Examples using Node.js
Contents:
Example 1: Always serving the same simple page
Example 2: Loading requests from disk
Example 3: Forum using file storage
Example 4: Forum posting via JavaScript
Example 5: Forum using database storage
Example 1: Always serving the same simple page
var http = require('http');
var url = require('url');
function processRequest(request, response) {
"use strict";
var pathname = url.parse(request.url).pathname;
console.log('Requested ' + pathname);
response.writeHead(200, { 'Content-Type': 'text/html' });
response.write('<!DOCTYPE html><html lang="en"><head>');
response.write('<meta charset="utf-8">');
response.write('<title>' + pathname + '</title>');
response.write('</head><body>');
response.write('<h1><tt>' + pathname + '</tt></h1>');
response.write('</body></html>');
response.end();
}
http.createServer(processRequest).listen(8888);
Example 2: Loading requests from disk
var http = require('http');
var url = require('url');
var path = require('path');
var fs = require('fs');
var mimeTypes = {'html': 'text/html', 'png': 'image/png',
'js': 'text/javascript', 'css': 'text/css'};
function processRequest(request, response) {
"use strict";
var uri, filename;
uri = url.parse(request.url).pathname;
filename = path.join(process.cwd(), uri);
// SECURITY HOLE: Check for invalid characters in filename.
// SECURITY HOLE: Check that this accesses file in CWD's hierarchy.
path.exists(filename, function (exists) {
var extension, mimeType, fileStream;
if (exists) {
extension = path.extname(filename).substr(1);
mimeType = mimeTypes[extension] || 'application/octet-stream';
response.writeHead(200, {'Content-Type': mimeType});
console.log('serving ' + filename + ' as ' + mimeType);
fileStream = fs.createReadStream(filename);
fileStream.pipe(response);
} else {
console.log('not exists: ' + filename);
response.writeHead(404, {'Content-Type': 'text/plain'});
response.write('404 Not Found\n');
response.end();
}
}); //end path.exists
}
http.createServer(processRequest).listen(8888);
Example 3: Forum using file storage
forum-base.html
<!DOCTYPE html>
<html lang="en"><head>
<meta charset="utf-8">
<title>Forum Example</title>
</head><body>
<h1>Forum Example</h1>
<div id="oldposts"></div>
<h2>Post a New Message</h2>
<form action="addnew" method="post">
Name: <input name="name"></input><br />
<textarea name="message"></textarea><br />
<button type="submit">Post Message</button>
</form>
<script src="jquery-1.7.1.js"></script>
<script src="forum-client.js"></script>
</body></html>
forum-client.js
function fetchPosts() {
"use strict";
$.ajax({ url: 'fetch', dataType: 'json',
error: function (jqxhr, textStatus, errorThrown) {
console.log('error', textStatus, '//', errorThrown);
},
success: function (json) {
var oldposts;
oldposts = $('#oldposts');
$.each(json.posts, function (i, post) {
var add;
add = $('<div class="post"></div>');
// SECURITY HOLE: Avoid posting raw HTML from record
add.html('<b>User:</b> ' + post.name + '<br />\n'
+ '<div class="message">' + post.message + '</div>');
oldposts.append(add);
});
}});
}
$(document).ready(fetchPosts);
posts.json
{ "name": "Bugs Bunny", "message": "What's up, doc?" }
,{ "name": "Elmer Fudd", "message": "I'm hunting wabbits!" }
,{ "name": "Bugs Bunny", "message": "What do you mean, a wabbit?" }
,{ "name": "Elmer Fudd", "message": "You know, with big wong ears, and a wittle white fwuffy tail, and he hops awound and awound!" }
,{ "name": "Bugs Bunny", "message": "Listen, Doc. Confidentially, I AM A WABBIT!" }
forum-file-server.js
var http = require('http');
var url = require('url');
var path = require('path');
var fs = require('fs');
var querystring = require('querystring');
var mimeTypes = {'html': 'text/html', 'png': 'image/png',
'js': 'text/javascript', 'css': 'text/css'};
function serveFromDisk(filename, response) {
"use strict";
var pathname;
pathname = path.join(process.cwd(), filename);
// SECURITY HOLE: Check for invalid characters in filename.
// SECURITY HOLE: Check that this accesses file in CWD's hierarchy.
