Trim IE's full file path in multipart uploads

lib/rack/utils.rb

@@ -293,6 +293,14 @@ def self.parse_multipart(env)
 
             if filename
               body.rewind
+
+              # Take the basename of the upload's original filename.
+              # This handles the full Windows paths given by Internet Explorer
+              # (and perhaps other broken user agents) without affecting
+              # those which give the lone filename.
+              filename =~ /^(?:.*[:\\\/])?(.*)/m
+              filename = $1
+
               data = {:filename => filename, :type => content_type,
                       :name => name, :tempfile => body, :head => head}
             else

test/multipart/ie

@@ -0,0 +1,6 @@
+--AaB03x
+Content-Disposition: form-data; name="files"; filename="C:\Documents and Settings\Administrator\Desktop\file1.txt"
+Content-Type: text/plain
+
+contents
+--AaB03x--

test/spec_rack_utils.rb

@@ -29,7 +29,7 @@
     Rack::Utils.parse_query("my+weird+field=q1%212%22%27w%245%267%2Fz8%29%3F").
       should.equal "my weird field" => "q1!2\"'w$5&7/z8)?"
   end
-  
+
   specify "should build query strings correctly" do
     Rack::Utils.build_query("foo" => "bar").should.equal "foo=bar"
     Rack::Utils.build_query("foo" => ["bar", "quux"]).
@@ -184,6 +184,19 @@ def context env, app=@app; app.call(env); end
     params["files"][:tempfile].read.length.should.equal 26473
   end
 
+  specify "should parse IE multipart upload and clean up filename" do
+    env = Rack::MockRequest.env_for("/", multipart_fixture(:ie))
+    params = Rack::Utils::Multipart.parse_multipart(env)
+    params["files"][:type].should.equal "text/plain"
+    params["files"][:filename].should.equal "file1.txt"
+    params["files"][:head].should.equal "Content-Disposition: form-data; " +
+      "name=\"files\"; " +
+      'filename="C:\Documents and Settings\Administrator\Desktop\file1.txt"' +
+      "\r\nContent-Type: text/plain\r\n"
+    params["files"][:name].should.equal "files"
+    params["files"][:tempfile].read.should.equal "contents"
+  end
+
   specify "rewinds input after parsing upload" do
     options = multipart_fixture(:text)
     input = options[:input]