How to make Universal Parser only for parsing?

Question

I am trying to get content from external feeds on my Django website with Universal Parser . I want to have some user error handling, for example. if the user supplies a URL that is not a feed. When I tried how feedparser responds to erroneous input, I was surprised to see that feedparser did not throw Exceptions at all. For instance. on HTML content, it tries to parse some information from HTML code and into non-existent domains, it returns a mostly empty dictionary:

{'bozo': 1,
'bozo_exception': URLError(gaierror(-2, 'Name or service not known'),),
'encoding': 'utf-8',
'entries': [],
'feed': {},
'version': None}

Another erroneous input appears in the values status_codeor namespacesin the returned dictionary.

So, what is the best approach for correct error checking without resorting to an infinite cascade if .. elif .. elif ...?

Answer 1

According to the documentation feedparserin the section

So, trying to parse the feed at any URL, you can check the “bozo bit” and raise the corresponding exception again:

f = feedparser.parse('http://example.com')
if f.bozo:
    raise f.bozo_exception

You can handle the exception according to the type and message, or make statements on other attributes of the object returned feedparser.parse(for example: f.feedmust be non-empty, f.statusmust be 200, f.entriesmust be non-empty, f.versionmust be a valid version of the feed format, etc.) so that nor was it reasonable for your application.