"node. js" II, based on Express framework + Connect MongoDB + Write back-end interface

In the previous section, we talked about how to build an express environment, and now we're talking about how to write a service interface to a front-end call through node. js

1. First build database and tables through MongoDB

For example, my database name is Db_demo and the database table is goods

The data structures in table goods are as follows:

‘ProductId’: {type: String}, // product id

‘ProductName’: String, // product name

‘SalePrice’: Number, // commodity price

‘ProductImage’: String // product image

2. Install Mongoose to drive and operate MongoDB

npm install mongoose

3. Under the server folder, create a new folder, models, which creates a js file about the commodity interface. The file structure is as follows:

The contents of goods.js are as follows:

var mongoose = require (‘mongoose’)

var Schema = mongoose.Schema

var productSchema = new Schema ({

 ‘ProductId’: {type: String},

 ‘ProductName’: String,

 ‘SalePrice’: Number,

 ‘ProductImage’: String

})

module.exports = mongoose.model (‘Good‘, productSchema)

4. Under the / routes / folder, create a new js file goods.js that specifically writes backend interface logic.

var express = require (‘express’)

var router = express.Router ()

var mongoose = require (‘mongoose’)

var Goods = require (‘../ models / goods’)

// Connect to MongoDB database

mongoose.connect (‘mongodb: //127.0.0.1: 27017 / db_demo’)

mongoose.connection.on (‘connected’, () => {

 console.log (‘MongoDB connected success.’)

})

mongoose.connection.on (‘error‘, () => {

 console.log (‘MongoDB connected fail.’)

})

mongoose.connection.on (‘disconnected’, () => {

 console.log (‘MongoDB connected disconnected.’)

})

// Query product list data

router.get ("/", (req, res, next) => {

 // Accept the parameters from the front end

 let page = parseInt (req.param (‘page‘))

 let pageSize = parseInt (req.param (‘pageSize’))

 let sort = req.param ("sort")

 let skip = (page-1) * pageSize

 let params = {};

 let goodsModel = Goods.find (params) .skip (skip) .limit (pageSize)

 goodsModel.sort ({‘salePrice‘: sort})

 goodsModel.exec ((err, doc) => {

   if (err) {

     res.json ({

       status: ‘1‘,

       msg: err.message

     })

   } else {

     res.json ({

       status: ‘0’,

       msg: ‘‘,

       result: {

         count: doc.length,

         list: doc

       }

     })

   }

 })

})

module.exports = router;

5. Finally, configure the routing address access / router / goods.js interface in app.js

6. Open the browser, the effect is as follows:

Successfully call the background interface, the background interface calls the MongoDB database, and finally returns the json data!

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[Node.js] Second, based on the Express framework + connect MongoDB + write back-end interface