Ubuntu 16.04 - Install PHP Inotify

Steps

Install inotify through PECL with the following commands:

sudo apt update
sudo apt install php-pear php7.0-dev -y
sudo pecl install inotify

Run these commands to add the extension to the PHP CLI:

SEARCH=";   extension=msql.so"
REPLACE=";   extension=msql.so\nextension=inotify.so"
FILEPATH="/etc/php/7.0/cli/php.ini"
sudo sed -i "s?$SEARCH?$REPLACE?" $FILEPATH

Run these commands to add the extension to PHP for Apache:

SEARCH=";   extension=msql.so"
REPLACE=";   extension=msql.so\nextension=inotify.so"
FILEPATH="/etc/php/7.0/apache2/php.ini"
sudo sed -i "s?$SEARCH?$REPLACE?" $FILEPATH

Helpful Starter Script

Below is a useful script to get you started with using inotify. You can use it to figure out what events get fired when you perform different actions.

#!/usr/local/bin/php
<?php

// Open an inotify instance
$inoInst = inotify_init();

// this is needed so inotify_read while operate in non blocking mode
stream_set_blocking($inoInst, 0);

// watch for everything in our input-bucket folder
$inputBucketWatcher = inotify_add_watch($inoInst, 'input-bucket', IN_ALL_EVENTS);

// add a secton watch to another directory, but only watch out create and delete.
$outputBucketWatcher = inotify_add_watch($inoInst, 'output-bucket', IN_CREATE | IN_DELETE);

// not the best way but sufficient for this example :-)
while (true)
{
    // read events
    $events = inotify_read($inoInst);

    if ($events[0]['wd'] === $inputBucketWatcher)
    {
        if ($events[0]['mask'] === IN_CREATE)
        {
            printf("Created file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_DELETE)
        {
            printf("Deleted file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_ACCESS)
        {
            printf("Accessed file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_MODIFY)
        {
            printf("Modified file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_ATTRIB)
        {
            printf("Metadata changed. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_CLOSE_WRITE)
        {
            printf("File opened for writing was closed. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_CLOSE_NOWRITE)
        {
            printf("File not opened for writing was closed. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_OPEN)
        {
            printf("File opened. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_MOVED_TO)
        {
            printf("File moved into directory. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_MOVED_FROM)
        {
            printf("File moved out of directory. file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_DELETE_SELF)
        {
            printf("Watched directory deleted. file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_MOVE_SELF)
        {
            printf("Watched directory moved. file: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_CLOSE)
        {
            printf("File closed. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_MOVE)
        {
            printf("File moved. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_ALL_EVENTS)
        {
            printf("IN_ALL_EVENTS activated. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_UNMOUNT)
        {
            printf("File system containing watched object was unmounted. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_Q_OVERFLOW)
        {
            printf("Event queue overflowed. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_IGNORED)
        {
            printf("Watch was removed. File: %s in watch_dir\n", $events[0]['name']);
        }

        if ($events[0]['mask'] === IN_ISDIR)
        {
            printf("Subject of this event is a directory. File: %s in watch_dir\n", $events[0]['name']);
        }
    }
    elseif ($events[0]['wd'] === $outputBucketWatcher)
    {
        // do something with other folder being watched.
    }
}

// stop watching our directories
inotify_rm_watch($inoInst, $inputBucketWatcher);
inotify_rm_watch($inoInst, $outputBucketWatcher);

// close our inotify instance
fclose($inoInst);

References

• Simplicity - Watching files and directories in PHP
• PHP Docs - Inotify - Predefined Constants