Force client-side purging of CSS/JS when updated.

app.py

@@ -2,9 +2,11 @@
 # -*- coding: utf-8  -*-
 
 from functools import wraps
+from hashlib import md5
 from json import dumps
 from logging import DEBUG, INFO, getLogger
 from logging.handlers import TimedRotatingFileHandler
+from os import path
 from time import asctime
 from traceback import format_exc
 
@@ -27,6 +29,7 @@ hand = TimedRotatingFileHandler("logs/app.log", when="midnight", backupCount=7)
 hand.setLevel(DEBUG)
 app.logger.addHandler(hand)
 app.logger.info(u"Flask server started " + asctime())
+app._hash_cache = {}
 
 def catch_errors(func):
     @wraps(func)
@@ -77,6 +80,22 @@ def close_databases(error):
     if g._db:
         g._db.close()
 
+def external_url_handler(error, endpoint, **values):
+    if endpoint == "static" and "file" in values:
+        fpath = path.join(app.static_folder, values["file"])
+        mtime = path.getmtime(fpath)
+        cache = app._hash_cache.get(fpath)
+        if cache and cache[0] == mtime:
+            hashstr = cache[1]
+        else:
+            with open(fpath, "rb") as f:
+                hashstr = md5(f.read()).hexdigest()
+            app._hash_cache[fpath] = (mtime, hashstr)
+        return "/static/{0}?v={1}".format(values["file"], hashstr)
+    raise error
+
+app.build_error_handler = external_url_handler
+
 @app.route("/")
 @catch_errors
 def index():

templates/api.mako

@@ -1,4 +1,7 @@
-<%! from json import dumps %>\
+<%!
+    from json import dumps
+    from flask import url_for
+%>\
 <%def name="do_indent(size)">
     <br />
     % for i in xrange(size):
@@ -31,7 +34,7 @@
     <head>
         <meta charset="utf-8">
         <title>API - Earwig's Copyvio Detector</title>
-        <link rel="stylesheet" href="${request.script_root}/static/api.min.css" type="text/css" />
+        <link rel="stylesheet" href="${request.script_root}$(url_for('static', file='api.min.css')" type="text/css" />
     </head>
     <body>
         % if help:

templates/support/header.mako

@@ -1,6 +1,6 @@
 <%page args="title"/>\
 <%!
-    from flask import g, request
+    from flask import g, request, url_for
     from copyvios.background import set_background
 %>\
 <!DOCTYPE html>
@@ -8,9 +8,9 @@
     <head>
         <meta charset="utf-8">
         <title>${title}</title>
-        <link rel="stylesheet" href="${request.script_root}/static/style.min.css" type="text/css" />
+        <link rel="stylesheet" href="${request.script_root}$(url_for('static', file='style.min.css')" type="text/css" />
         <script src="//code.jquery.com/jquery-1.11.1.min.js" type="text/javascript"></script>
-        <script src="${request.script_root}/static/script.min.js" type="text/javascript"></script>
+        <script src="${request.script_root}/$(url_for('static', file='script.min.js')" type="text/javascript"></script>
     </head>
     <% selected = g.cookies["CopyviosBackground"].value if "CopyviosBackground" in g.cookies else "list" %>\
     % if selected == "plain":