Node.js を使用して MVC フレームワークを実装する方法の簡単な分析例

const http = require('http');
const url = require('url');

http.createServer((req, res) => {
  const pathName = url.parse(req.url).pathname;
  if (['/actors', '/actresses'].includes(pathName)) {
    res.writeHead(200, {
      'Content-Type': 'text/html'
    });
    const actors = ['Leonardo DiCaprio', 'Brad Pitt', 'Johnny Depp'];
    const actresses = ['Jennifer Aniston', 'Scarlett Johansson', 'Kate Winslet'];
    let lists = [];
    if (pathName === '/actors') {
      lists = actors;
    } else {
      lists = actresses;
    }

    const content = lists.reduce((template, item, index) => {
      return template + `<p>No.${index+1} ${item}</p>`;
    }, `<h1>${pathName.slice(1)}</h1>`);
    res.end(content);
  } else {
    res.writeHead(Node.js を使用して MVC フレームワークを実装する方法の簡単な分析例);
    res.end(&#39;<h1>Requested page not found.</h1>&#39;)
  }
}).listen(9527);

-- server.js
-- lib
  -- router.js
-- views
-- controllers
-- models

const http = require('http');
const router = require('./lib/router')();

router.get('/actors', (req, res) => {
  res.end('Leonardo DiCaprio, Brad Pitt, Johnny Depp');
});

http.createServer(router).listen(9527, err => {
  if (err) {
    console.error(err);
    console.info('Failed to start server');
  } else {
    console.info(`Server started`);
  }
});

const router = require('./lib/router')();
const actorsController = require('./controllers/actors');

router.use((req, res, next) => {
  console.info('New request arrived');
  next()
});

router.get('/actors', (req, res) => {
  actorsController.fetchList();
});

router.post('/actors/:name', (req, res) => {
  actorsController.createNewActor();
});

router.use(fn);

router.use((req, res, next) => {
  console.info('New request arrived');
  next()
});

router.HTTP_METHOD(path, fn)

const METHODS = ['GET', 'POST', 'PUT', 'DELETE', 'HEAD', 'OPTIONS'];

module.exports = () => {
  const routes = [];

  const router = (req, res) => {
    
  };

  router.use = (fn) => {
    routes.push({
      method: null,
      path: null,
      handler: fn
    });
  };

  METHODS.forEach(item => {
    const method = item.toLowerCase();
    router[method] = (path, fn) => {
      routes.push({
        method,
        path,
        handler: fn
      });
    };
  });
};

 const router = (req, res) => {
    const pathname = decodeURI(url.parse(req.url).pathname);
    const method = req.method.toLowerCase();
    let i = 0;

    const next = () => {
      route = routes[i++];
      if (!route) return;
      const routeForAllRequest = !route.method && !route.path;
      if (routeForAllRequest || (route.method === method && pathname === route.path)) {
        route.handler(req, res, next);
      } else {
        next();
      }
    }

    next();
  };

router.use((req, res, next) => {
  console.info('New request arrived');
  next()
});

router.get('/actors', (req, res) => {
  res.end('Leonardo DiCaprio, Brad Pitt, Johnny Depp');
});

router.get('/actresses', (req, res) => {
  res.end('Jennifer Aniston, Scarlett Johansson, Kate Winslet');
});

router.use((req, res, next) => {
  res.statusCode = Node.js を使用して MVC フレームワークを実装する方法の簡単な分析例;
  res.end();
});

router.all = (path, fn) => {
    METHODS.forEach(item => {
      const method = item.toLowerCase();
      router[method](path, fn);
    })
  };

const defaultErrorHander = (err, req, res) => {
  res.statusCode = 500;
  res.end();
};

module.exports = (errorHander) => {
  const routes = [];

  const router = (req, res) => {
      ...
    errorHander = errorHander || defaultErrorHander;

    const next = (err) => {
      if (err) return errorHander(err, req, res);
      ...
    }

    next();
  };

