applyCacheBustPostBuild static method

Future<void> applyCacheBustPostBuild(BPConfig config)

This function modifies the build output of the Flutter web

Flutter has no built-in method to bust certain caches, so, this function will add the version number to some paths. e.g. main.dart.js?v=0.12.3

By adding the version number, the browser will re-fetch the files again

Implementation

static Future<void> applyCacheBustPostBuild(BPConfig config) async {
  WebVersioningType versioningType = config.web?.webConfig?.webVersioningType ?? WebVersioningType.hash;
  String introText = versioningType.isHash ? "Applying web cache busting" : "Applying web cache busting for version: ${config.version}";

  List<String> logLines = LogUtils.getActionStartLines(introText);
  print(introText);

  String vValue = versioningType.isHash ? md5.convert(utf8.encode(DateTime.now().toIso8601String())).toString() : config.version;

  (String, String) mainDartJSPattern = (
    r'main\.dart\.js',
    "main.dart.js?v=$vValue",
  );

  // Files to be modified
  // Each file has a list of records, the first item is the regex and the second is the replacement
  final Map<String, List<(String, String)>> filesToPatch = {
    WebUtils._getFilePath('flutter.js'): [
      mainDartJSPattern,
    ],
    WebUtils._getFilePath('flutter_bootstrap.js'): [
      mainDartJSPattern,
    ],
    WebUtils._getFilePath('main.dart.js'): [
      (r'window\.fetch\(a\),', "window.fetch(a + '?v=$vValue'),"),
    ],
    WebUtils._getFilePath('index.html'): [
      (r'manifest\.json', 'manifest.json?v=$vValue'),
      (r'flutter_bootstrap\.js', "flutter_bootstrap.js?v=$vValue"),
    ],
  };

  // Patching the files
  for (final single in filesToPatch.entries) {
    final file = File(single.key);
    if (await file.exists()) {
      try {
        String content = await file.readAsString();
        List<String> ll = ["\n[file] > ${single.key}"];
        for (var i = 0; i < single.value.length; i++) {
          content = content.replaceAll(
            RegExp(single.value[i].$1, caseSensitive: false),
            single.value[i].$2,
          );
          ll.add(
            "[replacement] > ${single.value[i].$1} to ${single.value[i].$2}",
          );
        }
        await file.writeAsString(content);
        logLines.addAll(ll);
      } catch (e) {
        print(e.toString());
        logLines.add("\n[file] > ${single.key}");
        logLines.add("[error] > ${e.toString()}");
      }
    } else {
      print('File not found: ${p.basename(single.key)}');
      logLines.add("\n[file] > ${single.key}");
      logLines.add(
        "[error] > This file could not be found: ${p.basename(single.key)}",
      );
    }
  }

  Console.logSuccess("√ Web cache busting complete.");
  logLines.addAll(LogUtils.getActionEndLines());
  await LogUtils.appendLogUsingStringList(config, logLines);
}