Index: publish.py
===================================================================
--- publish.py	(revision 24226)
+++ publish.py	(working copy)
@@ -56,6 +56,10 @@
 </html>
 """
 
+TIDY_IGNORE = [
+    'Warning: <table> lacks "summary" attribute',
+    ]
+
 class Publisher:
     """
     The core of Quixote and of any Quixote application.  This class is
@@ -502,11 +506,50 @@
         """Hook for post processing the output.  Subclasses may wish to
         override (e.g. check HTML syntax).
         """
+        c_type=request.response.headers.get("content-type")
         if (output and
+                (not c_type or c_type=="text/html") and
+                not isinstance(output, Stream)):
+            self.html_tidy(request, output)
+        if (output and
                 self.config.compress_pages and
                 not isinstance(output, Stream)):
             output = self.compress_output(request, str(output))
         return output
+
+    def html_tidy(self, request, output):
+        """
+        Small hack to call html-tidy for every html
+        page which is serverd by quixote.
+
+        It is used for checking the html syntax only, the html
+        output won't be changed.
+        """
+        import os, tempfile
+        htmlfile = tempfile.NamedTemporaryFile()
+        htmlfile.write(str(output))
+        htmlfile.flush()
+        htmlfile.seek(0)
+        fp = os.popen("tidy -q -e '%s' 2>&1" % htmlfile.name, "r")
+        errors = []
+        for line in fp:
+            line = line.strip()
+            if line:
+                for ign in TIDY_IGNORE:
+                    if ign in line:
+                        break
+                else:
+                    errors.append(line)
+        if errors:
+            self.log("HTML-Tidy: %s" % request.get_path())
+            for line in errors[:20]:
+                self.log("   " + line)
+            if len(errors) > 20:
+                self.log("   [...more errors...]")
+        else:
+            self.log("HTML-Tidy: %s okay" % request.get_path())
+        fp.close()
+        htmlfile.close()
     
     def process_request (self, request, env):
         """process_request(request : HTTPRequest, env : dict) : string