demo: Access bucket via IPv6-capable endpoint

demo/_synctiles.py

@@ -43,7 +43,8 @@
 
 STAMP_VERSION = 'size-510'  # change to retile without OpenSlide version bump
 S3_BUCKET = 'openslide-demo'
-BASE_URL = 'https://%s.s3.amazonaws.com/' % S3_BUCKET
+S3_REGION = 'us-east-1'
+BASE_URL = 'https://%s.s3.dualstack.%s.amazonaws.com/' % (S3_BUCKET, S3_REGION)
 CORS_ORIGINS = ['*']
 DOWNLOAD_BASE_URL = 'http://openslide.cs.cmu.edu/download/openslide-testdata/'
 DOWNLOAD_INDEX = 'index.json'

demo/index.html

@@ -103,7 +103,7 @@
                 }
             },
             'timeout': 60000,
-            'url': 'https://openslide-demo.s3.amazonaws.com/status.json',
+            'url': 'https://openslide-demo.s3.dualstack.us-east-1.amazonaws.com/status.json',
         });
     }
     $(window).on('visibilitychange', function() {
@@ -286,7 +286,7 @@
             $('#images').removeClass('loading').
                     html("<div class='error'>Couldn't load slides</div>");
         },
-        'url': 'https://openslide-demo.s3.amazonaws.com/info.json'
+        'url': 'https://openslide-demo.s3.dualstack.us-east-1.amazonaws.com/info.json'
     });
 
     // CSS doesn't provide a good way to specify a div of height