Initial commit

.env.example

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+TARGET_HOST=api.yourservice.com
+USER_FIELD=email

.eslintignore

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+dist
+node_modules
+.env

.eslintrc

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+{
+  "root": true,
+  "extends": [
+    "eslint:recommended",
+    "plugin:n/recommended",
+    "airbnb-base",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:@typescript-eslint/recommended-requiring-type-checking",
+    "airbnb-typescript/base",
+    "plugin:prettier/recommended"
+  ],
+  "parserOptions": {
+    "project": ["./tsconfig.json"],
+    "ecmaVersion": 2022,
+    "sourceType": "module"
+  },
+  "env": {
+    "node": true
+  },
+  "rules": {
+    "import/prefer-default-export": "off",
+    "node/no-missing-import": "off",
+    "@typescript-eslint/return-await": ["error", "always"],
+    "@typescript-eslint/member-ordering": ["error"],
+    "@typescript-eslint/no-empty-function": ["error", { "allow": ["private-constructors"] }],
+    "@typescript-eslint/array-type": ["error", { "default": "array-simple", "readonly": "array-simple" }]
+  }
+}

.github/codecov.yml

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+coverage:
+  status:
+    project:
+      default:
+        informational: true
+    patch:
+      default:
+        informational: true

.github/renovate.json

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+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": ["config:base"],
+  "assigneesFromCodeOwners": true,
+  "reviewersFromCodeOwners": true,
+  "labels": ["dependencies"],
+  "major": {
+    "dependencyDashboardApproval": false
+  }
+}

.github/workflows/ci.yaml

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+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - '**'
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: false
+
+jobs:
+  install:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-node@v3
+        with:
+          node-version: lts/*
+          cache: "yarn"
+
+      - name: Restore node_modules
+        uses: actions/cache@v3
+        with:
+          path: node_modules
+          key: ${{ runner.os }}-${{ hashFiles('yarn.lock') }}
+
+      - run: yarn install --immutable
+
+  lint:
+    needs: [install]
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-node@v3
+        with:
+          node-version: lts/*
+          cache: "yarn"
+
+      - name: Restore node_modules
+        uses: actions/cache@v3
+        with:
+          path: node_modules
+          key: ${{ runner.os }}-${{ hashFiles('yarn.lock') }}
+
+      - run: yarn lint
+
+  build:
+    needs: [install]
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-node@v3
+        with:
+          node-version: lts/*
+          cache: "yarn"
+
+      - name: Restore node_modules
+        uses: actions/cache@v3
+        with:
+          path: node_modules
+          key: ${{ runner.os }}-${{ hashFiles('yarn.lock') }}
+
+      - run: yarn build

.gitignore

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+dist
+node_modules
+.env
+
+# https://yarnpkg.com/getting-started/qa#which-files-should-be-gitignored
+.pnp.*
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/sdks
+!.yarn/versions

.prettierrc

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+{
+  "tabWidth": 2,
+  "useTabs": false,
+  "semi": true,
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 120,
+  "arrowParens": "avoid",
+  "endOfLine": "lf"
+}

.yarnrc.yml

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+enableGlobalCache: true
+
+nodeLinker: node-modules
+
+yarnPath: .yarn/releases/yarn-3.5.0.cjs

nest-cli.json

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+{
+  "$schema": "https://json.schemastore.org/nest-cli",
+  "collection": "@nestjs/schematics",
+  "sourceRoot": "src"
+}

package.json

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+{
+  "name": "hydra-proxy",
+  "version": "1.0.0",
+  "main": "index.js",
+  "type": "module",
+  "license": "MIT",
+  "packageManager": "[email protected]",
+  "engines": {
+    "node": ">=18.0.0"
+  },
+  "scripts": {
+    "build": "nest build -p ./tsconfig.json",
+    "dev": "nest start --watch",
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "9.4.2",
+    "@tsconfig/esm": "1.0.3",
+    "@tsconfig/node18": "2.0.0",
+    "@tsconfig/strictest": "2.0.1",
+    "@types/express": "4.17.17",
+    "@types/morgan": "1.9.4",
+    "@types/node": "18.16.3",
+    "@typescript-eslint/eslint-plugin": "5.59.1",
+    "@typescript-eslint/parser": "5.59.1",
+    "eslint": "8.39.0",
+    "eslint-config-airbnb-base": "15.0.0",
+    "eslint-config-airbnb-typescript": "17.0.0",
+    "eslint-config-prettier": "8.8.0",
+    "eslint-plugin-import": "2.27.5",
+    "eslint-plugin-n": "15.7.0",
+    "eslint-plugin-prettier": "4.2.1",
+    "prettier": "2.8.8"
+  },
+  "dependencies": {
+    "@nestjs/common": "9.4.0",
+    "@nestjs/config": "2.3.1",
+    "@nestjs/core": "9.4.0",
+    "@nestjs/platform-express": "9.4.0",
+    "express": "4.18.2",
+    "morgan": "1.10.0",
+    "node-fetch": "^3.3.1",
+    "reflect-metadata": "0.1.13",
+    "typescript": "5.0.4",
+    "zod": "3.21.4"
+  }
+}

