From 9fd9efa49222c65e255085cfaabf4924721c833d Mon Sep 17 00:00:00 2001 From: Bradley Farias Date: Tue, 9 Jul 2019 16:03:07 -0500 Subject: [PATCH] esm: support loading data URLs Co-Authored-By: Jan Olaf Krems PR-URL: https://github.com/nodejs/node/pull/28614 Reviewed-By: Jan Krems --- doc/api/esm.md | 30 ++++++- lib/internal/modules/esm/default_resolve.js | 22 +++++- lib/internal/modules/esm/loader.js | 7 +- lib/internal/modules/esm/translators.js | 86 +++++++++++++++------ test/es-module/test-esm-data-urls.js | 63 +++++++++++++++ 5 files changed, 179 insertions(+), 29 deletions(-) create mode 100644 test/es-module/test-esm-data-urls.js diff --git a/doc/api/esm.md b/doc/api/esm.md index 17d98ab2085792..277f5cf8300403 100644 --- a/doc/api/esm.md +++ b/doc/api/esm.md @@ -312,13 +312,38 @@ There are four types of specifiers: Bare specifiers, and the bare specifier portion of deep import specifiers, are strings; but everything else in a specifier is a URL. -Only `file://` URLs are supported. A specifier like +Only `file:` and `data:` URLs are supported. A specifier like `'https://example.com/app.js'` may be supported by browsers but it is not supported in Node.js. Specifiers may not begin with `/` or `//`. These are reserved for potential future use. The root of the current volume may be referenced via `file:///`. +#### `data:` Imports + + + +[`data:` URLs][] are supported for importing with the following MIME types: + +* `text/javascript` for ES Modules +* `application/json` for JSON +* `application/wasm` for WASM. + +`data:` URLs only resolve [_Bare specifiers_][Terminology] for builtin modules +and [_Absolute specifiers_][Terminology]. Resolving +[_Relative specifiers_][Terminology] will not work because `data:` is not a +[special scheme][]. For example, attempting to load `./foo` +from `data:text/javascript,import "./foo";` will fail to resolve since there +is no concept of relative resolution for `data:` URLs. An example of a `data:` +URLs being used is: + +```mjs +import 'data:text/javascript,console.log("hello!");' +import _ from 'data:application/json,"world!"' +``` + ## import.meta * {Object} @@ -869,6 +894,8 @@ $ node --experimental-modules --es-module-specifier-resolution=node index success! ``` +[Terminology]: #esm_terminology +[`data:` URLs]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs [`export`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/export [`import`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import [`import()`]: #esm_import-expressions @@ -877,6 +904,7 @@ success! [CommonJS]: modules.html [ECMAScript-modules implementation]: https://github.com/nodejs/modules/blob/master/doc/plan-for-new-modules-implementation.md [Node.js EP for ES Modules]: https://github.com/nodejs/node-eps/blob/master/002-es-modules.md +[special scheme]: https://url.spec.whatwg.org/#special-scheme [WHATWG JSON modules specification]: https://html.spec.whatwg.org/#creating-a-json-module-script [ES Module Integration Proposal for Web Assembly]: https://github.com/webassembly/esm-integration [dynamic instantiate hook]: #esm_dynamic_instantiate_hook diff --git a/lib/internal/modules/esm/default_resolve.js b/lib/internal/modules/esm/default_resolve.js index 46e7b2415a92e0..580419deac6c05 100644 --- a/lib/internal/modules/esm/default_resolve.js +++ b/lib/internal/modules/esm/default_resolve.js @@ -12,7 +12,7 @@ const typeFlag = getOptionValue('--input-type'); const experimentalWasmModules = getOptionValue('--experimental-wasm-modules'); const { resolve: moduleWrapResolve, getPackageType } = internalBinding('module_wrap'); -const { pathToFileURL, fileURLToPath } = require('internal/url'); +const { URL, pathToFileURL, fileURLToPath } = require('internal/url'); const { ERR_INPUT_TYPE_NOT_ALLOWED, ERR_UNKNOWN_FILE_EXTENSION } = require('internal/errors').codes; @@ -45,12 +45,32 @@ if (experimentalWasmModules) extensionFormatMap['.wasm'] = legacyExtensionFormatMap['.wasm'] = 'wasm'; function resolve(specifier, parentURL) { + try { + const parsed = new URL(specifier); + if (parsed.protocol === 'data:') { + const [ , mime ] = /^([^/]+\/[^;,]+)(;base64)?,/.exec(parsed.pathname) || [ null, null, null ]; + const format = ({ + '__proto__': null, + 'text/javascript': 'module', + 'application/json': 'json', + 'application/wasm': experimentalWasmModules ? 