feature: add linkable-spec utility lib

packages/libraries/linkable-specs/README.md

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+# GraphQL Hive - linkable-specs
+
+[Hive](https://the-guild.dev/graphql/hive) is a fully open-source schema registry, analytics,
+metrics and gateway for [GraphQL federation](https://the-guild.dev/graphql/hive/federation) and
+other GraphQL APIs.
+
+---
+
+Utility classes for parsing federated `@link`s.

packages/libraries/linkable-specs/package.json

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+{
+  "name": "@graphql-hive/linkable-specs",
+  "version": "0.0.1",
+  "type": "module",
+  "repository": {
+    "type": "git",
+    "url": "graphql-hive/platform",
+    "directory": "packages/libraries/linkable-specs"
+  },
+  "homepage": "https://the-guild.dev/graphql/hive",
+  "author": {
+    "email": "[email protected]",
+    "name": "The Guild",
+    "url": "https://the-guild.dev"
+  },
+  "license": "MIT",
+  "private": true,
+  "engines": {
+    "node": ">=16.0.0"
+  },
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "exports": {
+    ".": {
+      "require": {
+        "types": "./dist/typings/index.d.cts",
+        "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",
+  "scripts": {
+    "build": "node ../../../scripts/generate-version.mjs && bob build",
+    "check:build": "bob check"
+  },
+  "peerDependencies": {
+    "graphql": "^0.13.0 || ^14.0.0 || ^15.0.0 || ^16.0.0"
+  },
+  "devDependencies": {
+    "graphql": "16.9.0",
+    "tslib": "2.8.1",
+    "vitest": "2.0.5"
+  },
+  "publishConfig": {
+    "registry": "https://registry.npmjs.org",
+    "access": "public",
+    "directory": "dist"
+  },
+  "sideEffects": false,
+  "typescript": {
+    "definition": "dist/typings/index.d.ts"
+  }
+}

packages/libraries/linkable-specs/src/__tests__/index.spec.ts

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+import { DocumentNode, parse, StringValueNode, visit } from 'graphql';
+import { detectLinkedImplementations, LinkableSpec } from '../index';
+
+describe('index', () => {
+  test('LinkableSpec and detectLinkedImplementations can be used to easily implement linked schema functionality', () => {
+    const sdl = `
+          directive @meta(name: String!, content: String!) on SCHEMA | FIELD
+          directive @metadata_example(eg: String!) on FIELD
+          extend schema
+            @link(url: "https://specs.apollo.dev/link/v1.0")
+            @link(url: "https://specs.graphql-hive.com/metadata/v0.1", import: ["@meta"])
+  
+          type Query {
+            ping: String @meta(name: "owner", content: "hive-console-team")
+            pong: String @metadata__example(eg: "1...2...3... Pong")
+          }
+      `;
+
+    const metaSpec = new LinkableSpec('https://specs.graphql-hive.com/metadata', {
+      // The return value could be used to map sdl, collect information, or create a graphql yoga plugin.
+      // In this test, it's used to collect metadata information from the schema.
+      'v0.1': resolveImportName => (typeDefs: DocumentNode) => {
+        const collectedMeta: Record<string, Record<string, string>> = {};
+        const metaName = resolveImportName('@meta');
+        const exampleName = resolveImportName('@example');
+        visit(typeDefs, {
+          FieldDefinition: node => {
+            let metaData: Record<string, string> = {};
+            const fieldName = node.name.value;
+            const meta = node.directives?.find(d => d.name.value === metaName);
+            if (meta) {
+              metaData['name'] =
+                (
+                  meta.arguments?.find(a => a.name.value === 'name')?.value as
+                    | StringValueNode
+                    | undefined
+                )?.value ?? '??';
+              metaData['content'] =
+                (
+                  meta.arguments?.find(a => a.name.value === 'content')?.value as
+                    | StringValueNode
+                    | undefined
+                )?.value ?? '??';
+            }
+
+            const example = node.directives?.find(d => d.name.value === exampleName);
+            if (example) {
+              metaData['eg'] =
+                (
+                  example.arguments?.find(a => a.name.value === 'eg')?.value as
+                    | StringValueNode
+                    | undefined
+                )?.value ?? '??';
+            }
+            if (Object.keys(metaData).length) {
+              collectedMeta[fieldName] ??= {};
+              collectedMeta[fieldName] = Object.assign(collectedMeta[fieldName], metaData);
+            }
+            return;
+          },
+        });
+        // collect metadata
+        return `running on v0.1.\nFound metadata: ${JSON.stringify(collectedMeta)}}`;
+      },
+      'v0.2': _resolveImportName => (_typeDefs: DocumentNode) => {
+        // collect metadata
+        return `running on v0.2...`;
+      },
+    });
+    const typeDefs = parse(sdl);
+    const linked = detectLinkedImplementations(typeDefs, [metaSpec]);
+    expect(linked.map(link => link(typeDefs))).toMatchInlineSnapshot(`
+      [
+        running on v0.1.
+      Found metadata: {"ping":{"name":"owner","content":"hive-console-team"},"pong":{"eg":"1...2...3... Pong"}}},
+      ]
+    `);
+  });
+});