path.exists(pathname, function (exists) {
var extension, mimeType, fileStream;
if (exists) {
extension = path.extname(pathname).substr(1);
mimeType = mimeTypes[extension] || 'application/octet-stream';
response.writeHead(200, {'Content-Type': mimeType});
console.log('serving ' + filename + ' as ' + mimeType);
fileStream = fs.createReadStream(pathname);
fileStream.pipe(response);
} else {
console.log('does not exist: ' + pathname);
response.writeHead(404, {'Content-Type': 'text/plain'});
response.write('404 Not Found\n');
response.end();
}
}); //end path.exists
}
function fetchMessages(response) {
"use strict";
var pathname, fileStream;
console.log('doing fetch');
pathname = path.join(process.cwd(), 'posts.json');
response.writeHead(200, {'Content-Type': 'application/json'});
response.write('{ "posts": [');
fileStream = fs.createReadStream(pathname);
fileStream.addListener('data', function (chunk) {
response.write(chunk, 'binary');
});
fileStream.addListener('close', function () {
response.write('] }');
response.end();
});
}
function addNewMessage(request, response) {
"use strict";
var postText;
postText = '';
console.log('doing add');
request.setEncoding('utf8');
request.addListener('data', function (postDataChunk) {
postText += postDataChunk;
});
request.addListener('end', function () {
var postData, pathname, fileStream;
postData = querystring.parse(postText);
pathname = path.join(process.cwd(), 'posts.json');
fileStream = fs.createWriteStream(pathname, { flags: 'a' });
// SECURITY HOLE: confirm name and message are reasonably short
// SECURITY HOLE: escape quotes and special chars
fileStream.write(',{ "name": "' + postData.name
+ '", "message": "' + postData.message + '" }\n');
fileStream.end();
serveFromDisk('forum-base.html', response);
});
}
function processRequest(request, response) {
"use strict";
var uri;
uri = url.parse(request.url).pathname;
if (uri === '/fetch') {
fetchMessages(response);
} else if (uri === '/addnew') {
addNewMessage(request, response);
} else if (uri === '/') {
serveFromDisk('forum-base.html', response);
} else {
serveFromDisk(uri, response);
}
}
http.createServer(processRequest).listen(8888);
Example 4: Forum posting via JavaScript
Modify the form element in
forum-base.html file to the following:
<form id="addnew">
Name: <input id="name"></input><br />
<textarea id="message"></textarea><br />
<button type="submit">Post Message</button>
</form>
And modify final line of forum-client.js to the following:
$(document).ready(function () {
fetchPosts();
$('#addnew').submit(function () {
$.ajax({ url: 'addnew', type: 'post', dataType: 'json',
data: { name: $('#name').val(), message: $('#message').val() },
error: function (jqxhr, textStatus, errorThrown) {
console.log('error', textStatus, '//', errorThrown);
},
success: function (json) {
fetchPosts();
}});
});
});
Example 5: Forum using database storage
forum-db-init.js
var sqlite3 = require('sqlite3');
var db = new sqlite3.Database('posts.db');
var data = [
["Bugs Bunny", "What's up, doc?"],
["Elmer Fudd", "I'm hunting wabbits!"],
["Bugs Bunny", "What do you mean, a wabbit?"],
["Elmer Fudd", "You know, with big wong ears, and a wittle white fwuffy tail, and he hops awound and awound!"],
["Bugs Bunny", "Listen, Doc. Confidentially, I AM A WABBIT!"]
];
db.run("CREATE TABLE posts ( name TEXT, message TEXT )", function () {
"use strict";
var insStmt, i;
insStmt = db.prepare('INSERT INTO posts (name, message) VALUES (?, ?)');
for (i = 0; i < data.length; i += 1) {
insStmt.run(data[i]);
}
insStmt.finalize();
});
forum-db-server.js
var http = require('http');
var url = require('url');
var path = require('path');
var fs = require('fs');
var querystring = require('querystring');
var sqlite3 = require('sqlite3');
var db = new sqlite3.Database('posts.db');
var dbSelectStmt = db.prepare('SELECT name, message FROM posts');
var dbInsertStmt = db.prepare('INSERT INTO posts (name, message) VALUES (?, ?)');
var mimeTypes = {'html': 'text/html', 'png': 'image/png',
'js': 'text/javascript', 'css': 'text/css'};
function serveFromDisk(filename, response) {
"use strict";
var pathname;
pathname = path.join(process.cwd(), filename);
// SECURITY HOLE: Check for invalid characters in filename.
// SECURITY HOLE: Check that this accesses file in CWD's hierarchy.
path.exists(pathname, function (exists) {
var extension, mimeType, fileStream;
if (exists) {
extension = path.extname(pathname).substr(1);
mimeType = mimeTypes[extension] || 'application/octet-stream';
response.writeHead(200, {'Content-Type': mimeType});
console.log('serving ' + filename + ' as ' + mimeType);
fileStream = fs.createReadStream(pathname);
fileStream.pipe(response);
} else {
console.log('does not exist: ' + pathname);
response.writeHead(404, {'Content-Type': 'text/plain'});
response.write('404 Not Found\n');
response.end();
}
}); //end path.exists
}
function fetchMessages(response) {
"use strict";
var jsonData;
console.log('doing fetch');
response.writeHead(200, {'Content-Type': 'application/json'});
jsonData = { posts: [] };
dbSelectStmt.each(function (err, row) {
jsonData.posts.push({ name: row.name, message: row.message });
}, function () {
response.write(JSON.stringify(jsonData));
response.end();
});
}
function addNewMessage(request, response) {
"use strict";
var postText = '';
console.log('doing add');
request.setEncoding('utf8');
request.addListener('data', function (postDataChunk) {
postText += postDataChunk;
});
request.addListener('end', function () {
// SECURITY HOLE: confirm name and message are reasonably short
var postData = querystring.parse(postText);
dbInsertStmt.run(postData.name, postData.message, function () {
serveFromDisk('forum-base.html', response);
});
});
}
function processRequest(request, response) {
"use strict";
var uri;
uri = url.parse(request.url).pathname;
if (uri === '/fetch') {
fetchMessages(response);
} else if (uri === '/addnew') {
addNewMessage(request, response);
} else if (uri === '/') {
serveFromDisk('forum-base.html', response);
} else {
serveFromDisk(uri, response);
}
}
http.createServer(processRequest).listen(8888);
console.log('started');