feat(codegen): bake isomorphic fetch into ORM client template (#754)

Generated SDKs now handle Node's *.localhost DNS and Host-header quirks
out of the box, so no separate @constructive-io/node shim is required.
The template resolves a default fetch at runtime: browsers/Deno/Bun use
globalThis.fetch; Node wraps it with a node:http/node:https
implementation that rewrites *.localhost hostnames to plain localhost
(RFC 6761 — resolves on both IPv4 and IPv6 loopback) while preserving
the original Host header so server-side subdomain routing keeps working.

@constructive-io/node is now a thin deprecation shim over
@constructive-io/sdk for backwards compatibility. Also ports the codegen
enum-type collection fix so input types referenced only by ENUM
arguments aren't dropped.

Validated end-to-end against a live PostGraphile dev server: sign-in at
auth.localhost:3000 returns a Bearer token that unlocks authenticated
queries against api.localhost:3000 — all handled by the generated SDK's
baked-in FetchAdapter with zero caller-side configuration.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: yyyyaaa

graphql/codegen/src/__tests__/codegen/__snapshots__/client-generator.test.ts.snap

@@ -116,25 +116,212 @@ export type {
   QueryResult,
 } from '@constructive-io/graphql-types';
 
+// ============================================================================
+// Isomorphic default fetch
+// ============================================================================
+//
+// In browsers and non-Node runtimes (Deno, Bun, edge workers), the native
+// \`globalThis.fetch\` is used directly. In Node, we wrap it with a
+// \`node:http\`/\`node:https\` implementation to work around two limitations of
+// Node's undici-backed fetch when talking to local PostGraphile servers:
+//
+//   1. \`*.localhost\` subdomains (e.g. \`auth.localhost\`) fail DNS resolution
+//      with ENOTFOUND — the connection target is rewritten to plain
+//      \`localhost\` (which resolves via both IPv4 and IPv6 loopback per
+//      RFC 6761) while the original \`Host\` header is preserved so
+//      server-side subdomain routing keeps working.
+//   2. The Fetch spec classifies \`Host\` as a forbidden request header and
+//      silently drops it. \`node:http\` has no such restriction.
+//
+// Callers can bypass this auto-detection by passing their own \`fetch\` to
+// \`OrmClientConfig\` / \`FetchAdapter\`.
+
+let _defaultFetchPromise: Promise<typeof globalThis.fetch> | undefined;
+
+function resolveDefaultFetch(): Promise<typeof globalThis.fetch> {
+  if (_defaultFetchPromise) return _defaultFetchPromise;
+  return (_defaultFetchPromise = (async () => {
+    const g = globalThis as {
+      document?: unknown;
+      process?: { versions?: { node?: string } };
+    };
+    // Browser or any runtime with a DOM: native fetch is fine.
+    if (typeof g.document !== 'undefined') {
+      return globalThis.fetch;
+    }
+    // Non-Node runtimes (Deno, Bun, edge workers): native fetch is fine.
+    const isNode = !!g.process?.versions?.node;
+    if (!isNode) return globalThis.fetch;
+    try {
+      // Bundler-opaque dynamic import — browser bundlers cannot statically
+      // resolve \`node:http\` through \`new Function\`, so this branch is treated
+      // as dead code in non-Node bundles.
+      // eslint-disable-next-line @typescript-eslint/no-implied-eval, no-new-func
+      const dynImport = new Function('s', 'return import(s)') as (
+        spec: string,
+      ) => Promise<unknown>;
+      const [http, https] = await Promise.all([
+        dynImport('node:http'),
+        dynImport('node:https'),
+      ]);
+      return buildNodeFetch(http, https);
+    } catch {
+      return globalThis.fetch;
+    }
+  })());
+}
+
+function buildNodeFetch(
+  http: unknown,
+  https: unknown,
+): typeof globalThis.fetch {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const httpMod: any = (http as any).default ?? http;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const httpsMod: any = (https as any).default ?? https;
+
+  return async (input, init) => {
+    const url = toUrl(input);
