fix: postbuild patched file hash recalculation

package.json

@@ -6,7 +6,9 @@
     "dev": "npm run clean && next dev",
     "build": "npm run clean && next build",
     "dev:export": "EXPORT_MODE=true npm run dev",
-    "build:export": "EXPORT_MODE=true npm run build && EXPORT_MODE=true next export",
+    "build:export": "EXPORT_MODE=true npm run build && npm run export",
+    "preexport": "node scripts/preexport.js",
+    "export": "npm run preexport && EXPORT_MODE=true next export",
     "start": "next start",
     "start:dev": "NODE_ENV=development next start",
     "start:export": "EXPORT_MODE=true next start",
@@ -65,6 +67,7 @@
     "eslint": "^8.26.0",
     "eslint-config-next": "12.0.10",
     "express": "^4.17.3",
+    "glob": "^10.3.10",
     "js-yaml": "^4.1.0",
     "lint-staged": "^13.0.3",
     "next-purgecss": "^4.0.0",

scripts/preexport.js

@@ -0,0 +1,57 @@
+const {join} = require('path');
+const crypto = require('crypto');
+const {globSync} = require('glob');
+const {readFileSync, writeFileSync} = require('fs');
+
+const BUILD_DIR = '.next';
+const ASSETS_MANIFEST_PART = join(BUILD_DIR, 'assets-manifest.json');
+const NEXT_OUT_DIR = '.next/server/pages';
+const POSTBUILD_PATCHED_FILES = ['_ssgManifest.js'];
+const SHA_FUNC = 'sha384';
+
+const assetsManifest = JSON.parse(readFileSync(ASSETS_MANIFEST_PART).toString());
+
+// Next.js patches some script files (like '_ssgManifest.js') after build, so need to run script like this to recalculate pathced file hashes and replace it in html files
+function main() {
+    const replacementPairs = POSTBUILD_PATCHED_FILES.map(getReplacementPair).filter(Boolean);
+
+    replaceInPages(replacementPairs);
+}
+
+function getReplacementPair(fileName) {
+    const fileInfo = getFileInfo(fileName);
+
+    if (fileInfo) {
+        const {src, integrity} = fileInfo;
+        const content = readFileSync(join(BUILD_DIR, src)).toString();
+        const postBuildIntegrity = getIntegrity(content);
+
+        return [integrity, postBuildIntegrity];
+    }
+
+    return null;
+}
+
+function replaceInPages(replacementPairs) {
+    globSync(`${NEXT_OUT_DIR}/**/*.html`).forEach((pageFile) => {
+        const content = readFileSync(pageFile).toString();
+        const newContent = replacementPairs.reduce(
+            (result, [oldValue, newValue]) => result.replaceAll(oldValue, newValue),
+            content,
+        );
+
+        writeFileSync(pageFile, newContent);
+    });
+}
+
+function getFileInfo(fileName) {
+    return Object.entries(assetsManifest).find(([asset]) => asset.includes(fileName))?.[1];
+}
+
+function getIntegrity(content) {
+    const digest = crypto.createHash(SHA_FUNC).update(content, 'utf8').digest();
+
+    return `${SHA_FUNC}-${digest.toString('base64')}`;
+}
+
+main();