From: Birk Nilson <me@birknilson.se>
Date: Fri, 2 Dec 2011 12:28:03 +0000 (+0000)
Subject: Separate generation of static URLs and versioning in order ease customization
X-Git-Tag: v2.2.0~11^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2468216f5918c16c055756f52bf95ac7b166c92e;p=thirdparty%2Ftornado.git

Separate generation of static URLs and versioning in order ease customization
of how versioning is handled in subclasses.
---

diff --git a/tornado/web.py b/tornado/web.py
index c7801a4fe..906b01284 100644
--- a/tornado/web.py
+++ b/tornado/web.py
@@ -1528,6 +1528,21 @@ class StaticFileHandler(RequestHandler):
         is the static path being requested.  The url returned should be
         relative to the current host.
         """
+        static_url_prefix = settings.get('static_url_prefix', '/static/')
+        version_hash = cls.get_version(settings, path)
+        if version_hash:
+            return static_url_prefix + path + "?v=" + version_hash
+        return static_url_prefix + path
+
+    @classmethod
+    def get_version(cls, settings, path):
+        """Generate the version string to be appended as a query string
+        to the static URL - allowing aggressive caching.
+
+        ``settings`` is the `Application.settings` dictionary and ```path``
+        is the relative location of the requested asset on the filesystem.
+        """
+        hsh = None
         abs_path = os.path.join(settings["static_path"], path)
         with cls._lock:
             hashes = cls._static_hashes
@@ -1539,12 +1554,8 @@ class StaticFileHandler(RequestHandler):
                 except Exception:
                     logging.error("Could not open static file %r", path)
                     hashes[abs_path] = None
-            hsh = hashes.get(abs_path)
-        static_url_prefix = settings.get('static_url_prefix', '/static/')
-        if hsh:
-            return static_url_prefix + path + "?v=" + hsh[:5]
-        else:
-            return static_url_prefix + path
+            hsh = hashes.get(abs_path)[:5]
+        return hsh
 
 
 class FallbackHandler(RequestHandler):