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276 views · 4 months ago



To bridge the gap between web-based and cloud-based applications, businesses often rely on skilled DevOps developers. These professionals play a crucial role in ensuring seamless integration, efficient customization, and robust back-end infrastructure for applications. The expertise of DevOps developers is indispensable for optimizing development workflows and enhancing collaboration between development and operations teams in the dynamic landscape of app development services.

In the realm of cloud computing, web based application in cloud computing play a pivotal role. Technically, web apps, as the name suggests, are applications hosted on remote servers & accessible through web browsers. On the other hand, cloud-based apps are web applications that come with advanced functionalities & elaborate compatibility.


In the realm of contemporary software development, the demand for innovative solutions is evident in the competition between web and cloud-based applications. These two platforms share similarities but diverge significantly in crucial aspects. This article will delve into the distinctions between web-based and cloud-based applications, exploring facets such as back-end infrastructure, scalability, and technical perspectives, shedding light on the nuances that developers navigate in this dynamic landscape, including the pivotal role of technologies like chatbot development.
What Is a Web Application?

A web-based app is an application designed and developed for the web browser. Unlike cloud based application development, the web app completely depends on the web server for functionality & processing. This application program is mainly stored on the remote server & delivered through a web browser interface over the internet. According to web application development company, web apps have client-server architecture & their codes are divided into 2 major components – server-side architecture & client-side architecture.

Server-side architecture: The server-side architecture or script usually deals with data processing. The web server can process a client request & send a response back. This web app architecture defines a simultaneous interaction between database instances, components, user interfaces, middleware systems, and servers.

Client-side architecture: The client-side architecture mainly deals with interface functionalities such as drop-down boxes and buttons. When a user clicks on the link, the browser will start loading the client-side script & rendering a text and graphic element for interaction.
Types of Web Apps
Nowadays, many businesses are already adopting various kinds of web-based applications because of their several advantages, features, and functionalities. 8 most popular types of web apps include:
    . Static Web Apps
Static web applications, constructed using HTML, CSS, and JavaScript, lack the flexibility of dynamic counterparts. These web based services provide content directly to users without requiring server-side modifications, resulting in simplicity and straightforward development. Key benefits of these apps include:
Very fast load time
Highly secure
Less complex to build
    . Dynamic Web Apps
This is a complex type that provides real-time data based on the server response and the user’s request. Dynamic web apps can be developed either as a conventional website with several pages and levels of navigation or as a single-page web application. They use several server-side and client-side languages to create web pages such as HTML, CSS, JavaScript, Python, PHP, Ruby, etc. Key benefits of dynamic web apps include:
Wider audience reach
Scalable in comparison to static web apps
Very flexible in terms of a new content update
    . Single Page Apps
A single page web app entirely runs on the browser & never requires browser reloading. This is actually a dynamic web app that manages all data on a single HTML page. This type of web app is faster than traditional websites as its logic is implemented in the browser directly than a server. Gmail, Netflix, Pinterest & Paypal are the best examples of single page applications. Key benefits include:
Enhanced user experience
Minimized server load
Improved app performance
    . Multiple-Page Apps
Multiple page apps are designed multiple pages separately and combined to form a website. They have different pages with static information like texts & images. Web based app development companies recommend using multiple-page apps as they offer excellent control over search engine optimization techniques. Major benefits of Multiple page apps include:
Ideal for SEO
Quick browser back or forward navigation
Simple to develop
    . Animated Web Apps
This is a type of web application that effectively supports synchronization & animation on the web platform. These applications are widely used by freelancers and creative companies to present their creativity better. Technically, JavaScript, HTML5, FLASH, and CSS are used to create animated web applications. Key benefits of AWAs include
Improved User Engagement
Enhanced Navigation
Excellent Branding
    . Web Apps with CMS
In this web application, content is updated constantly. It helps to manage, modify and create digital content with ease. WordPress is one of the best examples of CMS web applications. A variety of languages are used to create content management systems such as C#, PHP, Java, and Python. Key advantages of CMS web apps include:
Quick content creation & management
Efficient & quick updates
A vast range of features
    . E-commerce Web Apps
It’s a complicated and advanced dynamic web application that allows users to buy & sell goods electronically. These web based services encompass transaction and payment integration as key components, facilitating seamless order processing, payment acceptance, and logistical management for businesses involved in online commerce. Key benefits of these web apps include:
Scale business quickly
Offers customer insights through tracking & analytics
Sell goods across the world
    . Progressive Web Apps
Progressive web apps or PWAs are also called cross-platform web apps usually built with HTML, CSS, & JavaScript. PWAs use different features, APIs, and progressive methods to deliver a seamless experience. Progressive web apps boost the adaptability and speed of web applications. These apps are still easy to access if internet connectivity is poor. Key benefits of progressive web apps include:
Fast loading time
No installation required
Quickly respond to user interactions
Enhanced cross-platform conversion