+    const headers = toHeaderRecord(init?.headers);
+    const method = init?.method ?? 'GET';
+    const body = init?.body ?? undefined;
+    const signal = init?.signal ?? undefined;
+
+    let requestUrl = url;
+    if (isLocalhostSubdomain(url.hostname)) {
+      headers['host'] = url.host;
+      requestUrl = new URL(url.href);
+      requestUrl.hostname = 'localhost';
+    }
+
+    return new Promise<Response>((resolve, reject) => {
+      if (signal?.aborted) {
+        reject(toAbortError(signal));
+        return;
+      }
+      const transport = requestUrl.protocol === 'https:' ? httpsMod : httpMod;
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const req: any = transport.request(
+        requestUrl,
+        { method, headers },
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (res: any) => {
+          const chunks: Uint8Array[] = [];
+          res.on('data', (chunk: Uint8Array) => chunks.push(chunk));
+          res.on('end', () => {
+            let total = 0;
+            for (const c of chunks) total += c.length;
+            const buf = new Uint8Array(total);
+            let offset = 0;
+            for (const c of chunks) {
+              buf.set(c, offset);
+              offset += c.length;
+            }
+            const outHeaders: [string, string][] = [];
+            for (const [k, v] of Object.entries(res.headers ?? {})) {
+              if (v === undefined) continue;
+              outHeaders.push([
+                k,
+                Array.isArray(v) ? v.join(', ') : String(v),
+              ]);
+            }
+            resolve(
+              new Response(buf, {
+                status: res.statusCode ?? 0,
+                statusText: res.statusMessage ?? '',
+                headers: outHeaders,
+              }),
+            );
+          });
+          res.on('error', reject);
+        },
+      );
+
+      req.on('error', reject);
+      if (signal) {
+        const onAbort = () => req.destroy(toAbortError(signal));
+        signal.addEventListener('abort', onAbort, { once: true });
+        req.on('close', () =>
+          signal.removeEventListener('abort', onAbort),
+        );
+      }
+      if (body !== null && body !== undefined) {
+        req.write(
+          typeof body === 'string' || body instanceof Uint8Array
+            ? body
+            : String(body),
+        );
+      }
+      req.end();
+    });
+  };
+}
+
+function toUrl(input: RequestInfo | URL): URL {
+  if (input instanceof URL) return input;
+  if (typeof input === 'string') return new URL(input);
+  return new URL((input as { url: string }).url);
+}
+
+function toHeaderRecord(
+  headers: HeadersInit | undefined,
+): Record<string, string> {
+  if (!headers) return {};
+  if (typeof Headers !== 'undefined' && headers instanceof Headers) {
+    const out: Record<string, string> = {};
+    headers.forEach((value, key) => {
+      out[key] = value;
+    });
+    return out;
+  }
+  if (Array.isArray(headers)) {
+    const out: Record<string, string> = {};
+    for (const [k, v] of headers) out[k] = v;
+    return out;
+  }
+  return { ...(headers as Record<string, string>) };
+}
+
+function isLocalhostSubdomain(hostname: string): boolean {
+  return hostname.endsWith('.localhost') && hostname !== 'localhost';
+}
+
+function toAbortError(signal: AbortSignal): Error {
+  const message =
+    (signal.reason as Error | undefined)?.message ??
+    'The operation was aborted';
+  const err = new Error(message);
+  err.name = 'AbortError';
+  return err;
+}
+
 /**
  * Default adapter that uses fetch for HTTP requests.
- * This is used when no custom adapter is provided.
+ *
+ * When no \`fetchFn\` is provided, defaults to an isomorphic fetch that uses
+ * \`globalThis.fetch\` in browsers/Deno/Bun and falls back to a Node-native
+ * wrapper in Node to handle \`*.localhost\` subdomain DNS and \`Host\` header
+ * preservation. Pass an explicit \`fetchFn\` to bypass this behavior.
  */
 export class FetchAdapter implements GraphQLAdapter {
   private headers: Record<string, string>;
+  private fetchFn: typeof globalThis.fetch | undefined;
 
