[Mongo] define schema and flexibly create and read Mongo (zero coding development) (3 / 3)

Time:2021-1-8
1. Configuration

conf.js

module.exports = {
    db: {
        url: 'mongodb://127.0.0.1:27017/local',
        options: {
            useNewUrlParser: true,
        }
    }
}
2. Entrance

index.js

const Koa = require('koa');
const app = new Koa();
const config = require('./conf')
const {loadModel} = require('./framework/loader')

//Load the configuration corresponding field of the model
loadModel(config)(app)

//Introduction of dynamic configuration API
const rest = require('./framework/router');
//Automatically convert the incoming body string to the object value, cxt.request.body
const bodyParser = require('koa-bodyparser');   

app.use(bodyParser());
app.use(rest);

const port = 3000;
app.listen(port, () => {
    console.log('link 3000');
})
3. Define schema

./model/user.js

module.exports = {
    schema: {
        mobile: {
            type: String,
            required: true,
        },
        realName: {
            type: String,
            required: true,
        },
    }
}
4. Load the defined schema file and read the configuration to Mongo

./framework/loader.js

const fs = require('fs');
const path = require('path');
const mongoose = require('mongoose');

function load (dir, cb) {
    //Get absolute path
    const url = path.resolve(__dirname, dir);
    const files = fs.readdirSync(url);
    files.forEach(filename => {
        filename = filename.replace('.js', '');
        const file = require(url + '/' + filename);
        cb(filename, file);
    })
}

const loadModel = (config) => {
    return (app) => {
        mongoose.connect(config.db.url, config.db.options);
        const conn = mongoose.connection;
        conn.on('error', () => {
            console.error ('connection failed ')
        })
        app.$model = {
        }
        load('../model', (filename, {schema}) => {
            console.log('load model '+ filename, schema)
            app.$model[filename] = mongoose.model(filename, schema)
        })
    }
}
module.exports = {
    loadModel
}

In the above steps, you can define the data model in Mongo database. Next, you can map the data model to the interface

5. Define interface name

./framework/router.js

const router = require('koa-router')();
const {
    init, get, create, update, del,
} = require('./api');

router.get('/api/:listname', init, get);
router.post('/api/:listname', init, create);
router.put('/api/:listname/:id', init, update);
router.delete('/api/:listname/:id', init, del);

module.exports = router.routes();
6. Specific handling of interface

./framework/api.js

module.exports = {
    async init (ctx, next) {
        console.log('init', ctx.params);
        
        const model = ctx.app.$model[ctx.params.listname];
        if (model) {
            ctx.listname = model;
            await next();
        } else {
            ctx.body = 'no this model'
        }
    },
    async get (ctx) {
        ctx.body = await ctx.listname.find({})
    },
    async create (ctx) {
        const req = await ctx.listname.create(ctx.request.body)
        console.log('req', req);
        console.log('ctx', ctx.listname);
        
        ctx.body = req;
    },
    async update (ctx) {
        const res = await ctx.listname.updateOne({
            _id: ctx.params.id
        }, ctx.request.body);
        ctx.body = res;
        console.log('res', res);
    },
    async del (ctx) {
        const res = await ctx.listname.deleteOne({
            _id: ctx.params.id
        })
        ctx.body = res;
    },
    async page (ctx) {
        console.log('page...', ctx.params.page);
        
        ctx.body = await ctx.listname.find({})
    },
}

So far, you can see the corresponding effect by using postman to access the interface
http://localhost:3000/api/user