I am working on attendance system where project management system is also handling using Javascript\Jquery at client side and PHP\MySQL at server side.
A feature in my web app is user message to admin. For this I have applied an ajax request which is made by setTimeout function (after every 15 seconds) to check that is there any new message comes in database if yes then return it to the admin.
It working fine but the drawback is (as you know) continuous request to server which really poor and bad. As I know that real time functionality can solve this problem I have checked some link websocket.io and signlR but there are applicable with Nodejs and asp.net.
So, how can I apply real time functionality with php or I get that new data have reached in to database without continues request with ajax.
There are actually some PHP tools for doing this now. For instance, check out Ratchet.
It's also possible to do bi-directional sockets by creating a simple TCP/IP server. I've done this before for bi-directional communication between a PHP server and a desktop app.
http://php.net/manual/en/sockets.examples.php
Related
I'm looking for technique or skils to fix the ways for new web site.
This site show the read time data which located on server as file or data on memory.
I'll use Node.js for server-side. But I can't fix how to get the data and show that to web site user.
Because this data have to update per 1 second at least.
I think it is similar to the stock price page.
I know there are a lot of ways to access data like AJAX, Angular.js, Socket.io..
Also each has pros and cons.
Which platform or framework is good in this situation?
This ultimately depends on how much control you have over the server side. For data that needs to be refreshed every second, doing the polling on client side would place quite the load on the browser.
For instance, you could do it by simply using one of the many available frameworks to make http requests inside some form of interval. The downsides to this approach include:
the interval needs to be run in the background all the time while the user is on the page
the http request needs to be made for every interval to check if the data has changed
comparison of data also needs to be performed by the browser, which can be quite heavy at 1 sec intervals
If you have some server control, it would be advisable to poll the data source on the server, i.e. using a proxying microservice, and use the server to perform change checking and only send data to clients when it has changed.
You could use Websockets to communicate those changes via a "push" style message instead of making the client browser do the heavy lifting. The flow would go something like:
server starts polling when a new client starts listening on its socket
server makes http requests for each polling interval, runs comparison for each result
when result has changed, server broadcasts a socket message to all connected clients with new data
The main advantage to this is that all the client needs to do is "connect and listen". This even works with data sources you don't control – the server you provide can perform any data manipulation needed before it sends a message to the client, the source just needs to provide data when requested.
EDIT: just published a small library that accomplishes this goal: Mighty Polling ⚡️ Socket Server. Still young, examine for your use if using.
As we know, if running application also manage sessions in main memory then is there any way for server to send responses to all web clients/browsers for new recorded data in a database.
Remember: I have not made any request to server or polling to server for new records update..
Let server make responses without web request..
Objective :
No all web browsers making request or polling to server for every certain interval therefore reducing the performance issue with the application memory..
Am just against of making so many ajax calls from every web client..
Need your ideas from your past, if experienced similar..
read about websockets and socket.io.
basically with socket.io you have a connection open between browser (client) and server and server can send data which the client than receives as an event.
the client doesn't need to send a request to get that data, only open the web socket connection.
you can look at socket.io chat example: http://socket.io/get-started/chat/
WebSocket is the best and easy solution if you don't want to go through the hassle to learn Angular or others.
Both server-side and client-side can build WebSocket, and it acts as a bridge to transmit data back and forth.
I just created an easy solution for this.
Please check my new library wsm - WebSocket Manager, it works for both server-side and client-side.
Websocket Server can be built easily; this library includes several useful features.
I am building a java chatting web application.(Server and Client in one project)
follow is my condition
Springframework 4.2.3
JSP
Maven Project which converted from a Dynamic Web Project
Unable to use node.js
So User scenario in my head is
User enters some text and press Send
Ajax call to deliver messages to server
Server checks the users who are currently connected(from Session maybe)
Server calls other users script to append new message
I am quite confusing with step4. Is it possible that Java calls DOM event trigger?
How could a client get a new message event from server?
Thanks. :D
P.S.
These days majority of chatting servers are event-driven. Is it possible to build an event driven chatting server with Java?
Your solution is formed as if there is no WebSocket technology available to you. WebSocket is implemented to solve real time messaging issues. It pushes message to the destination.
But if to stick wih your method following is meaningful.
You need someplace to keep incoming messages such as database or session.setAttribute [bad idea]. Then use some ajax call loop on the clients machine to ask for a new incoming message from server.
Probably your server will slow down due to incoming flood of GET requests from multiple users.
to Your last question in post scriptum: yes, I use tomcat websocket api.jar in my projects. There is well written documentation on apache.org
As I mentioned, learn WebSocket if your users are not using old internet explorer browsers. There are bunch of tutorials on it...
i have developing a website that user can chat with other user if they are online . if one user send a message will notify that receiver on their screen , these checking process are happen in background process , i have an option of using
setinterval method and javascript self execution method
but i am looking much faster background process methods which will check every seconds if message or notification arrived .
could any one give suggestion for this.
