Engine routing (#82)

* refactor: move engines to folder

* refactor: engine class

* refactor: add distributor and readability, searx engines class

* delete: google engine

useless since searx added

* fix: stackoverflow

* update version

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "txtdot",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "txtdot",
-      "version": "1.5.2",
+      "version": "1.5.3",
       "license": "MIT",
       "dependencies": {
         "@fastify/static": "^6.12.0",
@@ -23,7 +23,8 @@
         "ip-range-check": "^0.2.0",
         "json-schema-to-ts": "^3.0.0",
         "linkedom": "^0.16.6",
-        "micromatch": "^4.0.5"
+        "micromatch": "^4.0.5",
+        "route-parser": "^0.0.5"
       },
       "devDependencies": {
         "@types/dompurify": "^3.0.5",
@@ -31,6 +32,7 @@
         "@types/jsdom": "^21.1.6",
         "@types/micromatch": "^4.0.6",
         "@types/node": "^20.10.6",
+        "@types/route-parser": "^0.1.7",
         "@typescript-eslint/eslint-plugin": "^6.18.0",
         "@typescript-eslint/parser": "^6.18.0",
         "clean-css-cli": "^5.6.3",
@@ -414,6 +416,12 @@
         "undici-types": "~5.26.4"
       }
     },
+    "node_modules/@types/route-parser": {
+      "version": "0.1.7",
+      "resolved": "https://registry.npmjs.org/@types/route-parser/-/route-parser-0.1.7.tgz",
+      "integrity": "sha512-haO+3HVio/4w+yuMJTjqfSo0ivOV8WnXaOReVD6QN729UGBEyizWNGc2Jd0OLsJDucIod4aJSsPLBeLj2uzMCQ==",
+      "dev": true
+    },
     "node_modules/@types/semver": {
       "version": "7.5.6",
       "resolved": "https://registry.npmjs.org/@types/semver/-/semver-7.5.6.tgz",
@@ -2964,6 +2972,14 @@
         "node": "*"
       }
     },
+    "node_modules/route-parser": {
+      "version": "0.0.5",
+      "resolved": "https://registry.npmjs.org/route-parser/-/route-parser-0.0.5.tgz",
+      "integrity": "sha512-nsii+MXoNb7NyF05LP9kaktx6AoBVT/7zUgDnzIb5IoYAvYkbZOAuoLJjVdsyEVxWv0swCxWkKDK4cMva+WDBA==",
+      "engines": {
+        "node": ">= 0.9"
+      }
+    },
     "node_modules/run-parallel": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/run-parallel/-/run-parallel-1.2.0.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "txtdot",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "private": true,
   "description": "",
   "main": "dist/app.js",
@@ -19,7 +19,8 @@
     "ip-range-check": "^0.2.0",
     "json-schema-to-ts": "^3.0.0",
     "linkedom": "^0.16.6",
-    "micromatch": "^4.0.5"
+    "micromatch": "^4.0.5",
+    "route-parser": "^0.0.5"
   },
   "devDependencies": {
     "@types/dompurify": "^3.0.5",
@@ -27,6 +28,7 @@
     "@types/jsdom": "^21.1.6",
     "@types/micromatch": "^4.0.6",
     "@types/node": "^20.10.6",
+    "@types/route-parser": "^0.1.7",
     "@typescript-eslint/eslint-plugin": "^6.18.0",
     "@typescript-eslint/parser": "^6.18.0",
     "clean-css-cli": "^5.6.3",

