file_get_contents('php://input') doesn't work with Bash pipe

Question

I was working on my project and suddenly stdin in PHP stops working.

I have code in PHP:

test.php

<?php

$stdin = file_get_contents('php://input');

echo ">>>>>";
echo $stdin;
echo "<<<<<";

and I'm executing it with:

echo 'HELLO' | php -f test.php
>>>>><<<<<

This works fine:

echo 'HELLO' | php -c "echo file_get_contents('php://input');"
HELLO

and it doesn't work, I'm spending way too much time on this. Why this simple code doesn't work? Any clues? I'm using Fedora GNU/Linux with php 7.4.19.

Answer 1

Your last example uses the -c parameter, from the man page:

-c

Look for php.ini file in the directory path or use the specified file

I guess you ment to use -r:

-r

Run PHP code without using script tags '<?..?>'

In your answer, the HELLO comes from the shell, if you replace -c with -r is shows nothing, for that, please continue reading

_{The above seen in shell, on my local machine, in a snippet because the answer is getting way to long}

$
$ echo 'HELLO' | php -c "echo 'Test'; echo file_get_contents('php://input');"
HELLO
$
$ # HELLO Comes from shell, no 'echo 'Test';
$
$ echo 'HELLO' | php -r "echo 'Test'; echo file_get_contents('php://input');"
Test%
$
$ # With `-r` only the Test echo, because php:// input is empty
$
$
$ echo 'HELLO' | php -r "echo 'Test'; echo file_get_contents('php://stdin');"
TestHELLO
$
$ # If we use php://stdin we get both the echo's
$

---

From the documentation:

php://input is a read-only stream that allows you to read raw data from the request body

Your data is in stdin, so you'll need file_get_contents('php://stdin'):

php://stdin, php://stdout and php://stderr allow direct access to the corresponding input or output stream of the PHP process.

^{Source of above quotes}

---

<?php

$stdin = file_get_contents('php://stdin');

echo ">>>>>";
echo $stdin;
echo "<<<<<";

Try it online!

---

Another option is to use stream_get_contents(STDIN):

<?php

$stdin = stream_get_contents(STDIN);

print(">>>>>");
print($stdin);
print("<<<<<");

Try it online!