You can use HTML5 websockets.
WebSockets is an advanced technology that makes it possible to open an interactive communication session between the user's browser and a server. With this API(JS functions), you can send messages to a server and receive event-driven responses without having to poll the server for a reply.
below is good link to start
http://www.sanwebe.com/2013/05/chat-using-websocket-php-socket
I think the best match for your needs will be http://elephant.io
Elephant.io provides a socket.io client fully written in PHP that should be usable everywhere in your project.
Take a look at the Thruway Project. It's a PHP websocket implementation using the WAMP protocol, which gives you Publish and Subscribe abilities (you can use that for your chat application) as well as RPC.
A good place to start would to take a look at this chat demo (source code) and then use Thruway as the WAMP router.
I'm one of the developers of the thruway project, so if you run into any issues or have any questions, feel free to ask.
I'm currently experimenting with WebSockets in a bid to reduce / remove the need for constant AJAX requests in a potentially low bandwidth environment. All devices are WebSocket compliant so there's no issue there, and I'm trying to keep it to native PHP WebSockets, no node.js or other frameworks / libraries (Which so far has been fine).
What I'm looking to do is to decide how to go about notifying connected clients about an update to a database by another Client. The use case in question is a person pressing a button on their device, which then alerts that persons manager(s) to that press. So the two options I have though of are as follows:
1. Looping a Database Query (PHP)
My first thought was to insert a query into the WebSocket server that is effectively saying "Has the alert field changed? If so, notify the manager(s)". Whilst this is the most straightforward and sensible approach (That I can think of), it seems wasteful to have a PHP script designed to reduce strain on the server, that is now running a query every second, however, at least this would ensure that when a Database update is detected, the update is sent.
2. Sending a notification from the Client
Another thought I had, was that when the client updates the Database, they could in fact send a WebSocket notification themself. This has the advantage of reducing any intensive and looped queries, but also means that I'd need to have a WebSocket message being sent every time I want to change any data, such as:
$.post("AttemptDatabaseUpdate.php", {Data}).function(Result) // Don't worry about the semantics of this, it's not actual code
{
if(Result == "Successful")
{
SendWebSocketNotification(OtherData);
}
}
Maybe this is the best option, as it is the most efficient, but I worry that there is a chance the connection may drop between updating the Database, and sending the WebSocket notification, which may create a need for a fallback check in the PHP file, much like the one in the first solution, albeit at a longer interval (Say every 30 seconds).
3. MySQL Trigger?
This is purely a guess, but perhaps another option is to create a MySQL trigger, which can somehow notify the server.php file directly? I've no idea how this would work, and would hazard a guess that this may end up with the same or similar Query requirements as solution #1, but it's just a though...
Thank you in advance for your help :)
EDIT: Solution possibility 4
Another thought has just popped into my head in fact, whereby the PHP file used to update the database could in fact have a WebSocket message built into it. So that when the PHP file updates the database, the WebSocket server is notified via PHP, is this possible?
If you use websockets, you should use notifications from client. That's one of their main use cases.
If you're worried about inconsistencies due to connection dropping or something changing in-between, you could implement a system similar to HTTP ETags, where client would send a hash code that you can respond on server side if there is a conflict in updating.
Update: I guess I understood your initial issue a bit wrong. If I understand your use case correctly: you are sending database updates from a client and after that all connected clients need to be updated. In that case, I think server should send the update messages after DB updates have been done, so I agree with solution 4. I am assuming here that your websocket server is the same server running PHP and doing the DB updates.
However, depending on your use case, client should still send a hash value on the next request identifying its "view of the world", so you would not be doing identical updates multiple times if a connection gets broken.
Update 2: so it was now understood that you indeed use a separate, standalone websocket server. Basically you have two different web servers on the server side and are having an issue on how to communicate between the two. This is a real issue, and I'd recommend only using one server at a time - either take a look at using Apache websocket support (experimental and not really recommended) or migrating your php scripts to the websocket instance.
Neither PHP or Apache was really build with websockets in mind. It is quite easy to set up a standalone websocket server using only PHP, but it might not be so easy then to migrate the rest of the PHP stack to it if the code is relying on Apache/web server on. Apache websocket support also is hardly optimal. For a real websocket solution, unfortunately, best practice would be using a technology that is built for it from the ground up.
The better answer is to send notification through Server side when database is updated by PHP script, so that script have to add options of web sockets to directly send notification to all web socket clients registered.
User send content->Php script process content and save data according to true condition->check database is updated by checking return of mysql_query/other alternative->if true than use web-socket and send notification to all users
now this is more easy/handy/bandwidth saver.