From 8c8054b785ab354dadf03a6dd385fde954201142 Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Wed, 29 Aug 2018 00:43:42 -0400
Subject: [PATCH] Better check for file extension, default to .gpx if `gpx=` in
 url (closes #5253)

---
 modules/renderer/background.js |  2 +-
 modules/svg/data.js            | 16 ++++++++--------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/modules/renderer/background.js b/modules/renderer/background.js
index 4b71ddfe1..b52db0415 100644
--- a/modules/renderer/background.js
+++ b/modules/renderer/background.js
@@ -452,7 +452,7 @@ export function rendererBackground(context) {
         if (q.gpx) {
             var gpx = context.layers().layer('data');
             if (gpx) {
-                gpx.url(q.gpx);
+                gpx.url(q.gpx, '.gpx');
             }
         }
 
diff --git a/modules/svg/data.js b/modules/svg/data.js
index b4ee1a7ac..a391c8f1f 100644
--- a/modules/svg/data.js
+++ b/modules/svg/data.js
@@ -316,10 +316,9 @@ export function svgData(projection, context, dispatch) {
     function getExtension(fileName) {
         if (!fileName) return;
 
-        var lastDotIndex = fileName.lastIndexOf('.');
-        if (lastDotIndex < 0) return;
-
-        return fileName.substr(lastDotIndex);
+        var re = /\.(gpx|kml|(geo)?json)$/i;
+        var match = fileName.match(re);
+        return match && match.length && match[0];
     }
 
 
@@ -471,15 +470,16 @@ export function svgData(projection, context, dispatch) {
     };
 
 
-    drawData.url = function(url) {
+    drawData.url = function(url, defaultExtension) {
         _template = null;
         _fileList = null;
         _geojson = null;
         _src = null;
 
-        var extension = getExtension(url);
-        var re = /\.(gpx|kml|(geo)?json)$/i;
-        if (re.test(extension)) {
+        // strip off any querystring/hash from the url before checking extension
+        var testUrl = url.split(/[?#]/)[0];
+        var extension = getExtension(testUrl) || defaultExtension;
+        if (extension) {
             _template = null;
             d3_text(url, function(err, data) {
                 if (err) return;