From 0ae2ff5cbdb6584b3a3bd452dc9225bff19ca97c Mon Sep 17 00:00:00 2001
From: Ryan Clark <ryan.clark.j@gmail.com>
Date: Wed, 21 Jan 2015 17:07:50 -0700
Subject: [PATCH] use mapnik geojson dstype

---
 lib/datasource-processor.js            | 71 ++++++++++++++++++--------
 test/fixtures/metadata_DC_polygon.json |  4 +-
 2 files changed, 53 insertions(+), 22 deletions(-)

diff --git a/lib/datasource-processor.js b/lib/datasource-processor.js
index 14a2148..0ccda53 100644
--- a/lib/datasource-processor.js
+++ b/lib/datasource-processor.js
@@ -514,6 +514,7 @@ function processOgrDatasource(file, filesize, proj, filetype, callback) {
                     "fields": fields
                 });
             });
+
             return callback(null, {
                 extent: results.extent,
                 center: results.center,
@@ -521,7 +522,7 @@ function processOgrDatasource(file, filesize, proj, filetype, callback) {
                 minzoom: min,
                 maxzoom: max,
                 layers: layers,
-                dstype: 'ogr'
+                dstype: ds.dstype
             });
         });
     });
@@ -536,44 +537,69 @@ function processOgrDatasource(file, filesize, proj, filetype, callback) {
  *          ds (mapnik Datasource)
  */
 function getDatasourceProperties(file, filetype, callback) {
-    var dstype = 'ogr';
-    var options = {};
+    var options = {
+        type: filetype === '.geojson' ? 'geojson' : 'ogr',
+        file: file
+    };
+
+    if (filetype === '.geojson') {
+        var ds;
+        try { ds = new mapnik.Datasource(options); }
+        catch(err) {
+            if (/Failed parse GeoJSON file/.test(err))
+                // If it couldn't be parsed, try again as topojson
+                return getDatasourceProperties(file, '.topojson', callback);
+            }
 
-    //Get layers for kml or geojson/topojson
-    if (filetype === '.kml' || filetype === '.geojson') {
-        options.type = dstype;
-        options.file = file;
+            var features = [];
+            var featureset = ds.featureset();
+            var feature = featureset.next();
+            if (feature === undefined) {
+                return callback(invalid('Source appears to have no features data.'));
+            }
 
-        //Get KML/geojson layer names from the OGR error message...for now
+        ds.dstype = 'geojson';
+        return callback(null, [ 'OGRGeoJSON' ], ds);
+    }
+
+    // Get layers for kml or topojson
+    else if (filetype === '.kml' || filetype === '.topojson') {
+        // Get KML layer names from the OGR error message...for now
         getLayers(options, function(err, layers) {
             if (err) return callback(err);
             getDatasource(options, layers, function(err, ds) {
                 if (err) return callback(err);
-                else return callback(null, layers, ds);
+                else {
+                    ds.dstype = 'ogr';
+                    return callback(null, layers, ds);
+                }
             });
         });
+    }
 
-        //Get layers for .gpx
-    } else if (filetype === '.gpx') {
-        options.type = dstype;
-        options.file = file;
-
-        //GPX files can only have these layers
+    // Get layers for .gpx
+    else if (filetype === '.gpx') {
+        // GPX files can only have these layers
         var layers = ['waypoints', 'routes', 'tracks', 'route_points', 'track_points'];
         getDatasource(options, layers, function(err, ds) {
             if (err) return callback(err);
+            ds.dstype = 'ogr';
             return callback(null, layers, ds);
         });
     }
+
+    else return callback(new Error('Unexpected filetype passed to getDatasourceProperties'));
 }
 
-//Sole purpose is to obtain layer names from OGR error message
+// Sole purpose is to obtain layer names from OGR error message
 function getLayers(options, callback) {
     var layers_array;
     var error;
-    //Expect an error in order to obtain layer names from the OGR Error string...for now
+
+    // Expect an error in order to obtain layer names from the OGR Error string...for now
+    var ds;
     try {
-        var ds = new mapnik.Datasource(options);
+        ds = new mapnik.Datasource(options);
     } catch (err) {
         if (err.message && err.message.indexOf('OGR Plugin: missing <layer>') != -1) {
             var layers = err.message.split("are: ")[1];
@@ -583,9 +609,14 @@ function getLayers(options, callback) {
             var layer_names = layers.split('\'').join('');
             //designate each index of the array by splitting by commas
             layers_array = layer_names.split(',');
-        } else error = err;
+        }
+
+        else error = err;
+    }
+    if (error === undefined)  {
+        // console.log(ds.layers.count());
+        return callback(null, layers_array);
     }
-    if (error === undefined) return callback(null, layers_array);
     else return callback(invalid('Error obtaining layer names'));
 }
 
diff --git a/test/fixtures/metadata_DC_polygon.json b/test/fixtures/metadata_DC_polygon.json
index 25c223e..c051739 100644
--- a/test/fixtures/metadata_DC_polygon.json
+++ b/test/fixtures/metadata_DC_polygon.json
@@ -32,6 +32,6 @@
   "layers": [
     "OGRGeoJSON"
   ],
-  "dstype": "ogr",
+  "dstype": "geojson",
   "filetype": ".geojson"
-}
\ No newline at end of file
+}