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php-useful-snippets.php

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:

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

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

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

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function getAge($birthdate = '0000-00-00') {
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    if ($birthdate == '0000-00-00') return 'Unknown';
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    $bits = explode('-', $birthdate);
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    $age = date('Y') - $bits[0] - 1;
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    $arr[1] = 'm';
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    $arr[2] = 'd';
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    for ($i = 1; $arr[$i]; $i++) {
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        $n = date($arr[$i]);
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        if ($n < $bits[$i])
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            break;
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        if ($n > $bits[$i]) {
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            ++$age;
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            break;
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        }
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    }
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    return $age;
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}
This function is to get age by given birthday (format: YYYY-MM-DD).

Extract files from ZIP archive

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

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

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