php[world] 2015 Schedule Announced

Input/output streams

O CLI SAPI define algumas constantes para I/O streams com o objetivo de tornar a programação em linha de comando um pouco mais fácil.

Constantes específicas da CLI
Constante Descrição
STDIN

Um stream já aberto para o stdin. Isso evita ter que abri-lo com

<?php
$stdin 
fopen('php://stdin''r');
?>
Se voê desejar ler uma única linha do stdin, você pode usar
<?php
$line 
trim(fgets(STDIN)); // reads one line from STDIN
fscanf(STDIN"%d\n"$number); // reads number from STDIN
?>

STDOUT

Um stream já aberto para o stdout. Isso evitar ter que abri-lo com

<?php
$stdout 
fopen('php://stdout''w');
?>

STDERR

Um stream já aberto com stderr. Isso evita ter que abri-lo com

<?php
$stderr 
fopen('php://stderr''w');
?>

Como dito acima, você não precisa por exemplo abrir um stream para stderr por si mesmo, basta usar a constante ao invés do recurso do stream:

php -r 'fwrite(STDERR, "stderr\n");'
Você não precisa fechar explicitamente esses streams, já que eles serão automaticamente fechados pelo PHP quando o script terminar.

Nota:

Essas constantes não estão disponíveis se estiver lendo os scripts PHP de stdin.

add a note add a note

User Contributed Notes 3 notes

up
17
Aurelien Marchand
4 years ago
Please remember in multi-process applications (which are best suited under CLI), that I/O operations often will BLOCK signals from being processed.

For instance, if you have a parent waiting on fread(STDIN), it won't handle SIGCHLD, even if you defined a signal handler for it, until after the call to fread has returned.

Your solution in this case is to wait on stream_select() to find out whether reading will block. Waiting on stream_select(), critically, does NOT BLOCK signals from being processed.

Aurelien
up
7
ecrist at secure-computing dot net
3 years ago
The following code shows how to test for input on STDIN.  In this case, we were looking for CSV data, so we use fgetcsv to read STDIN, if it creates an array, we assume CVS input on STDIN, if no array was created, we assume there's no input from STDIN, and look, later, to an argument with a CSV file name.

Note, without the stream_set_blocking() call, fgetcsv() hangs on STDIN, awaiting input from the user, which isn't useful as we're looking for a piped file. If it isn't here already, it isn't going to be.

<?php
stream_set_blocking
(STDIN, 0);
$csv_ar = fgetcsv(STDIN);
if (
is_array($csv_ar)){
  print
"CVS on STDIN\n";
} else {
  print
"Look to ARGV for CSV file name.\n";
}
?>
up
-9
James Zhu
4 years ago
Example:

<?php
function ReadStdin($prompt, $valid_inputs, $default = '') {
    while(!isset(
$input) || (is_array($valid_inputs) && !in_array($input, $valid_inputs)) || ($valid_inputs == 'is_file' && !is_file($input))) {
        echo
$prompt;
       
$input = strtolower(trim(fgets(STDIN)));
        if(empty(
$input) && !empty($default)) {
           
$input = $default;
        }
    }
    return
$input;
}

// you can input <Enter> or 1, 2, 3
$choice = ReadStdin('Please choose your answer or press Enter to continue: ', array('', '1', '2', '3'));

// check input is valid file name, use /var/path for input nothing
$file = ReadStdin('Please input the file name(/var/path):', 'is_file', '/var/path');
?>

you can add more functions if you want.
To Top