I have a task that consists of writing a web based interface to monitor the status of a machine having around 80 status indicators. The machine sends it's status information to the server (a linux host) via a serial interface. I currently have a daemon process (written in C) that receives this information, processes and formats it, and then writes it to a unix IPC socket.
The web server (nginx) uses a PHP module that reads this IPC socket and forwards the information to the web browser using SSE (Server Sent Events). The browser is running a javascript EventSource in order to update the web page in real time.
This is all working extremely well except that it will not support multiple clients concurrently :-(. I need to find a way to send the same information to each client (browser) that connects.
I am now looking to use a shared memory approach to achieve this and I believe it could be done using the classic Reader/Writer locking approach. Ref: https://arxiv.org/ftp/arxiv/papers/1309/1309.4507.pdf
The server daemon that handles the serial data stream is the only writer in this situation. All clients will only be readers.
I would like to know if anyone else out there has faced a similar problem and if so, how it was solved. I don't want to waste time chasing rainbows :-).
I will also have the problem of accessing data written by a C program using PHP, but this is another battle to be fought down the line. (Perhaps I should look into running a C program in place of PHP)
Any useful feedback will be very much appreciated.