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Type
Widely Used In
Advantages
Dynamic web apps
Social media
Healthcare
IT Industry
Logistics and transportations
Retail and ecommerce sectors
On-demand
Directly manage websites to update & change the information
Quick user management to protect servers & control all website users
Static web apps
Book publishing sectors
Works in offline mode
No 3rd party software installation required to access web apps
Single page apps
Email service
Communication sectors
Allows navigation & optimized routing experience
Keeps visual structure of web apps consistently through presentation logic
Multiple page apps
E-commerce sectors
Enterprise industries
Enables optimizing every page for the search engine
Allows users to access other pages
Animated web apps
Animation
Education
Gaming industries
Hold user attention for a very long time due to its attractive approach & unique design
Aspect ratios, landscape orientations, portrait, and viewing distances & different pixel densities are considered
Web apps with CMS
Blogging platforms
Sales & marketing platform
News portals
Easily organizes the web content Offers group & user functionality
Simple language support & integration
E-commerce web apps
E-commerce sectors
Allows sellers to sell products using a single platform
Helps you expand business globally & reach maximum audience
Progressive Web Apps
On-demand
Healthcare
Retail and e-commerce
Logistics and transportations
Social media
IT sectors
Responsive & Browser Compatibility Works in online & offline mode
Updates with no user interaction

Key Benefits of Web Apps
Web apps enable businesses to interact with their customers more efficiently. These applications can make it easy to track & measure data that are essential to keep business operations streamlined. Key advantages of web apps include:
Easily accessible through any kind of web browser
Runs on multiple platforms that make it cross-platform compatible
Minimizes the risk of compatibility issues
Requires less maintenance & support from the developer’s end
Helps to ease usability for the customers
Effectively eliminates hard drive space limitations
Apps can be maintained & updated without software reinstallation on several devices
Offers high scalability and flexibility
Simple to deploy, maintain, and update
The cost of routine maintenance is minimized as the data is stored on remote servers
What is a Cloud Based App?
These apps are online software programs with elements accessible via a local server and executed on the cloud environment. As internet-based software, cloud applications are stored in the remote data center & handled by cloud-service providers. These apps are used for file sharing & storage, order entry, word processing, inventory management, financial accounting, customer relationship management, data collection, etc.

According to the report, the global market size of cloud apps is projected to reach approx 168.6 billion USD by 2025. Cloud apps usually support several user requirements through customization and provide several services to meet storage, backup & security needs. Some major characteristics of cloud apps include:
Agile application
Microservices-oriented
API-backed
Continuously integrated & delivered
DevOps-enabled
Analytics-infused
User experience-centric
Types of Cloud-based Applications
Cloud apps are divided into three major cloud computing models – SaaS, PaaS, and IaaS. Each model also shows several parts of cloud computing stacks. Take a closer look at these types:
    . SaaS or Software as a Service
SaaS is one of the best cloud apps that enable users to easily access full-functioning software applications over the internet. These cloud applications are primarily designed for freelance services, large enterprises & SMBs. Some of the best examples of SaaS applications are HubSpot CRM, Wrike, MS Office 365, Sisense, Wix, etc.
    . PaaS or Platform as a Service
PaaS provides users with the infrastructure, computing platforms, and solutions to build their own applications. Platform as a Service is ideal for businesses that mainly engage in collaboration, testing, and development of cloud solutions. PaaS applications have a deployment environment including run-time system libraries, operating systems, and graphic UI. Some of the best examples of PaaS apps are Google App Engine, Microsoft Azure, Rackspace Cloud Sites, etc.
    . IaaS or Infrastructure as a Service
IaaS consists of basic building blocks that offer access to networking functionalities, features & data storage space. It enables users to outsource IT infrastructures like servers, processing, virtual machines, storage, networking & other resources. IaaS applications also offer a good level of management control and flexibility over IT resources. Some of the best examples of IaaS apps are Amazon WorkSpaces, IBM Cloud, Google Cloud, etc.
Benefits of Cloud Apps
Web based application in cloud computing boost productivity, accessibility, security, and data safety. They help businesses make the process of collaboration more effective and easier. Key benefits of cloud applications include:
Minimal service provider interaction & management effort
Provides large computing capabilities, online & offline
Provides access to information from any device or place
Offers fast access to important applications through cloud servers
The performance of the availability of cloud apps enhances profitability & streamlines workflows
Serves multiple consumers with virtual and physical needs
Provides high transparency to resource providers & consumers
Offers improved collaboration options
Web Apps Vs Cloud Apps – Key Differences
Web apps and cloud apps both come with a wide range of functionalities & have noticeable distinctions. Web-based applications usually are accessible via web browsers, whereas cloud app’s infrastructure and data aren’t only accessible through the web browser but also downloadable. So, all cloud apps are web apps with additional features. Other differences between web and cloud apps are listed below.

