路由器在Express.js中返回404

Question

I'm currently learning and a newbie to Node.js . I'm trying to build a simple REST API and currently getting an error 404 when try post to a particular route in postman to test if data has successfully been sent to Mongo db . I'm sure what i'm missing. I have double checked all my routes and they seem fine. It works when i make a get request and falls through when i make a post request.

This is my app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var mongoose = require('mongoose');
var logger = require('morgan');
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var Developer = require('./models/developers');
var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(bodyParser.urlencoded({ extended: true}));
app.use(express.static(path.join(__dirname, 'public')));
app.use(bodyParser.json());
app.use('/', indexRouter);
app.use('/users', usersRouter);

// Connect to DB
mongoose.connect('mongodb://127.0.0.1:27017');

// API Routes
var router = express.Router();

// Routes will be prefixed with /api
app.use('/api', router);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

// Test Route
router.get('/', function (req, res) {
  res.json({message: 'Welcome to my simple API!'});
});

router.route('/developers')
    .post(function (req, res) {
      var developer = new Developer(); // New instance of sa developer
      developer.firstName = req.body.firstName;
      developer.lastName = req.body.lastName;
      developer.jobTitle = req.body.jobTitle;

      developer.save(function (err) {
        if (err) {
          res.send(err);
        } else {
          res.json('Developer was successfully fetched');
        }
      });
    })

    .get(function (req, res) {
      Developer.find(function (err, developers) {
        if (err) {
          res.send(err);
        } else
          res.json(developers);
      });
    });

router.route('/developer/:developer_id')
    .get(function (req, res) {
      Developer.findById(res.params.developer_id, function (err, developer) {
        if (err) {
          res.send(err);
        }
        res.json(developer);
      });
    });

router.route('/developer/firstName/:firstName')
    .get(function (req, res) {
      Developer.find({firstName:res.params.firstName}, function (err, developer) {
        if (err) {
          res.send(err);
        }
        res.json(developer);
      });
    });

My model is developer.js

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var DevelopersSchema = new Schema({
   firstName: String,
   lastName: String,
   jobTitle: String
});

module.exports = mongoose.model('Developers', DevelopersSchema);

Answer 1

To connect the database, instead of

mongoose.connect('mongodb://127.0.0.1:27017');

Use,

mongoose.connect('mongodb://127.0.0.1:27017/yourDatabaseName');

Check the doc .

Mongoose database connection require a database name in connect() method.

Your final app.js should be like,

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var mongoose = require('mongoose');
var logger = require('morgan');
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var Developer = require('./models/developers');
var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(bodyParser.urlencoded({ extended: true}));
app.use(express.static(path.join(__dirname, 'public')));
app.use(bodyParser.json());
app.use('/', indexRouter);
app.use('/users', usersRouter);

// Connect to DB
mongoose.connect('mongodb://127.0.0.1:27017/my_unique_data_base_name');

// API Routes
var router = express.Router();

// Routes will be prefixed with /api
app.use('/api', router);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

// Test Route
router.get('/', function (req, res) {
  res.json({message: 'Welcome to my simple API!'});
});

router.route('/developers')
    .post(function (req, res) {
      var developer = new Developer(); // New instance of sa developer
      developer.firstName = req.body.firstName;
      developer.lastName = req.body.lastName;
      developer.jobTitle = req.body.jobTitle;

      developer.save(function (err) {
        if (err) {
          res.send(err);
        } else {
          res.json('Developer was successfully fetched');
        }
      });
    })

    .get(function (req, res) {
      Developer.find(function (err, developers) {
        if (err) {
          res.send(err);
        } else
          res.json(developers);
      });
    });

router.route('/developer/:developer_id')
    .get(function (req, res) {
      Developer.findById(res.params.developer_id, function (err, developer) {
        if (err) {
          res.send(err);
        }
        res.json(developer);
      });
    });

router.route('/developer/firstName/:firstName')
    .get(function (req, res) {
      Developer.find({firstName:res.params.firstName}, function (err, developer) {
        if (err) {
          res.send(err);
        }
        res.json(developer);
      });
    });

Answer 2

if I'm correct, the line of app.use('/api', router); does nothing. When coming a request for /api endpoint, a response should be sent at the end of operations. The code pass the request to router . And router does nothing.

Then if createError(404) method calls res.send() or res.end() methods you should move the use() method to the bottom of your code page:

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

Because at every single time it works before the other routes.

IMHO, using a standard coding style make more readable the program-flow.

Good luck..