implement placeholder replacement so it still works with minification

.eslintrc.js

@@ -15,7 +15,11 @@ module.exports = {
         "no-unused-vars": "warn"
     },
     "globals": {
-        "HYDROGEN_VERSION": "readonly",
+        "DEFINE_VERSION": "readonly",
-        "HYDROGEN_GLOBAL_HASH": "readonly"
+        "DEFINE_GLOBAL_HASH": "readonly",
+        // only available in sw.js
+        "DEFINE_UNHASHED_PRECACHED_ASSETS": "readonly",
+        "DEFINE_HASHED_PRECACHED_ASSETS": "readonly",
+        "DEFINE_HASHED_CACHED_ON_REQUEST_ASSETS": "readonly"
     }
 };

scripts/build-plugins/service-worker.js

@@ -8,7 +8,7 @@ function contentHash(str) {
     return hasher.digest();
 }
 
-module.exports = function injectServiceWorker(swFile, otherUnhashedFiles, globalHashPlaceholderLiteral, chunkNamesWithGlobalHash) {
+function injectServiceWorker(swFile, otherUnhashedFiles, placeholdersPerChunk) {
     const swName = path.basename(swFile);
     let root;
     let version;
@@ -26,7 +26,7 @@ module.exports = function injectServiceWorker(swFile, otherUnhashedFiles, global
         },
         configResolved: config => {
             root = config.root;
-            version = JSON.parse(config.define.HYDROGEN_VERSION); // unquote
+            version = JSON.parse(config.define.DEFINE_VERSION); // unquote
         },
         generateBundle: async function(options, bundle) {
             const unhashedFilenames = [swName].concat(otherUnhashedFiles);
@@ -41,9 +41,11 @@ module.exports = function injectServiceWorker(swFile, otherUnhashedFiles, global
             const assets = Object.values(bundle);
             const hashedFileNames = assets.map(o => o.fileName).filter(fileName => !unhashedFileContentMap[fileName]);
             const globalHash = getBuildHash(hashedFileNames, unhashedFileContentMap);
-            const sw = bundle[swName];
+            const placeholderValues = {
-            sw.code = replaceCacheFilenamesInServiceWorker(sw, unhashedFilenames, assets);
+                DEFINE_GLOBAL_HASH: `"${globalHash}"`,
-            replaceGlobalHashPlaceholderInChunks(assets, chunkNamesWithGlobalHash, globalHashPlaceholderLiteral, `"${globalHash}"`);
+                ...getCacheFileNamePlaceholderValues(swName, unhashedFilenames, assets, placeholdersPerChunk)
+            };
+            replacePlaceholdersInChunks(assets, placeholdersPerChunk, placeholderValues);
             console.log(`\nBuilt ${version} (${globalHash})`);
         }
     };
@@ -76,8 +78,7 @@ function isPreCached(asset) {
             fileName.endsWith(".js") && !NON_PRECACHED_JS.includes(path.basename(name));
 }
 
-function replaceCacheFilenamesInServiceWorker(swChunk, unhashedFilenames, assets) {
+function getCacheFileNamePlaceholderValues(swName, unhashedFilenames, assets) {
-    let swSource = swChunk.code;
     const unhashedPreCachedAssets = [];
     const hashedPreCachedAssets = [];
     const hashedCachedOnRequestAssets = [];
@@ -86,7 +87,7 @@ function replaceCacheFilenamesInServiceWorker(swChunk, unhashedFilenames, assets
         const {name, fileName} = asset;
         // the service worker should not be cached at all,
         // it's how updates happen
-        if (fileName === swChunk.fileName) {
+        if (fileName === swName) {
             continue;
         } else if (unhashedFilenames.includes(fileName)) {
             unhashedPreCachedAssets.push(fileName);
@@ -97,33 +98,57 @@ function replaceCacheFilenamesInServiceWorker(swChunk, unhashedFilenames, assets
         }
     }
 
-    const replaceArrayInSource = (name, value) => {
+    return {
-        const newSource = swSource.replace(`${name} = []`, `${name} = ${JSON.stringify(value)}`);
+        DEFINE_UNHASHED_PRECACHED_ASSETS: JSON.stringify(unhashedPreCachedAssets),
-        if (newSource === swSource) {
+        DEFINE_HASHED_PRECACHED_ASSETS: JSON.stringify(hashedPreCachedAssets),
-            throw new Error(`${name} was not found in the service worker source: ` + swSource);
+        DEFINE_HASHED_CACHED_ON_REQUEST_ASSETS: JSON.stringify(hashedCachedOnRequestAssets)
     }
-        return newSource;
-    };
-    const replaceStringInSource = (name, value) => {
-        const newSource = swSource.replace(new RegExp(`${name}\\s=\\s"[^"]*"`), `${name} = ${JSON.stringify(value)}`);
-        if (newSource === swSource) {
-            throw new Error(`${name} was not found in the service worker source: ` + swSource);
-        }
-        return newSource;
-    };
-
-    swSource = replaceArrayInSource("UNHASHED_PRECACHED_ASSETS", unhashedPreCachedAssets);
-    swSource = replaceArrayInSource("HASHED_PRECACHED_ASSETS", hashedPreCachedAssets);
-    swSource = replaceArrayInSource("HASHED_CACHED_ON_REQUEST_ASSETS", hashedCachedOnRequestAssets);
-    return swSource;
 }
 