src/app.module.ts

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+import { Module } from '@nestjs/common';
+import { ConfigModule, ConfigService } from '@nestjs/config';
+import { z } from 'zod';
+import { HydraController } from './hydra.controller.js';
+
+const envSchema = z.object({
+  TARGET_HOST: z.string(),
+  USER_FIELD: z.string().optional(),
+});
+
+export type EnvironmentVariables = z.infer<typeof envSchema>;
+
+export type AppConfigService = ConfigService<EnvironmentVariables>;
+
+@Module({
+  controllers: [HydraController],
+  exports: [],
+  imports: [
+    ConfigModule.forRoot({
+      cache: true,
+      isGlobal: true,
+      validate: config => envSchema.parse(config),
+    }),
+  ],
+  providers: [],
+})
+export class AppModule {}

src/hydra.controller.ts

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+import {
+  BadRequestException,
+  Controller,
+  Inject,
+  Logger,
+  Req,
+  RequestMapping,
+  RequestMethod,
+  Res,
+} from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import type { Request, Response } from 'express';
+import fetch, { type RequestInit } from 'node-fetch';
+import type { AppConfigService } from './app.module.js';
+
+@Controller({ path: '*' })
+export class HydraController {
+  private readonly logger = new Logger(HydraController.name);
+
+  constructor(
+    @Inject(ConfigService)
+    private configService: AppConfigService,
+  ) {}
+
+  @RequestMapping({ path: '*', method: RequestMethod.ALL })
+  async index(@Req() req: Request, @Res() clientResponse: Response): Promise<void> {
+    const { method, url, headers } = req;
+
+    const [type, base64] = headers.authorization?.split(' ') ?? [];
+
+    if (!type || !base64) {
+      throw new BadRequestException(`Missing authorization header`);
+    }
+
+    if (type !== 'Basic') {
+      throw new BadRequestException(`Unsupported authorization type: ${type}`);
+    }
+
+    const [user, password] = Buffer.from(base64, 'base64').toString().split(':');
+
+    if (!user || !password) {
+      throw new BadRequestException(`Missing user or password`);
+    }
+
+    const userField = this.configService.get('USER_FIELD', { infer: true }) ?? 'username';
+
+    const body = JSON.stringify({ [userField]: user, password });
+
+    const targetUrl = new URL(url, `https://${this.configService.getOrThrow('TARGET_HOST', { infer: true })}`);
+
+    const reqInit: RequestInit = {
+      method,
+      body,
+      headers: { 'content-type': 'application/json' },
+    };
+
+    try {
+      const targetResponse = await fetch(targetUrl, reqInit);
+
+      if (targetResponse.status >= 500) {
+        this.logger.warn(`Target server responded with ${targetResponse.status}`);
+      }
+
+      targetResponse.headers.forEach((value, key) => {
+        clientResponse.setHeader(key, value);
+      });
+
+      clientResponse.status(targetResponse.status).send(targetResponse.body);
+    } catch (err) {
+      this.logger.error(err);
+      this.logger.log(reqInit);
+      throw err;
+    }
+  }
+}

src/main.ts

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+import { NestFactory } from '@nestjs/core';
+import morgan from 'morgan';
+import { Logger } from '@nestjs/common';
+import { AppModule } from './app.module.js';
+
+async function bootstrap() {
+  const app = await NestFactory.create(AppModule);
+  const morganLogger = new Logger('morgan');
+  app.use(
+    morgan('[:date[iso]] ":method :url HTTP/:http-version" :status :res[content-length]', {
+      stream: {
+        write: msg => morganLogger.debug(msg.trim()),
+      },
+    }),
+  );
+  await app.listen(80);
+}
+
+bootstrap().catch(err =>
+  // eslint-disable-next-line no-console -- we're in main
+  console.error(err),
+);