I currently have a PHP back-end and a jQuery front-end on my web application. The app constantly updates a stream of data on the front-end; right now it does this by continually polling a PHP script from jQuery's $.post() function. This is not efficient and causes delays in the data. I believe a socket (maybe Socket.io?) can solve this problem, but I don't know much about them. How can I setup a socket with PHP and my Javascript front-end? Where can I get more information about this? Where could I find an example?
Thank you,
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I have a web application with a client that receives data from a server. I have the data in NodeJS, but I want to pass the data to a Javascript file. The Javascript file is included in a HTML file, so I can't make the files communicate with eachother.
I am new to NodeJS, so it can be a stupid question, but anyones help is appreciated
This is for a project where I need have a data stream, and I need to pass it into a web application. I tried to pass the data to different page inside my application and then I tried to get that data on that page inside my web application via Javascript, but I couldn't make that work. I'm not even sure if its possible at this point.
Your node server can't communicate with your front-end without a specific way of communication like websocket, you have many other way to communicate with your front-end as node-server, take a look at server send event for example.
By the way your front-end can call your node server more easely with a get request as said #tomerpacific in comment.
For that you have to open a route with your express app. Routing with express
And for call it on a GET request, for that you can use the XMLHttpRequest, and if you have implemented jQuery on your front, you can use Ajax jQuery.
so on client side running in the browser I have a javascript code that has a variable (namely a url that is 1500 characters long), and which I need to insert it into a online database that lives on the webserver where I have hosted my website. I have these two technologies on my website, mysql DB and PHP.
Please kindly would someone recommend the best way to do this?
showing examples, specifically, how to send this data over to the remote server and how to process return data it may send back to me??
what i was thinking if there's a way to send over this variable string that is 1500 characters long, over to a PHP file living on my website which this PHP file will be able to insert the data into the DB, and then some time afterwards my same script running on the client browser will check and pull data from the remote DB back to itself...... I've tried to follow along some example searches googling but none of them are making sense to me, sorry I am visual learner , and would greatly appreciate any help you may provide me with this task .....
The solution already discussed here is the proper one. You need an API (also called a service).
I don't know who downvoted it but its the right one.
And you need it for several reasons.
Performance issues. Your solution "writting to a file" will be slow. And even "writting to a file" will require a service on top.
Security reasons. To allow in any other kind of way for a user to write in your server directly (FTP or other methods) is a big security risk and your server might end up being attacked.
Scalability and mantainance.
I would recommend reading more at
https://code.tutsplus.com/tutorials/a-beginners-guide-to-http-and-rest--net-16340
And if you are a bigginer an want to start something fast loopback is an amazing option, but you need NodeJS in your server.
In broad terms what you need to do is set up a API on the PHP side of things. Basically you want a structure where your javascript can send the request, and then, using promises, wait till it gets a response to get the data. That way your PHP server can take however long it needs to put the data in the database and process it properly.
Here's a tutorial on how to make a restful api in php
I want to know how can I reflect the change on the HTML as soon as the data changes on the database.
I am aware that I could poll the php file with setInterval function to periodically check if database value changed. However I am interested to know if it could be done without the setInterval function?
Presently the app uses jquery library and PHP backend.
thanks for any help in advance.
Based on the comments below and more research Accessing socket.io server via Apache served pages
Accessing socket.io server via Apache served pages
I understand I need to have a node package running on my server to work with socket.io or websocket.io. I cannot take the liberty of installing it since I am on a VPS.
Therefore, its best to use Simple long polling example with JavaScript and jQuery as a snippet to my situation
I have a web site showing some data. It is constructed of:
- A web app, showing data.(ASP.Net app, but I don't use server side features in showing data; It's pure HTML and JavaScript)
- A Service providing data in Json format.(WCF)
the client requests data and receives and shows them.
Now I want to change the process in order to works in push base strategy.
I googled and I found out that that Comet is a good choice, but I don't found practical samples in my case.
Some samples had client with php (server-side) and so on.
Now I want some hints on using comet in a way that client is pure JavaScript and HTML and server is WCF (server pushes Json to JavaScript )
look at nComet it is an asp.net implementation of comet, not sure if it is wcf yet, but i would have thought much of the code would be reusable.
Or better pokein
when i use comet iframe i just send script tags from backend php file to front end and javascript is displaying it.
can someone explain briefly where a comet server comes up in the picture and how the communication will be between frontend (javascript), backend (php) and the comet server.
cause i read that if you are going to let a lot of users use your comet application it's better to have a comet server. but i dont quite understand the coupling between these parts.
use this link:
http://www.zeitoun.net/articles/comet_and_php/start
That is the best tutorial i could found, and takes 1 min to try;
in short:
( image from that tutorial )
index, can be html or php, creates a request, which php doesnt answer until there is data to send back, with chat, when someone sends you a message.
If you have many users chatting, i recommend using a java chat app
otherwise your server will load up with running php engines ( each unanswered request keeps a php engine alive, which is server capacity ).
http://streamhub.blogspot.com/2009/07/tutorial-building-comet-chat.html
this should help you out with that, but you do need java hosting :)
have fun
edit:
just read the other server part; sending requests to your own server can get messed because the timeout function may not work well, so the server crashes, an independant server timeouts the connection after a certain amount of time, no matter what.
I have a very simple example here that can get you started with comet. It covers compiling Nginx with the NHPM module and includes code for simple publisher/subscriber roles in jQuery, PHP, and Bash.
http://blog.jamieisaacs.com/2010/08/27/comet-with-nginx-and-jquery/
A working example (simple chat) can be found here:
http://cheetah.jamieisaacs.com/