How to provide default value for user input in PHP? - php

Question

Is there a PHP functionallity same as read -i in BASH so that a script can prompt the user and provide a default answer like this:
Are you doing ok? (yes/no): yes
Where "yes" is the default answer provided by the script, which the user can erase and input another.
The readline function does not seem to have what it takes. Is there any other way to do this?
Using a stream does not seem to work either:
<?php
echo "Are you doing ok? (yes/no): ";
$in = fopen('php://stdin', 'rw+');
fputs($in, 'yes'); // should be the default?
$answer = fgets($in);
fclose($in);
echo "\nYou entered: {$answer}\n";
Whatever is in written by the fputs($in, 'yes'); line is ignored:
Are you doing ok? (yes/no): yes
You entered:
Am I using the stream incorrectly? Or maybe there is some other way to achive the default value?
EDIT:
Maybe I simlified the example to much. The real issue is not a simple yes/no prompt - this is just an example. Let me emphasize again: I'm aiming for providing exactly the same functionallity as the read -i BASH command. The $answer in my specific case holds an URL, so I would like for the user to be provided with the first part of the url (scheme, host, port), so he can add/edit the rest (path, query), fragment. Like this:
Enter url: http://www.example.com/foo/
now the user complement the path with bar/baz and we get:
You entered: http://www.example.com/foo/bar/baz
But on the other hand the user also should have the option to erase the first part of the url and provide completely different string:
Enter url: ftp://www.my-super-specific-domain.com/foo/bar

Answer 1

There's no built in way of doing this because writing some code that does it is quite straight forward:
function writeQuestion($question, $answers)
{
echo $question . ' (' . implode('/', $answers) . '): ' . PHP_EOL;
}
function readAnswer($possibleAnswers, $defaultAnswer)
{
$in = fopen('php://stdin', 'rw+');
$answer = trim(fgets($in));
if(!in_array($answer, $possibleAnswers))
{
return $defaultAnswer;
}
return $answer;
}
$question = 'Are you doing ok?';
$answers = array('yes', 'no');
$defaultAnswer = 'yes';
writeQuestion($question, $answers);
$answer = readAnswer($answers, $defaultAnswer);

Answer 2

You can wrap standard bash read for prefilled/populated edit and call it from you main php cli script
bash script named xreadline:
#! /bin/bash
IFS="";read -r -p "$1" -i "$2" -e STRING;echo "$STRING"
main php cli script:
#!/usr/bin/php
<?php
function xreadline ($prompt,$prefill)
{
$on = exec ('./xreadline "'.$prompt.'" "'.$prefill.'"');
return $on;
}
$answer = xreadline ('Your answer: ', 'xyz');
echo $answer;
.....
This approach fully supports UTF8 instead of native PHP readline.

Answer 3

Comment messed my code so here is standalone php cli file with function call to "read" command.
Little bit tricky, but hopefully will work as supposed to. :-)
#!/usr/bin/php
<?php
function xreadline ($prompt,$prefill)
{
return exec ('/bin/bash -c \'read -r -p "'.$prompt.'" -i "'.$prefill.'" -e STRING;echo "$STRING";\'');
}
echo "Prompt test :\n";
$output = xreadline ("edit this prefilled prompt: ","prefilled stuff");
echo "\n";
echo $output;