Parameters
Cloud apps
Web apps
Internet
Work partially or entirely without the internet connectivity
Work with the internet only
Security
Ensures high security measures for sensitive & confidential information
It can verify client info on authentic servers
Technology
It needs a back–end framework & a JavaScript-based structure like React Js, Angular, etc
It has inbuilt languages such as PHP, Python & Ruby, and databases like MySQL.
Access
It’s not dependent on the web browser
Accessed via the web browser only
Customization
Customization features improve functionalities.
Never provides customization and similar functionalities
Costs
Expensive as compared to web apps
Development cost is less than cloud apps
Types
SaaS, PaaS, IaaS, RaaS
Static web apps, dynamic web apps portal web apps, etc
Scalability
Inherently scalable
Limited scalability
Availability
High uptime
Limited uptime
Storage
Multiple replicated center
Single data center

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Final Words
Web apps and cloud apps both are continuing to deliver users as the most crucial touch point. Since they are packed with similarities and dissimilarities in terms of software architecture, storage, and other aspects, selecting the right application always depends on customer preferences, business needs, and operations. Are you planning to build a custom web application or looking for web app development services? Get in touch with our experts for complete assistance.

5783 views · 2 years ago
A Beginners Guide To Artificial Intelligence For Web Developers

Artificial Intelligence has significantly transformed the way we work and interpret information. With technologies such as OCR, machine learning, deep learning, natural language processing, and computer vision; machines are now able to provide greater insights and perform tasks that typically required hours and hours of work from humans.

What is artificial intelligence?


A.I. or artificial intelligence is the technology that enables machines to perform tasks that usually require human intelligence. But instead of using human brains, A.I. uses different technologies such as computers, or even software algorithms, to perform tasks. Some of the most common A.I. technologies include speech recognition, voice recognition, machine translation, natural language processing, computer vision, and predictive analytics. The term artificial intelligence comes from the combination of artificial and intelligence. While artificial intelligence is a property of the physical world, intelligence is the property of the mind. How does it make sense in Web Development? As mentioned earlier, A.I. has significantly transformed the way we work and interpret information.

How is AI applied to web development?


In the majority of cases, AI is used to assist a developer in a number of functions: Automatically format existing content, analyze images for semantic meaning Break down complex tasks into smaller pieces Example applications of AI in web development Example image compression algorithms. Tools such as image recognition and machine learning have been key factors in the development of new image processing algorithms. Traditionally, manually processing an image was a lengthy and tedious process, but when computer vision was introduced into the process it drastically decreased the amount of time required to complete this task. Now, programs such as image recognition can identify objects in images and classify them based on both visual and metadata attributes.

Machine learning


When data is fed into a machine learning algorithm, the machine learns to understand it. For instance, if you provide a machine learning algorithm examples of dogs verses blueberries, the machine will learn to identify what a picture of a blueberry looks like, verses a picture of a dog. Natural Language Processing Natural language processing is a sub-field of machine learning. You can apply natural language processing for reading emails, chatting, or writing blog posts (such as this one!). A good example of natural language processing in action can be found in Microsoft's Cortana. Deep learning This is the most popular type of artificial intelligence today.

