I am looking to create a Web Chat system using PHP, MySQL and JavaScript.
Currently, I am storing messages in a MySQL database with an incremental ID (Yes, it is indexed), a timestamp, the sender, and the message itself. I am then using AJAX to query the database every 500ms, seeing if there are any more recent messages than the last one received. However, I have a feeling that this is probably horribly inefficient as it will result in a large load on the MySQL server when multiple users are online. Having looked around a bit on Google and on here, everything seems to point to this way of doing it.
My question: is there a better way to do this? Any tips on how to reduce the load on the server would also be welcome.
I'm using PHP 5.3, on an Apache webserver, so libraries or plugins compatible with those would be fine.
EDIT:
Forgot to mention in the original post, but I'm not worried about supporting IE or other outdated browsers.
Potentially viable basic approach:
Cache your 50 most recent messages in memcache. Reset this whenever a new entry is added to the database. When new users connect, serve them these 50 messages to populate their chatroom.
Use a third party service like http://www.pubnub.com/ to send messages to your clients. Whenever a new message is sent to your chatroom, send it out on pubnub. Your server code will do this after writing to your database successfully.
notes: I'm not affiliated with pubnub. You don't need to use 50 messages above either. You don't even have to give them any messages when they connect depending on how you want to set it up. The point is that you want to avoid your users reading from your database in this case - that model isn't likely to scale for this type of application.
Ideally, an evented environment would be ideal for this kind of app. The LAMP stack is not particularly well suited.
I would recommend using this library, Pubnub. Pubnub is an easy way to send radio signals via javascript, or any TCP language (such as PHP) - and javascript instantly recieves the sent messages.
In PHP, you could simply have it save to your database - then use Pubnub's PHP API's to send the message to everyone else on the page.
If your familiar with Html, Javascript, and PHP - it can be fairly easy to learn. I would recommend it.
You are asking about a web chat system specifically built in PHP, MySQL and HTML with JavaScript. There are many options including Pre-built solutions: http://www.cometchat.com/ and http://www.arrowchat.com/ which all have chat comet services powered by a cloud offering like http://www.pubnub.com/ with options to host it yourself. See more about CometServices http://www.cometchat.com/cometservice/third-party-alternatives where you compare the service providers. There are several more options, however I recommend starting there. If you needs something more simple, like HTML and JavaScript only solution, you can check out http://www.pubnub.com/blog/build-real-time-web-apps-easy which is a blog about building real-time web apps easy with an example chat app in 10 lines of JavaScript Code. The solution Cuts Development Time by providing full Cross Platform for all browsers and mobile devices.
You should look into ajax long polling, in a nutshell this a simple ajax call but will not return a result from the server if there is no new data. You just do a simple loop on the server side until new data will be available then return it. Of course you have to stop this eventually if there's no result to send to client after a while (eg. 1 minute) then restart the call.
I suppose, that chat is too intensive for storage engines MySQL. Maybe, MEMORY table type will be ok, never used it. I spoken to several developers and everybody agree, that best option for chat is Memcache or even writing your own custom daemon (with memory-only storage as weel).
For client part you may read about short-polling, long-poling and web-sockets / sockets via flash/Java object.
using AJAX to query the database every 500ms
Is short-polling.
Sockets are a better solution than AJAX polling, however isn't much around about how you can integrate socket based chats with MySQL.
I have done a few tests and have a basic example working here: https://github.com/andrefigueira/PHP-MySQL-Sockets-Chat
It makes use of Ratchet (http://socketo.me/) for the creation of the chat server in PHP.
And you can send chat messages to the DB by sending the server JSON with the information of who is chatting, (if of course you have user sessions)
Related
I am currently creating an app where 2 users will have the ability to chat with one another. Specifically, it will be an iOS app using Swift as the main language. Most chat app tutorials on the web recommend using Firebase but I personally want to use MySQL since the rest of my database activities for this app are done using MySQL. I also do not want to use any existing libraries and want to do this all on my own.
I only have questions regarding the efficiency of using MySQL. When accessing the database, I create a URLSession using swift which then uses a predetermined link that points to my PHP scripts on the backend to handle the database accessions. The only problem with this is that my chat functionality of the app will have to refresh messages (to see messages that the other user has sent you within a second or so). I am confused as how to go about this. My current idea is to have a Timer that calls the URLSession data task every second or so to retrieve new messages from the database then display them on the user's screen. Would this be efficient or is there a better way to do this? I feel as if this would bog down MySQL in some way and would over all slow down the efficiency of the database. Is there a better way to go about this?
Thanks in advance.
