What are the built-in modules of nodejs?

first, the Express framework

has been introduced in the previous chapters, and you can use npm to install the node.js module. Please refer to the previous introduction to nodejs for specific operations.

Express is a web open source framework of nodejs, which is used to build web projects quickly. It mainly integrates the odejs.org/topic/5a1fcc7637ffa4155b5a264

V of the web, and the request module

The request module provides a simple way for developers to access HTTP requests. Request also supports the access method of HTTPS.

installation:

NPM install requset

the request module basically covers all HTTP request methods such as GET, POST, HEAD, DEL, etc. But the two basic methods are request.get () and request. post ().

The difference between get and post

get:

1. Requests sent and received to the server by using get will be attached to the url. Similar:? id=1221& Name=5555 Two parameters are passed in this url, one is id and the other is name.

2. the get request cannot exceed 124 bytes.

post has no restrictions and will not be attached to the url.

Next, make a simple example

get example:

First, create a new server app _ get.js

var http = require ("http");

http.createServer(function(req,res){

res.writeHead(2,{'content-Type':'text/plain'});

res.end('Hello world\n'+req.method);

}).listen(1337,"127...1");

create another request_get.js file for sending intercession

var request=require('request');

request.get("http://127...1:1337",function(error,response,result){

console.log(result);

});

run app_get.js in CMD. After running successfully, open another cmd (don't close the previous cmd) and execute the request_get.js file.

the result after execution is as follows

hello world

GET

As you can see, the result returned by accessing

http://127...1:1337 through the request.get method is the parameter

post instance of res.end ():

Same as above, Create a new server app _ post.js

var http = require ("http"),

querystring = require ('querystring');

http.createServer(function(req,res){ var postData=""; //start receiving the data of the client post asynchronously

req.addlistener ("data", function (post data chunk) {

post data+= post data chunk;

}); //after receiving asynchronous post data, execute anonymous callback function

req.addlistener ("end", function () {var poststr = JSON.stringify (querystring.parse (post data));

res.writeHead(2,{'content-Type':'text/plain'});

res.end(postStr+'\n'+req.method);

});

}).listen(14,"127...1");

then create a new request _ post.js

var request = require ("request");

request.post('http://127...1:14',{form:{'name':'ermu','book':'node.js'}},function (error,response,result) {

console.log(result);

})

The results displayed after executing in cmd as above are as follows:

D:\nodejs\src\request> Node request _ POST.js

{"name": "ermu", "book": "node.js"}

post

request post submitted a json object {"name": "ermu", "book": "node.js"} and the server then obtained the post data.

the requestpost parameter can be passed in two ways.

among them, the first one is to pass the data of url and form as json parameters in request post. Examples are as follows:

request.post ('URL':' http://127...1: 14', form: {'name':' ermu',' book':' node.js'}}, function (error, response, result).

})

The other is to take url and form as two parameters, which is the method used in the above example.

6.? Formidable module

The purpose of this module is to solve the problem of file uploading.

in the native node.js module, the method of obtaining post data is provided, but the uploaded file is not directly obtained.