I have read a few good articles about coding a socket server but thought I would ask here to see if there is any further knowledge/ideas about what I actually need.
I run multiple websites for clients all running off the same server, connecting to the same DB etc. Each client website has a form where users can submit their details for services we offer. These users are spread out across the world but what I am wanting to build is a monitoring system where my interface displays the users IP address, client website they are on, the page they are on etc. From the IP I will do a country/state look up (I know its not 100% accurate but close enough is good).
I would like the visiting site to send a packet to the socket server which in turns sends the output information to my screen in real time (after I perform some actions). I guess you could say I am building a mini NOC to monitor website activity. I would also like the output information to be most recent activity at top of screen but also show a scroll bar to view all activity.
Are sockets the best mechanism for this system? Any other suggestions or tutorials on how to achieve the outcome?
Many thanks.
Before you begin down this road, have you checked out the realtime part of Google Analytics? It does most of what you are looking for.
When someone is visiting your site, you aren't typically going to have a persistent connection. I'd suggest that rather than creating one, parse your server logs or store user information in a database, and query for the last x minutes of visitors.
For updating the viewing page that you are on in realtime, Web Sockets are best for this if you need very fast response time, but are currently quite the hassle to do in PHP. In addition, browser support isn't very wide. If you insist on using PHP, I'd recommend polling over AJAX. Otherwise, look into using Node.JS with Socket.IO. Socket.IO wraps up a lot of similar methods to web sockets to get the same effect with little effort. Still use PHP for your application... just use the Node.JS/Socket.IO part for your monitor interface.
Finally, I'd suggest questioning again why you might want this. You can spend a lot of time on a project like this, and the truth is that your analytics data over time is far more valuable than a snapshot when you are looking at it.
Related
I set myself a challenge today to write a jQuery chat in under half an hour. It eventually took me 40 minutes.
However, I want to improve it so the load on the server and browser isnt horrendous.
Currently the user types into a text box, presses enter, this data is sent to a .php file which updates a mySQL table and outputs all the rows on the table.
There is a set Interval on the div every two seconds to update if anyone said anything without the user pressing enter.
I just wanted to know thoughts on how to do perform this in a better way, or the most efficient way. I want to understand the best technology to use and why.
Thanks for all your input, I love stack overflow, its been invaluable to me.
Using ajax polling for a chat application with the "php back"/"javascript front" technology stack will inevitably result in a heavy server load. Http is just not designed for that kind of communication, and if you're using apache (as I assume) there is a really heavy overhead for each request.
As some of the commments indicated, you could investigate using a full stack javascript framework (i.e. Node.js on the backend).
When I had the task of accelerating an existing chat application with php backend and Javascript frontend (using periodic ajax poll), I ended up using a 3rd party server side product to handle lightweight XMPP requests. This server side product was OpenFire, but you could use eJabberd for even better performance - OpenFire is easier to set up and maintain though. The results were more than satisfactory, server load dropped significantly, and messages were delivered instantly for ~1000 online users chatting wildly away (on a less-than-average performance dedicated linux box).
It's hard to explain all the tiny details within a SO answer's scope, but luckily Ben Werdmuller # IBM went out of his way to write an awesome tutorial on this topic.
I have been in search of making live websites by using PHP. (COMET) I have been searching for a very long time already. (around a month) I have even checked some PHP chat scripts and used on my webserver, but I had some problems on most of them. (will be explained)
So far, most of the people tells the same thing: PHP isn't the best language could be used with COMET. The chat/comet examples are hacky at best.
I am asking this because, I want to have some features on my websites, like allow logged in people to chat with each other. That is where I need an alive connection to PHP pages. I am also planning on making a browser based game, and an alive connection will still be a must!
AJAX was a rare thing 2 years ago, shined with Facebook. Now pretty much everyone uses it, and it became a standard on web development. Now, the COMET based websites are growing. Youtube, Google+, Facebook, EA's Battlelog and such. I believe I should learn how to use it.
Okay, here are my questions. (Some of the information at below are the ones I gathered while searching on Google. Not sure if they're correct or not.)
