tunnel.httpOverHttp({
                 proxy: {
@@ -46,6 +51,7 @@ if (config.proxyUri && typeof config.proxyUri === 'string') {
             });
             break;
         case 'https':
+            tunnel = tunnel || require('tunnel');
             agent.http = tunnel.httpOverHttps({
                 proxy: {
                     host: config.proxy.host,