Add xp bundle subcommand

bin/xp.xp-forge.frontend.bundle

@@ -0,0 +1,2 @@
+#!/usr/bin/env php
+This must be run from within an XP runner

composer.json

@@ -8,11 +8,13 @@
   "require" : {
     "xp-framework/core": "^10.0 | ^9.0 | ^8.0 | ^7.0",
     "xp-forge/web": "^2.0 | ^1.0",
+    "xp-forge/json": "^4.0",
     "php": ">=7.0.0"
   },
   "require-dev" : {
     "xp-framework/unittest": "^11.0 | ^10.0 | ^9.0 | ^8.0 |^7.0"
   },
+  "bin": ["bin/xp.xp-forge.frontend.bundle"],
   "autoload" : {
     "files" : ["src/main/php/autoload.php"]
   }

src/main/php/xp/frontend/BundleRunner.class.php

@@ -0,0 +1,73 @@
+<?php namespace xp\frontend;
+
+use io\streams\{InputStream, Streams, StreamTransfer};
+use io\{File, Folder};
+use lang\{Environment, IllegalArgumentException};
+use peer\http\{HttpConnection, HttpRequest};
+use text\json\{Json, FileInput, StreamInput};
+use util\URI;
+use util\cmd\Console;
+
+/**
+ * Bundle assets
+ * =============
+ * Inside your Composer file, add the following alongside "require":
+ * `
+ *   "require-assets": {
+ *     "bundle": {
+ *       "handlebars@^4.7": ["dist/handlebars.min.js"],
+ *       "simplemde@^1.11": ["dist/simplemde.min.js", "dist/simplemde.min.css"]
+ *       "transliteration@^2.1": ["dist/browser/bundle.umd.min.js"]
+ *     }
+ *   }`
+ *
+ * - Bundle libraries into the given target directory
+ *   ```sh
+ *   $ xp bundle src/main/webapp/static
+ *   ```
+ * - Use supplied configuration file instead of `./composer.json`
+ *   ```sh
+ *   $ xp bundle -c ../composer.json dist
+ *   ```
+ * 
+ * This will create `bundle`.js and `bundle`.css from the given libraries and
+ * place them in the given target directory.
+ */
+class BundleRunner {
+
+  /** Displays error message */
+  private static function error(int $code, string $message): int {
+    Console::$err->writeLine("\e[31mError: $message\e[0m");
+    return $code;
+  }
+
+  /** Entry point */
+  public static function main(array $args): int {
+    $config= 'composer.json';
+    $target= 'static';
+    for ($i= 0, $s= sizeof($args); $i < $s; $i++) {
+      if ('-c' === $args[$i]) {
+        $config= $args[++$i];
+      } else {
+        $target= $args[$i];
+      }
+    }
+
+    if ('-' === $config) {
+      $input= new StreamInput(Console::$in->stream());
+    } else if (is_dir($config)) {
+      $input= new FileInput($config.DIRECTORY_SEPARATOR.'composer.json');
+    } else if (is_file($config)) {
+      $input= new FileInput($config);
+    } else {
+      return self::error(2, 'No configuration file found, tried '.$config);
+    }
+
+    if (!($require= Json::read($input)['require-assets'] ?? null)) {
+      return self::error(1, 'No assets found in '.$config);
+    }
+
+    Console::writeLine($require);
+    return 0;
+  }
+}