index.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    $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
 */

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

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

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

$parameters = $_GET['parameters'];
$orderby = $_GET['orderby'];

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

$limit = $_GET['limit'];

$offset = $_GET['offset'];

# Connect to PostgreSQL database
$conn = pg_connect("dbname='mydbname' user='myusername' password='mypassword' host='localhost'");
if (!$conn) {
    echo "Not connected : " . pg_error();
    exit;
}

$sql = "SELECT $fields, st_asgeojson(transform($geomfield, $srid)) AS geojson FROM events");
if (strlen(trim($parameters)) > 0) { $sql .= " WHERE $parameters"; }
if (strlen(trim($orderby))    > 0) { $sql .= " ORDER BY $orderby $sort"; }
if (strlen(trim($limit))      > 0) { $sql .= " LIMIT $limit"; }
if (strlen(trim($offset))     > 0) { $sql .= " OFFSET $offset"; }
$sql = pg_escape_string($sql);

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

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

while ($row = pg_fetch_assoc($rs)) {
    $output['features'][] = array(
      'type' => 'Feature',
      'geometry' => $row['geojson'],
      'properties' => $row,
      'id' => $row['id']
    )
}

echo json_encode($output);