'wasm' : null + })[mime] || null; + return { + url: specifier, + format + }; + } + } catch {} if (NativeModule.canBeRequiredByUsers(specifier)) { return { url: specifier, format: 'builtin' }; } + if (parentURL && parentURL.startsWith('data:')) { + // This is gonna blow up, we want the error + new URL(specifier, parentURL); + } const isMain = parentURL === undefined; if (isMain) diff --git a/lib/internal/modules/esm/loader.js b/lib/internal/modules/esm/loader.js index bffefa884e4821..09109d3c71287f 100644 --- a/lib/internal/modules/esm/loader.js +++ b/lib/internal/modules/esm/loader.js @@ -102,9 +102,12 @@ class Loader { } } - if (format !== 'dynamic' && !url.startsWith('file:')) + if (format !== 'dynamic' && + !url.startsWith('file:') && + !url.startsWith('data:') + ) throw new ERR_INVALID_RETURN_PROPERTY( - 'file: url', 'loader resolve', 'url', url + 'file: or data: url', 'loader resolve', 'url', url ); return { url, format }; diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js index 584a3303002f3d..26508e744e47ea 100644 --- a/lib/internal/modules/esm/translators.js +++ b/lib/internal/modules/esm/translators.js @@ -9,6 +9,8 @@ const { StringPrototype } = primordials; +const { Buffer } = require('buffer'); + const { stripBOM, loadNativeModule @@ -23,6 +25,8 @@ const { debuglog } = require('internal/util/debuglog'); const { promisify } = require('internal/util'); const esmLoader = require('internal/process/esm_loader'); const { + ERR_INVALID_URL, + ERR_INVALID_URL_SCHEME, ERR_UNKNOWN_BUILTIN_MODULE } = require('internal/errors').codes; const readFileAsync = promisify(fs.readFile); @@ -33,6 +37,31 @@ const debug = debuglog('esm'); const translators = new SafeMap(); exports.translators = translators; +const DATA_URL_PATTERN = /^[^/]+\/[^,;]+(;base64)?,([\s\S]*)$/; +function getSource(url) { + const parsed = new URL(url); + if (parsed.protocol === 'file:') { + return readFileAsync(parsed); + } else if (parsed.protocol === 'data:') { + const match = DATA_URL_PATTERN.exec(parsed.pathname); + if (!match) { + throw new ERR_INVALID_URL(url); + } + const [ , base64, body ] = match; + return Buffer.from(body, base64 ? 'base64' : 'utf8'); + } else { + throw new ERR_INVALID_URL_SCHEME(['file', 'data']); + } +} + +function errPath(url) { + const parsed = new URL(url); + if (parsed.protocol === 'file:') { + return fileURLToPath(parsed); + } + return url; +} + function initializeImportMeta(meta, { url }) { meta.url = url; } @@ -44,7 +73,7 @@ async function importModuleDynamically(specifier, { url }) { // Strategy for loading a standard JavaScript module translators.set('module', async function moduleStrategy(url) { - const source = `${await readFileAsync(new URL(url))}`; + const source = `${await getSource(url)}`; debug(`Translating StandardModule ${url}`); const { ModuleWrap, callbackMap } = internalBinding('module_wrap'); const module = new ModuleWrap(source, url); @@ -111,26 +140,32 @@ translators.set('builtin', async function builtinStrategy(url) { translators.set('json', async function jsonStrategy(url) { debug(`Translating JSONModule ${url}`); debug(`Loading JSONModule ${url}`); - const pathname = fileURLToPath(url); - const modulePath = isWindows ? - StringPrototype.replace(pathname, winSepRegEx, '\\') : pathname; - let module = CJSModule._cache[modulePath]; - if (module && module.loaded) { - const exports = module.exports; - return createDynamicModule([], ['default'], url, (reflect) => { - reflect.exports.default.set(exports); - }); + const pathname = url.startsWith('file:') ? fileURLToPath(url) : null; + let modulePath; + let module; + if (pathname) { + modulePath = isWindows ? + StringPrototype.replace(pathname, winSepRegEx, '\\') : pathname; + module = CJSModule._cache[modulePath]; + if (module && module.loaded) { + const exports = module.exports; + return createDynamicModule([], ['default'], url, (reflect) => { + reflect.exports.default.set(exports); + }); + } } - const content = await readFileAsync(pathname, 'utf-8'); - // A require call could have been called on the same file during loading and - // that resolves synchronously. To make sure we always return the identical - // export, we have to check again if the module already exists or not. - module = CJSModule._cache[modulePath]; - if (module && module.loaded) { - const exports = module.exports; - return createDynamicModule(['default'], url, (reflect) => { - reflect.exports.default.set(exports); - }); + const content = `${await getSource(url)}`; + if (pathname) { + // A require call could have been called on the same file during loading and + // that resolves synchronously. To make sure we always return the identical + // export, we have to check again if the module already exists or not. + module = CJSModule._cache[modulePath]; + if (module && module.loaded) { + const exports = module.exports; + return createDynamicModule(['default'], url, (reflect) => { + reflect.exports.default.set(exports); + }); + } } try { const exports = JsonParse(stripBOM(content)); @@ -143,10 +178,12 @@ translators.set('json', async function jsonStrategy(url) { // parse error instead of just manipulating the original error message. // That would allow to add further properties and maybe additional // debugging information. - err.message = pathname + ': ' + err.message; + err.message = errPath(url) + ': ' + err.message; throw err; } - CJSModule._cache[modulePath] = module; + if (pathname) { + CJSModule._cache[modulePath] = module; + } return createDynamicModule([], ['default'], url, (reflect) => { debug(`Parsing JSONModule ${url}`); reflect.exports.default.set(module.exports); @@ -155,14 +192,13 @@ translators.set('json', async function jsonStrategy(url) { // Strategy for loading a wasm module translators.set('wasm', async function(url) { - const pathname = fileURLToPath(url); - const buffer = await readFileAsync(pathname); + const buffer = await getSource(url); debug(`Translating WASMModule ${url}`); let compiled; try { compiled = await WebAssembly.compile(buffer); } catch (err) { - err.message = pathname + ': ' + err.message; + err.message = errPath(url) + ': ' + err.message; throw err; } diff --git a/test/es-module/test-esm-data-urls.js b/test/es-module/test-esm-data-urls.js new file mode 100644 index 00000000000000..bc781b0363cc44 --- /dev/null +++ b/test/es-module/test-esm-data-urls.js @@ -0,0 +1,63 @@ +// Flags: --experimental-modules +'use strict'; +const common = require('../common'); +const assert = require('assert'); +function createURL(mime, body) { + return `data:${mime},${body}`; +} +function createBase64URL(mime, body) { + return `data:${mime};base64,${Buffer.from(body).toString('base64')}`; +} +(async () => { + { + const body = 'export default {a:"aaa"};'; + const plainESMURL = createURL('text/javascript', body); + const ns = await import(plainESMURL); + assert.deepStrictEqual(Object.keys(ns), ['default']); + assert.deepStrictEqual(ns.default.a, 'aaa'); + const importerOfURL = createURL( + 'text/javascript', + `export {default as default} from ${JSON.stringify(plainESMURL)}` + ); + assert.strictEqual( + (await import(importerOfURL)).default, + ns.default + ); + const base64ESMURL = createBase64URL('text/javascript', body); + assert.notStrictEqual( + await import(base64ESMURL), + ns + ); + } + { + const body = 'export default import.meta.url;'; + const plainESMURL = createURL('text/javascript', body); + const ns = await import(plainESMURL); + assert.deepStrictEqual(Object.keys(ns), ['default']); + assert.deepStrictEqual(ns.default, plainESMURL); + } + { + const body = '{"x": 1}'; + const plainESMURL = createURL('application/json', body); + const ns = await import(plainESMURL); + assert.deepStrictEqual(Object.keys(ns), ['default']); + assert.deepStrictEqual(ns.default.x, 1); + } + { + const body = '{"default": 2}'; + const plainESMURL = createURL('application/json', body); + const ns = await import(plainESMURL); + assert.deepStrictEqual(Object.keys(ns), ['default']); + assert.deepStrictEqual(ns.default.default, 2); + } + { + const body = 'null'; + const plainESMURL = createURL('invalid', body); + try { + await import(plainESMURL); + common.mustNotCall()(); + } catch (e) { + assert.strictEqual(e.code, 'ERR_INVALID_RETURN_PROPERTY_VALUE'); + } + } +})().then(common.mustCall());