NoSQL mongodb - 04 mongodb database and web service combination case

Case study 1： stay Nodejs In the operation MongoDB

MongoDB The authorities provide a lot drive （Drivers） Used to operate MongoDB.

These drivers include almost all major back-end languages , In fact, it is the package corresponding to each platform , Used to connect operations MongoDB.

Here's a simple Node.js operation MongoDB The case of , Reference resources ：MongoDB Node Driver — Node.js

Please guarantee MongoDB The service is on .

Initialize the sample project

mkdir node-mongodb-demo
cd node-mongdb-demo
npm init -y
# mongodb  It's official  Node.js  Lower operation  MongoDB  The toolkit 
npm i mongodb

Connect MongoDB

const {
     MongoClient } = require('mongodb')

//  Create a client instance that connects to the database 
const client = new MongoClient('mongodb://127.0.0.1:27017')

async function run() {
    
  try {
    
    //  Connect the client to the database service 
    await client.connect()

    //  Connect  test  database 
    const testDb = client.db('test')

    //  obtain  inventory  aggregate 
    const inventoryCollection = testDb.collection('inventory')

    //  Query the document 
    const ret = await inventoryCollection.find()
    // find  Method returns a pointer to the management query result , You can use  toArray()  Method traversal view 
    console.log(await ret.toArray())
  } catch (err) {
    
    //  The connection fails 
    console.log(' The connection fails ')
  } finally {
    
    //  Make sure that / When an error occurs, the client will close the connection 
    await client.close()
  }
}

run()

CRUD operation

On every platform CRUD Operation methods can be found in official documents MongoDB CRUD Operations Find , Switch... In the page “Select your language” Choose the language to use .

create documents

const ret = await inventoryCollection.insertOne({
     item: 'card', qty: 15 })
console.log(ret)

Query the document

const ret = await inventoryCollection.find({
     item: 'card' })
console.log(await ret.toArray())

const ret = await inventoryCollection.findOne({
     item: 'card' })
console.log(ret)

Modify the document

const ret = await inventoryCollection.updateOne(
    {
    
        item: 'card'
    },
    {
    
        $set: {
    
            qty: 100
        }
    }
)
console.log(ret)

Delete the document

The following example uses _id Match the document to be deleted , By default _id yes ObjectId object , Need to use ObjectId Class to create an instance .

Be careful ：MongoDB Previous versions used the name ObjectID Methods , Now the name has been discarded , Recommend and change to ObjectId.

const {
     ObjectId } = require('mongodb')

await inventoryCollection.deleteOne({
    
    _id: ObjectId('61b691a3db3aa35bcac3f440')
})

Case study 2：MongoDB Database integration Web service

Case introduction

This example sets up a support MongoDB database CRUD Operation of the Web Interface services , Used to manage blog posts .

Interface design

This example interface is based on RESTful The interface specification , Reference resources ：

• understand RESTful framework
• RESTful API Design Guide

This example interface data format ：application/json

This example USES postman Debug test interface .

Create articles

• Request path ： POST /articles
• Request parameters ：Body
  • title
  • description
  • body
  • tagList

Request body example ：

{
    
  "article": {
    
    "title": "How to train your dragon",
    "description": "Ever wonder how?",
    "body": "You have to believe",
    "tagList": ["reactjs", "angularjs", "dragons"]
  }
}

Sample response data ：

• Status code ：201
• The response data ：

{
    
  "article": {
    
    "_id": 123,
    "title": "How to train your dragon",
    "description": "Ever wonder how?",
    "body": "It takes a Jacobian",
    "tagList": ["dragons", "training"]
  }
}

Get article list

• Request path ： GET /articles
• Request parameters ：Query
  • _page： Page number
  • _size： The size of each page

Sample response data ：

• Status code ：200
• The response data ：

{
    
  "articles":[{
    
    "_id": "how-to-train-your-dragon",
    "title": "How to train your dragon",
    "description": "Ever wonder how?",
    "body": "It takes a Jacobian",
    "tagList": ["dragons", "training"],
    "createdAt": "2016-02-18T03:22:56.637Z",
    "updatedAt": "2016-02-18T03:48:35.824Z"
  }, {
    
    "_id": "how-to-train-your-dragon-2",
    "title": "How to train your dragon 2",
    "description": "So toothless",
    "body": "It a dragon",
    "tagList": ["dragons", "training"],
    "createdAt": "2016-02-18T03:22:56.637Z",
    "updatedAt": "2016-02-18T03:48:35.824Z"
  }],
  "articlesCount": 2
}

Get a single article

• Request path ： GET /articles/:id

Sample response data ：

• Status code ：200
• The response data ：

{
    
  "article": {
    
    "_id": "dsa7dsa",
    "title": "How to train your dragon",
    "description": "Ever wonder how?",
    "body": "It takes a Jacobian",
    "tagList": ["dragons", "training"],
    "createdAt": "2016-02-18T03:22:56.637Z",
    "updatedAt": "2016-02-18T03:48:35.824Z"
  }
}

Update article

• Request path ： PATCH /articles/:id
• Request parameters ：Body
  • title
  • description
  • body
  • tagList

Request body example ：

{
    
  "article": {
    
    "title": "Did you train your dragon?"
  }
}

Sample response data ：

• Status code ：201
• The response data ：

{
    
  "article": {
    
    "_id": 123,
    "title": "How to train your dragon",
    "description": "Ever wonder how?",
    "body": "It takes a Jacobian",
    "tagList": ["dragons", "training"],
    "createdAt": "2016-02-18T03:22:56.637Z",
    "updatedAt": "2016-02-18T03:48:35.824Z"
  }
}