Deep learning


Deep learning algorithms are very similar to how the human brain works, with its built in mechanisms to learn and memorise a vast amount of information. It's these connections that enable machines to be able to recognise patterns and learn from them. An example of this is Google Translate, which recognises more than a 1,000 languages. This isn't an example of AI but it shows how useful these programs can be. Deep learning is one of the hottest technologies in the field of machine learning and this explains why almost all of the major technology companies are pushing these advances forward.

Natural language processing


For example, your phone can understand you better when you speak to it. If you say “Hey, Siri,” your phone will listen to you and respond to your questions. In general, it means that the system has been trained and is able to better understand the context of what you’re trying to communicate. This type of Natural Language Processing is used in the majority of companies today, including the likes of Google and Apple, to improve the user experience, provide better customer service, and to aid in the effective execution of processes. Machine learning Machine Learning is an extremely powerful technique used to further improve the knowledge of artificial intelligence, as well as to make machines smarter by discovering patterns and generalities in vast amounts of data.

Computer vision


Computer vision is a technology that has been able to recognize objects in images and video for eons. A popular example is Apple's Siri, which was one of the first software to use computer vision to provide contextual awareness. AI is built on this technology, providing the capability to recognize various images and videos. The industry is still in its infancy, but what we have seen so far has been incredibly incredible. What's amazing is that just a few years ago we thought that vision was completely under our control, but now, it has evolved to understand the nuances of objects.

Conclusion

“In the year 2050, the Amazon book you ordered for your Kindle will be delivered by a drone.”

This futuristic statement by Amazon CEO Jeff Bezos did leave you pondering. But it is one thing to dream about the future and another thing to think about the innovations taking place in the present and how you can exploit them to drive better business results. To make the most of the technologies coming to our everyday lives, we must acquire a knowledge of the AI technology, its features, and its application. Succeeding in today’s competitive and challenging business world, requires a broad set of skills such as coding, business analysis, computer programming, and ecommerce marketing.

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6078 views · 3 years ago
Web Sockets in PHP

In his talk Websockets in PHP, John Fransler walks us through the use of WebSockets in PHP.

While discussing bi-directional real-time application development, John notes that PHP is often not invited to the table due to its lack of native support. Of all the possible attempts to bring in PHP on this stage of real-time development, Ratchet, a PHP WebSocket library, comes closest. "Ratchet is a loosely coupled PHP library providing developers with tools to create real-time, bi-directional applications between clients and servers over WebSockets."* Ahem!

Today's dynamic world


In today's dynamic content world of the internet, it is required to serve real-time bi-directional messages between clients and servers. WebSockets are simple, full-duplex, and persistent. They work over Http and are a standard today.

WebSockets have compatibility with 96.5% of clients globally

There's a very high chance your client has the necessary plumbing to access your content via WebSockets. WebSockets gives the ability to have real-time data on to your clients without the need for polling.

To understand WebSockets, John takes an example of a Javascript client and Ratchet Server. Javascript has everything built in to allow access to a socket. For example, you can use the send method on a WebSocket variable to send a message to the server, or if you want to respond to a message from the server, you use the OnConnection method.

While on the Server, John uses Ratchet, which is built on React PHP. A server script is then configured and set up to run and listen on a port for incoming HTTP requests. For messages, JSON is used, and to find public methods, a router is set up. He then goes on to instantiate the server-side script in Ratchet.

There are four functions of a Ratchets message component interface that are used in this example:

OnOpen gets called when a new connection is made.

OnClose gets called when a client quits. It's essential to keep an eye on memory management, and essential to keep tidying up as you move through the code.

OnError gets called when there is an exception faced by the user.

OnMessage gives the text of the JSON message, which is being exchanged with the client.

For Initialization, Jason continues to walk through the example. He shows how one can loop through the clients, both inside the server and outside the server. Outside the server, it’s a feature of React PHP. On database access, and with traditional standard synchronous MySQL in PHP, what usually happens is that it forces the code to wait for the query to return a result and do nothing — Fortunately, with Asynchronous MySQLi, that is not the case.