   constructor(
     private endpoint: string,
     headers?: Record<string, string>,
+    fetchFn?: typeof globalThis.fetch,
   ) {
     this.headers = headers ?? {};
+    this.fetchFn = fetchFn;
   }
 
   async execute<T>(
     document: string,
     variables?: Record<string, unknown>,
   ): Promise<QueryResult<T>> {
-    const response = await fetch(this.endpoint, {
+    const fetchImpl = this.fetchFn ?? (await resolveDefaultFetch());
+    const response = await fetchImpl(this.endpoint, {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
@@ -188,15 +375,22 @@ export class FetchAdapter implements GraphQLAdapter {
 
 /**
  * Configuration for creating an ORM client.
- * Either provide endpoint (and optional headers) for HTTP requests,
+ * Either provide endpoint (and optional headers/fetch) for HTTP requests,
  * or provide a custom adapter for alternative execution strategies.
  */
 export interface OrmClientConfig {
   /** GraphQL endpoint URL (required if adapter not provided) */
   endpoint?: string;
   /** Default headers for HTTP requests (only used with endpoint) */
   headers?: Record<string, string>;
-  /** Custom adapter for GraphQL execution (overrides endpoint/headers) */
+  /**
+   * Custom fetch implementation. If omitted, an isomorphic default is
+   * used that auto-handles Node's \`*.localhost\` / Host-header quirks.
+   * Pass your own fetch to override that behavior (e.g. a mock in tests,
+   * or a fetch with preconfigured credentials/proxy).
+   */
+  fetch?: typeof globalThis.fetch;
+  /** Custom adapter for GraphQL execution (overrides endpoint/headers/fetch) */
   adapter?: GraphQLAdapter;
 }
 
@@ -221,7 +415,11 @@ export class OrmClient {
     if (config.adapter) {
       this.adapter = config.adapter;
     } else if (config.endpoint) {
-      this.adapter = new FetchAdapter(config.endpoint, config.headers);
+      this.adapter = new FetchAdapter(
+        config.endpoint,
+        config.headers,
+        config.fetch,
+      );
     } else {
       throw new Error(
         'OrmClientConfig requires either an endpoint or a custom adapter',

graphql/codegen/src/__tests__/codegen/client-generator.test.ts

@@ -60,6 +60,30 @@ describe('client-generator', () => {
       expect(result.content).toContain('QueryResult<T>');
       expect(result.content).toContain('GraphQLRequestError');
     });
+
+    it('exposes an optional fetch injection in OrmClientConfig (issue #754)', () => {
+      const result = generateOrmClientFile();
+
+      expect(result.content).toContain('fetch?: typeof globalThis.fetch');
+      expect(result.content).toContain('config.fetch');
+    });
+
+    it('bakes in isomorphic default fetch with Node quirks handling (issue #754)', () => {
+      const result = generateOrmClientFile();
+
+      // Browser/runtime detection short-circuits first
+      expect(result.content).toContain("g.document");
+      // Node-only code path uses bundler-opaque dynamic import
+      expect(result.content).toContain("new Function('s', 'return import(s)')");
+      expect(result.content).toContain("'node:http'");
+      expect(result.content).toContain("'node:https'");
+      // *.localhost rewrite + Host header preservation
+      expect(result.content).toContain(".endsWith('.localhost')");
+      expect(result.content).toContain("requestUrl.hostname = 'localhost'");
+      expect(result.content).toContain("headers['host'] = url.host");
+      // Execute uses the resolved default when no fetchFn is injected
+      expect(result.content).toContain('await resolveDefaultFetch()');
+    });
   });
 
