[Product-Developers] Traversing to an object like the publisher does

[Jan Hackel]

On Thursday 14 May 2009 Jan Hackel wrote:
> I need to write a test that essentially needs to traverse to an operation
> like the following tal-expression would:
>
> tal:condition="context/@@plone_context_state/is_view_template"
>
> It seems I cannot use "(un)restrictedTraverse" because it does not trigger
> my custom IPublishTraverse adapter. Using "Request.traverse" looks
> promising but I cannot get authorization to work with it, i.e. I get an
> UnauthorizedException.
>
> Is there a canonical way of simulating the tal-expression given above?

Here is the solution which I for now have to settle with. Mind that it is used 
for testing only. Protect your eyes!

    >>> from ZPublisher.tests.testBaseRequest import DummyResponse
    >>> from ZPublisher.HTTPRequest import HTTPRequest
    >>> from ZPublisher.HTTPResponse import HTTPResponse
    >>> from Products.PloneTestCase import PloneTestCase
    >>> import base64
    >>> user_id = PloneTestCase.default_user
    >>> password = PloneTestCase.default_password
    >>> encoded = base64.encodestring( '%s:%s' % ( user_id, password ) )
    >>> auth_header = 'basic %s' % encoded
    >>> resp = DummyResponse()
    >>> env={'SERVER_URL':'http://nohost/plone',
    ...          'URL':'http://nohost/plone',
    ...          'HTTP_AUTHORIZATION': auth_header,
    ...          'REQUEST_METHOD': 'GET',
    ...          'steps': [],
    ...          '_hacked_path': 0,
    ...          '_test_counter': 0,
    ...          'response' : resp
    ... }
    >>> request = HTTPRequest(stdin=None, environ=env, response=resp)
    >>> request['PARENTS'] = [self.getPortal()]

Now the traversal up the context state view.
     
    >>> contextState = request.traverse("weblog/issue193/"
    ...                  "@@plone_context_state")

The call to "request.traverse" differs from what TAL-traversal does. The 
request URL has the view name '@@plone_context_state' appended. In my case I 
had to remove that before the actual call.

    >>> request['ACTUAL_URL'] = 'http://nohost/weblog/issue193'
    >>> contextState.is_view_template()
    True    

Grüße
Jan Hackel