webpack/lib/schemes/DataUriPlugin.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const NormalModule = require("../NormalModule");

/** @typedef {import("../Compiler")} Compiler */

// data URL scheme: "data:text/javascript;charset=utf-8;base64,some-string"
// http://www.ietf.org/rfc/rfc2397.txt
const URIRegEx = /^data:([^;,]+)?((?:;[^;,]+)*?)(?:;(base64)?)?,(.*)$/i;

/**
 * @param {string} uri data URI
 * @returns {Buffer | null} decoded data
 */
const decodeDataURI = uri => {
	const match = URIRegEx.exec(uri);
	if (!match) return null;

	const isBase64 = match[3];
	const body = match[4];

	if (isBase64) {
		return Buffer.from(body, "base64");
	}

	// CSS allows to use `data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg"><rect width="100%" height="100%" style="stroke: rgb(223,224,225); stroke-width: 2px; fill: none; stroke-dasharray: 6px 3px" /></svg>`
	// so we return original body if we can't `decodeURIComponent`
	try {
		return Buffer.from(decodeURIComponent(body), "ascii");
	} catch (_) {
		return Buffer.from(body, "ascii");
	}
};

const PLUGIN_NAME = "DataUriPlugin";

class DataUriPlugin {
	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap(
			PLUGIN_NAME,
			(compilation, { normalModuleFactory }) => {
				normalModuleFactory.hooks.resolveForScheme
					.for("data")
					.tap(PLUGIN_NAME, resourceData => {
						const match = URIRegEx.exec(resourceData.resource);
						if (match) {
							resourceData.data.mimetype = match[1] || "";
							resourceData.data.parameters = match[2] || "";
							resourceData.data.encoding = match[3] || false;
							resourceData.data.encodedContent = match[4] || "";
						}
					});
				NormalModule.getCompilationHooks(compilation)
					.readResourceForScheme.for("data")
					.tap(PLUGIN_NAME, resource => decodeDataURI(resource));
			}
		);
	}
}

module.exports = DataUriPlugin;