I have to build a project that connects a Java application with a node.js server. I've already built the server part, it uses MySQL to store values and can process HTTP requests to return them in JSON format.
The Java app must be able to retrieve data from the server and then process it. The thing is, this application must be receiving information constantly from the server because it will be updating frequently.
Any hints on how to start or documentation you recommend to build this?
Thank you in advance.
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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.
I've been through a number of Node.js, Express, and other tutorials/posts, and I'm struggling with how to think about connecting to a database on various pages throughout a webapp.
I would like to run a Node.js app (with a server.js file that connects to a database) and then query that database as needed on every page throughout the app.
So if I have an inventory.html page I should be able to have javascript that queries the inventory table and displays various inventory items throughout that html page.
Problem #1. I can't find a way to use mysql on any client-side pages, since javascript can't use node's require() function client-side. As detailed in this StackOverflow post ("require is not defined").
Problem #2. I can't figure out an elegant way to pass a database connection to other pages in my app. A page can send a POST request back to the server.js file, but this really isn't as flexible as I want.
I'm really looking for the modern, preferred way to do a bunch of PHP scripting in my Node app. Can anyone guide me to the right way to do this? Thank you!
You just can't directly call mysql from the client. Even if it worked imagine that anybody could modify the SQL queries and access all your data.
The only way how to do it is this:
js client app ------> js server app -------> mysql
You just must have 2 apps: one running in the user's browser sending requests to the server and the other running on the server answering the requests.
all.
I have a raspberry pi running a node.JS web app that uses Express to serve up a static html page. The web app simply runs on localhost, on an instance of chrome. The webpage does not need to be accessed by anything but the pi, so I'm essentially using the node environment and html as my UI for the project.
I'm just wondering how I can get data from the GPIO (using onoff npm library) onto the webpage.
Interactions with the GPIO would be considered server side, whilst the HTML webpage and any javascript running on it is client side.
How can I read from a GPIO and update the locally served webpage in realtime?
Thanks!
You need to write some form of web service.
At the simplest level, this will be an HTTP server which generates an HTML document with the data in it on demand.
If you want to get more complicated, poll the server with Ajax and have it return the data to client-side JS.
A step further would involve the use of WebSockets (consider Sockets.io) to push the data to the client.
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.
sorry to bother you, but I've been looking for answers and I couldn't find them anywhere... Well i'm a fresh dude in the field of javascript and node.js and here's my problem:
I've created an application based on the tutorial of socket.io - Here's the link to the completed project of their chat example. everything is working as it should, but I would really need to trigger somekind of a command while node server is running... command should be triggered via php script.
The command should trigger an emit event - so every client in our case would see a new message sent via php.
I saw couple of suggestions to do it from another server with php/using cURL. The problem is that I don't know how to fetch POST data sent from php to node.js server.
Any solution to command node with php is more than welcome and again i'm sorry to bother you :)
You can use a bridge to exchange data between NodeJS and PHP. You will need to implement a PHP server that exposes remote procedures and a NodeJS client that calls those remote procedures. You can send any data to the NodeJS application from PHP using these remote procedures.
Here are a few links to get you started:
http://bergie.iki.fi/blog/dnode-make_php_and_node-js_talk_to_each_other/
https://github.com/bergie/dnode-php