Question

I’m using php to return an array of data, with the command json_encode(). I want to also send some other data after I send this array. I’m using the jquery library. My php code is as follows:

<?php    

////  Query
$sql = "SELECT gtn FROM $table WHERE gid < 10";

//// Open connection 
$con = pg_connect("host=12.12.2.2 port=5434 dbname=spatial_data user=postgres password=****");  
if (!$con){echo 'error connecting'; die; }

//// Run query
$query = pg_query($con, $sql);
$arrayData = array(); // Store results from query in arrays

//// Parse results
while($r = pg_fetch_row($query)) {
    $arrayData[] = $r[0];
}
echo json_encode($arrayData);

//// Return metadata about calculation
//echo "$('#messages').html('Result returned for New York')";

//// close connection
pg_close($con);   

?>

This php is responding to a jquery post command:

$.ajax({ 
  type: "POST",
  url: "/php/array_test_v3.php",  
  data:{vertices: pointlist},  
  success: function(arrayData){  
    //console.log(arrayData[0])
    for(i=0;i<arrayData.length; i++){
      setGeoJson(arrayData[i]);
    }
  }, 
  dataType:'json'
}); 

This is a spatial database, and when I query the information, I also want to return some other values. For example, if the area is New York, I want to return an array of data and also the string New York. At the moment the line echo "$('#messages').html('Result returned for New York')"; just appends to the array of information. Is there a way that I can escape from the array, or do I need to have a separate post function to get this information.

Answer 1

Instead of echo json_encode($arrayData);, just fetch the meta data and then do:

echo json_encode(array(
    'data' => $arrayData,
    'meta' => $metaData
));

And then in JQuery:

  success: function(result){  
    for(i=0;i<result.data.length; i++){
      setGeoJson(result.data[i]);
    }
    // do something with result.meta
  },