Delete articles

• Request path ： DELETE /articles/:id

Sample response data ：

• Status code ：204

Initialize project

mkdir article-end
cd article-end
npm init -y
npm i express mongodb

Create an entry file app.js：

// app.js
const express = require('express')

const app = express()

//  Configure parsing request body data  application/json
//  The middleware will put the parsed request body data into  req.body
app.use(express.json())

app.get('/', (req, res) => {
    
  res.send('Hello World!')
})

app.listen(3000, () => {
    
  console.log('app listenning at port 3000.')
})

Start the service ：

#  Global installation is recommended  nodemon  Used to start services 
npm i -g nodemon
#  Start the service 
nodemon app.js

Routing configuration

// app.js
const express = require('express')

const app = express()

//  Configure parsing request body data  application/json
//  The middleware will put the parsed request body data into  req.body
app.use(express.json())

app.get('/', (req, res) => {
    
  res.send('Hello World!')
})

//  Create articles 
app.post('/articles', (req, res) => {
    
  res.send('post /articles')
})

//  Get article list 
app.get('/articles', (req, res) => {
    
  res.send('get /articles')
})

//  Get a single article 
app.get('/articles/:id', (req, res) => {
    
  res.send('get /articles/:id')
})

//  Update article 
app.patch('/articles/:id', (req, res) => {
    
  res.send('patch /articles/:id')
})

//  Delete articles 
app.delete('/articles/:id', (req, res) => {
    
  res.send('delete /articles/:id')
})

app.listen(3000, () => {
    
  console.log('app listenning at port 3000.')
})

Create articles

// app.js
const express = require('express')

//  database 
const {
     MongoClient } = require('mongodb')
const connectUri = 'mongodb://localhost:27017'
const dbClient = new MongoClient(connectUri)

//...

//  Create articles 
app.post('/articles', async (req, res) => {
    
  try {
    
    // 1.  Get client form data 
    const {
     article } = req.body

    // 2.  data validation 
    if (!article || !article.title || !article.description || !article.body) {
    
      return res.status(422).json({
    
        error: ' The request parameter does not meet the rule requirements '
      })
    }

    // 3.  Insert the verified data into the database 
    await dbClient.connect()
    const collection = dbClient.db('test').collection('articles')
    const ret = await collection.insertOne(article)
    article._id = ret.insertedId

    // 4.  Send successfully / Failure response 
    res.status(201).json(article)
  } catch (err) {
    
    res.status(500).json({
    
      error: err.message
    })
  }
})

//...

Unified processing of server errors

//...

//  Create articles 
app.post('/articles', async (req, res, next) => {
    
  try {
    
    //...
  } catch (err) {
    
    //  The error handling middleware will handle it uniformly 
    next(err)
  }
})

//...

//  Error handling middleware 
//  Before that, all routes call  next(err)  Will enter here 
//  Be careful ： Must have  4  Parameters will be identified as error handling middleware 
app.use((err, req, res, next) => {
    
  res.status(500).json({
    
    error: err.message
  })
})

app.listen(3000, () => {
    
  console.log('app listenning at port 3000.')
})

Get article list

//  Get article list 
app.get('/articles', async (req, res, next) => {
    
  try {
    
    let {
     _page = 1, _size = 10 } = req.query
    _page = parseInt(_page)
    _size = parseInt(_size)

    await dbClient.connect()
    const collection = dbClient.db('test').collection('articles')
    const ret = await collection
      .find() //  Query data （ To obtain the cursor ）
      .skip((_page - 1) * _size) //  How many 
      .limit(_size) //  How many 
    const articles = await ret.toArray()
    const articlesCount = await collection.countDocuments()
    res.status(200).json({
    
      articles,
      articlesCount
    })
  } catch (err) {
    
    next(err)
  }
})

Get article details

//  introduce  ObjectId  Method 
const {
     MongoClient, ObjectId } = require('mongodb')

//...

//  Get a single article 
app.get('/articles/:id', async (req, res, next) => {
    
  try {
    
    await dbClient.connect()
    const collection = dbClient.db('test').collection('articles')
    const article = await collection.findOne({
     _id: ObjectId(req.params.id) })
    res.status(200).json({
    
      article
    })
  } catch (err) {
    
    next(err)
  }
})

Update article

//  Update article 
app.patch('/articles/:id', async (req, res, next) => {
    
  try {
    
    await dbClient.connect()
    const collection = dbClient.db('test').collection('articles')
    const article = await collection.updateOne(
      {
     _id: ObjectId(req.params.id) },
      {
    
        $set: req.body.article
      }
    )

    // req.body.article  After the update, the status information of the update result will be changed 
    //  Query the updated data ( Match only  _id  It can be abbreviated as "pass parameter" )
    const ret = await collection.findOne(ObjectId(req.params.id))
    res.status(201).json(ret)
  } catch (err) {
    
    next(err)
  }
})

Delete articles

//  Delete articles 
app.delete('/articles/:id', async (req, res, next) => {
    
  try {
    
    await dbClient.connect()
    const collection = dbClient.db('test').collection('articles')
    const article = await collection.deleteOne({
     _id: ObjectId(req.params.id) })
    res.status(204).json({
    })
  } catch (err) {
    
    next(err)
  }
})