fix handling of empty files

lib/mbtiles.js

@@ -376,14 +376,23 @@ MBTiles.prototype.getInfo = function(callback) {
         if (err) return callback(err);
         var range = parseInt(info.maxzoom, 10) - parseInt(info.minzoom, 10);
         info.minzoom = parseInt(info.minzoom, 10);
+        if (isNaN(info.minzoom) || typeof info.minzoom !== 'number') delete info.minzoom;
         info.maxzoom = parseInt(info.maxzoom, 10);
+        if (isNaN(info.maxzoom) || typeof info.maxzoom !== 'number') delete info.maxzoom;
+
         info.bounds = _((info.bounds || '').split(',')).map(parseFloat);
+        if (info.bounds.length !== 4 || info.bounds[0] === null) delete info.bounds;
+
         if (info.center) info.center = _((info.center).split(',')).map(parseFloat);
-        if (!info.center || info.center.length !== 3) info.center = [
+        if ((!info.center || info.center.length !== 3) && info.bounds) info.center = [
             (info.bounds[2] - info.bounds[0]) / 2 + info.bounds[0],
             (info.bounds[3] - info.bounds[1]) / 2 + info.bounds[1],
             (range <= 1) ? info.maxzoom : Math.floor(range * 0.5) + info.minzoom
         ];
+        if (info.center && (info.center.length !== 3 || info.center[0] === null)) {
+            delete info.center;
+        }
+
         return callback(null, info);
     });
 };

test/info.test.js

@@ -0,0 +1,70 @@
+process.env.NODE_ENV = 'test';
+
+var fs = require('fs');
+var Step = require('step');
+var assert = require('assert');
+var MBTiles = require('..');
+
+var fixtures = {
+    plain_1: __dirname + '/fixtures/plain_1.mbtiles',
+    empty: __dirname + '/fixtures/empty.mbtiles'
+};
+
+try { fs.unlink(fixtures.empty); } catch (err) {}
+
+
+exports['get metadata'] = function(beforeExit) {
+    var completed = false;
+
+    new MBTiles(fixtures.plain_1, function(err, mbtiles) {
+        if (err) throw err;
+
+        mbtiles.getInfo(function(err, data) {
+            completed = true;
+            if (err) throw err;
+
+            assert.deepEqual({
+                name: 'plain_1',
+                description: 'demo description',
+                version: '1.0.3',
+                scheme: 'tms',
+                minzoom: 0,
+                maxzoom: 4,
+                formatter: null,
+                center: [ 0, 7.500000001278025, 2 ],
+                bounds: [ -179.9999999749438, -69.99999999526695, 179.9999999749438, 84.99999999782301 ],
+
+                // These aren't part of TileJSON, but exist in an MBTiles file.
+                filesize: 561152,
+                type: 'baselayer',
+                id: 'plain_1',
+                basename: 'plain_1.mbtiles'
+            }, data);
+        })
+    });
+
+    beforeExit(function() {
+        assert.ok(completed);
+    });
+};
+
+exports['get/put metadata from empty file'] = function(beforeExit) {
+    var completed = false;
+
+    new MBTiles(fixtures.empty, function(err, mbtiles) {
+        if (err) throw err;
+
+        mbtiles.getInfo(function(err, data) {
+            completed = true;
+            if (err) throw err;
+
+            assert.deepEqual({
+                basename: "empty.mbtiles",
+                filesize: 16384,
+                id: "empty",
+                scheme: "tms"
+            }, data);
+        })
+    });
+};
+

test/read.test.js

@@ -15,39 +15,6 @@ var fixtures = {
 
 try { fs.unlink(fixtures.non_existent); } catch (err) {}
 
-exports['get metadata'] = function(beforeExit) {
-    var completed = false;
-
-    new MBTiles(fixtures.plain_1, function(err, mbtiles) {
-        mbtiles.getInfo(function(err, data) {
-            completed = true;
-            if (err) throw err;
-
-            assert.deepEqual({
-                name: 'plain_1',
-                description: 'demo description',
-                version: '1.0.3',
-                scheme: 'tms',
-                minzoom: 0,
-                maxzoom: 4,
-                formatter: null,
-                center: [ 0, 7.500000001278025, 2 ],
-                bounds: [ -179.9999999749438, -69.99999999526695, 179.9999999749438, 84.99999999782301 ],
-
-                // These aren't part of TileJSON, but exist in an MBTiles file.
-                filesize: 561152,
-                type: 'baselayer',
-                id: 'plain_1',
-                basename: 'plain_1.mbtiles'
-            }, data);
-        })
-    });
-
-    beforeExit(function() {
-        assert.ok(completed);
-    });
-};
-
 function yieldsError(status, error, msg) {
     return function(err) {
         assert.ok(err);