中间件 ～ body-parser

最近一致在写中间件，此次的目标是body-parser，哇咔咔, 模块须要安装的哦～

body-parser应用

body-parser 能够帮咱们解析请求体，假设写一个请求

client.js

let http = require('http');


let client = http.request({
    hostname:'localhost',
    port:3000,
    path:'/',
    method:'post',
    headers:{
        'Content-Type':'application/x-www-form-urlencode'
    }
},function (res) {
});
client.end('name=zdl&age=9');
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express.js

let express = require('express');
let app = express();
let bodyParser = require('body-parser');

app.use(bodyParser.urlencoded({extended:true}))
app.post('/',function(req,res){
    console.log(req.body);
    res.end();
})
app.listen(3000)
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解析后运行express.js node client.js,输出{ name: 'zdl', age: '9' }

body-parser的实现

urlencoded

let express = require('express');
let app = express();
let bodyParser = require('body-parser');
function urlencoded({extended}){
    return (req,res,next)=>{
        let buffers = [];
        req.on('data',function(data){
            buffers.push(data);
        })
        req.on('end',function(){
            let str = Buffer.concat(buffers).toString();
            if(extended){
                req.body = require('querystring').parse(str);
            }else{
                req.body = require('qs').parse(str); 
            }
            next()
        })
    }
}
app.use(urlencoded({extended:true}))
app.post('/',function(req,res){
    console.log(req.body);
    res.end();
})
app.listen(3000)
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注： querystring不支持嵌套，故而有extended的区分

text

text很简单，可是有点小麻烦，由于假设用户传的是gbk格式，而 node又不支持这种格式，咱们须要用到iconv-lite库转码(须要安装)，

• 首先咱们须要将'Content-Type'格式转换成'text/plain;charset=gbk'
• 引用iconv-lite 传输数据
• 安装content-type包解析编码格式

'Content-Type':'text/plain;charset=gbk'
 }
},function (res) {
});
let iconv = require('iconv-lite');
client.end(iconv.encode('我很帅','gbk'));
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express.js

function text(){
    return (req,res,next)=>{
        let buffers = [];
        req.on('data',function(data){
            buffers.push(data);
        })
        req.on('end',function(){
            let str = Buffer.concat(buffers);
            let contentType = require('content-type');
            let iconvLite = require('iconv-lite');
            let { parameters: { charset }, type} = contentType.parse(req.headers['content-type']);
            if(type === 'text/plain'){
                // 解码操做
                req.body = iconvLite.decode(str, charset);
                console.log(req.body);
            }
            next()
        })
    }
}
app.use(text())
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因此整个express.js文件以下

let express = require('express');
let app = express();
let bodyParser = require('body-parser');
function urlencoded({extended}){
    return (req,res,next)=>{
        let buffers = [];
        req.on('data',function(data){
            buffers.push(data);
        })
        req.on('end',function(){
            let str = Buffer.concat(buffers).toString();
            if(extended){
                req.body = require('querystring').parse(str);
            }else{
                req.body = require('qs').parse(str); 
            }
            next()
        })
    }
}
app.use(urlencoded({extended:true}))
function text(){
    return (req,res,next)=>{
        let buffers = [];
        req.on('data',function(data){
            buffers.push(data);
        })
        req.on('end',function(){
            let str = Buffer.concat(buffers);
            let contentType = require('content-type');
            let iconvLite = require('iconv-lite');
            let { parameters: { charset }, type} = contentType.parse(req.headers['content-type']);
            if(type === 'text/plain'){
                // 解码操做
                req.body = iconvLite.decode(str, charset);
                console.log(req.body);
            }
            next()
        })
    }
}
app.use(text())
app.post('/',function(req,res){
    console.log(req.body);
    res.end();
})
app.listen(3000)
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