src/handlers/distributor.ts

@@ -0,0 +1,87 @@
+import { IHandlerOutput } from './handler.interface';
+import axios from '../types/axios';
+
+import micromatch from 'micromatch';
+
+import DOMPurify from 'dompurify';
+
+import { Readable } from 'stream';
+
+import isLocalResource from '../utils/islocal';
+
+import { LocalResourceError, NotHtmlMimetypeError } from '../errors/main';
+import { HandlerInput } from './handler-input';
+import { decodeStream, parseEncodingName } from '../utils/http';
+import replaceHref from '../utils/replace-href';
+import { parseHTML } from 'linkedom';
+import { Engine } from './engine';
+
+interface IEngineId {
+  [key: string]: number;
+}
+
+export class Distributor {
+  engines_id: IEngineId = {};
+  fallback: Engine[] = [];
+  list: string[] = [];
+  constructor() {}
+
+  engine(engine: Engine) {
+    this.engines_id[engine.name] = this.list.length;
+    this.fallback.push(engine);
+    this.list.push(engine.name);
+  }
+
+  async handlePage(
+    remoteUrl: string, // remote URL
+    requestUrl: URL, // proxy URL
+    engineName?: string,
+    redirectPath: string = 'get'
+  ): Promise<IHandlerOutput> {
+    const urlObj = new URL(remoteUrl);
+
+    if (await isLocalResource(urlObj)) {
+      throw new LocalResourceError();
+    }
+
+    const response = await axios.get(remoteUrl);
+    const data: Readable = response.data;
+    const mime: string | undefined =
+      response.headers['content-type']?.toString();
+
+    if (mime && mime.indexOf('text/html') === -1) {
+      throw new NotHtmlMimetypeError();
+    }
+
+    const engine = this.getFallbackEngine(urlObj.hostname, engineName);
+    const output = await engine.handle(
+      new HandlerInput(
+        await decodeStream(data, parseEncodingName(mime)),
+        remoteUrl
+      )
+    );
+
+    // post-process
+
+    const dom = parseHTML(output.content);
+    replaceHref(dom, requestUrl, new URL(remoteUrl), engineName, redirectPath);
+
+    const purify = DOMPurify(dom.window);
+    output.content = purify.sanitize(dom.document.toString());
+
+    return output;
+  }
+
+  getFallbackEngine(host: string, specified?: string): Engine {
+    if (specified) {
+      return this.fallback[this.engines_id[specified]];
+    }
+    for (const engine of this.fallback) {
+      if (micromatch.isMatch(host, engine.domains)) {
+        return engine;
+      }
+    }
+
+    return this.fallback[0];
+  }
+}

src/handlers/engine.ts

@@ -0,0 +1,38 @@
+import Route from 'route-parser';
+import { HandlerInput } from './handler-input';
+import { IHandlerOutput } from './handler.interface';
+import { EngineParseError } from '../errors/main';
+import { EngineFunction } from '../types/handlers';
+
+interface IRoute {
+  route: Route;
+  handler: EngineFunction;
+}
+
+export class Engine {
+  name: string;
+  domains: string[];
+  routes: IRoute[] = [];
+  constructor(name: string, domains: string[] = []) {
+    this.domains = domains;
+    this.name = name;
+  }
+
+  route(path: string, handler: EngineFunction) {
+    this.routes.push({ route: new Route(path), handler: handler });
+  }
+
+  async handle(input: HandlerInput): Promise<IHandlerOutput> {
+    const url = new URL(input.getUrl());
+    const path = url.pathname + url.search + url.hash;
+    for (const route of this.routes) {
+      const match = route.route.match(path);
+
+      if (match) {
+        return await route.handler(input, match);
+      }
+    }
+
+    throw new EngineParseError(`No handler for ${path}. [${this.name}]`);
+  }
+}

src/handlers/engines/readability.ts

@@ -0,0 +1,26 @@
+import { Readability } from '@mozilla/readability';
+import { EngineParseError } from '../../errors/main';
+
+import { Engine } from '../engine';
+
+const ReadabilityEngine = new Engine('Readability');
+
+ReadabilityEngine.route('*path', async (input, req) => {
+  const reader = new Readability(input.parseDom().window.document);
+  const parsed = reader.parse();
+
+  if (!parsed) {
+    throw new EngineParseError(
+      `Parse error (${req.path}). [${ReadabilityEngine.name}]`
+    );
+  }
+
+  return {
+    content: parsed.content,
+    textContent: parsed.textContent,
+    title: parsed.title,
+    lang: parsed.lang,
+  };
+});
+
+export default ReadabilityEngine;

src/handlers/engines/searx.ts

@@ -1,29 +1,24 @@
-import { HandlerInput } from './handler-input';
-import { IHandlerOutput } from './handler.interface';
+import { Engine } from '../engine';
 