...
const router = require('./lib/router')((err, req, res) => {
  console.error(err);
  res.statusCode = 500;
  res.end(err.stack);
});
...

router.use((req, res, next) => {
  console.info('New request arrived');
  next(new Error('an error'));
});

localhost:9527/actors/Leonardo

router.get('/actors/:name', someRouteHandler);

const getRoutePattern = pathname => {
 pathname = '^' + pathname.replace(/(\:\w+)/g, '\(\[a-zA-Z0-9-\]\+\\s\)') + '$';
 return new RegExp(pathname);
};

    const matchedResults = pathname.match(route.pattern);
    if (route.method === method && matchedResults) {
      addParamsToRequest(req, route.path, matchedResults);
      route.handler(req, res, next);
    } else {
      next();
    }

const addParamsToRequest = (req, routePath, matchedResults) => {
  req.params = {};
  let urlParameterNames = routePath.match(/:(\w+)/g);
  if (urlParameterNames) {
    for (let i=0; i < urlParameterNames.length; i++) {
      req.params[urlParameterNames[i].slice(1)] = matchedResults[i + 1];
    }
  }
}

router.get('/actors/:year/:country', (req, res) => {
  res.end(`year: ${req.params.year} country: ${req.params.country}`);
});

...
const actorsController = require('./controllers/actors');
...
router.get('/actors', (req, res) => {
  actorsController.getList(req, res);
});

router.get('/actors/:name', (req, res) => {
  actorsController.getActorByName(req, res);
});

router.get('/actors/:year/:country', (req, res) => {
  actorsController.getActorsByYearAndCountry(req, res);
});
...

const actorsTemplate = require('../views/actors-list');
const actorsModel = require('../models/actors');

exports.getList = (req, res) => {
  const data = actorsModel.getList();
  const htmlStr = actorsTemplate.build(data);
  res.writeHead(200, {
    'Content-Type': 'text/html'
  });
  res.end(htmlStr);
};

exports.getActorByName = (req, res) => {
  const data = actorsModel.getActorByName(req.params.name);
  const htmlStr = actorsTemplate.build(data);
  res.writeHead(200, {
    'Content-Type': 'text/html'
  });
  res.end(htmlStr);
};

exports.getActorsByYearAndCountry = (req, res) => {
  const data = actorsModel.getActorsByYearAndCountry(req.params.year, req.params.country);
  const htmlStr = actorsTemplate.build(data);
  res.writeHead(200, {
    'Content-Type': 'text/html'
  });
  res.end(htmlStr);
};

[
  {
    "name": "Leonardo DiCaprio",
    "birth year": 1974,
    "country": "US",
    "movies": ["Titanic", "The Revenant", "Inception"]
  },
  {
    "name": "Brad Pitt",
    "birth year": 1963,
    "country": "US",
    "movies": ["Fight Club", "Inglourious Basterd", "Mr. & Mrs. Smith"]
  },
  {
    "name": "Johnny Depp",
    "birth year": 1963,
    "country": "US",
    "movies": ["Edward Scissorhands", "Black Mass", "The Lone Ranger"]
  }
]

const actors = require('./test-data');

exports.getList = () => actors;

exports.getActorByName = (name) => actors.filter(actor => {
  return actor.name == name;
});

exports.getActorsByYearAndCountry = (year, country) => actors.filter(actor => {
  return actor["birth year"] == year && actor.country == country;
});

const actorTemplate = `
<h1>{name}</h1>
<p><em>Born: </em>{contry}, {year}</p>
<ul>{movies}</ul>
`;

exports.build = list => {
  let content = &#39;&#39;;
  list.forEach(actor => {
    content += actorTemplate.replace(&#39;{name}&#39;, actor.name)
          .replace(&#39;{contry}&#39;, actor.country)
          .replace(&#39;{year}&#39;, actor["birth year"])
          .replace(&#39;{movies}&#39;, actor.movies.reduce((moviesHTML, movieName) => {
            return moviesHTML + `<li>${movieName}</li>`
          }, &#39;&#39;));
  });
  return content;
};