readline_callback_handler_install

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

readline_callback_handler_install — Initializes the readline callback interface and terminal, prints the prompt and returns immediately

Description

readline_callback_handler_install(string $prompt, callable $callback): bool

Sets up a readline callback interface then prints prompt and immediately returns. Calling this function twice without removing the previous callback interface will automatically and conveniently overwrite the old interface.

The callback feature is useful when combined with stream_select() as it allows interleaving of IO and user input, unlike readline().

Parameters

prompt: The prompt message.
callback: The callback function takes one parameter; the user input returned.

Return Values

Returns true on success or false on failure.

Examples

Example #1 Readline Callback Interface Example

<?php
function rl_callback($ret)
{
    global $c, $prompting;

    echo "You entered: $ret\n";
    $c++;

    if ($c > 10) {
        $prompting = false;
        readline_callback_handler_remove();
    } else {
        readline_callback_handler_install("[$c] Enter something: ", 'rl_callback');
    }
}

$c = 1;
$prompting = true;

readline_callback_handler_install("[$c] Enter something: ", 'rl_callback');

while ($prompting) {
    $w = NULL;
    $e = NULL;
    $n = stream_select($r = array(STDIN), $w, $e, null);
    if ($n && in_array(STDIN, $r)) {
        // read a character, will call the callback when a newline is entered
        readline_callback_read_char();
    }
}

echo "Prompting disabled. All done.\n";
?>

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User Contributed Notes 1 note

down

thflori ¶

6 years ago

To read byte wise and multi line you can check the line_buffer from readline_info:

<?php

function read(int $count, string $prompt = null): string
{
    $previous = '';
    readline_callback_handler_install($prompt ?? " \e[D", function ($str) use (&$previous) {
        $previous .= $str . PHP_EOL;
    });
    do {
        $r = array(STDIN);
        $n = stream_select($r, $w, $e, null);
        if ($n && in_array(STDIN, $r)) {
            readline_callback_read_char();
            $str = $previous . readline_info('line_buffer');
        }
    } while (mb_strlen($str) < $count); // use strlen if you need the exact byte count
    readline_callback_handler_remove();

    return $str;
}