-export default async function searx(
-  input: HandlerInput
-): Promise<IHandlerOutput> {
+const SearXEngine = new Engine('SearX', ['searx.*']);
+
+SearXEngine.route('/search?q=:search', async (input, req) => {
   const document = input.parseDom().window.document;
-
-  const search = document.getElementById('q') as HTMLTextAreaElement;
-
+  const search = req.search;
   const url = new URL(input.getUrl());
-
   const page = parseInt(url.searchParams.get('pageno') || '1');
 
   const page_footer = `${
     page !== 1
-      ? `<a href="${url.origin}${url.pathname}?q=${search.value}&pageno=${
+      ? `<a href="${url.origin}${url.pathname}?q=${search}&pageno=${
           page - 1
         }">Previous </a>|`
       : ''
-  }<a href="${url.origin}${url.pathname}?q=${search.value}&pageno=${
+  }<a href="${url.origin}${url.pathname}?q=${search}&pageno=${
     page + 1
   }"> Next</a>`;
 
   const articles = Array.from(document.querySelectorAll('.result'));
-
   const articles_parsed = articles.map((a) => {
     const parsed = {
       url:
@@ -51,9 +46,9 @@ export default async function searx(
   return {
     content,
     textContent,
-    title: `${search.value} - Searx - Page ${page}`,
+    title: `${search} - Searx - Page ${page}`,
     lang: document.documentElement.lang,
   };
-}
+});
 
-export const SearxDomains = ['searx.*'];
+export default SearXEngine;

src/handlers/engines/stackoverflow.ts

@@ -0,0 +1,45 @@
+import { Engine } from '../engine';
+
+const SOE = new Engine('StackOverflow', [
+  'stackoverflow.com',
+  '*.stackoverflow.com',
+  '*.stackexchange.com',
+  'askubuntu.com',
+  'stackapps.com',
+  'mathoverflow.net',
+  'superuser.com',
+  'serverfault.com',
+]);
+
+SOE.route('/questions/:id/:slug', async (input, req) => {
+  const document = input.parseDom().window.document;
+
+  const questionEl = document.getElementById('question');
+  const question = postParser(questionEl);
+
+  const title = document.querySelector('.question-hyperlink')?.innerHTML || '';
+
+  const allAnswers = [...document.querySelectorAll('.answer')];
+  const answers = allAnswers.map((a) => postParser(a));
+
+  return {
+    content: `${question}<hr>${answers.length} answers <hr>${answers.join(
+      '<hr>'
+    )}`,
+    textContent: `${req.id}/${req.slug}\n`,
+    title,
+    lang: 'en',
+  };
+});
+
+function postParser(el: Element | null): string {
+  if (!el) {
+    return '';
+  }
+  const body = el.querySelector('.js-post-body')?.innerHTML || '';
+  const voteCount = el.querySelector('.js-vote-count')?.textContent || '';
+
+  return `<h3>${voteCount} votes</h3>${body}`;
+}
+
+export default SOE;

