Ticket #763 (defect)

CherryPy 3.0.2 and 3.1beta throws exception when parsing content types that ends with a ";" An example of a Content-Type header that gives such an error is:

  Content-Type: application/x-www-form-urlencoded; charset=utf-8;

It will produce the following exception:

*** got error ***
[08/Jan/2008:08:37:50]  Traceback (most recent call last):
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/_cprequest.py", line 90, in run
    hook()
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/_cprequest.py", line 58, in __call__
    return self.callback(**self.kwargs)
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/lib/encoding.py", line 10, in decode
    ct = cherrypy.request.headers.elements("Content-Type")
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/lib/http.py", line 350, in elements
    return header_elements(key, h)
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/lib/http.py", line 191, in header_elements
    hv = HeaderElement.from_str(element)
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/lib/http.py", line 131, in from_str
    ival, params = cls.parse(elementstr)
  File "/Library/Python/2.5/site-packages/CherryPy-3.1b1-py2.5.egg/cherrypy/lib/http.py", line 120, in parse
    key = atom.pop(0)
IndexError: pop from empty list

The problem with the content-type is the separator ";" at the end. One could question if it legal to end the content-type header with a ";", but CherryPy should probably not give an expection when trying to parse it. CherryPy 2.2.1 does not throw an exception when parsing such a content-type header.

A simple fix for lib/http.py is:

   def parse(elementstr):
        """Transform 'token;key=val' to ('token', {'key': 'val'})."""
        # Split the element into a value and parameters. The 'value' may
        # be of the form, "token=token", but we don't split that here.
-        atoms = [x.strip() for x in elementstr.split(";")]
+        atoms = [x.strip() for x in elementstr.split(";") if x]
        initial_value = atoms.pop(0).strip()
        params = {}
        for atom in atoms:
            atom = [x.strip() for x in atom.split("=", 1) if x.strip()]
            key = atom.pop(0)
            if atom:
                val = atom[0]
            else:
                val = ""
            params[key] = val
        return initial_value, params
    parse = staticmethod(parse)

-- Dag