Use browser detection to decide how many features to show

Modern browsers are quite happy showing far more than 100 features in
the data browser, so increase the limit to 2000 by default, but keep it
restricted to 500 for IE8 and 100 for older IEs.

Gemfile

@@ -25,6 +25,9 @@ gem 'http_accept_language', '>= 1.0.2'
 gem 'paperclip', '~> 2.0'
 gem 'deadlock_retry', '>= 1.2.0'
 
+# Browser detection support
+gem 'browser'
+
 # Markdown formatting support
 gem 'redcarpet'
 

Gemfile.lock

@@ -31,6 +31,7 @@ GEM
       multi_json (~> 1.0)
     arel (3.0.2)
     bigdecimal (1.1.0)
+    browser (0.1.3)
     builder (3.0.0)
     cocaine (0.2.1)
     coffee-rails (3.2.2)
@@ -157,6 +158,7 @@ PLATFORMS
 DEPENDENCIES
   SystemTimer (>= 1.1.3)
   bigdecimal
+  browser
   coffee-rails (~> 3.2.1)
   composite_primary_keys (= 5.0.4)
   deadlock_retry (>= 1.2.0)

app/controllers/browse_controller.rb

@@ -7,6 +7,11 @@ class BrowseController < ApplicationController
   around_filter :web_timeout, :except => [:start]
 
   def start 
+    @max_features = case
+                    when browser.ie? && browser.version.to_i < 8 then 100
+                    when browser.ie? && browser.version.to_i < 9 then 500
+                    else 2000
+                    end
   end
   
   def relation

app/views/browse/start.js.erb

@@ -245,7 +245,7 @@ function loadGML(url, reload) {
     browseDataLayer = new OpenLayers.Layer.GML("Data", url, {
       format: OpenLayers.Format.OSM,
       formatOptions: formatOptions,
-      maxFeatures: 100,
+      maxFeatures: <%= @max_features %>,
       requestSuccess: customDataLoader,
       displayInLayerSwitcher: false,
       styleMap: new OpenLayers.StyleMap({