Useful PHP Snippets

Useful PHP Snippets

PHP is the most widely used language when it comes to server-side programming. If you are a beginner or an advanced programmer and you use it in your work – our article will be very useful for you. Because today I want to bring to your attention a small collection of quite interesting and useful php snippets. They are designed as finished functions, and you can easily transfer them in a class or a library file for later use in your projects.

---

Calculate the distance between two coordinates

When we need to measure the distance between two points, we may use one of the following formulas: Haversine formula or Vincenty’s formula. There are two appropriately named functions:

function haversineGreatCircleDistance($latitudeFrom, $longitudeFrom, $latitudeTo, $longitudeTo, $earthRadius = 6371000) {
  // convert from degrees to radians
  $latFrom = deg2rad($latitudeFrom);
  $lonFrom = deg2rad($longitudeFrom);
  $latTo = deg2rad($latitudeTo);
  $lonTo = deg2rad($longitudeTo);
  $latDelta = $latTo - $latFrom;
  $lonDelta = $lonTo - $lonFrom;
  $angle = 2 * asin(sqrt(pow(sin($latDelta / 2), 2) +
    cos($latFrom) * cos($latTo) * pow(sin($lonDelta / 2), 2)));
  return $angle * $earthRadius;
}
public static function vincentyGreatCircleDistance($latitudeFrom, $longitudeFrom, $latitudeTo, $longitudeTo, $earthRadius = 6371000) {
  // convert from degrees to radians
  $latFrom = deg2rad($latitudeFrom);
  $lonFrom = deg2rad($longitudeFrom);
  $latTo = deg2rad($latitudeTo);
  $lonTo = deg2rad($longitudeTo);
  $lonDelta = $lonTo - $lonFrom;
  $a = pow(cos($latTo) * sin($lonDelta), 2) +
    pow(cos($latFrom) * sin($latTo) - sin($latFrom) * cos($latTo) * cos($lonDelta), 2);
  $b = sin($latFrom) * sin($latTo) + cos($latFrom) * cos($latTo) * cos($lonDelta);
  $angle = atan2(sqrt($a), $b);
  return $angle * $earthRadius;
}

Both functions use the following parameters:

• float $latitudeFrom – Latitude of start point in [deg decimal]
• float $longitudeFrom – Longitude of start point in [deg decimal]
• float $latitudeTo – Latitude of target point in [deg decimal]
• float $longitudeTo – Longitude of target point in [deg decimal]
• float $earthRadius – Mean earth radius in miles

Functions return – (float) Distance between points in miles (same as earthRadius)

---

Email debug PHP errors

function errorHandler($sMessage = '', $aVars = array()) {
    $sScript = $_SERVER['PHP_SELF'];
    $sParams = print_r($_REQUEST, true);
    $sVars = print_r($aVars, true);
    $aBackTrace = debug_backtrace();
    unset($aBackTrace[0]);
    $sBackTrace = print_r($aBackTrace, true);
    $sExplanation = <<<EOF
<p>Additional explanation: {$sMessage}</p>
<p>Additional variables: <pre>{$sVars}</pre></p><hr />
<p>Called script: {$sScript}</p>
<p>Request parameters: <pre>{$sParams}</pre></p><hr />
<p>Debug backtrace:</p>
<pre>{$sBackTrace}</pre>
EOF;
    $sHeader = "Subject: Error occurred\r\nContent-type: text/html; charset=UTF-8\r\n";
    error_log($sExplanation, 1, '[email protected]', $sHeader);
}

This function is to email you about all occured errors on your website (this is much better instead of displaying it to the public). There are only two optional params:

• string $sMessage – Custom message
• array $aVars – Additional array to be sent by email

---

Convert PDF to JPG

function pdfToJpg($pdf, $jpg) {
    $im = new Imagick();
    $im->setResolution(300,300);
    $im->readimage($pdf);
    $im->setImageFormat('jpeg');
    $im->writeImage($jpg);
    $im->clear();
    $im->destroy();
}

This function is to convert PDF files into image file. It takes two params:

• string $pdf – Path to the initial PDF file
• string $jpg – Path to the image file

---

Get age by birth date

function getAge($birthdate = '0000-00-00') {
    if ($birthdate == '0000-00-00') return 'Unknown';
    $bits = explode('-', $birthdate);
    $age = date('Y') - $bits[0] - 1;
    $arr[1] = 'm';
    $arr[2] = 'd';
    for ($i = 1; $arr[$i]; $i++) {
        $n = date($arr[$i]);
        if ($n < $bits[$i])
            break;
        if ($n > $bits[$i]) {
            ++$age;
            break;
        }
    }
    return $age;
}

This function is to get age by given birthday (format: YYYY-MM-DD).

---

Extract files from ZIP archive

function unzipArchive($file, $destinationFolder){
        // create ZipArchive object
        $zip = new ZipArchive() ;
        // open archive
        if ($zip->open($file) !== TRUE) {
                die ('Could not open archive');
        }
        // extract it's content to destination folder
        $zip->extractTo($destinationFolder);
        // close archive
        $zip->close();
}

This function takes two parameters:

• string $file – Path to the initial ZIP file
• string $destinationFolder – Path to the destination folder for files

---

Conclusion

Today is all, thank you for your attention, do not forget to visit us from time to time.