fix(nestjs): Lookup request from GraphQL context in ArcjetGuard (#1857)

This adds support for using ArcjetGuard globally on GraphQL applications. With this, we'll check the context type and lookup the request if it is `"http"` or `"graphql"`.

I've also added an example for using ArcjetGuard with a NestJS GraphQL server.

Closes #1856

.github/dependabot.yml

@@ -636,6 +636,34 @@ updates:
       - dependency-name: "@typescript-eslint/eslint-plugin"
         versions: [">=8"]
 
+  - package-ecosystem: npm
+    directory: /examples/nestjs-graphql
+    schedule:
+      # Our dependencies should be checked daily
+      interval: daily
+    assignees:
+      - blaine-arcjet
+    reviewers:
+      - blaine-arcjet
+    commit-message:
+      prefix: deps(example)
+      prefix-development: deps(example)
+    groups:
+      dependencies:
+        patterns:
+          - "*"
+    ignore:
+      # NestJS uses Express 4
+      - dependency-name: "@types/express"
+        versions: [">=5"]
+      # TODO(#539): Upgrade to eslint 9
+      - dependency-name: eslint
+        versions: [">=9"]
+      - dependency-name: "@typescript-eslint/parser"
+        versions: [">=8"]
+      - dependency-name: "@typescript-eslint/eslint-plugin"
+        versions: [">=8"]
+
   - package-ecosystem: npm
     directory: /examples/nestjs-launchdarkly
     schedule:

.github/workflows/reusable-examples.yml

@@ -85,6 +85,46 @@ jobs:
         working-directory: examples/nestjs-fastify
         run: npm run build
 
+  nestjs-graphql:
+    name: NestJS + GraphQL
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      # Environment security
+      - name: Harden Runner
+        uses: step-security/harden-runner@91182cccc01eb5e619899d80e4e971d6181294a7 # v2.10.1
+        with:
+          disable-sudo: true
+          egress-policy: block
+          allowed-endpoints: >
+            github.com:443
+            registry.npmjs.org:443
+
+      # Checkout
+      # Most toolchains require checkout first
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # Language toolchains
+      - name: Install Node
+        uses: actions/[email protected]
+        with:
+          node-version: 20
+
+      # Workflow
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install example dependencies
+        working-directory: examples/nestjs-graphql
+        run: npm ci
+
+      - name: Build
+        working-directory: examples/nestjs-graphql
+        run: npm run build
+
   nestjs-launchdarkly:
     name: NestJS + LaunchDarkly
     runs-on: ubuntu-latest

arcjet-nest/index.ts

@@ -24,6 +24,7 @@ import { Inject, SetMetadata } from "@nestjs/common";
 import type {
   CanActivate,
   ConfigurableModuleAsyncOptions,
+  ContextType,
   DynamicModule,
   ExecutionContext,
   FactoryProvider,
@@ -376,6 +377,43 @@ export const ARCJET = Symbol("ARCJET");
 const ARCJET_OPTIONS = Symbol("ARCJET_OPTIONS");
 const ARCJET_WITH_RULES = Symbol("ARCJET_WITH_RULES");
 
+type GqlContextType = "graphql" | ContextType;
+
+function requestFromContext(context: ExecutionContext) {
+  const contextType = context.getType<GqlContextType>();
+  switch (contextType) {
+    case "graphql": {
+      // The `req` property should exist on the context at position 2
+      // https://github.com/nestjs/graphql/blob/8d19548dd8cb8c6d6003552673a6646603d2e22f/packages/graphql/lib/services/gql-execution-context.ts#L37
+      const ctx = context.getArgByIndex<{ req?: ArcjetNestRequest }>(2);
+      if (typeof ctx === "object" && ctx !== null && "req" in ctx) {
+        return ctx.req;
+      }
+
+      // If it isn't there for some reason, we just return undefined
+      return;
+    }
+    case "http": {
+      // The request object is at position 0
+      // https://github.com/nestjs/nest/blob/9825529f405fa6064eb98d8ecb2a5d3d5f1e41f9/packages/core/helpers/execution-context-host.ts#L52
+      return context.getArgByIndex<ArcjetNestRequest>(0);
+    }
+    case "ws": {
+      // TODO: Figure out if we can support "ws" context types
+      return;
+    }
+    case "rpc": {
+      // TODO: Figure out if we can support "rpc" context types
+      return;
+    }
+    default: {
+      // Avoiding the _exhaustive check to avoid some TypeScript errors in with
+      // different compiler options
+      return;
+    }
+  }
+}
+
 let ArcjetGuard = class ArcjetGuard implements CanActivate {
   aj: ArcjetNest<WithoutCustomProps>;
 
