PHP SQLite to GeoJSON

sqlite_geojson.php

<?php
/**
 * SQLite to GeoJSON (Requires https://github.com/phayes/geoPHP)
 * Query a SQLite table or view (with a WKB GEOMETRY field) and return the results in GeoJSON format, suitable for use in OpenLayers, Leaflet, etc.
 * 
 * @param 		string		$geotable		The SQLite table name *REQUIRED*
 * @param 		string		$geomfield		The WKB GEOMETRY field *REQUIRED*
 * @param 		string 		$fields 		Fields to be returned *OPTIONAL (If omitted, all fields will be returned)*
 * @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
 */

# Include required geoPHP library and define wkb_to_json function
include_once('geoPHP.inc');
function wkb_to_json($wkb) {
  $geom = geoPHP::load($wkb,'wkb');
  return $geom->out('json');
}

# Connect to SQLite database
$db = new PDO('sqlite:mydbfile.sqlite');
 
# Retrive URL variables
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['fields'])) {
    $fields = '*';
} else
    $fields = $_GET['fields'];
	
if (empty($_GET['parameters'])) {
    $parameters = '';
} else
    $parameters = $_GET['parameters'];

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

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

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

# Build SQL SELECT statement and return the geometry as a GeoJSON element
$sql = "SELECT " . sqlite_escape_string($fields) . ", " . sqlite_escape_string($geomfield) . " AS geojson FROM " . sqlite_escape_string($geotable);
if (strlen(trim($parameters)) > 0) {
    $sql .= " WHERE " . sqlite_escape_string($parameters);
}
if (strlen(trim($orderby)) > 0) {
    $sql .= " ORDER BY " . sqlite_escape_string($orderby) . " " . $sort;
}
if (strlen(trim($limit)) > 0) {
    $sql .= " LIMIT " . sqlite_escape_string($limit);
}
if (strlen(trim($offset)) > 0) {
    $sql .= " OFFSET " . sqlite_escape_string($offset);
}
//echo $sql;

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

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

while ($row = $rs->fetch(PDO::FETCH_ASSOC)) {
    $rowOutput = (strlen($rowOutput) > 0 ? ',' : '') . '{"type": "Feature", "geometry": ' . wkb_to_json($row['geojson']) . ', "properties": {';
    $props = '';
    $id    = '';
    foreach ($row as $key => $val) {
        if ($key != "geojson") {
            $props .= (strlen($props) > 0 ? ',' : '') . '"' . $key . '":"' . $val . '"';
        }
        if ($key == "id") {
            $id .= ',"id":"' . $val . '"';
        }
    }
    
    $rowOutput .= $props . '}';
    $rowOutput .= $id;
    $rowOutput .= '}';
    $output .= $rowOutput;
}

$output = '{ "type": "FeatureCollection", "features": [ ' . $output . ' ]}';
echo $output;
$db = NULL;
?>