John gets into the details explaining Variables, References & Pointers. He also gives a demo where a central site has updated information on the Bitcoin and ether prices. A client terminal reflects the last values. Now the client doesn't have to poll the server for new values. When there is a change in the Bitcoin or ether values, the server pushes down the client's update. No polling helps with a lot of overheads and gets closer to real-time.

Using Supervisord


For Long-running applications - Jason recommends running a supervisord, use proxy to expose the port, and add a site certificate. Supervisord keeps an eye out for the server running the service; it can be used to restart the service and log any service issues. Recommended proxies are AWS load balancer, Nginx, and HA Proxy. For scalability, use multiple smaller WebSocket servers and a smaller number of clients per server used and load balancing. If one has to support a chat feature to allow clients to talk to each other in near real-time, it is recommended to use Redis. The Redis server proxies the messages between the server nodes.

The talk concludes with John summarizing best practices on error handling and takes QnA on various aspects of WebSockets such as handling load balancers and asynchronous calls to MSQLi.

The presentation for this video, along with the code, is hosted at John Curt's GitHub. More info about John's current areas of interest can be found on John's Blog.

Watch the video now


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24622 views · 4 years ago
PHP CHAT WITH SOCKETS

Hey Friends,

I am sharing a very interesting blog on how to create a chat system in php without using ajax. As we all know ajax based chat system in php is not a good solution
because itincreases the server load and redundant xhr calls on our server.

Instead, I am going to use sockets for incoming messages from and send messages to another user. So lets try them out using the following steps:


Step 1: Cross check in php.ini that sockets extension is enabled


;extension=sockets
extension=sockets


Step 2: Create server.php file


This file will handle the incoming and outgoing messages on sockets, Add following variables in top of the file:

$host = 'localhost';
$port = '9000';
$null = NULL; 


Step 3: After it add helper methods


The following code for handshake with new incoming connections and encrypt and decrypt messages incoming and outgoing over sockets:

function send_message($msg)
{
global $clients;
foreach($clients as $changed_socket)
{
@socket_write($changed_socket,$msg,strlen($msg));
}
return true;
}
function unmask($text) {
$length = ord($text[1]) & 127;
if($length == 126) {
$masks = substr($text, 4, 4);
$data = substr($text, 8);
}
elseif($length == 127) {
$masks = substr($text, 10, 4);
$data = substr($text, 14);
}
else {
$masks = substr($text, 2, 4);
$data = substr($text, 6);
}
$text = "";
for ($i = 0; $i < strlen($data); ++$i) {
$text .= $data[$i] ^ $masks[$i%4];
}
return $text;
}
function mask($text)
{
$b1 = 0x80 | (0x1 & 0x0f);
$length = strlen($text);

if($length <= 125)
$header = pack('CC', $b1, $length);
elseif($length > 125 && $length < 65536)
$header = pack('CCn', $b1, 126, $length);
elseif($length >= 65536)
$header = pack('CCNN', $b1, 127, $length);
return $header.$text;
}
function perform_handshaking($receved_header,$client_conn, $host, $port)
{
$headers = array();
$lines = preg_split("/

/", $receved_header);
foreach($lines as $line)
{
$line = chop($line);
if(preg_match('/\A(\S+): (.*)\z/', $line, $matches))
{
$headers[$matches[1]] = $matches[2];
}
}
$secKey = $headers['Sec-WebSocket-Key'];
$secAccept = base64_encode(pack('H*', sha1($secKey . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')));
$upgrade = "HTTP/1.1 101 Web Socket Protocol Handshake

" .
"Upgrade: websocket

" .
"Connection: Upgrade

" .
"WebSocket-Origin: $host

" .
"WebSocket-Location: ws://$host:$port/php-ws/chat-daemon.php

".
"Sec-WebSocket-Accept:$secAccept



";
socket_write($client_conn,$upgrade,strlen($upgrade));
}


Step 4: Now add following code to create bind and listen tcp/ip sockets:


$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1);
socket_bind($socket, 0, $port);
socket_listen($socket);
$clients = array($socket);