packages/libraries/linkable-specs/src/__tests__/link-url.spec.ts

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+import { FederatedLinkUrl } from '../link-url';
+
+describe('FederatedLinkUrl', () => {
+  test.each([
+    [
+      'https://spec.example.com/a/b/mySchema/v1.0/',
+      'https://spec.example.com/a/b/mySchema',
+      'mySchema',
+      'v1.0',
+    ],
+    ['https://spec.example.com', 'https://spec.example.com', null, null],
+    [
+      'https://spec.example.com/mySchema/v0.1?q=v#frag',
+      'https://spec.example.com/mySchema',
+      'mySchema',
+      'v0.1',
+    ],
+    ['https://spec.example.com/v1.0', 'https://spec.example.com', null, 'v1.0'],
+    ['https://spec.example.com/vX', 'https://spec.example.com/vX', 'vX', null],
+  ])('fromUrl', (url, identity, name, version) => {
+    const spec = FederatedLinkUrl.fromUrl(url);
+    expect(spec.identity).toBe(identity);
+    expect(spec.name).toBe(name);
+    expect(spec.version).toBe(version);
+  });
+
+  test.each([
+    ['https://spec.example.com/a/b/mySchema/v1.2/', 'https://spec.example.com/a/b/mySchema/v1.0/'],
+    ['https://spec.example.com', 'https://spec.example.com'],
+    ['https://spec.example.com/mySchema/v0.1?q=v#frag', 'https://spec.example.com/mySchema/v0.1'],
+    ['https://spec.example.com/v1.100', 'https://spec.example.com/v1.0'],
+    ['https://spec.example.com/vX', 'https://spec.example.com/vX'],
+  ])(
+    'supports returns true for specs with the same identity and compatible versions',
+    (url0, url1) => {
+      expect(FederatedLinkUrl.fromUrl(url0).supports(FederatedLinkUrl.fromUrl(url1))).toBe(true);
+    },
+  );
+
+  test.each([
+    ['https://spec.example.com/a/b/mySchema/v1.0/', 'https://spec.example.com/a/b/mySchema/v1.2/'],
+    ['https://spec.example.com/mySchema/v0.1?q=v#frag', 'https://spec.example.com/mySchema/v0.2'],
+    ['https://spec.example.com/v1.0', 'https://spec.example.com/v1.100'],
+  ])(
+    'supports returns false for specs with the same identity and incompatible versions',
+    (url0, url1) => {
+      expect(FederatedLinkUrl.fromUrl(url0).supports(FederatedLinkUrl.fromUrl(url1))).toBe(false);
+    },
+  );
+
+  test.each([
+    ['https://spec.example.com/a/b/mySchema/v1.0/', 'https://spec.example.com/a/b/mySchema/v1.0'],
+    ['https://spec.example.com', 'https://spec.example.com'],
+    ['https://spec.example.com/mySchema/v0.1?q=v#frag', 'https://spec.example.com/mySchema/v0.1'],
+    ['https://spec.example.com/v1.0', 'https://spec.example.com/v1.0'],
+    ['https://spec.example.com/vX', 'https://spec.example.com/vX'],
+  ])('toString returns the normalized url', (url, str) => {
+    expect(FederatedLinkUrl.fromUrl(url).toString()).toBe(str);
+  });
+});

