PHP PostGIS to GeoJSON - with BBOX query

getfeature.php

<?php
/**
 * PostGIS to GeoJSON
 * Query a PostGIS table or view and return the results in GeoJSON format, suitable for use in OpenLayers, Leaflet, etc.
 * 
 * @param		string		$bbox			Bounding box of request *REQUIRED*
 * @param 		string		$geotable		The PostGIS layer name *REQUIRED*
 * @param 		string		$geomfield		The PostGIS geometry field *REQUIRED*
 * @param 		string		$srid			The SRID of the returned GeoJSON *OPTIONAL (If omitted, EPSG: 4326 will be used)*
 * @param 		string 		$fields 		Fields to be returned *OPTIONAL (If omitted, all fields will be returned)* NOTE- Uppercase field names should be wrapped in double quotes
 * @param 		string		$parameters		SQL WHERE clause parameters *OPTIONAL*
 * @param 		string		$orderby		SQL ORDER BY constraint *OPTIONAL*
 * @param 		string		$sort			SQL ORDER BY sort order (ASC or DESC) *OPTIONAL*
 * @param 		string		$limit			Limit number of results returned *OPTIONAL*
 * @param 		string		$offset			Offset used in conjunction with limit *OPTIONAL*
 * @return 		string						resulting geojson string
 */
 
$dbconn = pg_connect ("host=localhost port=5432 dbname=db user=user password=pass");
if (!$dbconn) {
     echo("Error in connection: " . pg_last_error());
 }   
$bbox = $_GET['bbox'];
list($bbox_west, $bbox_south, $bbox_east, $bbox_north) = split(",", $bbox);

if (empty($_GET['geotable'])) {
    echo "missing required parameter: <i>geotable</i>";
    exit;
} else
    $geotable = $_GET['geotable'];

if (empty($_GET['geomfield'])) {
    echo "missing required parameter: <i>geomfield</i>";
    exit;
} else
    $geomfield = $_GET['geomfield'];

if (empty($_GET['srid'])) {
    $srid = '4326';
} else
    $srid = $_GET['srid'];

if (empty($_GET['fields'])) {
    $fields = '*';
} else
    $fields = $_GET['fields'];

$parameters = $_GET['parameters'];

$orderby    = $_GET['orderby'];

if (empty($_GET['sort'])) {
    $sort = 'ASC';
} else
    $sort = $_GET['sort'];
	
$limit      = $_GET['limit'];

$offset     = $_GET['offset'];

# Build SQL SELECT statement and return the geometry as a GeoJSON element in EPSG: 4326
$sql = "SELECT " . pg_escape_string($fields) . ", st_asgeojson(transform(" . pg_escape_string($geomfield) . ",$srid)) AS geojson FROM " . pg_escape_string($geotable);
if (strlen(trim($parameters)) > 0) {
    $sql .= " WHERE " . pg_escape_string($parameters);
    $sql .= " AND (box(point(" . $bbox_west . "," . $bbox_south . "),point(" . $bbox_east . "," . $bbox_north . ")) ~ (". $geomfield ."))";
}
else {
	$sql .= " WHERE (box(point(" . $bbox_west . "," . $bbox_south . "),point(" . $bbox_east . "," . $bbox_north . ")) ~ (". $geomfield ."))";
}
if (strlen(trim($orderby)) > 0) {
    $sql .= " ORDER BY " . pg_escape_string($orderby) . " " . $sort;
}
if (strlen(trim($limit)) > 0) {
    $sql .= " LIMIT " . pg_escape_string($limit);
}
if (strlen(trim($offset)) > 0) {
    $sql .= " OFFSET " . pg_escape_string($offset);
}
$sql .= ";";
//echo $sql;

# Try query or error
$rs = pg_query($dbconn, $sql);
if (!$rs) {
    echo "An SQL error occured.\n";
    exit;
}

# Build GeoJSON
#$output    = '';
#$rowOutput = '';

$geojson = array(
       'type'      => 'FeatureCollection',
       'features'  => array()
    );

    
while($row=pg_fetch_assoc($rs)) {  
	   $properties = array();
       foreach ($row as $key => $val) {
		   if ($key != 'geojson') {
			  // array_push($properties,$key,$val);
			  $properties[$key] = $val;
		   };
	   };
	  $feature = array(
          'type' => 'Feature',
          'properties' => $properties,
          'geometry' => json_decode($row['geojson'], true),       
          );
       // Add feature array to feature collection array
       array_push($geojson['features'], $feature);
    }
 
    // Close database connection
    pg_close($dbconn);
 
    //header('Content-type: application/json',true);
    echo json_encode($geojson); 

?>