Node.js從服務器主動發送請求

服務器請求百度首頁

• 參考文檔鏈接

//服務器發送請求
const http = require('http');
const path = require('path');
const fs = require('fs');

let options = {
  hostname: 'www.baidu.com',
  port: '80'
}

let req = http.request(options, (res) => {
  let info = '';
  res.on('data', (chunk) => {
    info += chunk;
  })

  res.on('end', () => {
    fs.writeFile(path.join(__dirname, 'baidu.html'), info, (err) => {
      if (!err) {
        console.log("百度主頁html內容加載完畢")
      }
    })
  })
})


req.end();

服務器向後臺接口發送請求

• 查詢數據

const http = require('http');

let options = {
  protocol: 'http:',
  hostname: 'localhost',
  port: '3000',
  path: '/books'
}

let req = http.request(options, (res) => {
  let info = '';
  res.on('data', (chunk) => {
    info += chunk;
  })

  res.on('end', () => {
    console.log(info);
  })
})

req.end();

• 添加數據
  • 需要在headers中指定Content-Type
  • 需要引入querystring模塊，對請求的參數對象轉成字符串進行處理
  • 需要調用req的write(data)方法將請求的參數寫入請求體中

//服務器向添加圖書resful接口發送帶參請求
const http = require('http');
const querystring = require('querystring');

let options = {
  protocol: 'http:',
  hostname: 'localhost',
  port: '3000',
  path: '/books/book',
  method: 'POST',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  }
};

//對應添加數據的字段和值
let addData = querystring.stringify({
  'name': '書名',
  'author': '作者',
  'category': '分類',
  'description': '描述'
});

let req = http.request(options, (res) => {
  let info = '';
  res.on('data', (chunk) => {
    info += chunk;
  })

  res.on('end', () => {
    console.log(info);  //打印接口返回的信息
  })
})

req.on('error', (e) => {
  console.error(`problem with request: ${e.message}`);
});

req.write(addData);
req.end();

• 帶參查詢數據
  • 在請求路徑後拼接參數Id（請求的後臺接口是resful接口）

//帶參查詢
const http = require('http');

let id = 9;
let options = {
  protocol: 'http:',
  hostname: 'localhost',
  port: '3000',
  path: '/books/book/' + id,
  method: 'GET'
};

let req = http.request(options, (res) => {
  let info = '';
  res.on('data', (chunk) => {
    info += chunk;
  })

  res.on('end', () => {
    console.log(info);
  })
})

req.on('error', (e) => {
  console.error(`problem with request: ${e.message}`);
});

req.end();

• 修改數據
  • 與添加數據基本一致，只需要更改請求方式爲put以及參數中添加修改的數據id

let options = {
  protocol: 'http:',
  hostname: 'localhost',
  port: '3000',
  path: '/books/book',
  method: 'PUT',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  }
};

//對應添加數據的字段和值
let addData = querystring.stringify({
  'id': 18,
  'name': '書名修改',
  'author': '作者修改',
  'category': '分類修改',
  'description': '描述修改'
});

• 刪除數據
  • 刪除數據與帶參查詢數據一致，只需要更改請求方式爲delete

let id = 18;
let options = {
  protocol: 'http:',
  hostname: 'localhost',
  port: '3000',
  path: '/books/book/' + id,
  method: 'delete'
};

請求第三方服務器的後臺接口

封裝天氣查詢模塊

//weather.js
const http = require('http');

//http://www.weather.com.cn/data/sk/101010100.html   通過拼接城區Id查詢
exports.queryWeather = (cityCode, callback) => {
  let options = {
    protocol: 'http:',
    hostname: 'www.weather.com.cn',
    port: '80',
    path: '/data/sk/' + cityCode + '.html',
    method: 'get'
  };

  let req = http.request(options, (res) => {
    let info = '';
    res.on('data', (chunk) => {
      info += chunk;
    })

    res.on('end', () => {
      info = JSON.parse(info);
      callback(info);
    })
  })

  req.on('error', (e) => {
    console.error(`problem with request: ${e.message}`);
  });

  req.end();
}

測試封裝模塊

//test.js
const weather = require('./weather.js')

weather.queryWeather('101020100', (data) => {
  console.log(data);  //打印出對應ID的天氣信息
})