Set 'referrer' and 'referrerPolicy' when fetching inline images, re: #…

…172

index.js

@@ -33,6 +33,7 @@ import humanDate from './src/util/human-date.js';
 import outputPath from './src/util/output-path.js';
 import getCssPageFormat from './src/util/get-css-page-format.js';
 import { resolveSequence, resolveParallel } from './src/util/promises.js';
+import { getUrlOrigin } from './src/util/url-origin.js';
 import addExif from './src/exif.js';
 import { hyphenateDom } from './src/hyphenate.js';
 import { textToIso6391, getLanguageAttribute } from './src/util/language.js';
@@ -296,13 +297,25 @@ async function cleanup(url, options) {
 
 		err.write(' ✓\n');
 
+		console.log(getUrlOrigin(final_url));
+
 		if (options.inline) {
 			await inlineImages(
 				parsed.content,
 				{
 					headers: {
 						'user-agent': UA
 					},
+					/*
+						Send the referrer as the browser would 
+						when fetching the image to render it.
+
+						The referrer policy would take care of 
+						stripping the URL down to its origin, 
+						but just in case, let’s strip it ourselves.
+					*/
+					referrer: final_url,
+					referrerPolicy: 'strict-origin-when-cross-origin',
 					timeout: 10 * 1000
 				},
 				options.debug ? out : undefined

src/util/url-origin.js

@@ -0,0 +1,9 @@
+export function getUrlOrigin(str) {
+	let origin;
+	try {
+		origin = new URL(str).origin;
+	} catch (err) {
+		// ignore
+	}
+	return origin && origin !== 'null' ? origin : undefined;
+}

test/url-origin.test.js

@@ -0,0 +1,9 @@
+import tape from 'tape';
+import { getUrlOrigin } from '../src/util/url-origin.js';
+
+tape('getUrlOrigin', t => {
+	t.equal(getUrlOrigin('invalid'), undefined);
+	t.equal(getUrlOrigin('file:///Users/myuser/'), undefined);
+	t.equal(getUrlOrigin('https://github.com/user/repo'), 'https://github.com');
+	t.end();
+});