-function replaceGlobalHashPlaceholderInChunks(assets, chunkNamesWithGlobalHash, globalHashPlaceholderLiteral, globalHashLiteral) {
+function replacePlaceholdersInChunks(assets, placeholdersPerChunk, placeholderValues) {
-    for (const name of chunkNamesWithGlobalHash) {
+    for (const [name, placeholderMap] of Object.entries(placeholdersPerChunk)) {
         const chunk = assets.find(a => a.type === "chunk" && a.name === name);
         if (!chunk) {
-            throw new Error(`could not find chunk ${name} to replace global hash placeholder`);
+            throw new Error(`could not find chunk ${name} to replace placeholders`);
+        }
+        for (const [placeholderName, placeholderLiteral] of Object.entries(placeholderMap)) {
+            const replacedValue = placeholderValues[placeholderName];
+            const oldCode = chunk.code;
+            chunk.code = chunk.code.replaceAll(placeholderLiteral, replacedValue);
+            if (chunk.code === oldCode) {
+                throw new Error(`Could not replace ${placeholderName} in ${name}, looking for literal ${placeholderLiteral}:\n${chunk.code}`);
+            }
         }
-        chunk.code = chunk.code.replaceAll(globalHashPlaceholderLiteral, globalHashLiteral);
     }
 }
+
+/** creates a value to be include in the `define` build settings,
+ * but can be replace at the end of the build in certain chunks.
+ * We need this for injecting the global build hash and the final
+ * filenames in the service worker and index chunk.
+ * These values are only known in the generateBundle step, so we
+ * replace them by unique strings wrapped in a prompt call so no
+ * transformation will touch them (minifying, ...) and we can do a
+ * string replacement still at the end of the build. */
+function definePlaceholderValue(mode, name, devValue) {
+    if (mode === "production") {
+        // note that `prompt(...)` will never be in the final output, it's replaced by the final value
+        // once we know at the end of the build what it is and just used as a temporary value during the build
+        // as something that will not be transformed.
+        // I first considered Symbol but it's not inconceivable that babel would transform this.
+        return `prompt(${JSON.stringify(name)})`;
+    } else {
+        return JSON.stringify(devValue);
+    }
+}
+
+function createPlaceholderValues(mode) {
+    return {
+        DEFINE_GLOBAL_HASH: definePlaceholderValue(mode, "DEFINE_GLOBAL_HASH", null),
+        DEFINE_UNHASHED_PRECACHED_ASSETS: definePlaceholderValue(mode, "UNHASHED_PRECACHED_ASSETS", []),
+        DEFINE_HASHED_PRECACHED_ASSETS: definePlaceholderValue(mode, "HASHED_PRECACHED_ASSETS", []),
+        DEFINE_HASHED_CACHED_ON_REQUEST_ASSETS: definePlaceholderValue(mode, "HASHED_CACHED_ON_REQUEST_ASSETS", []),
+    };
+}
+
+module.exports = {injectServiceWorker, createPlaceholderValues};

src/platform/web/Platform.js

@@ -277,7 +277,7 @@ export class Platform {
     }
 
     get version() {
-        return HYDROGEN_VERSION;
+        return DEFINE_VERSION;
     }
 
     dispose() {

src/platform/web/dom/ServiceWorkerHandler.js

@@ -181,11 +181,11 @@ export class ServiceWorkerHandler {
     }
 
     get version() {
-        return HYDROGEN_VERSION;
+        return DEFINE_VERSION;
     }
 
     get buildHash() {
-        return HYDROGEN_GLOBAL_HASH;
+        return DEFINE_GLOBAL_HASH;
     }
 
     async preventConcurrentSessionAccess(sessionId) {

src/platform/web/sw.js

@@ -17,11 +17,11 @@ limitations under the License.
 
 import NOTIFICATION_BADGE_ICON from "./assets/icon.png?url";
 // replaced by the service worker build plugin
-const UNHASHED_PRECACHED_ASSETS = [];
+const UNHASHED_PRECACHED_ASSETS = DEFINE_UNHASHED_PRECACHED_ASSETS;
-const HASHED_PRECACHED_ASSETS = [];
+const HASHED_PRECACHED_ASSETS = DEFINE_HASHED_PRECACHED_ASSETS;
-const HASHED_CACHED_ON_REQUEST_ASSETS = [];
+const HASHED_CACHED_ON_REQUEST_ASSETS = DEFINE_HASHED_CACHED_ON_REQUEST_ASSETS;
 