If you really want to use MYSQL as a way of delivering messages then you can look into #TekShock's comment about using Apple's PushNotifications. You can also use Long Polling however it is not favorable at all.
I personally would not use MYSQL as a way of delivering messages just because there is a lot more better options. You can pick from messaging protocols like XMPP and MQTT to deliver your messages. I have personally have used MQTT in the past and thought it was really simple to get the hang and will fit your needs perfectly. It has a couple of really good swift clients like SwiftMQTT. You will have each device subscribe and publish to a room so it can receive and send messages. So in your case you can have a User A subscribe to ROOM 1 and a User B subscribe to the same room and they will both receive all the messages published to that specific room.
You can then if you want to store delivered messages to a MYSQL db so when the user opens the app back up you can load all their previous messages. You can also use Sqlite or Realm to store these messages locally instead of storing them online.
EDIT:
Scaling is also pretty simple with MQTT if this is something you will consider. You could place a queuing system between your application and the MQTT broker, possibly something like Apache Kafka which would be your best bet.
I'm trying to figure out a way for users of a website (say a student and teacher) to share a secure connection where real time updates on one page are viewed by both of them.
From research I've concluded that some of the real time updates could be performed using ajax and javascript.
But I'm stumped as to how users could share a connection where only the two users would be viewing the updates that take place on the website (such as flash animations of a drawing board.) I'm also confused how you would even begin to set up a connection like this.
I've looked intp php sessions and cookies but I'm not sure I'm doing the right research.
Any pointers as to how two specific users could share a secure connection where real time updates are viewed by the both of them only. I don't want a terse response please. I'm looking for specific details like functions and syntax specific to php. I appreciate the help and will rate you up if you give me good answers!
You cannot share a secure connection (e.g. HTTPS) its one client to one server.
If both clients are logged in and have a background AJAX task running in the browser, is it acceptable to have each client "pull" every few seconds the same data to display for both users?
This would require the "drawing board" updates to also be sent continuously back to the server to share the updated data with the other client. I'm sure there will be an event you can use to trigger the post of data (e.g. on mouse up).
If performance is an issue, you'd want to use a better server technology like Java that is able to keep session state between requests without having to persist to a database.
You can look at ajax push techniques. I used comet once where an administrator posted messages and everybody who was logged in saw that message appear on their screen. I don't know if comet supports PHP. I only used it with JSP. Just search for "ajax push" in Google.
Flash allows for connections between users, I think they refer to them as sockets.
If you want to use Ajax, et al, you need a server side technology that supports push.
Node is the standard in this regard, and you can set up a Heroku instance for free.
There are others, and you need to learn tools before even beginning to learn application.
Among the many overviews, this might interest you:
http://arstechnica.com/business/2012/05/say-hello-to-the-real-real-time-web/?1
A few good examples where this is happening:
Google Docs
Etherpad
HTML5 Games: Multi player
Techniques you can use (with varying browser support)
HTML5 WebSockets (Wikipedia; MDN; HTML5 Demo)
Comet (Wikipedia)
Really pushing data to a web browser client from a server (which would do that when it receives something from another client) is only possible with WebSockets as far as I know. Other mechanism would either require browser plugins or a stand-alone application.
However with Comet (through AJAX) you can get really close to pushing data by polling the server periodically for data. However contrary to traditional polling (e.g. where a clients asks for data every 5 seconds), with the Comet principle the server will hold that periodic request hostage for, say, up to 30 seconds. The server will not send back data until either it has data or the time out is reached. That way, during those 30 seconds, any data that the server receives can be instantly pushed back to the other clients. And right after that the client starts a new 30 second session, and so forth.
Although both Comet and WebSockets should work with a PHP backend served by Apache. I'd recommend looking into NodeJS (as server technology) for this.
There is a lot of information regarding Comet on the internet, I suggest you google it, maybe start at Wikipedia.
The great thing about Comet is that it is more a principle than a technology. It uses what we already have (simple HTTP requests with AJAX), so browser support is very wide.
You could also do a combination, where you use sockets if supported and fallback to Comet.
I'm sure you have looked into this. The opinion that this can be done via ajax is misleading to believe that two users of a website can communicate via javascript.
As you are aware, javascript happens on the client and ajax is essentially 'talking to the server without a page change or refresh'.
The communication between two users of the website has to happen via the server - php and some chosen datastore.
Hope that wasn't terse.
cheers, Rob
I'm working on a chat application which I would love to use a SQL db for.
My problem is, after a few google searches, i have people telling me from one site, that using a DB would be much slower then using a normal file (e.g Text or JSON file), but then on some other sites, people are saying the complete opposite. And I don't know about you guys, but when it comes to creating web apps for users, the users always come first.
