A file-based hit counter implementation

org.ermshaus.Counter.bundle.php

<?php // File: org.ermshaus.Counter.bundle.php

namespace org\ermshaus;

use Exception;

/**
 *
 */
class CounterException extends Exception
{

}

/**
 *
 *
 * Usage example:
 *
 *     require_once __DIR__ . '/org.ermshaus.Counter.bundle.php';
 *
 *     $counter = new org\ermshaus\Counter(__DIR__ . '/counter.dat');
 *
 *     $counter->increase();
 *
 *     echo $counter->get(), ' / ', $counter->getTotal();
 */
class Counter
{
    /**
     * Path to storage file
     *
     * @var string
     */
    protected $dataFile;

    /**
     *
     * @param string|null $dataFile If null, __DIR__ . '/data/counter.dat' will
     *                              be used
     */
    public function __construct($dataFile = null)
    {
        if ($dataFile !== null) {
            if (!is_string($dataFile)) {
                throw new CounterException('Argument needs to be string');
            }

            $this->setDataFile($dataFile);
        } else {
            $this->setDataFile(__DIR__ . '/data/counter.dat');
        }
    }

    /**
     * Returns the PATH component of the current request
     *
     * @return string
     */
    protected function getPath()
    {
        $requestUri = $_SERVER['REQUEST_URI'];
        return parse_url($requestUri, PHP_URL_PATH);
    }

    /**
     * Increases the counter value for an identifier
     *
     * @param string $identifier If null, request path will be used
     */
    public function increase($identifier = null)
    {
        if ($identifier === null) {
            $identifier = $this->getPath();
        }

        if (!is_string($identifier)) {
            throw new CounterException('Argument needs to be string');
        }

        $h = fopen($this->dataFile, 'c+b');

        if (flock($h, LOCK_EX)) {
            $contents = '';

            while (!feof($h)) {
                $contents .= fread($h, 8192);
            }

            $counterData = array();

            if ('' !== trim($contents)) {
                $counterData = unserialize($contents);
            }

            if (!array_key_exists($identifier, $counterData)) {
                $counterData[$identifier] = 0;
            }

            $counterData[$identifier]++;

            ftruncate($h, 0);
            rewind($h);

            $serialized = serialize($counterData);

            fwrite($h, $serialized, strlen($serialized));

            flock($h, LOCK_UN);
        } else {
            throw new CounterException('Unable to obtain lock');
        }

        fclose($h);
    }

    /**
     * Returns the current counter value for an identifier
     *
     * @param string|null $identifier If null, request path will be used
     * @return int
     */
    public function get($identifier = null)
    {
        if ($identifier === null) {
            $identifier = $this->getPath();
        }

        if (!is_string($identifier)) {
            throw new CounterException('Argument needs to be string');
        }

        $returnValue = 0;

        $h = fopen($this->dataFile, 'rb');

        if (flock($h, LOCK_SH)) {
            $contents = '';

            while (!feof($h)) {
                $contents .= fread($h, 8192);
            }

            $counterData = array();

            if ('' !== trim($contents)) {
                $counterData = unserialize($contents);
            }

            if (array_key_exists($identifier, $counterData)) {
                $returnValue = $counterData[$identifier];
            }

            flock($h, LOCK_UN);
        } else {
            throw new CounterException('Unable to obtain lock');
        }

        fclose($h);

        return $returnValue;
    }

    /**
     * Returns see sum of all current counter values
     *
     * @return int
     */
    public function getTotal()
    {
        $returnValue = 0;

        $h = fopen($this->dataFile, 'rb');

        if (flock($h, LOCK_SH)) {
            $contents = '';

            while (!feof($h)) {
                $contents .= fread($h, 8192);
            }

            $counterData = array();

            if ('' !== trim($contents)) {
                $counterData = unserialize($contents);
            }

            $returnValue = array_sum($counterData);

            flock($h, LOCK_UN);
        } else {
            throw new CounterException('Unable to obtain lock');
        }

        fclose($h);

        return $returnValue;
    }

    /**
     * Returns all stored counter data
     *
     * @return array
     */
    public function getAllData()
    {
        $returnValue = array();

        $h = fopen($this->dataFile, 'rb');

        if (flock($h, LOCK_SH)) {
            $contents = '';

            while (!feof($h)) {
                $contents .= fread($h, 8192);
            }

            $counterData = array();

            if ('' !== trim($contents)) {
                $counterData = unserialize($contents);
            }

            $returnValue = $counterData;

            flock($h, LOCK_UN);
        } else {
            throw new CounterException('Unable to obtain lock');
        }

        fclose($h);

        return $returnValue;
    }

    /**
     * Gets the file in which counter values are stored
     *
     * @return string
     */
    public function getDataFile()
    {
        return $this->dataFile;
    }

    /**
     * Sets the file in which counter values are stored
     *
     * @param string $dataFile
     */
    public function setDataFile($dataFile)
    {
        if (!is_string($dataFile)) {
            throw new CounterException('Argument needs to be string');
        }

        $dataFile_rp = realpath($dataFile);

        if (false === $dataFile_rp) {
            if (false === touch($dataFile)) {
                throw new CounterException(sprintf(
                    'Unable to create data file %s',
                    $dataFile
                ));
            }

            $dataFile_rp = realpath($dataFile);

            if (false === $dataFile_rp) {
                throw new CounterException('Unknown error');
            }
        }

        $this->dataFile = $dataFile_rp;
    }
}