source: trunk/workshop-routing-foss4g/web/php/pgrouting.php @ 77

<?php

   // Database connection settings
   define("PG_DB"  , "routing");
   define("PG_HOST", "localhost"); 
   define("PG_USER", "postgres");
   define("PG_PORT", "5432"); 
   define("TABLE",   "ways");

   // Retrieve start point
   $start = split(' ',$_REQUEST['startpoint']);
   $startPoint = array($start[0], $start[1]);

   // Retrieve end point
   $end = split(' ',$_REQUEST['finalpoint']);
   $endPoint = array($end[0], $end[1]);
   
?>

<?php

   // Find the nearest edge
   $startEdge = findNearestEdge($startPoint);
   $endEdge   = findNearestEdge($endPoint);

   // FUNCTION findNearestEdge
   function findNearestEdge($lonlat) {

      // Connect to database
      $con = pg_connect("dbname=".PG_DB." host=".PG_HOST." user=".PG_USER);

      $sql = "SELECT gid, source, target, the_geom, 
                          distance(the_geom, GeometryFromText(
                           'POINT(".$lonlat[0]." ".$lonlat[1].")', 4326)) AS dist 
                     FROM ".TABLE."  
                     WHERE the_geom && setsrid(
                           'BOX3D(".($lonlat[0]-0.1)." 
                                  ".($lonlat[1]-0.1).", 
                                  ".($lonlat[0]+0.1)." 
                                  ".($lonlat[1]+0.1).")'::box3d, 4326) 
                     ORDER BY dist LIMIT 1";

      $query = pg_query($con,$sql);  

      $edge['gid']      = pg_fetch_result($query, 0, 0);  
      $edge['source']   = pg_fetch_result($query, 0, 1);  
      $edge['target']   = pg_fetch_result($query, 0, 2);  
      $edge['the_geom'] = pg_fetch_result($query, 0, 3);  

      // Close database connection
      pg_close($con);

      return $edge;
   }
   
?>

<?php

   // Select the routing algorithm
   switch($_REQUEST['method']) {

      case 'SPD' : // Shortest Path Dijkstra 

        $sql = "SELECT rt.gid, ST_AsGeoJSON(rt.the_geom) AS geojson, 
                         length(rt.the_geom) AS length, ".TABLE.".gid 
                      FROM ".TABLE.", 
                          (SELECT gid, the_geom 
                              FROM dijkstra_sp_delta(
                                  '".TABLE."',
                                  ".$startEdge['source'].",
                                  ".$endEdge['target'].",
                                  0.1)
                           ) as rt 
                      WHERE ".TABLE.".gid=rt.gid;";
        break;
        
      case 'SPA' : // Shortest Path A* 

        $sql = "SELECT rt.gid, ST_AsGeoJSON(rt.the_geom) AS geojson, 
                           length(rt.the_geom) AS length, ".TABLE.".gid 
                        FROM ".TABLE.", 
                            (SELECT gid, the_geom 
                                FROM astar_sp_delta(
                                    '".TABLE."',
                                    ".$startEdge['source'].",
                                    ".$endEdge['target'].",
                                    0.1)
                             ) as rt 
                        WHERE ".TABLE.".gid=rt.gid;";  
        break;

      case 'SPS' : // Shortest Path Shooting*

        $sql = "SELECT rt.gid, ST_AsGeoJSON(rt.the_geom) AS geojson, 
                           length(rt.the_geom) AS length, ".TABLE.".gid 
                        FROM ".TABLE.", 
                            (SELECT gid, the_geom 
                                FROM shootingstar_sp(
                                    '".TABLE."',
                                    ".$startEdge['gid'].",
                                    ".$endEdge['gid'].",
                                    0.1, 'length', true, true)
                             ) as rt 
                        WHERE ".TABLE.".gid=rt.gid;";
        break;   

   } // close switch

   // Connect to database
   $dbcon = pg_connect("dbname=".PG_DB." host=".PG_HOST." user=".PG_USER);

   // Perform database query
   $query = pg_query($dbcon,$sql); 
   
?>

<?php

   // Return route as GeoJSON
   $geojson = array(
      'type'      => 'FeatureCollection',
      'features'  => array()
   ); 
  
   // Add edges to GeoJSON array
   while($edge=pg_fetch_assoc($query)) {  

      $feature = array(
         'type' => 'Feature',
         'geometry' => json_decode($edge['geojson'], true),
         'crs' => array(
            'type' => 'EPSG',
            'properties' => array('code' => '4326')
         ),
         'properties' => array(
            'id' => $edge['id'],
            'length' => $edge['length']
         )
      );
      
      // Add feature array to feature collection array
      array_push($geojson['features'], $feature);
   }

        
   // Close database connection
   pg_close($dbcon);

   // Return routing result
   header('Content-type: application/json',true);
   echo json_encode($geojson);
   
?>