src/handlers/google.ts

@@ -1,75 +0,0 @@
-import { HandlerInput } from './handler-input';
-import { IHandlerOutput } from './handler.interface';
-import { EngineParseError } from '../errors/main';
-
-export default async function google(
-  input: HandlerInput
-): Promise<IHandlerOutput> {
-  const window = input.parseDom().window;
-
-  const googleAnchors = [
-    ...window.document.querySelectorAll('a[jsname=UWckNb]'),
-  ] as HTMLAnchorElement[];
-
-  if (!googleAnchors) {
-    throw new EngineParseError(
-      'Failed to find anchors in search result [google]'
-    );
-  }
-
-  const results = googleAnchors
-    .map((a: HTMLAnchorElement): GoogleProps => {
-      const parsedHref = new URL(new URL(a.href).searchParams.get('url')!);
-      return {
-        href: a.href!,
-        siteName: parsedHref.hostname,
-        heading: a.childNodes[1]?.textContent,
-      };
-    })
-    .filter((a) => a.heading);
-
-  const convertToFormat = (result: GoogleProps, isHtml: boolean) => {
-    return isHtml
-      ? `<p><a href="${result.href}">${result.siteName} - ${result.heading}</p>`
-      : `${result.siteName} - ${result.heading} > ${result.href}`;
-  };
-
-  const content = results.map((result) => {
-    return convertToFormat(result, true);
-  });
-
-  const textContent = results.map((result) => {
-    return convertToFormat(result, false);
-  });
-
-  const search = window.document.getElementById(
-    'APjFqb'
-  ) as HTMLTextAreaElement;
-
-  const searchForm = `
-  <form onsubmit="window.location.href = '/get?url=https://www.google.com/search?q='+ document.getElementById('q').value.split(' ').join('+'); return false">
-    <input type="text" name="q" id="q" value="${search?.value}">
-    <input type="button" value="Search" onclick="window.location.href = '/get?url=https://www.google.com/search?q='+ document.getElementById('q').value.split(' ').join('+');">
-  </form>
-  `;
-
-  return {
-    content: `${searchForm}${content.join('')}`,
-    textContent: textContent.join('\n'),
-  };
-}
-
-export const GoogleDomains = [
-  'google.*',
-  'google.co.*',
-  'google.com.*',
-  'www.google.*',
-  'www.google.co.*',
-  'www.google.com.*',
-];
-
-interface GoogleProps {
-  href: string;
-  siteName: string;
-  heading: string | null;
-}

src/handlers/main.ts

@@ -1,97 +1,13 @@
-import { IHandlerOutput } from './handler.interface';
-import { Engines, EngineFunction, EnginesMatch } from '../types/handlers';
-import axios from '../types/axios';
+import { Distributor } from './distributor';
+import Readability from './engines/readability';
+import SearX from './engines/searx';
+import StackOverflow from './engines/stackoverflow';
 
-import micromatch from 'micromatch';
+const distributor = new Distributor();
 
-import DOMPurify from 'dompurify';
+distributor.engine(Readability);
+distributor.engine(SearX);
+distributor.engine(StackOverflow);
 