So as much as I'd love to use a SQL DB as 1.) I have good experience with it and 2.) it allows me to make the application much more cooler (more features). but if it would slow things down on the users end (a noticeable lag), then its a no-no.
Either way, I will be "polling" the server continuously with AJAX and PHP to check the file/DB (for new messages, contact requests, ect ect).
Also, incase your wondering, the application wont be like a 1-to-1 chat, it will have "rooms" where multiple users can join and talk with all users joining in. The users will also be able to request a "private chat" with another user, where a 1-to-1 connection opens up.
So, MySQL Database OR a boring TEXT/JSON/OTHER file, in regards to performance?
Oh, one more thing, I don't want to use any third party libraries or APIs. Hate relying on other peoples work (been let down to many times).
If you're looking to implement an IRC clone, I think you've chosen all the wrong tools.
The best way to do this would be to write a custom HTTP server that handles everything in memory. No databases, no constant polling of files. When a message arrives, you simply loop through the correct in-memory list and dispatch the message to other users. For the browser to server connection, I suggest "Comet" (with web sockets for browsers that support them, if you're feeling up to it).
PHP likely isn't the language of choice for this, because pretty much all work done with PHP is based on traditional short, isolated requests. For a long-running process which serves multiple clients in real time, I'd suggest something like Python or Node.js.
You don't really want to be storing chats in files, that can create a management nightmare, I would recommend you go with MySQL and to make sure it works probably go with Sockets instead of AJAX polling, Sockets will scale really well.
However there isn't much around about how you can integrate socket based chats with MySQL.
I have done a few tests and have a basic example working here: https://github.com/andrefigueira/PHP-MySQL-Sockets-Chat
It makes use of Ratchet (http://socketo.me/) for the creation of the chat server in PHP.
And you can send chat messages to the DB by sending the server JSON with the information of who is chatting, (if of course you have user sessions)
I'd like to create an application where when a Super user clicks a link the users should get a notification or rather a content like a pdf for them to access on the screen.
Use Case: When a teacher wants to share a PDF with his students he should be able to notify his students about the pdf available for download and a link has to be provided to do the same.
There are several ways you can accomplish this. The most supported way is through a technique called Comet or long-polling. Basically, the client sends a request to the server and the server doesn't send a response until some event happens. This gives the illusion that the server is pushing to the client.
There are other methods and technologies that actually allow pushing to the client instead of just simulating it (i.e. Web Sockets), but many browsers don't support them.
As you want to implement this in CakePHP (so I assume it's a web-based application), the user will have to have an 'active' page open in order to receive the push messages.
It's worth looking at the first two answers to this, but also just think about how other sites might achieve this. Sites like Facebook, BBC, Stackoverflow all use techniques to keep pages up to date.
I suspect Facebook just uses some AJAX that runs in a loop/timer to periodically pull updates in a way that would make it look like push. If the update request is often enough (short time period), it'll almost look realtime. If it's a long time period it'll look like a pull. Finding the right balance between up-to-dateness and browser/processor/network thrashing is the key.
The actual request shouldn't thrash the system, but the reply in some applications may be much bigger. In your case, the data in each direction is tiny, so you could make the request loop quite short.
Experiment!
Standard HTTP protocol doesn't allow push from server to client. You can emulate this by using for example AJAX requests with small interval.
Have a look at php-amqplib and RabbitMQ. Together they can help you implement AMQP (Advanced Message Queuing Protocol). Essentially your web page can be made to update by pushing a message to it.
[EDIT] I recently came across Pusher which I have implemented for a project. It is a HTML5 WebSocket powered realtime messaging service. It works really well and has a free bottom tier plan. It's also extremely simple to implement.
Check out node.js in combination with socket.io and express. Great starting point here
I've written a php file that changes a MySql table entry when it receives an http post. I would also like the php file to send out a notification to the table entry's owner. This idea is similar to a chat room or instant messengering program. I've looked at php chat scripts but I really need something that has a very simple interface that is customizable. Can anyone point me in the right direction?
So you want to synchronize a set of clients, do you?
If so, look at the Long Polling technique. It's quite simple: The client opens a connection but the server does not respond until data is updated.
On the downside this won't work well with PHP. You will need to sleep() several connections, therefore blocking PHP processes.
If you have the possibility I would recommend using node.js to do stuff like that. Long Polling Chats are quire simple to implement using node ;)
I would use a named look for event triggerning and a jabber bot (extensions exist for several languages).
http://www.xaprb.com/blog/2007/08/29/how-to-notify-event-listeners-in-mysql/