fix Content-Type for gzip in StaticFileHandler

MANIFEST.in

@@ -8,6 +8,9 @@ include tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.mo
 include tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.po
 include tornado/test/options_test.cfg
 include tornado/test/static/robots.txt
+include tornado/test/static/sample.xml
+include tornado/test/static/sample.xml.gz
+include tornado/test/static/sample.xml.bz2
 include tornado/test/static/dir/index.html
 include tornado/test/static_foo.txt
 include tornado/test/templates/utf8.html

setup.py

@@ -146,6 +146,9 @@ def build_extension(self, ext):
             "gettext_translations/fr_FR/LC_MESSAGES/tornado_test.po",
             "options_test.cfg",
             "static/robots.txt",
+            "static/sample.xml",
+            "static/sample.xml.gz",
+            "static/sample.xml.bz2",
             "static/dir/index.html",
             "static_foo.txt",
             "templates/utf8.html",

tornado/test/static/sample.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+<data>
+    <country name="Liechtenstein">
+        <rank>1</rank>
+        <year>2008</year>
+        <gdppc>141100</gdppc>
+        <neighbor name="Austria" direction="E"/>
+        <neighbor name="Switzerland" direction="W"/>
+    </country>
+    <country name="Singapore">
+        <rank>4</rank>
+        <year>2011</year>
+        <gdppc>59900</gdppc>
+        <neighbor name="Malaysia" direction="N"/>
+    </country>
+    <country name="Panama">
+        <rank>68</rank>
+        <year>2011</year>
+        <gdppc>13600</gdppc>
+        <neighbor name="Costa Rica" direction="W"/>
+        <neighbor name="Colombia" direction="E"/>
+    </country>
+</data>

tornado/test/web_test.py

@@ -978,6 +978,19 @@ def test_static_files(self):
 
         response = self.fetch('/static/robots.txt')
         self.assertTrue(b"Disallow: /" in response.body)
+        self.assertEqual(response.headers.get("Content-Type"), "text/plain")
+
+    def test_static_compressed_files(self):
+        response = self.fetch("/static/sample.xml.gz")
+        self.assertEqual(response.headers.get("Content-Type"),
+                         "application/gzip")
+        response = self.fetch("/static/sample.xml.bz2")
+        self.assertEqual(response.headers.get("Content-Type"),
+                         "application/octet-stream")
+        # make sure the uncompressed file still has the correct type
+        response = self.fetch("/static/sample.xml")
+        self.assertTrue(response.headers.get("Content-Type")
+                        in set(("text/xml", "application/xml")))
 
     def test_static_url(self):
         response = self.fetch("/static_url/robots.txt")

tornado/web.py

@@ -2495,7 +2495,19 @@ def get_content_type(self):
         .. versionadded:: 3.1
         """
         mime_type, encoding = mimetypes.guess_type(self.absolute_path)
-        return mime_type
+        # per RFC 6713, use the appropriate type for a gzip compressed file
+        if encoding == "gzip":
+            return "application/gzip"
+        # As of 2015-07-21 there is no bzip2 encoding defined at
+        # http://www.iana.org/assignments/media-types/media-types.xhtml
+        # So for that (and any other encoding), use octet-stream.
+        elif encoding is not None:
+            return "application/octet-stream"
+        elif mime_type is not None:
+            return mime_type
+        # if mime_type not detected, use application/octet-stream
+        else:
+            return "application/octet-stream"
 
     def set_extra_headers(self, path):
         """For subclass to add extra headers to the response"""