-import { Readable } from 'stream';
-
-import readability from './readability';
-import google, { GoogleDomains } from './google';
-import stackoverflow, { StackOverflowDomains } from './stackoverflow/main';
-import searx, { SearxDomains } from './searx';
-
-import isLocalResource from '../utils/islocal';
-
-import { LocalResourceError, NotHtmlMimetypeError } from '../errors/main';
-import { HandlerInput } from './handler-input';
-import { decodeStream, parseEncodingName } from '../utils/http';
-import replaceHref from '../utils/replace-href';
-import { parseHTML } from 'linkedom';
-
-export default async function handlePage(
-  remoteUrl: string, // remote URL
-  requestUrl: URL, // proxy URL
-  engine?: string,
-  redirectPath: string = 'get'
-): Promise<IHandlerOutput> {
-  const urlObj = new URL(remoteUrl);
-
-  if (await isLocalResource(urlObj)) {
-    throw new LocalResourceError();
-  }
-
-  const response = await axios.get(remoteUrl);
-  const data: Readable = response.data;
-  const mime: string | undefined = response.headers['content-type']?.toString();
-
-  if (mime && mime.indexOf('text/html') === -1) {
-    throw new NotHtmlMimetypeError();
-  }
-
-  const handler = getFallbackEngine(urlObj.hostname, engine);
-  const output = await handler(
-    new HandlerInput(
-      await decodeStream(data, parseEncodingName(mime)),
-      remoteUrl
-    )
-  );
-
-  // post-process
-
-  const dom = parseHTML(output.content);
-  replaceHref(dom, requestUrl, new URL(remoteUrl), engine, redirectPath);
-
-  const purify = DOMPurify(dom.window);
-  output.content = purify.sanitize(dom.document.toString());
-
-  return output;
-}
-
-function getFallbackEngine(host: string, specified?: string): EngineFunction {
-  if (specified) {
-    return engines[specified];
-  }
-  for (const engine of fallback) {
-    if (micromatch.isMatch(host, engine.pattern)) {
-      return engine.engine;
-    }
-  }
-  return engines.readability;
-}
-
-export const engines: Engines = {
-  readability,
-  google,
-  stackoverflow,
-  searx,
-};
-
-export const engineList: string[] = Object.keys(engines);
-
-export const fallback: EnginesMatch = [
-  {
-    pattern: GoogleDomains,
-    engine: engines.google,
-  },
-  {
-    pattern: StackOverflowDomains,
-    engine: engines.stackoverflow,
-  },
-  {
-    pattern: SearxDomains,
-    engine: engines.searx,
-  },
-];
+export const engineList = distributor.list;
+export default distributor;

src/handlers/readability.ts

@@ -1,22 +0,0 @@
-import { Readability } from '@mozilla/readability';
-import { HandlerInput } from './handler-input';
-import { IHandlerOutput } from './handler.interface';
-import { EngineParseError } from '../errors/main';
-
-export default async function readability(
-  input: HandlerInput
-): Promise<IHandlerOutput> {
-  const reader = new Readability(input.parseDom().window.document);
-  const parsed = reader.parse();
-
-  if (!parsed) {
-    throw new EngineParseError('Failed to parse [readability]');
-  }
-
-  return {
-    content: parsed.content,
-    textContent: parsed.textContent,
-    title: parsed.title,
-    lang: parsed.lang,
-  };
-}

src/handlers/stackoverflow/main.ts

@@ -1,43 +0,0 @@
-import { HandlerInput } from '../handler-input';
-import { IHandlerOutput } from '../handler.interface';
-import { EngineParseError } from '../../errors/main';
-import qPostsHandler from './questions-posts';
-
-export default async function stackoverflow(
-  input: HandlerInput
-): Promise<IHandlerOutput> {
-  const window = input.parseDom().window;
-
-  const url = new URL(window.location.href);
-  const path = url.pathname.split('/').filter((p) => p !== '');
-
-  let result: IHandlerOutput = {
-    content: '',
-    textContent: '',
-    title: '',
-    lang: '',
-  };
-
-  if (path[0] === 'questions') {
-    if (path.length === 3) {
-      result = await qPostsHandler(window);
-    } else if (path.length === 1) {
-      result.content = 'questions';
-    } else {
-      throw new EngineParseError('Invalid URL [stackoverflow]');
-    }
-  }
-
-  return result;
-}
-
-export const StackOverflowDomains = [
-  'stackoverflow.com',
-  '*.stackoverflow.com',
-  '*.stackexchange.com',
-  'askubuntu.com',
-  'stackapps.com',
-  'mathoverflow.net',
-  'superuser.com',
-  'serverfault.com',
-];

src/handlers/stackoverflow/post-parser.ts

@@ -1,9 +0,0 @@
-export default function postParser(el: Element | null): string {
-  if (!el) {
-    return '';
-  }
-  const body = el.querySelector('.js-post-body')?.innerHTML || '';
-  const voteCount = el.querySelector('.js-vote-count')?.textContent || '';
-
-  return `<h3>${voteCount} votes</h3>${body}`;
-}

