fix: treat index.html as special case for netlify

Signed-off-by: Andres Correa Casablanca <andreu@kindspells.dev>

Author: castarco

@kindspells/astro-shield/package.json

@@ -1,6 +1,6 @@
 {
 	"name": "@kindspells/astro-shield",
-	"version": "1.5.1",
+	"version": "1.5.2",
 	"description": "Astro integration to enhance your website's security with SubResource Integrity hashes, Content-Security-Policy headers, and other techniques.",
 	"private": false,
 	"type": "module",

@kindspells/astro-shield/src/netlify.mts

@@ -3,6 +3,7 @@ import { readFile, writeFile } from 'node:fs/promises'
 import type {
 	CSPDirectives,
 	HashesCollection,
+	PerPageHashes,
 	SecurityHeadersOptions,
 } from './types.mts'
 import { serialiseCspDirectives, setSrcDirective } from './headers.mts'
@@ -251,9 +252,16 @@ export const buildNetlifyHeadersConfig = (
 		entries: [],
 	}
 
-	for (const [page, hashes] of Array.from(
-		resourceHashes.perPageSriHashes,
-	).sort()) {
+	const pagesToIterate: [string, PerPageHashes][] = []
+	for (const [page, hashes] of resourceHashes.perPageSriHashes) {
+		if (page === 'index.html' || page.endsWith('/index.html')) {
+			pagesToIterate.push([page.slice(0, -10), hashes])
+		}
+		pagesToIterate.push([page, hashes])
+	}
+	pagesToIterate.sort()
+
+	for (const [page, hashes] of pagesToIterate) {
 		const pathEntries: (HeaderEntry | CommentEntry)[] = []
 
 		if (securityHeadersOptions.contentSecurityPolicy !== undefined) {

@kindspells/astro-shield/src/tests/netlify.test.mts

@@ -235,6 +235,77 @@ describe('buildNetlifyHeadersConfig', () => {
 			],
 		} satisfies NetlifyHeadersRawConfig)
 	})
+
+	it('creates a "double entry" for "index.html" files', () => {
+		const config = buildNetlifyHeadersConfig(
+			{ contentSecurityPolicy: {} },
+			{
+				perPageSriHashes: new Map([
+					[
+						'index.html',
+						{
+							scripts: new Set([
+								'sha256-071spvYLMvnwaR0H7M2dfK0enB0cGtydTbgJkdoWq7c=',
+							]),
+							styles: new Set(),
+						},
+					],
+					[
+						'es/index.html',
+						{
+							scripts: new Set([
+								'sha256-071spvYLMvnwaR0H7M2dfK0enB0cGtydTbgJkdoWq7c=',
+							]),
+							styles: new Set(),
+						},
+					],
+					[
+						'fakeindex.html',
+						{
+							scripts: new Set([
+								'sha256-071spvYLMvnwaR0H7M2dfK0enB0cGtydTbgJkdoWq7c=',
+							]),
+							styles: new Set(),
+						},
+					],
+				]),
+			},
+		)
+
+		const testEntries = [
+			{
+				headerName: 'content-security-policy',
+				value:
+					"script-src 'self' 'sha256-071spvYLMvnwaR0H7M2dfK0enB0cGtydTbgJkdoWq7c='; style-src 'none'",
+			},
+		]
+
+		expect(config).toEqual({
+			indentWith: '\t',
+			entries: [
+				{
+					path: '/',
+					entries: testEntries,
+				},
+				{
+					path: '/es/',
+					entries: testEntries,
+				},
+				{
+					path: '/es/index.html',
+					entries: testEntries,
+				},
+				{
+					path: '/fakeindex.html',
+					entries: testEntries,
+				},
+				{
+					path: '/index.html',
+					entries: testEntries,
+				},
+			],
+		} satisfies NetlifyHeadersRawConfig)
+	})
 })
 
 describe('mergeNetlifyHeadersConfig', () => {