React Native启动流程

function checkForVersionArgument() {
  if (process.argv.indexOf('-v') >= 0 || process.argv.indexOf('--version') >= 0) {
    console.log('react-native-cli: ' + require('./package.json').version);
    try {
      console.log('react-native: ' + require(REACT_NATIVE_PACKAGE_JSON_PATH()).version);
    } catch (e) {
      console.log('react-native: n/a - not inside a React Native project directory')
    }
    process.exit();
  }
}

var CLI_MODULE_PATH = function() {
  return path.resolve(
    process.cwd(),
    'node_modules',
    'react-native',
    'cli.js'
  );
};

var cli;
var cliPath = CLI_MODULE_PATH();
if (fs.existsSync(cliPath)) {
  cli = require(cliPath);
}

if (cli) {
  cli.run();
}

var args = process.argv.slice(2);
if (args.length === 0) {
  console.error(
    'You did not pass any commands, did you mean to run `react-native init`?'
  );
  process.exit(1);
}

switch (args[0]) {
case 'init':
  if (args[1]) {
    var verbose = process.argv.indexOf('--verbose') >= 0;
    init(args[1], verbose);
  } else {
    console.error(
      'Usage: react-native init <ProjectName> [--verbose]'
    );
    process.exit(1);
  }
  break;
default:
  console.error(
    'Command `%s` unrecognized. ' +
    'Did you mean to run this inside a react-native project?',
    args[0]
  );
  process.exit(1);
  break;
}

function init(name, verbose) {
  validatePackageName(name);

  if (fs.existsSync(name)) {
    createAfterConfirmation(name, verbose);
  } else {
    createProject(name, verbose);
  }
}

cli = require(CLI_MODULE_PATH());
cli.init(root, projectName);

'use strict';

// gracefulify() has to be called before anything else runs
require('graceful-fs').gracefulify(require('fs'));

// This file must be able to run in node 0.12 without babel so we can show that
// it is not supported. This is why the rest of the cli code is in `cliEntry.js`.
require('./server/checkNodeVersion')();

require('../setupBabel')();

var cliEntry = require('./cliEntry');

if (require.main === module) {
  cliEntry.run();
}

module.exports = cliEntry;

function run() {
  const setupEnvScript = /^win/.test(process.platform)
    ? 'setup_env.bat'
    : 'setup_env.sh';

  childProcess.execFileSync(path.join(__dirname, setupEnvScript));

  commands.forEach(cmd => addCommand(cmd, config));

  commander.parse(process.argv);

  const isValidCommand = commands.find(cmd => cmd.name.split(' ')[0] === process.argv[2]);

  if (!isValidCommand) {
    printUnknownCommand(process.argv[2]);
    return;
  }

  if (!commander.args.length) {
    commander.help();
  }
}

const commands: Array<CommandT> = [
  ...documentedCommands,
  ...undocumentedCommands,
  ...getProjectCommands(),
];

const documentedCommands = [
  require('./server/server'),
  require('./runIOS/runIOS'),
  require('./runAndroid/runAndroid'),
  require('./library/library'),
  require('./bundle/bundle'),
  require('./bundle/unbundle'),
  require('./eject/eject'),
  require('./link/link'),
  require('./link/unlink'),
  require('./install/install'),
  require('./install/uninstall'),
  require('./upgrade/upgrade'),
  require('./logAndroid/logAndroid'),
  require('./logIOS/logIOS'),
  require('./dependencies/dependencies'),
  require('./info/info'),
];

/**
 * Starts the app on a connected Android emulator or device.
 */
function runAndroid(argv, config, args) {
  if (!checkAndroid(args.root)) {
    const reactNativeScriptsPath = findReactNativeScripts();
    if (reactNativeScriptsPath) {
      child_process.spawnSync(
        reactNativeScriptsPath,
        ['android'].concat(process.argv.slice(1)),
        {stdio: 'inherit'}
      );
    } else {
      console.log(chalk.red('Android project not found. Maybe run react-native android first?'));
    }
    return;
  }

  if (!args.packager) {
    return buildAndRun(args);
  }

  return isPackagerRunning(args.port).then(result => {
    if (result === 'running') {
      console.log(chalk.bold('JS server already running.'));
    } else if (result === 'unrecognized') {
      console.warn(chalk.yellow('JS server not recognized, continuing with build...'));
    } else {
      // result == 'not_running'
      console.log(chalk.bold('Starting JS server...'));
      startServerInNewWindow(args.port);
    }
    return buildAndRun(args);
  });
}

/**
 * Indicates whether or not the packager is running. It returns a promise that
 * when fulfilled can returns one out of these possible values:
 *   - `running`: the packager is running
 *   - `not_running`: the packager nor any process is running on the expected
 *                    port.
 *   - `unrecognized`: one other process is running on the port we expect the
 *                     packager to be running.
 */
function isPackagerRunning(packagerPort = (process.env.RCT_METRO_PORT || 8081)) {
  return fetch(`http://localhost:${packagerPort}/status`).then(
    res => res.text().then(body =>
      body === 'packager-status:running' ? 'running' : 'unrecognized'
    ),
    () => 'not_running'
  );
}

function startServerInNewWindow(port) {
  const scriptFile = /^win/.test(process.platform) ?
    'launchPackager.bat' :
    'launchPackager.command';
  const scriptsDir = path.resolve(__dirname, '..', '..', 'scripts');
  const launchPackagerScript = path.resolve(scriptsDir, scriptFile);
  const procConfig = {cwd: scriptsDir};
  const terminal = process.env.REACT_TERMINAL;

