Use memory instead of filesystem for bundle header & footer

prebid · Jun 2, 2022 · 2bb042d · 2bb042d
1 parent 0460510
commit 2bb042d
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Showing 3 changed files with 57 additions and 58 deletions.
diff --git a/gulpfile.js b/gulpfile.js
@@ -26,7 +26,7 @@ var jsEscape = require('gulp-js-escape');
 const path = require('path');
 const execa = require('execa');
 const {minify} = require('terser');
-const tmp = require('tmp');
+const Vinyl = require('vinyl');
 
 var prebid = require('./package.json');
 var port = 9999;
@@ -172,37 +172,48 @@ function nodeBundle(modules, dev = false) {
   });
 }
 
-function generateHeaderAndFooter(dev, modules) {
+function wrapWithHeaderAndFooter(dev, modules) {
   // NOTE: gulp-header, gulp-footer & gulp-wrap do not play nice with source maps.
-  // gulp-concat does; for that reason we are generating temporary files to pass to it.
-  const placeholder = '$$PREBID_SOURCE$$';
-  const tpl = _.template(fs.readFileSync('./bundle-template.txt'))({
-    prebid,
-    modules: getModulesListToAddInBanner(modules),
-    enable: !argv.manualEnable
-  });
-  return (dev ? Promise.resolve(tpl) : minify(tpl, {format: {comments: true}}).then((res) => res.code))
-    .then((tpl) => {
-      // wrap source placeholder in a closure to make it an expression (so that it works with minify output)
-      const parts = tpl.replace(placeholder, `(function(){$$${placeholder}$$})()`).split(placeholder);
-      if (parts.length !== 2) {
-        throw new Error(`Cannot parse bundle template; it must contain exactly one instance of '${placeholder}'`);
-      }
-      const [header, footer] = parts;
-      const base = tmp.dirSync().name;
-      const [headerFn, footerFn] = [path.resolve(base, 'prebid-header.js'), path.resolve(base, 'prebid-footer.js')];
-      fs.writeFileSync(headerFn, header);
-      fs.writeFileSync(footerFn, footer);
-      return {
-        header: headerFn,
-        footer: footerFn,
-        cleanup: function () {
-          fs.unlinkSync(headerFn);
-          fs.unlinkSync(footerFn);
-          fs.rmdirSync(base);
-        }
-      };
+  // gulp-concat does; for that reason we are prepending and appending the source stream with "fake" header & footer files.
+  function memoryVinyl(name, contents) {
+    return new Vinyl({
+      cwd: '',
+      base: 'generated',
+      path: name,
+      contents: Buffer.from(contents, 'utf-8')
+    });
+  }
+  return function wrap(stream) {
+    const wrapped = through.obj();
+    const placeholder = '$$PREBID_SOURCE$$';
+    const tpl = _.template(fs.readFileSync('./bundle-template.txt'))({
+      prebid,
+      modules: getModulesListToAddInBanner(modules),
+      enable: !argv.manualEnable
     });
+    (dev ? Promise.resolve(tpl) : minify(tpl, {format: {comments: true}}).then((res) => res.code))
+      .then((tpl) => {
+        // wrap source placeholder in an IIFE to make it an expression (so that it works with minify output)
+        const parts = tpl.replace(placeholder, `(function(){$$${placeholder}$$})()`).split(placeholder);
+        if (parts.length !== 2) {
+          throw new Error(`Cannot parse bundle template; it must contain exactly one instance of '${placeholder}'`);
+        }
+        const [header, footer] = parts;
+        wrapped.push(memoryVinyl('prebid-header.js', header));
+        stream.pipe(wrapped, {end: false});
+        stream.on('end', () => {
+          wrapped.push(memoryVinyl('prebid-footer.js', footer));
+          wrapped.push(null);
+        });
+        stream.on('error', (err) => {
+          wrapped.destroy(err);
+        })
+      })
+      .catch((err) => {
+        wrapped.destroy(err);
+      });
+    return wrapped;
+  }
 }
 
 function bundle(dev, moduleArr) {
@@ -221,35 +232,25 @@ function bundle(dev, moduleArr) {
       });
     }
   }
-  const stream = through.obj();
-  generateHeaderAndFooter(dev, modules).then(({header, footer, cleanup}) => {
-    try {
-      var entries = [header, helpers.getBuiltPrebidCoreFile(dev)].concat(helpers.getBuiltModules(dev, modules)).concat([footer]);
 
-      var outputFileName = argv.bundleName ? argv.bundleName : 'prebid.js';
+  var entries = [helpers.getBuiltPrebidCoreFile(dev)].concat(helpers.getBuiltModules(dev, modules));
 
-      // change output filename if argument --tag given
-      if (argv.tag && argv.tag.length) {
-        outputFileName = outputFileName.replace(/\.js$/, `.${argv.tag}.js`);
-      }
+  var outputFileName = argv.bundleName ? argv.bundleName : 'prebid.js';
 
-      gutil.log('Concatenating files:\n', entries);
-      gutil.log('Appending ' + prebid.globalVarName + '.processQueue();');
-      gutil.log('Generating bundle:', outputFileName);
-
-      gulp.src(entries)
-        .pipe(gulpif(sm, sourcemaps.init({ loadMaps: true })))
-        .pipe(concat(outputFileName))
-        .pipe(gulpif(sm, sourcemaps.write('.')))
-        .pipe(stream)
-        .on('error', cleanup)
-        .on('end', cleanup);
-    } catch (e) {
-      cleanup();
-      throw e;
-    }
-  });
-  return stream;
+  // change output filename if argument --tag given
+  if (argv.tag && argv.tag.length) {
+    outputFileName = outputFileName.replace(/\.js$/, `.${argv.tag}.js`);
+  }
+
+  gutil.log('Concatenating files:\n', entries);
+  gutil.log('Appending ' + prebid.globalVarName + '.processQueue();');
+  gutil.log('Generating bundle:', outputFileName);
+
+  const wrap = wrapWithHeaderAndFooter(dev, modules);
+  return wrap(gulp.src(entries))
+    .pipe(gulpif(sm, sourcemaps.init({ loadMaps: true })))
+    .pipe(concat(outputFileName))
+    .pipe(gulpif(sm, sourcemaps.write('.')));
 }
 
 // Run the unit tests.

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -103,7 +103,6 @@
     "resolve-from": "^5.0.0",
     "sinon": "^4.1.3",
     "through2": "^4.0.2",
-    "tmp": "^0.2.1",
     "url": "^0.11.0",
     "url-parse": "^1.0.5",
     "webdriverio": "^7.6.1",