Ok now a endless loop that will use for handeling incominga nd send messages:

while (true) {
$changed = $clients;
socket_select($changed, $null, $null, 0, 10);

if (in_array($socket, $changed)) {
$socket_new = socket_accept($socket); $clients[] = $socket_new;
$header = socket_read($socket_new, 1024); perform_handshaking($header, $socket_new, $host, $port);
socket_getpeername($socket_new, $ip); $response = mask(json_encode(array('type'=>'system', 'message'=>$ip.' connected'))); send_message($response);
$found_socket = array_search($socket, $changed);
unset($changed[$found_socket]);
}

foreach ($changed as $changed_socket) {

while(socket_recv($changed_socket, $buf, 1024, 0) >= 1)
{
$received_text = unmask($buf); $tst_msg = json_decode($received_text, true); $user_name = $tst_msg['name']; $user_message = $tst_msg['message']; $user_color = $tst_msg['color'];
$response_text = mask(json_encode(array('type'=>'usermsg', 'name'=>$user_name, 'message'=>$user_message, 'color'=>$user_color)));
send_message($response_text); break 2; }

$buf = @socket_read($changed_socket, 1024, PHP_NORMAL_READ);
if ($buf === false) { $found_socket = array_search($changed_socket, $clients);
socket_getpeername($changed_socket, $ip);
unset($clients[$found_socket]);

$response = mask(json_encode(array('type'=>'system', 'message'=>$ip.' disconnected')));
send_message($response);
}
}
}
socket_close($socket);


So you are ready with server side socket program, Now its time to move on front side where we will implement w3c provided client side Web Socket Apis,

Step 5: create a file named index.php for frontend usage with following initial code


$host = 'localhost';
$port = '9000';
$subfolder = "php_ws/";
$colors = array('#007AFF','#FF7000','#FF7000','#15E25F','#CFC700','#CFC700','#CF1100','#CF00BE','#F00');
$color_pick = array_rand($colors);
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<div class="chat-wrapper">
<div id="message-box"></div>
<div class="user-panel">
<input type="text" name="name" id="name" placeholder="Your Name" maxlength="15" />
<input type="text" name="message" id="message" placeholder="Type your message here..." maxlength="100" />
<button id="send-message">Send</button>
</div>
</div>
</body>
</html>


Now add some basic styling in the head section using following code:

<style type="text/css">
.chat-wrapper {
font: bold 11px/normal 'lucida grande', tahoma, verdana, arial, sans-serif;
background: #00a6bb;
padding: 20px;
margin: 20px auto;
box-shadow: 2px 2px 2px 0px #00000017;
max-width:700px;
min-width:500px;
}
#message-box {
width: 97%;
display: inline-block;
height: 300px;
background: #fff;
box-shadow: inset 0px 0px 2px #00000017;
overflow: auto;
padding: 10px;
}
.user-panel{
margin-top: 10px;
}
input[type=text]{
border: none;
padding: 5px 5px;
box-shadow: 2px 2px 2px #0000001c;
}
input[type=text]#name{
width:20%;
}
input[type=text]#message{
width:60%;
}
button#send-message {
border: none;
padding: 5px 15px;
background: #11e0fb;
box-shadow: 2px 2px 2px #0000001c;
}
</style>


Ok Style is all set now need to add a jquery script and create web socket object and handle all events on it as following code need to add before closing of bosy tag:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script language="javascript" type="text/javascript">
var msgBox = $('#message-box');
var wsUri = "ws://".$host.":".$port."/php-ws/server.php";
websocket = new WebSocket(wsUri);

websocket.onopen = function(ev) { msgBox.append('<div class="system_msg" style="color:#bbbbbb">Welcome to my "Chat box"!</div>'); }
websocket.onmessage = function(ev) {
var response = JSON.parse(ev.data);
var res_type = response.type; var user_message = response.message; var user_name = response.name; var user_color = response.color; switch(res_type){
case 'usermsg':
msgBox.append('<div><span class="user_name" style="color:' + user_color + '">' + user_name + '</span> : <span class="user_message">' + user_message + '</span></div>');
break;
case 'system':
msgBox.append('<div style="color:#bbbbbb">' + user_message + '</div>');
break;
}
msgBox[0].scrollTop = msgBox[0].scrollHeight; };

websocket.onerror = function(ev){ msgBox.append('<div class="system_error">Error Occurred - ' + ev.data + '</div>'); };
websocket.onclose = function(ev){ msgBox.append('<div class="system_msg">Connection Closed</div>'); };
$('#send-message').click(function(){
send_message();
});

