readline()

(PHP 4, PHP 5, PHP 7)

读取一行

说明

readline([string $prompt]): string

从用户端读取一行.你必须自己使用readline_add_history()将这一行添加到历史记录中

参数

$prompt

你可以指定一个字符串来作为用户的提示信息

返回值

从用户端返回一个行字符串.返回的该行的行尾换行符会被删除

范例

readline() Example

<?php
//get 3 commands from user
for ($i=0; $i < 3; $i++) {
        $line = readline("Command: ");
        readline_add_history($line);
}
//dump history
print_r(readline_list_history());
//dump variables
print_r(readline_info());
?>

The readline library is not available on Windows.
<?php
if (PHP_OS == 'WINNT') {
 echo '$ ';
 $line = stream_get_line(STDIN, 1024, PHP_EOL);
} else {
 $line = readline('$ ');
}
?>

Works under windows, and under php 7.2.0 :
$arr = [];
for ($i=0; $i < 3; $i++) {
    $arr[$i] = readline("Commande : ");
}
// Output
print_r($arr);
----------
Output:
Commande : 658
Commande : 965
Commande : 478
Array
(
  [0] => 658
  [1] => 965
  [2] => 478
)

If your CLI script accepts input from STDIN and you also want it to prompt for a password (e.g. as mysql client does), then readline() won't work for you. 
What you need to do is read from the terminal device as shown below.
function readline_terminal($prompt = '') {
  $prompt && print $prompt;
  $terminal_device = '/dev/tty';
  $h = fopen($terminal_device, 'r');
  if ($h === false) {
    #throw new RuntimeException("Failed to open terminal device $terminal_device");
    return false; # probably not running in a terminal.
  }
  $line = rtrim(fgets($h),"\r\n");
  fclose($h);
  return $line;
}
$pass = readline_terminal('Password: ');

Note that readline() will return boolean "false" when the user presses CTRL+D.

A workaround if readline is not compiled into php, because for example the command is only needed within an installation routine. It works as follows under Linux:
$f=popen("read; echo \$REPLY","r");
$input=fgets($f,100);
pclose($f);    
echo "Entered: $input\n";

If you want to prefill the prompt with something when using readline, this worked for me:
<?php
 function readline_callback($ret)
 {
  global $prompt_answer, $prompt_finished;
  $prompt_answer = $ret;
  $prompt_finished = TRUE;
  readline_callback_handler_remove();
 }
 readline_callback_handler_install('Enter some text> ',
                  'readline_callback');
 $prefill = 'foobar';
 for ($i = 0; $i < strlen($prefill); $i++)
 {
  readline_info('pending_input', substr($prefill, $i, 1));
  readline_callback_read_char();
 }
 $prompt_finished = FALSE;
 $prompt_answer = FALSE;
 while (!$prompt_finished)
  readline_callback_read_char();
 echo 'You wrote: ' . $prompt_answer . "\n";
?>

To haukew at gmail dot com: 
readline provides more features than reading a single line of input ... your example misses line editing and history. If you don't need that, use something as simple as this:
function readline( $prompt = '' )
{
  echo $prompt;
  return rtrim( fgets( STDIN ), "\n" );
}

In CGI mode be sure to call:
ob_implicit_flush(true);
at the top of your script if you want to be able to output data before and after the prompt.
-- Tomas V.V.Cox

If you want to block remove previous text and wonder that an empty string does not work: the workaround is to use an space with cursor left:
<?php
echo "> ";
readline(" \e[D");
?>

<?php
class ConsoleQuestion
{
  function readline()
  {
    return rtrim(fgets(STDIN));
  }
}
//Example1
$line = new ConsoleQuestion();
$prompt = "What Is Your Name: ";
echo $prompt;
$answer = $line->readline();
echo "You Entered: " . $answer;
//Example2 (comment Ex1 then uncomment Ex2)
/*$prompt = "What Is Your Name: ";
echo $prompt;
$answer = "You Entered: " . rtrim( fgets( STDIN ));
echo $answer;*/
?>

I wanted a function that would timeout if readline was waiting too long... this works on php CLI on linux:
<?php
function readline_timeout($sec, $def)
{
  return trim(shell_exec('bash -c ' .
    escapeshellarg('phprlto=' .
      escapeshellarg($def) . ';' .
      'read -t ' . ((int)$sec) . ' phprlto;' .
      'echo "$phprlto"')));
}
?>
Just call readline_timeout(5, 'whatever') to either read something from stdin, or timeout in 5 seconds and default to 'whatever'. I tried just using shell_exec without relying on bash -c, but that didn't work for me, so I had to go the round about way.

a few observations....
I use Cygwin PHP v7 and readline is available. The readline_list_history() function though is not defined.
A prompt with escape sequences are sanitized, so use something like:
<?php
  echo("\e[0m\e[34mPromt>\e[0m");
  $inp = readline(' ');
?>
I have not fully documented it, but I see that sometimes strings beginning with punctuation characters do not make it into the history with readline_add_history(). They also sometimes clear the prompt string.