Escape '.', '+', '$' and parens in literal paths [#124]

Since Sinatra turns literal paths into a regular expression,
we need to escape dots and pluses, as they have special
meanings inside a regex, but not ?, since we need that
for optional parameters.

lib/sinatra/base.rb

@@ -600,11 +600,15 @@ module Sinatra
       def compile(path)
         keys = []
         if path.respond_to? :to_str
+          special_chars = %w{. + ( )}
           pattern =
-            URI.encode(path).gsub(/((:\w+)|\*)/) do |match|
-              if match == "*"
+            URI.encode(path).gsub(/((:\w+)|[\*#{special_chars.join}])/) do |match|
+              case match
+              when "*"
                 keys << 'splat'
                 "(.*?)"
+              when *special_chars
+                Regexp.escape(match)
               else
                 keys << $2[1..-1]
                 "([^/?&#\.]+)"

test/routing_test.rb

@@ -1,5 +1,10 @@
 require File.dirname(__FILE__) + '/helper'
 
+# Helper method for easy route pattern matching testing
+def route_def(pattern)
+  mock_app { get(pattern) { } }
+end
+
 describe "Routing" do
   %w[get put post delete head].each do |verb|
     it "defines #{verb.upcase} request handlers with #{verb}" do
@@ -119,6 +124,38 @@ describe "Routing" do
     assert ok?
   end
 
+  it "literally matches . in paths" do
+    route_def '/test.bar'
+
+    get '/test.bar'
+    assert ok?
+    get 'test0bar'
+    assert not_found?
+  end
+
+  it "literally matches $ in paths" do
+    route_def '/test$/'
+
+    get '/test$/'
+    assert ok?
+  end
+
+  it "literally matches + in paths" do
+    route_def '/te+st/'
+
+    get '/te+st/'
+    assert ok?
+    get '/teeeeeeest/'
+    assert not_found?
+  end
+
+  it "literally matches () in paths" do
+    route_def '/test(bar)/'
+
+    get '/test(bar)/'
+    assert ok?
+  end
+
   it "supports basic nested params" do
     mock_app {
       get '/hi' do