   describe('generateQueryBuilderFile', () => {

graphql/codegen/src/__tests__/codegen/input-types-generator.test.ts

@@ -863,6 +863,39 @@ describe('collectInputTypeNames', () => {
 
     expect(result.has('UserFilter')).toBe(true);
   });
+
+  it('collects ENUM arg type names without Input/Filter suffix', () => {
+    const operations = [
+      {
+        args: [
+          { name: 'role', type: createTypeRef('ENUM', 'UserRole') },
+          {
+            name: 'status',
+            type: createNonNull(createTypeRef('ENUM', 'AccountStatus')),
+          },
+        ] as Argument[],
+      },
+    ];
+
+    const result = collectInputTypeNames(operations);
+
+    expect(result.has('UserRole')).toBe(true);
+    expect(result.has('AccountStatus')).toBe(true);
+  });
+
+  it('collects INPUT_OBJECT arg type names without suffix match', () => {
+    const operations = [
+      {
+        args: [
+          { name: 'custom', type: createTypeRef('INPUT_OBJECT', 'CustomPatch') },
+        ] as Argument[],
+      },
+    ];
+
+    const result = collectInputTypeNames(operations);
+
+    expect(result.has('CustomPatch')).toBe(true);
+  });
 });
 
 describe('collectPayloadTypeNames', () => {

graphql/codegen/src/core/codegen/orm/custom-ops-generator.ts

@@ -10,6 +10,7 @@ import type { Argument, Operation } from '../../../types/schema';
 import { addJSDocComment, generateCode } from '../babel-ast';
 import { NON_SELECT_TYPES, getSelectTypeName } from '../select-helpers';
 import {
+  getBaseTypeKind,
   getTypeBaseName,
   isTypeRequired,
   scalarToTsType,
@@ -32,13 +33,15 @@ function collectInputTypeNamesFromOps(operations: Operation[]): string[] {
   for (const op of operations) {
     for (const arg of op.args) {
       const baseName = getTypeBaseName(arg.type);
-      if (
-        baseName &&
-        (baseName.endsWith('Input') ||
-          baseName.endsWith('Filter') ||
-          baseName.endsWith('OrderBy') ||
-          baseName.endsWith('Condition'))
-      ) {
+      if (!baseName) continue;
+      const baseKind = getBaseTypeKind(arg.type);
+      const isInputShape =
+        baseKind === 'INPUT_OBJECT' ||
+        baseName.endsWith('Input') ||
+        baseName.endsWith('Filter') ||
+        baseName.endsWith('OrderBy') ||
+        baseName.endsWith('Condition');
+      if (isInputShape || baseKind === 'ENUM') {
         inputTypes.add(baseName);
       }
     }

graphql/codegen/src/core/codegen/orm/input-types-generator.ts

@@ -20,7 +20,7 @@ import type {
 } from '../../../types/schema';
 import { addJSDocComment, addLineComment, generateCode } from '../babel-ast';
 import { BASE_FILTER_TYPE_NAMES, SCALAR_NAMES, scalarToFilterType, scalarToTsType } from '../scalars';
-import { getTypeBaseName } from '../type-resolver';
+import { getBaseTypeKind, getTypeBaseName } from '../type-resolver';
 import {
   getCreateInputTypeName,
   getFilterTypeName,
@@ -1521,10 +1521,14 @@ export function collectInputTypeNames(
 
   function collectFromTypeRef(typeRef: Argument['type']) {
     const baseName = getTypeBaseName(typeRef);
-    if (baseName && baseName.endsWith('Input')) {
-      inputTypes.add(baseName);
-    }
-    if (baseName && baseName.endsWith('Filter')) {
+    if (!baseName) return;
+    const baseKind = getBaseTypeKind(typeRef);
+    if (
+      baseName.endsWith('Input') ||
+      baseName.endsWith('Filter') ||
+      baseKind === 'INPUT_OBJECT' ||
+      baseKind === 'ENUM'
+    ) {
       inputTypes.add(baseName);
     }
   }