Non-blocking on STDIN in PHP CLI

Just a notice, that non blocking STDIN working, now.

system('stty cbreak');
while(true){
    if($char = fread(STDIN, 1)) {
        echo chr(8) . mb_strtoupper($char);
    }
}

Petah, I can't help with the PHP side of this directly, but I can refer you to an article I ran across a while ago in which someone emulated transistors by testing within a shell script for the existence of pending data for a named pipe. It's a fascinating read, and takes shell scripting to a whole new level of geekiness. :-)

The article is here: http://www.linusakesson.net/programming/pipelogic/

So ... in answer to your "crude hacks" request, I suppose you could shunt your stdio through named pipes, then exec() the tool whose source is included at the URL above to test whether anything is waiting to be sent through the pipe. You'd probably want to develop some wrapper functions to help with stuff.

I suspect the pipelogic solution is Linux-only, or at least would require a unix-like operating system. No idea how this could be accomplished on Windows.

When building CLI utilities with PHP I wanted my utility to both utilize arguments and/or pipes.
To solve this issue I've came up with this snippet that can be put at the top of your script.

$stdin = null;
$is_stdin = fstat(STDIN)["size"] > 0;

if ($is_stdin) {
    while (true) {
        $c = fgetc(STDIN);

        // Why? Read this: https://www.php.net/manual/en/function.feof.php#67261
        if ($c === false)
            break;

        $stdin .= $c;
    }
}

This way you'll be able to check whether STDIN or Arguments were provided to the script.
You can utilize both at the same time if you want.

Using Martins Example above, and adding user3684669 code with a little modification of my own. Here is a small program displaying a clock and updating every second. When ever a key is pressed I echo it to the screen. I also hide the default echoing of the character to the screen. Works in Linux.

<?php
//-- Save the keyboard state
//-- then use cbreak and turn off echo
$stty_orig = '';
function init_keyboard() {
  global $stty_orig;

  $stty_orig = shell_exec("stty -g");
  system('stty cbreak -echo');
}

//-- Return keyboard state
function close_keyboard() {
  global $stty_orig;

  system('stty '.$stty_orig);
}

//-- clear the screen
function clear() {
  echo "\x1B[2J\x1B[0m";
}

//-- move cursor to x,y on the screen
function gotoxy($x, $y) {
  echo "\x1B[".$y.";".$x."H";
}

//-- print a string at x,y on the screen
function printxy($x, $y, $str) {
  gotoxy($x,$y);
  echo $str;
}

//-- Check if we have a character and return it if we do.
function non_block_read($fd) {
    $read = array($fd);
    $write = array();
    $except = array();
    $result = stream_select($read, $write, $except, 0);
    if($result === false) throw new Exception('stream_select failed');
    if($result === 0) return false;
    $data = stream_get_line($fd, 1);
    return $data;
}

//-- main program starts here.
init_keyboard();
clear();
printxy(20,15,'Press Q to quit!');
while(1) {
    $x = "";
    if($x = non_block_read(STDIN)) {
        //echo "Input: " . $x . "\n";
        // handle your input here
        printxy(20,13,'Last Key Pressed: ['.$x."]  ");
        if ($x == 'Q') {
            printxy(1,20,"bye!\n");
            break;
        }
    } else {
        // perform your processing here
        $date_time = date('F j,Y h:i:sa');
        printxy(20,12,$date_time."   ");
    }
    sleep(1);
}
close_keyboard();