src/handlers/stackoverflow/questions-posts.ts

@@ -1,25 +0,0 @@
-import { IHandlerOutput } from '../handler.interface';
-import postParser from './post-parser';
-
-export default async function qPostsHandler(
-  window: Window
-): Promise<IHandlerOutput> {
-  const questionEl = window.document.getElementById('question');
-  const question = postParser(questionEl);
-
-  const title =
-    window.document.querySelector('.question-hyperlink')?.innerHTML || '';
-
-  const allAnswers = [...window.document.querySelectorAll('.answer')];
-
-  const answers = allAnswers.map((a) => postParser(a));
-
-  return {
-    content: `${question}<hr>${answers.length} answers <hr>${answers.join(
-      '<hr>'
-    )}`,
-    textContent: 'question',
-    title,
-    lang: 'en',
-  };
-}

src/publicConfig.ts

@@ -1,5 +1,5 @@
 export default {
-  version: '1.5.2',
+  version: '1.5.3',
   description:
     'txtdot is an HTTP proxy that parses only text, links and pictures from pages reducing internet bandwidth usage, removing ads and heavy scripts',
 };

src/routes/api/parse.ts

@@ -6,7 +6,7 @@ import {
   parseSchema,
 } from '../../types/requests/api';
 
-import handlePage from '../../handlers/main';
+import distributor from '../../handlers/main';
 import { generateRequestUrl } from '../../utils/generate';
 
 export default async function parseRoute(fastify: FastifyInstance) {
@@ -15,7 +15,7 @@ export default async function parseRoute(fastify: FastifyInstance) {
     { schema: parseSchema },
     async (request: EngineRequest) => {
       return {
-        data: await handlePage(
+        data: await distributor.handlePage(
           request.query.url,
           generateRequestUrl(
             request.protocol,

src/routes/api/raw-html.ts

@@ -2,7 +2,7 @@ import { FastifyInstance } from 'fastify';
 
 import { IParseSchema, rawHtmlSchema } from '../../types/requests/api';
 
-import handlePage from '../../handlers/main';
+import distributor from '../../handlers/main';
 import { generateRequestUrl } from '../../utils/generate';
 
 export default async function rawHtml(fastify: FastifyInstance) {
@@ -12,7 +12,7 @@ export default async function rawHtml(fastify: FastifyInstance) {
     async (request, reply) => {
       reply.type('text/html; charset=utf-8');
       return (
-        await handlePage(
+        await distributor.handlePage(
           request.query.url,
           generateRequestUrl(
             request.protocol,

src/routes/browser/get.ts

@@ -1,7 +1,7 @@
 import { FastifyInstance } from 'fastify';
 
 import { GetSchema, IGetSchema } from '../../types/requests/browser';
-import handlePage from '../../handlers/main';
+import distributor from '../../handlers/main';
 import { generateRequestUrl } from '../../utils/generate';
 
 import getConfig from '../../config/main';
@@ -14,7 +14,7 @@ export default async function getRoute(fastify: FastifyInstance) {
       const remoteUrl = request.query.url;
       const engine = request.query.engine;
 
-      const parsed = await handlePage(
+      const parsed = await distributor.handlePage(
         remoteUrl,
         generateRequestUrl(
           request.protocol,

src/types/handlers.ts

@@ -1,8 +1,9 @@
+import { Engine } from '../handlers/engine';
 import { HandlerInput } from '../handlers/handler-input';
 import { IHandlerOutput } from '../handlers/handler.interface';
 
 export interface Engines {
-  [key: string]: EngineFunction;
+  [key: string]: Engine;
 }
 
 export type EngineMatch = {
@@ -10,5 +11,12 @@ export type EngineMatch = {
   engine: EngineFunction;
 };
 
-export type EngineFunction = (input: HandlerInput) => Promise<IHandlerOutput>;
+export interface RouteValues {
+  [key: string]: string;
+}
+
+export type EngineFunction = (
+  input: HandlerInput,
+  req: RouteValues
+) => Promise<IHandlerOutput>;
 export type EnginesMatch = EngineMatch[];