Lazy Schema Plugin

.changeset/healthy-waves-sing.md

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+---
+'@graphql-yoga/plugin-lazy-schema': major
+---
+
+New Lazy Schema

packages/plugins/lazy-schema/package.json

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+{
+  "name": "@graphql-yoga/plugin-lazy-schema",
+  "version": "0.0.0",
+  "description": "Lazy Schema plugin for GraphQL Yoga.",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/dotansimha/graphql-yoga.git",
+    "directory": "packages/plugins/apq"
+  },
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "scripts": {
+    "check": "tsc --pretty --noEmit"
+  },
+  "author": "Arda TANRIKULU <ardatanrikulu@gmail.com>",
+  "license": "MIT",
+  "exports": {
+    ".": {
+      "require": {
+        "types": "./dist/typings/index.d.ts",
+        "default": "./dist/cjs/index.js"
+      },
+      "import": {
+        "types": "./dist/typings/index.d.ts",
+        "default": "./dist/esm/index.js"
+      },
+      "default": {
+        "types": "./dist/typings/index.d.ts",
+        "default": "./dist/esm/index.js"
+      }
+    },
+    "./package.json": "./package.json"
+  },
+  "typings": "dist/typings/index.d.ts",
+  "typescript": {
+    "definition": "dist/typings/index.d.ts"
+  },
+  "publishConfig": {
+    "directory": "dist",
+    "access": "public"
+  },
+  "peerDependencies": {
+    "graphql-yoga": "^2.13.4",
+    "graphql": "*"
+  },
+  "type": "module"
+}

packages/plugins/lazy-schema/src/index.ts

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+import { GraphQLError, GraphQLSchema } from 'graphql'
+import { Plugin, PromiseOrValue, YogaInitialContext } from 'graphql-yoga'
+
+export const useLazySchema = (
+  schemaFactory: (request: Request) => PromiseOrValue<GraphQLSchema>,
+): Plugin<YogaInitialContext> => {
+  const schemaByRequest = new WeakMap<Request, GraphQLSchema>()
+  return {
+    async onRequest({ request }) {
+      const schema = await schemaFactory(request)
+      schemaByRequest.set(request, schema)
+    },
+    onEnveloped({ setSchema, context }) {
+      if (context?.request) {
+        const schema = schemaByRequest.get(context.request)
+        if (schema) {
+          setSchema(schema)
+        }
+      } else {
+        throw new GraphQLError(
+          'Request object is not available in the context. Make sure you use this plugin with GraphQL Yoga.',
+          {
+            extensions: {
+              http: {
+                status: 500,
+              },
+            },
+          },
+        )
+      }
+    },
+  }
+}

packages/plugins/lazy-schema/test/lazy-schema-plugin.test.ts

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+import { makeExecutableSchema } from '@graphql-tools/schema'
+import { parse } from 'graphql'
+import { createYoga, YogaInitialContext } from 'graphql-yoga'
+import { useLazySchema } from '../src'
+
+describe('useLazySchema', () => {
+  it('should work', async () => {
+    let count = 0
+    const schemaFactory = async (request: Request) => {
+      const countFromContext = request.headers.get('count')
+      return makeExecutableSchema<YogaInitialContext>({
+        typeDefs: /* GraphQL */ `
+                type Query {
+                    foo${countFromContext}: Boolean
+                }
+            `,
+        resolvers: {
+          Query: {
+            [`foo${countFromContext}`]: (_, __, { request }) =>
+              countFromContext === request.headers.get('count'),
+          },
+        },
+      })
+    }
+    const yoga = createYoga({
+      plugins: [useLazySchema(schemaFactory)],
+    })
+    while (true) {
+      if (count === 3) {
+        break
+      }
+      count++
+      const query = /* GraphQL */ `
+            query {
+                foo${count}
+            }
+        `
+      const result = await yoga.fetch('http://localhost:3000/graphql', {
+        method: 'POST',
+        body: JSON.stringify({ query }),
+        headers: {
+          count: count.toString(),
+          'Content-Type': 'application/json',
+        },
+      })
+      const { data } = await result.json()
+      expect(data).toEqual({
+        [`foo${count}`]: true,
+      })
+    }
+    expect.assertions(3)
+  })
+})