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];
        }
    }
}

添加个 route 测试一下:

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

访问http://localhost:9527/actors/1990/China试试:

router 模块就写到此，至于查询参数的格式化以及获取请求主体，比较琐碎就不试验了，需要可以直接使用 bordy-parser 等模块。

controller

现在我们已经创建好了router模块，接下来将 route handler 内的业务逻辑都转移到 controller 中去。

修改__server.js__，引入 controller:

...
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);
});
...

新建__controllers/actors.js__:

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);
};

在 controller 中同时引入了 view 和 model， 其充当了这二者间的粘合剂。回顾下 controller 的任务：

1. controller 收到请求，向 model 索要数据
2. model 给 controller 返回其所需数据
3. controller 可能需要对收到的数据做一些再加工
4. controller 将处理好的数据交给 view

在此 controller 中，我们将调用 model 模块的方法获取演员列表，接着将数据交给 view，交由 view 生成呈现出演员列表页的 html 字符串。最后将此字符串返回给客户端，在浏览器中呈现列表。

从 model 中获取数据

通常 model 是需要跟数据库交互来获取数据的，这里我们就简化一下，将数据存放在一个 json 文件中。

/models/test-data.json

[
    {
        "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"]
    }
]

接着就可以在 model 中定义一些方法来访问这些数据。

models/actors.js