  // setup the .packager.env file to ensure the packager starts on the right port
  const packagerEnvFile = path.join(__dirname, '..', '..', 'scripts', '.packager.env');
  const content = `export RCT_METRO_PORT=${port}`;
  // ensure we overwrite file by passing the 'w' flag
  fs.writeFileSync(packagerEnvFile, content, {encoding: 'utf8', flag: 'w'});

  if (process.platform === 'darwin') {
    if (terminal) {
      return child_process.spawnSync('open', ['-a', terminal, launchPackagerScript], procConfig);
    }
    return child_process.spawnSync('open', [launchPackagerScript], procConfig);

  } else if (process.platform === 'linux') {
    procConfig.detached = true;
    if (terminal){
      return child_process.spawn(terminal, ['-e', 'sh ' + launchPackagerScript], procConfig);
    }
    return child_process.spawn('sh', [launchPackagerScript], procConfig);

  } else if (/^win/.test(process.platform)) {
    procConfig.detached = true;
    procConfig.stdio = 'ignore';
    return child_process.spawn('cmd.exe', ['/C', launchPackagerScript], procConfig);
  } else {
    console.log(chalk.red(`Cannot start the packager. Unknown platform ${process.platform}`));
  }
}

node "./local-cli/cli.js" start "$@"

module.exports = {
  name: 'start',
  func: server,
  description: 'starts the webserver',
  options: [{
    command: '--port [number]',
    default: process.env.RCT_METRO_PORT || 8081,
    parse: (val: string) => Number(val),
  }, {
    command: '--host [string]',
    default: '',
  }, {
    command: '--root [list]',
    description: 'add another root(s) to be used by the packager in this project',
    parse: (val: string) => val.split(',').map(root => path.resolve(root)),
    default: [],
  }, {
    command: '--projectRoots [list]',
    description: 'override the root(s) to be used by the packager',
    parse: (val: string) => val.split(','),
    default: (config: ConfigT) => config.getProjectRoots(),
  }, {
    command: '--assetExts [list]',
    description: 'Specify any additional asset extensions to be used by the packager',
    parse: (val: string) => val.split(','),
    default: (config: ConfigT) => config.getAssetExts(),
  }, {
    command: '--sourceExts [list]',
    description: 'Specify any additional source extensions to be used by the packager',
    parse: (val: string) => val.split(','),
    default: (config: ConfigT) => config.getSourceExts(),
  }, {
    command: '--platforms [list]',
    description: 'Specify any additional platforms to be used by the packager',
    parse: (val: string) => val.split(','),
    default: (config: ConfigT) => config.getPlatforms(),
  }, {
    command: '--providesModuleNodeModules [list]',
    description: 'Specify any npm packages that import dependencies with providesModule',
    parse: (val: string) => val.split(','),
    default: (config: RNConfig) => {
      if (typeof config.getProvidesModuleNodeModules === 'function') {
        return config.getProvidesModuleNodeModules();
      }
      return null;
    },
  }, {
    command: '--max-workers [number]',
    description: 'Specifies the maximum number of workers the worker-pool ' +
      'will spawn for transforming files. This defaults to the number of the ' +
      'cores available on your machine.',
    parse: (workers: string) => Number(workers),
  }, {
    command: '--skipflow',
    description: 'Disable flow checks'
  }, {
    command: '--nonPersistent',
    description: 'Disable file watcher'
  }, {
    command: '--transformer [string]',
    description: 'Specify a custom transformer to be used'
  }, {
    command: '--reset-cache, --resetCache',
    description: 'Removes cached files',
  }, {
    command: '--custom-log-reporter-path, --customLogReporterPath [string]',
    description: 'Path to a JavaScript file that exports a log reporter as a replacement for TerminalReporter',
  }, {
    command: '--verbose',
    description: 'Enables logging',
  }, {
    command: '--https',
    description: 'Enables https connections to the server',
  }, {
    command: '--key [path]',
    description: 'Path to custom SSL key',
  }, {
    command: '--cert [path]',
    description: 'Path to custom SSL cert',
  }],
};

/**
 * Starts the React Native Packager Server.
 */
function server(argv: mixed, config: RNConfig, allArgs: Object) {
  const {root, ...args} = allArgs;
  args.projectRoots = args.projectRoots.concat(root);

  const startedCallback = logReporter => {
    logReporter.update({
      type: 'initialize_started',
      port: args.port,
      projectRoots: args.projectRoots,
    });

    process.on('uncaughtException', error => {
      logReporter.update({
        type: 'initialize_failed',
        port: args.port,
        error,
      });

      process.exit(11);
    });
  };

  const readyCallback = logReporter => {
    logReporter.update({
      type: 'initialize_done',
    });
  };
  const runServerArgs: RunServerArgs = args;
  /* $FlowFixMe: ConfigT shouldn't be extendable. */
  const configT: ConfigT = config;
  runServer(runServerArgs, configT, startedCallback, readyCallback);
}

const app = connect()
  .use(loadRawBodyMiddleware)
  .use(compression())
  .use(
    '/debugger-ui',
    serveStatic(path.join(__dirname, 'util', 'debugger-ui')),
  )
  .use(
    getDevToolsMiddleware(args, () => wsProxy && wsProxy.isChromeConnected()),
  )
  .use(getDevToolsMiddleware(args, () => ms && ms.isChromeConnected()))
  .use(openStackFrameInEditorMiddleware(args))
  .use(copyToClipBoardMiddleware)
  .use(statusPageMiddleware)
  .use(systraceProfileMiddleware)
  .use(indexPageMiddleware)
  .use(packagerServer.processRequest.bind(packagerServer));

/**
 * Status page so that anyone who needs to can verify that the packager is
 * running on 8081 and not another program / service.
 */
module.exports = function(req, res, next) {
  if (req.url === '/status') {
    res.end('packager-status:running');
  } else {
    next();
  }
};