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// Copyright (c) 2022-2023 Cloudflare, Inc.
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// Licensed under the Apache 2.0 license found in the LICENSE file or at:
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//     https://opensource.org/licenses/Apache-2.0
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import { StructureGroups } from '@workerd/jsg/rtti';
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import { Message } from 'capnp-es';
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import extraDefinitions from 'raw:../../defines';
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import comments from 'virtual:comments.json';
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import paramNames from 'virtual:param-names.json';
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import rtti from 'workerd:rtti';
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import { installParameterNames } from '../generator/parameter-names';
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import { printDefinitions } from '../index';
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installParameterNames(paramNames);
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/**
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 * Worker for generating TypeScript types based on an arbitrary compatibility date
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 * and optional compatibility flags. Accepts paths of the form  `/<compat-date>(+<compat_flag>)*`
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 * (e.g. `/2024-01-01+nodejs_compat+no_global_navigator`)
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 */
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export default {
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  async fetch(request): Promise<Response> {
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    try {
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      // Ensure pathname matches expected pattern
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      let { pathname } = new URL(request.url);
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      if (
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        !/^\/\d{4}-\d{2}-\d{2}\+?/.test(pathname) &&
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        !pathname.startsWith('/experimental')
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      ) {
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        return new Response('Not Found', { status: 404 });
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      }
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      // Extract response format
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      let format: 'ambient' | 'importable' | 'bundle' = 'ambient';
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      if (pathname.endsWith('.d.ts')) {
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        pathname = pathname.slice(0, -'.d.ts'.length);
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      } else if (pathname.endsWith('.ts')) {
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        pathname = pathname.slice(0, -'.ts'.length);
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        format = 'importable';
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      } else if (pathname.endsWith('.bundle')) {
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        pathname = pathname.slice(0, -'.bundle'.length);
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        format = 'bundle';
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      }
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      // Export RTTI for specified compatibility settings
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      const [compatDate, ...compatFlags] = pathname.substring(1).split('+');
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      let rttiCapnpBuffer: ArrayBuffer;
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      if (compatDate === 'experimental') {
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        rttiCapnpBuffer = rtti.exportExperimentalTypes();
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      } else {
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        rttiCapnpBuffer = rtti.exportTypes(compatDate, compatFlags);
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      }
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      const message = new Message(rttiCapnpBuffer, /* packed */ false);
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      const root = message.getRoot(StructureGroups);
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      // Generate and return types in correct format
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      const { ambient, importable } = printDefinitions(
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        root,
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        comments,
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        extraDefinitions
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      );
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      if (format === 'ambient') return new Response(ambient);
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      if (format === 'importable') return new Response(importable);
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      const bundle = new FormData();
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      bundle.set('index.d.ts', ambient);
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      bundle.set('index.ts', importable);
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      return new Response(bundle);
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    } catch (e) {
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      return new Response(e.stack, { status: 500 });
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    }
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  },
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} satisfies ExportedHandler;