-const unhashedCacheName = `hydrogen-assets-${HYDROGEN_GLOBAL_HASH}`;
+const unhashedCacheName = `hydrogen-assets-${DEFINE_GLOBAL_HASH}`;
 const hashedCacheName = `hydrogen-assets`;
 const mediaThumbnailCacheName = `hydrogen-media-thumbnails-v2`;
 
@@ -175,7 +175,7 @@ self.addEventListener('message', (event) => {
     } else {
         switch (event.data?.type) {
             case "version":
-                reply({version: HYDROGEN_VERSION, buildHash: HYDROGEN_GLOBAL_HASH});
+                reply({version: DEFINE_VERSION, buildHash: DEFINE_GLOBAL_HASH});
                 break;
             case "skipWaiting":
                 self.skipWaiting();

src/platform/web/ui/login/common.js

@@ -15,10 +15,10 @@ limitations under the License.
 */
 
 export function hydrogenGithubLink(t) {
-    if (HYDROGEN_VERSION && HYDROGEN_GLOBAL_HASH) {
+    if (DEFINE_VERSION && DEFINE_GLOBAL_HASH) {
         return t.a({target: "_blank",
-            href: `https://github.com/vector-im/hydrogen-web/releases/tag/v${HYDROGEN_VERSION}`},
+            href: `https://github.com/vector-im/hydrogen-web/releases/tag/v${DEFINE_VERSION}`},
-            `Hydrogen v${HYDROGEN_VERSION} (${HYDROGEN_GLOBAL_HASH}) on Github`);
+            `Hydrogen v${DEFINE_VERSION} (${DEFINE_GLOBAL_HASH}) on Github`);
     } else {
         return t.a({target: "_blank", href: "https://github.com/vector-im/hydrogen-web"},
             "Hydrogen on Github");

vite.config.js

@@ -1,24 +1,19 @@
 const cssvariables = require("postcss-css-variables");
-const autoprefixer = require("autoprefixer");
+//const autoprefixer = require("autoprefixer");
 const flexbugsFixes = require("postcss-flexbugs-fixes");
 
 const fs = require("fs");
 const path = require("path");
-const GLOBAL_HASH_PLACEHOLDER = "hydrogen-global-hash-placeholder-4cf32306-5d61-4262-9a57-c9983f472c3c";
 
 const injectWebManifest = require("./scripts/build-plugins/manifest");
-const injectServiceWorker = require("./scripts/build-plugins/service-worker");
+const {injectServiceWorker, createPlaceholderValues} = require("./scripts/build-plugins/service-worker");
 // const legacyBuild = require("./scripts/build-plugins/legacy-build");
-
+const {defineConfig} = require('vite');
-// we could also just import {version} from "../../package.json" where needed,
-// but this won't work in the service worker yet as it is not transformed yet
-// TODO: we should emit a chunk early on and then transform the asset again once we know all the other assets to cache
 const version = JSON.parse(fs.readFileSync(path.join(__dirname, "package.json"), "utf8")).version;
-const {defineConfig} = require("vite");
-let polyfillSrc;
-let polyfillRef;
 
-export default {
+export default defineConfig(({mode}) => {
+    const definePlaceholders = createPlaceholderValues(mode);
+    return {
         public: false,
         root: "src/platform/web",
         base: "./",
@@ -37,7 +32,7 @@ export default {
         build: {
             outDir: "../../../target",
             emptyOutDir: true,
-        minify: true,
+            minify: false,
             sourcemap: false,
             assetsInlineLimit: 0,
             polyfillModulePreload: false,
@@ -51,11 +46,15 @@ export default {
             // important this comes before service worker
             // otherwise the manifest and the icons it refers to won't be cached
             injectWebManifest("assets/manifest.json"),
-        injectServiceWorker("./src/platform/web/sw.js", ["index.html"], JSON.stringify(GLOBAL_HASH_PLACEHOLDER), ["index", "sw"]),
+            injectServiceWorker("./src/platform/web/sw.js", ["index.html"], {
+                // placeholders to replace at end of build by chunk name
+                "index": {DEFINE_GLOBAL_HASH: definePlaceholders.DEFINE_GLOBAL_HASH},
+                "sw": definePlaceholders
+            }),
         ],
         define: {
-        "HYDROGEN_VERSION": JSON.stringify(version),
+            DEFINE_VERSION: JSON.stringify(version),
-        "HYDROGEN_GLOBAL_HASH": JSON.stringify(GLOBAL_HASH_PLACEHOLDER)
+            ...definePlaceholders
         },
         css: {
             postcss: {
@@ -72,7 +71,8 @@ export default {
                 ]
             }
         }
-};
+    };
+});
 
 function scriptTagPath(htmlFile, index) {
     return `${htmlFile}?html-proxy&index=${index}.js`;