Nodejs Basic Applications

This article mainly introduces the basic application of nodejs. It has good reference value. Let's take a look at the first nodejs Application below.

N1_hello.js

Console. log ('Hello word! ');

Execute the file in command line cmd (Open command line in the file ):

Node nw.hello.js

The command line cmd returns the result:

Hello word!

Ii. Basic nodejs format

// Step 1: Introduce the require module and load the require command into the http module var http = require ('http'); // Step 2: Create the Server http. createServer (function (request, response) {// send HTTP header // HTTP status value: 200: OK // content type: text/html response. writeHead (200, {'content-type': 'text/html; chaset = UTF-8; '}); // Step 3: accept the request and Response request if (request. url! = '/Favicon. ico '){...... // send response data response. end (''); // required. If not, there is no protocol end }}). listen (8000); // The terminal prints the following information: console. log ('server running at http: // 127.0.0.1: 8000 /');

3. Call functions in nodejs

----------------- Call a local function -----------------------------

Var http = require ('http'); http. createServer (function (request, response) {response. writeHead (200, {'content-type': 'text/html; chaset = UTF-8; '}); if (request. url! = '/Favicon. ico ') {fun1 (response); // send response data response. end ('');}}). listen (8000); // The terminal prints the following information: console. log ('server running at http: // 127.0.0.1: 8000/'); function fun1 (res) {console. log ('fun1'); res. write ('Hello, I am fun1 ');}

----------------- Call an external function -----------------------------

Note: external functions must be written in module. exports. exports is an interface exposed by the module.

------------ (1) only calls one function -----------

In the main program:

Var http = require ('http'); var otherfun = require (". /models/otherfuns. js "); // call the fun2http of the external page. createServer (function (request, response) {response. writeHead (200, {'content-type': 'text/html; chaset = UTF-8; '}); if (request. url! = '/Favicon. ico ') {otherfun (response); // response when a function is supported. end ('');}}). listen (8000); // The terminal prints the following information: console. log ('server running at http: // 127.0.0.1: 8000 /');

Otherfuns. js

Function fun2 (res) {console. log ('fun2'); res. write ('Hello !, I'm fun2');} module. exports = fun2; // only one function is supported.

------------ (2) call multiple functions -----------

In the main program:

Var http = require ('http'); var otherfun = require (". /models/otherfuns. js "); // call the otherfuns external page of The Write function. jshttp. createServer (function (request, response) {response. writeHead (200, {'content-type': 'text/html; chaset = UTF-8; '}); if (request. url! = '/Favicon. ico ') {// todo object. the method name calls otherfun. fun2 (response); otherfun. fun3 (response); // todo calls the corresponding function as a string (the result is the same as above) // otherfun ['fun2'] (response ); // otherfun ['fun3'] (response); response. end ('');}}). listen (8000); // The terminal prints the following information: console. log ('server running at http: // 127.0.0.1: 8000 /');}

Otherfuns. js

Module. exports = {fun2: function (res) {// anonymous function console. log ('fun2'); res. write ('Hello !, I'm fun2'); // output on the page}, fun3: function (res) {console. log ('fun3'); res. write ('Hello !, I'm fun3 ');},......}

Iv. nodejs route preliminary

Main Program n4_rout.js:

Var http = require ('http'); // introduce the url module var url = require ('url'); http. createServer (function (request, response) {response. writeHead (200, {'content-type': 'text/html; chaset = UTF-8; '}); if (request. url! = '/Favicon. ico ') {var pathname = url. parse (request. url ). pathname; pathname = pathname. replace (//, ''); // replace the previous/console. log (pathname); response. end ('');}}). listen (8000); // The terminal prints the following information: console. log ('server running at http: // 127.0.0.1: 8000 /');

Run the file in command line cmd and enter the route address in access: http: // localhost: 8000/, for example, and observe the command line.

V. nodejs reading files

Main Program:

Var http = require ('http'); var optfile = require ('. /models/optfile '); // import the file http. createServer (function (request, response) {// send HTTP header // HTTP status value: 200: OK // content type: text/html response. writeHead (200, {'content-type': 'text/html; chaset = UTF-8; '}); if (request. url! = '/Favicon. ico ') {// clear 2nd accesses to the optfile. readfileSync ('. /views/login.html '); // synchronously calls the readfileSync () method to read files. // optfile. readfile ('. /views/login.html ', response); // calls the readfile () method response asynchronously. end ('OK !!!!! '); // Do not write the console. log ('the main program has been executed! ') ;}}). Listen (8000); // The terminal prints the following information: console. log ('server running at http: // 127.0.0.1: 8000 /');

In optfile. js:

Var fs = require ('fs'); // Node: class module for importing file system module (fs) syntax to fs operation file. exports = {readfileSync: function (path) {// synchronously read var data = fs. readFileSync (path, 'utf-8'); // read the path of the synchronization file in Chinese. log ("the synchronization method has been executed. ") ;}, Readfile: function (path) {// asynchronously reads fs. readFile (path, function (err, data) {if (err) {console. error (err);} else {console. log ("Asynchronous read:" + data. toString () ;}}); console. log ("Asynchronous Method execution is complete. ");},}

Result: In command line cmd

(1) Synchronous file reading:

The above is all the content of this article. I hope this article will help you in your study or work, and I also hope to support PHP!

For more articles about nodejs basic applications, refer to PHP!