Some languages like Python have special web servers designed for this job. I believe one of them is called Tornado Web Server. Developed and configured to simulate thousands of alive connections. I believe there is no such option in Appserv, but some people told NGINX can handle it with a decent configuration. Is it true? What configurations should be made? Is there any PHP web servers for this job?
Some of the most suggested things are:
a. Using APE.
b. Using Socket.IO
c. Node.js
Is there any way we can use them with PHP? Which one is the most promising? Could you give some guidance on them? Is there anything else than these?
I have used a comet chat script. Basically, you kept querying database and output the result with flush() to browser by sleeping it with usleep() in a loop. (This one became hard to understand so I will provide a quick code)
while(true)
{
// query database
// output the result
// flush the browser
// sleep for few seconds to lower cpu load
}
usleep() function basically destroyed my web server on Windows based operating systems. Is it normal to rely on usleep() on comet applications which runs on windows based OS? I mean, is there even a way to "sleep" PHP scripts? No matter what I do, CPU load goes to %100 on both WIN and UNIX servers.
Is PHP "really" that weak on this area? Should I give up with PHP and focus on other languages? If so, which language would you suggest? (That language should be promising. For example, there is no much use of AS3 after HTML5 addition, and AS3 is more likely to die soon while JS shines.)
What is WebSync? Can it be used with PHP?
Please bear in mind that I need to use COMET to make following applications:
A chat script, where logged in players will be able to chat eachother.
A browser based game. I already use JSON/AJAX and things like that when coding, but to receive opponents steps, I should pull the data, so an alive connection is needed. (Don't imagine advanced games, I am speaking about games like chess at best.)
I would appreciate if you can give me a short guidance. After all, I have been getting confused day by day since there are SO MANY random articles on internet. People even call setInterval() as COMET, so it is a complete mess.
There needs to be some clarification here. What you're looking for is not language specific per se. If you wanted to achieve the comet functionality with PHP you'd be relying on the Web Server (e.g Apache) to do the HTTP streaming. Also you need to understand that this is not supported in HTTP versions prior to HTTP/1.1. With that said, if you want to have a non-blocking event based web server, you're better off looking at Tornado and Node as suggested.
Comet is a programming technique that enables web servers to send data to the client without having any need for the client to request it This technique will produce more responsive applications than classic AJAX The user must create a request (for example by clicking on a link) or a periodic AJAX request must happen in order to get new data fro the server.
but it's create lots of traffic on your web server. If you want to build chat application in PHP use pusher which is a third party service and easy to use.
here is a link for pusher https://pusher.com/tutorials/realtime_chat_widget
the second suggestion is use ratchet for creating a chat application.
here is link for ratchet http://socketo.me/docs/hello-world
i hope it will help you
The challenge I'm facing is simulating a communication channel between two users of a website (e.g. gaming site), by using solely the technologies mentioned in the title.
Recently I've developed an online chess website where, the idea behind which was to give users the chance to play "live" matches too, not just lengthy games where you would make a move, then come back in 1-15 days to see if your opponent has responded. And the way this game engine works implies sending asynchronous requests to the server, both to update the info related to the game (in case you make a move), but also to verify if anything has changed (if you are waiting for the opponent to move).
To better explain this... the player whose turn it is (the browser of course) sends an async. request to update the game info, exactly when he makes his move. Meanwhile, the opponent sends PERIODIC requests, "asking" if anything has changed. If anything does change, the roles switch after the board updates.
Timers are behind the functionality of the engine, so my question to you is this: How would you go about simulating a com channel between two players, while trying not to put too much stress on the server, but also having games update as fast as possible, in order to maintain the "live" feeling to it. This is most important in 1 minute games (one of the available categories). Because in that case, requests NEED to take place VERY often (at least 1 second). But server responses could delay, there would be much stress on the server when having hundreds of games available at the same time etc... so you see my problem.
I look forward to hearing from you guys and picking your brain if you have any good ideas :)
Cheers!
