Express Middleware body-parser

Request body contains the http request species, POST, PUT, PATCH three kinds of request methods, the so-called request, the native http Nodejs module, the request based on the flow body to receive and parse manner.
body-parser parsing an HTTP request body middleware , using this module may parse JSON, Raw, text, URL-encoded format request body,

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Node native http module, data is encapsulated into a user request for a request req object, the object is a IncomingMessage, the object is also read a stream object. When native Http server does not rely on third parties or parsing module, the following method may request and parses the request body

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    const http = require('http');

    http.createServer(function(req, res){
        if(req.method.toLowerCase() === 'post'){
            let body = '';
            //此步骤为接收数据
            req.on('data', function(chunk){
                body += chunk;
            });
            //开始解析
            req.on('end', function(){
                if(req.headers['content-type'].indexOf('application/json')!==-1){
                    JSON.parse(body);
                }else if(req.headers [ 'Content-type'] the indexOf ( 'file application / OCTET-Stream') == -.!. 1 ) {
                     // Rwa request body format parsing 
                } the else  IF (req.headers [ 'Content-type'] .indexOf ( 'text / Plain') == -!. 1 ) {
                     // text request body text parsing 
                } the else  IF (req.headers [ 'Content-type'] the indexOf ( 'file application / X-WWW-form-. ! urlencoded ') == -. 1 ) {
                     // urlencoded format request body parsing 
                } the else {
                 // other format parsing 
                } 
            }) 
        } the else { 
            RES.end('Other mode' ) 
        } 
    }). The listen ( 3000)

 

 

Express default frame body-parser parses the request body as middleware, can be found after the creation of the Express project in app.js file

/* 引入依赖项 */
var express = require('express');
// ……
var bodyParser = require('body-parser');

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

// ……

// 解析 application/json
app.use(bodyParser.json()); 
// 解析 application/x-www-form-urlencoded
app.use(bodyParser.urlencoded());

 

This allows the application program level, the introduction of the body-parser module to process the request thereof. In the above code, the processing module application / x-www-form-urlencoded, application / json request body two formats.

After this intermediate, you can access request parameters in all routing processor req.body

In a real project, the different paths may require the user to use different types of content , body-parser also express support for individual routing addition request parsing thereof, such as

Express the require = var ( 'Express' ); 
var bodyParser = the require ( 'body-Parser' ); 

var App = new new Express (); 

// Create application / json parsing 
var jsonParser = bodyParser.json (); 

// Create application / X-WWW-form-urlencoded 
var urlencodedParser = bodyParser.urlencoded ({Extended: to false }); 

// Get URL-encoded POST / login request body 
app.post ( '/ Login' , urlencodedParser, function (REQ, RES ) {
     IF (req.body)! return res.sendStatus (400 ); 
    res.send ( 'available for purchase,' + req.body.username); 
}) 

//POST / api / users acquired JSON-encoded request body 
app.post ( '/ API / Users' , jsonParser, function (REQ, RES) {
     IF (req.body)! Return res.sendStatus (400 );
     // Create User req.body in 
})

 

 

 

<< request type specifies >>
body-Parser supports the specification of one or analytically for a certain type of content type of the request body, means the timing can be modified by adding a type parameter specifies the Content-Type analytically in the analysis method.
For example, for text / plain content type using JSON parsing

app.use(bodyParser.json({type: 'text/plain'}))

 

This option is more resolved in a non-standard request header

// parse JSON custom 
app.use (bodyParser.json ({type: 'file application / JSON * +' })) 

// parsing custom Buffer 
app.use (bodyParser.raw ({type: 'file application / VND type-.custom ' })) 

// the request body as HTML string processing 
app.use (bodyParser.text ({type:' text / html '}))

 

 

<< body-parser module API >>

When the body resolve the request, the analytical value is placed req.body properties, when the time is empty, an empty subject} {
 --- bodyParser.json () - Parsing JSON format
 --- bodyParser.raw ( ) - parsing binary format
 --- bodyParser.text () - parse text format
 --- bodyParser.urlencoded () - parse text format

 

Source: https: //www.jianshu.com/p/cd3de110b4b6