$( "#message" ).on( "keydown", function( event ) {
if(event.which==13){
send_message();
}
});

function send_message(){
var message_input = $('#message'); var name_input = $('#name');
if(message_input.val() == ""){ alert("Enter your Name please!");
return;
}
if(message_input.val() == ""){ alert("Enter Some message Please!");
return;
}
var msg = {
message: message_input.val(),
name: name_input.val(),
color : '<?php echo $colors[$color_pick]; ?>'
};
websocket.send(JSON.stringify(msg));
message_input.val(''); }
</script>


Ok All set, Now need to run the server.php file using following php-cli utility,make sure you have php cli utility installed in your system:

php -q c:\xampp\htdocs\php-ws\server.php


Now you may access the front index.php file via the browser url like following and see a chatbox and connection status, you may use the same url or different browser to check the chat system is working or not.
8592 views · 5 years ago
Underclocking a Website

For those of you not familiar with the concept of underclocking: it's the opposite of overclocking, that is, you don't speed up CPU but instead slow it down..

What for?

Ask the underclockers, I'm totally not sure. Actually, hanging around the Web these days leaves a feeling that nearly every website out there must have been underclocked, but most of the time it's about tons of unnecessary images, megabytes of javascript (of which hardly a hundred kilobytes gets actually executed), and all that. In this post I will, however, tell you about a server-side approach to underclocking, with a help of our good old friend - the MySQL Database Server.

Today I had a nice chat in my client's development telegram channel. The two other devs, R** and V**, were making a switch of the old image API app to a new MySQL server. A couple of days before that, we have discussed a plan, it was as dumb as possible, just as I like it. Super-simple clear steps that a five-year-old can make. Switch to readonly mode (stop uploads), dump DB, restore the dump on the new server, update database connection details, turn off readonly mode. What could possibly go wrong?

Nothing. Except that it did go wrong. The app that I'm talking about, is a really ancient piece of what is gently called "legacy". Once the app was back to normal again, we noticed a significant slowdown on every page that made use of images. Before that point, I never got to that app and/or its database. I logged in to the MySQL console, and started investigating, at the same point chatting with colleagues.

Me: Is that really important that the tables are MyISAM? It's 2018, you know.. There are dozens of queries in queue waiting for table-level locks.

R**: Are they MyISAM? Really?

Me: Yes.. Any objection against converting them to InnoDB? With the current state of the website, with all those tons of Gateway Timeouts, it's not going to make it worse if I do it right now..


    . minutes later:

Me: Nah, it didn't help a lot.. But, looking at the SHOW PROCESSLIST output, I see something weird. What, do you think, this query does? SELECT LAST_INSERT_ID() FROM images? 

R**: ehh... Gets you the last AUTO_INCREMENT id from images table?

Me: Let's play another good news bad news joke.. Good news: you're right, it gets you the last AUTO_INCREMENT id. Bad news: it's not for table, it's for the session. Worse news: this query gets you the last AUTO_INCREMENT id and does it exactly as many times as there are rows in the images table. how many are there?

R**: about 8mln. #@%&! It's sending 8mln rows on every image upload, through the network!

Me: Bingo! 8mln rows, with one and the same integer value in all of them.

R**: Ouch... Aaaand... Before today, it was not an issue. Because the database was on the same server as the application..

Me: Exactly, it used the loopback interface, and now it's using ehternet, which, apparently, doesn't have a super good bandwidth. We don't have a gigabit channel between servers, do we?

R**: No, it's 100 Mbit

Me: Are you fixing the query, BTW?

R**: yeah, man, deploying it...


Another 10 minutes later, problem is gone, performance is back to normal.

What conclusions can one make from this story?

I can think of two at least:
First: never underestimate legacy code. The ways it can move to bite you in the ass, are mysterious.
Second: if you're working with MySQL or another RDBMS, learn SQL, learn the specific SQL dialect you're using and learn how to trouble shoot issues. In this case, I did not need to look in the PHP code at all in order to help my fellow colleagues out. You can also generalize this principle as "you have to know the tools you're using".

Happy optimizing, folks! Comments appreciated!

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