Andrei
PS: In case you want to try it, the name is e-chess960.com
you would want to builds a socket server. node.js would be a good javascript based library to use for a socket server. each client would create a socket connection to the socket server, then when a client sends a message to the socket server, the socket server could immediately send the message back out to its subscribers without having to store it anywhere.
socket servers require socket access, which usually requires a vps instead of a shared server.
to make the solution work, you would require that the clients have the ability to create socket connections to your server. some browsers already can as part of html5, but not all yet. you could also use Flash as a way to create a socket connection.
What you actually want is not pulling the server every second, but instead keep a connection open and use the observer-pattern to distribute updates to the specific clients (in other words: push instead of pull). That way, your server resources will not get swamped by a new connection for every second and every client. A library to accomplish that is the Comet Library. Check out this nice tutorial for a sample application.
I am developing a non-real time browser RPG game (think Kingdom of Loathing) which would be played from within a Flash app. At first I just wanted to make the communication with server using simply URLLoader to tell PHP what I am doing, and using $_SESSION to store data needed in-between request.
I wonder if it wouldn't be better to base it on a socket connection, an app residing on a server written in Java or Python. The problem is I have never ever written such an app so I have no idea how much I'd have to "shift" my thoughts from simple responding do request (like PHP) to continuously working application. I won't hide I am also concerned about the memory and CPU usage of such Server app, when for example there would be hundreds of users connected. I've done some research.
I have tried to do some research, but thanks to my nil knowledge on the sockets subject I haven't found anything helpful. So, considering the fact I don't need real time data exchange, will it be wise to develop the server side part as socket server, not in plain ol' PHP?
Since your game isn't something that's working in realtime you probably don't need to go down the socket route, though it's certainly a viable option. The nice thing about sockets is that updates would be instant without requiring page refresh (or server poll), so you're right to at least consider it.
If you do want to do a more real-time server setup, you might consider using something like Electroserver - this abstracts out much of the setup for you so you don't have to write your own server from scratch, plus it's free up to a certain number of concurrent users if I recall correctly.
Finally, a third option you have is a modified POST approach using AMF. Look into AMFPHP, it lets you call methods on a PHP back-end directly from your flash application. A little bit faster and easier than simply using POST stuff, but not quite as seamless as a socket connection or a specifically built gaming server.
Lots of options out there, it sounds like you are aware of this and kudos for trying to come up with the best approach rather than just rolling with what you know! I hope this helps, let me know if you have any questions.
Here's a link to Electroserver - http://www.electro-server.com/
I am interested in a really good way of doing instant messaging like meebo and facebook and myspace all have, also for notifications on a page. Example on my site now, when a user receives a new mail message, photo comment, profile comment, friend request, some other things, they will receive a notification message and link on the page they are on using jQuery and AJAX.
I believe on a large scale that this is not the best way to do it though as my jquery code will have to basically run a PHP script to query the mysql table every 30 seconds or so for every user who has the page open with this script running. I would like to eventually add in some sort of instant messaging like facebook has in a chat bar at the bottom of the screen if I can find out an efficient way of doing it.
I have heard the terms Comet and HTML5 WebSockets but I am not sure if these are the solutions I should be looking at for such a feature? I would like to keep bandwidth at a minimum and running a query every few seconds does not seem very efficient on a high traffic site.
If you know some good solutions, please explain how they work a little bit please
You're looking for a "comet" server. Since you're talking PHP, your best solution would be a SaaS solution, such as WebSync On-Demand, since PHP has issues with scaling when it comes to large numbers of concurrent connections being held open. See also this question.
I think Facebook uses XMPP for their chat, so have a look at it.
XMPP is
an open technology for real-time communication, which powers a wide range of applications including instant messaging, presence, multi-party chat, voice and video calls, collaboration, lightweight middleware, content syndication, and generalized routing of XML data.
You'd install a separate server to handle messaging and in your app you'd implement a client with one of the available libraries.
Could you have a shared message queue that ajax can query? Maybe its a php script that stores a majority of the message in memcached (and possibly write to db in case of failure).
Not sure, but curious to hear other solutions ...
The basic problem is that you need to implement a Comet server (ie implement Server Push). The standard web hosts and apache don't readily allow you to do this easily. Another hosted solution (apart from Web Sync) is Goldfish Server. Currently free.