index.js

var PluginError = require("plugin-error");

var crypto = require("crypto");
var fs = require("fs");
var through = require("through2");

const PLUGIN_NAME = "gulp-wp-cache-bust";

function md5(str) {
  var hash = crypto.createHash("md5");
  hash.update(fs.readFileSync(str));
  return hash.digest("hex");
}

function removePreviousVersioning(filePath) {
  // Remove any previous cache busting references
  return filePath.lastIndexOf("?v=") > 0
    ? filePath.substring(0, filePath.lastIndexOf("?v=")) + "'"
    : filePath;
}

function gulpWPCacheBust(options) {
  options = options || {};

  if (!options.rootPath) {
    options.rootPath = "";
  }

  return through.obj(function (file, enc, cb) {
    if (file.isNull()) {
      cb(null, file);
      return;
    }

    if (file.isStream()) {
      throw new PluginError(PLUGIN_NAME, "Streaming not supported!");
    }

    if (file.isBuffer()) {
      file.contents = Buffer.from(String(file.contents));

      var regex = /(define\(([^;]+)\))/g;

      var m;
      var buffer = Buffer.from(String(file.contents));
      while ((m = regex.exec(buffer)) !== null) {
        // This is necessary to avoid infinite loops with zero-width matches
        if (m.index === regex.lastIndex) {
          regex.lastIndex++;
        }

        if (m[2]) {
          var ogDefinition = m[2];
          var nonVersionedDefinition = removePreviousVersioning(ogDefinition);
          var params = nonVersionedDefinition.split(",");

          if (params[1]) {
            filePath = params[1].trim();

            // Only check local files
            if (!/(http:\/\/|https:\/\/)/.test(filePath)) {
              // remove ticks/quotes
              var r = /(['"]+)/g;
              cleanFilePath = filePath.replace(r, "");

              // if using get_template_directory_uri or get_stylesheet_directory_uri
              // swap for themeFolder
              var r = /(get_template_directory_uri\(\)[ .]+)/g;
              var j = /(get_stylesheet_directory_uri\(\)[ .]+)/g;
              if (r.test(cleanFilePath)) {
                if (options.themeFolder) {
                  cleanFilePath = cleanFilePath
                    .replace(r, options.themeFolder)
                    .replace(/\/\//g, "/");
                } else {
                  throw new PluginError(
                    PLUGIN_NAME,
                    "Theme folder is not defined."
                  );
                }
              } else if (j.test(cleanFilePath)) {
                if (options.themeFolder) {
                  cleanFilePath = cleanFilePath
                    .replace(j, options.themeFolder)
                    .replace(/\/\//g, "/");
                } else {
                  throw new PluginError(
                    PLUGIN_NAME,
                    "Theme folder is not defined."
                  );
                }
              } else if (cleanFilePath[0] === "/") {
                // Absolute path
                cleanFilePath = cleanFilePath.replace("/", options.rootPath);
              } else {
                return;
              }

              var hashCSS = md5(cleanFilePath);

              var slashSplits = cleanFilePath.split("/");
              var fileName = slashSplits[slashSplits.length - 1];
              var versionedFileName = fileName + "?v=" + hashCSS;
              var newDefinition = nonVersionedDefinition.replace(
                fileName,
                versionedFileName
              );

              file.contents = Buffer.from(
                String(file.contents).replace(ogDefinition, newDefinition)
              );
            }
          }
        }
      }

      this.push(file);
    }

    cb(null, file);
  });
}

module.exports = gulpWPCacheBust;