@@ -395,7 +433,12 @@ let ArcjetGuard = class ArcjetGuard implements CanActivate {
       aj = rules.reduce((aj, rule) => aj.withRule(rule), aj);
     }
 
-    const request = context.switchToHttp().getRequest();
+    const request = requestFromContext(context);
+
+    // If we cannot access the request, we "fail open" by allowing the request
+    if (typeof request === "undefined") {
+      return true;
+    }
 
     const decision = await aj.protect(request);
 

examples/nestjs-graphql/.env.local.example

@@ -0,0 +1,4 @@
+# NODE_ENV is not set by the environment
+ARCJET_ENV=development
+# Add your Arcjet key from https://app.arcjet.com
+ARCJET_KEY=

examples/nestjs-graphql/.eslintrc.cjs

@@ -0,0 +1,25 @@
+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    tsconfigRootDir: __dirname,
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint/eslint-plugin'],
+  extends: [
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  ignorePatterns: ['.eslintrc.js'],
+  rules: {
+    '@typescript-eslint/interface-name-prefix': 'off',
+    '@typescript-eslint/explicit-function-return-type': 'off',
+    '@typescript-eslint/explicit-module-boundary-types': 'off',
+    '@typescript-eslint/no-explicit-any': 'off',
+  },
+};

examples/nestjs-graphql/.gitignore

@@ -0,0 +1,56 @@
+# compiled output
+/dist
+/node_modules
+/build
+
+# Logs
+logs
+*.log
+npm-debug.log*
+pnpm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# OS
+.DS_Store
+
+# Tests
+/coverage
+/.nyc_output
+
+# IDEs and editors
+/.idea
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# IDE - VSCode
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+
+# dotenv environment variable files
+.env
+.env.development.local
+.env.test.local
+.env.production.local
+.env.local
+
+# temp directory
+.temp
+.tmp
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json

examples/nestjs-graphql/.prettierrc

@@ -0,0 +1,4 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all"
+}

examples/nestjs-graphql/README.md

@@ -0,0 +1,51 @@
+<a href="https://arcjet.com" target="_arcjet-home">
+  <picture>
+    <source media="(prefers-color-scheme: dark)" srcset="https://arcjet.com/logo/arcjet-dark-lockup-voyage-horizontal.svg">
+    <img src="https://arcjet.com/logo/arcjet-light-lockup-voyage-horizontal.svg" alt="Arcjet Logo" height="128" width="auto">
+  </picture>
+</a>
+
+# Arcjet Protection with NestJS + GraphQL
+
+This example shows how to use Arcjet to protect [NestJS](https://nestjs.com/)
+GraphQL applications using the `@arcjet/nest` adapter.
+
+## How to use
+
+1. From the root of the project, install the SDK dependencies.
+
+   ```bash
+   npm ci
+   ```
+
+2. Enter this directory and install the example's dependencies.
+
+   ```bash
+   cd examples/nestjs-graphql
+   npm ci
+   ```
+
+3. Rename `.env.local.example` to `.env.local` and add your Arcjet key.
+
+4. Start the server.
+
+   ```bash
+   npm start
+   ```
+
+5. Visit `http://localhost:3000/graphql` in a browser and submit a GraphQL
+   query.
+
+   ```graphql
+   query {
+      recipes {
+         id
+         title
+         description
+         ingredients
+      }
+   }
+   ```
+
+6. In the UI, change the headers to include `{ "user-agent": "curl" }` and
+   submit another GraphQL query and the request should be blocked.

examples/nestjs-graphql/nest-cli.json

@@ -0,0 +1,8 @@
+{
+  "$schema": "https://json.schemastore.org/nest-cli",
+  "collection": "@nestjs/schematics",
+  "sourceRoot": "src",
+  "compilerOptions": {
+    "deleteOutDir": true
+  }
+}