packages/libraries/linkable-specs/src/__tests__/link.spec.ts

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+import { parse } from 'graphql';
+import { FederatedLink } from '../link';
+
+function trimMultiline(str: string): string {
+  return str
+    .split('\n')
+    .map(s => s.trim())
+    .filter(l => !!l)
+    .join('\n');
+}
+
+describe('FederatedLink', () => {
+  test.each([
+    `
+      extend schema
+        @link(url: "https://specs.apollo.dev/link/v1.0")
+        @link(url: "https://specs.apollo.dev/federation/v2.0")
+    `,
+    `
+      extend schema
+        @link(url: "https://specs.apollo.dev/link/v1.0", as: "@linkz")
+        @link(url: "https://specs.apollo.dev/federation/v2.0", as: "fed", import: ["@key"])
+    `,
+    `
+      extend schema
+        @link(url: "https://specs.apollo.dev/link/v1.0")
+        @link(url: "https://specs.apollo.dev/federation/v2.0", import: [{ name: "@key", as: "@lookup" }])
+    `,
+  ])('fromTypedefs', (sdl: string) => {
+    // string manipulate to extract just the link trings
+    const firstLinkPos = sdl.indexOf('@link(');
+    const linksOnly = trimMultiline(sdl.substring(firstLinkPos));
+    // compare to parsed result
+    const typeDefs = parse(sdl);
+    const links = FederatedLink.fromTypedefs(typeDefs);
+    expect(links.join('\n')).toBe(linksOnly);
+  });
+
+  test('resolveImportName', () => {
+    const sdl = `
+      extend schema
+        @link(url: "https://specs.apollo.dev/link/v1.0")
+        @link(url: "https://specs.apollo.dev/federation/v2.0", import: [{ name: "@key", as: "@lookup" }, "@provides"])
+        @link(url: "https://unnamed.graphql-hive.com/v0.1", import: ["@meta"])
+        @link(url: "https://specs.graphql-hive.com/hive/v0.1", import: ["@group"], as: "hivelink")
+    `;
+    const links = FederatedLink.fromTypedefs(parse(sdl));
+    const federationLink = links.find(l => l.identity === 'https://specs.apollo.dev/federation');
+    expect(federationLink).toBeDefined();
+    // aliased
+    expect(federationLink?.resolveImportName('@key')).toBe('lookup');
+    // unimported
+    expect(federationLink?.resolveImportName('@external')).toBe('federation__external');
+    // imported by name only
+    expect(federationLink?.resolveImportName('@provides')).toBe('provides');
+
+    // default import
+    const linkLink = links.find(l => l.identity === 'https://specs.apollo.dev/link');
+    expect(linkLink?.resolveImportName('@link')).toBe('link');
+
+    // unnamespaced
+    const unnamedLink = links.find(l => l.identity === 'https://unnamed.graphql-hive.com');
+    expect(unnamedLink).toBeDefined();
+    expect(unnamedLink?.resolveImportName('@meta')).toBe('meta');
+    expect(unnamedLink?.resolveImportName('@unmentioned')).toBe('unmentioned');
+
+    // imported as
+    const hiveLink = links.find(l => l.identity === 'https://specs.graphql-hive.com/hive');
+    expect(hiveLink?.resolveImportName('@group')).toBe('group');
+    expect(hiveLink?.resolveImportName('@eg')).toBe('hivelink__eg');
+  });
+});

packages/libraries/linkable-specs/src/__tests__/linkable-spec.spec.ts

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+import { parse } from 'graphql';
+import { FederatedLink } from '../link';
+import { LinkableSpec } from '../linkable-spec';
+
+describe('LinkableSpec', () => {
+  test('getSupportingVersion returned the most compatible version.', () => {
+    const spec = new LinkableSpec('https://specs.graphql-hive.com/example', {
+      'v2.0': _resolveImportName => 'Version 2.0 used.',
+      'v1.0': _resolveImportName => 'Version 1.0 used.',
+    });
+    const sdl = `
+      extend schema
+        @link(url: "https://specs.graphql-hive.com/example/v1.1")
+    `;
+
+    const links = FederatedLink.fromTypedefs(parse(sdl));
+    const specImpl = spec.detectImplementation(links);
+    expect(specImpl).toBe('Version 1.0 used.');
+  });
+});

packages/libraries/linkable-specs/src/index.ts

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+import { DocumentNode } from 'graphql';
+import { FederatedLink } from './link';
+import type { LinkableSpec } from './linkable-spec';
+
+export * from './link-import';
+export * from './link-url';
+export * from './link';
+export * from './linkable-spec';
+
+export function detectLinkedImplementations<T>(
+  typeDefs: DocumentNode,
+  supportedSpecs: LinkableSpec<T>[],
+): T[] {
+  const links = FederatedLink.fromTypedefs(typeDefs);
+  return supportedSpecs
+    .map(spec => {
+      const specImpl = spec.detectImplementation(links);
+      return specImpl;
+    })
+    .filter(v => v !== undefined);
+}

packages/libraries/linkable-specs/src/link-import.ts

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+import { ConstValueNode, Kind, StringValueNode } from 'graphql';
+
+export class FederatedLinkImport {
+  constructor(
+    public name: string,
+    public as: string | null,
+  ) {}
+
+  public toString(): string {
+    return this.as ? `{ name: "${this.name}", as: "${this.as}" }` : `"${this.name}"`;
+  }
+
+  static fromTypedefs(node: ConstValueNode): FederatedLinkImport[] {
+    if (node.kind == Kind.LIST) {
+      const imports = node.values.map(v => {
+        if (v.kind === Kind.STRING) {
+          return new FederatedLinkImport(v.value, null);
+        }
+        if (v.kind === Kind.OBJECT) {
+          let name: string = '';
+          let as: string | null = null;
+
+          v.fields.forEach(f => {
+            if (f.name.value === 'name') {
+              if (f.value.kind !== Kind.STRING) {
+                throw new Error(
+                  `Expected string value for @link "name" field but got "${f.value.kind}"`,
+                );
+              }
+              name = f.value.value;
+            } else if (f.name.value === 'as') {
+              if (f.value.kind !== Kind.STRING) {
+                throw new Error(
+                  `Expected string value for @link "as" field but got "${f.value.kind}"`,
+                );
+              }
+              as = f.value.value;
+            }
+          });
+          return new FederatedLinkImport(name, as);
+        }
+        throw new Error(`Unexpected value kind "${v.kind}" in @link import declaration`);
+      });
+      return imports;
+    }
+    throw new Error(`Expected a list of @link imports but got "${node.kind}"`);
+  }
+}