Add job option ignore_incomplete_reads.

Sometimes web servers return incomplete responses, triggering an
`InvalidChunkLength` exception in urlwatch. Enable this job option to
ignore these errors.

#725

lib/urlwatch/jobs.py

@@ -263,7 +263,7 @@ class UrlJob(Job):
     __required__ = ('url',)
     __optional__ = ('cookies', 'data', 'method', 'ssl_no_verify', 'ignore_cached', 'http_proxy', 'https_proxy',
                     'headers', 'ignore_connection_errors', 'ignore_http_error_codes', 'encoding', 'timeout',
-                    'ignore_timeout_errors', 'ignore_too_many_redirects')
+                    'ignore_timeout_errors', 'ignore_too_many_redirects', 'ignore_incomplete_reads')
 
     CHARSET_RE = re.compile('text/(html|plain); charset=([^;]*)')
 
@@ -391,6 +391,8 @@ def ignore_error(self, exception):
             return True
         if isinstance(exception, requests.exceptions.TooManyRedirects) and self.ignore_too_many_redirects:
             return True
+        if isinstance(exception, requests.exceptions.ChunkedEncodingError) and self.ignore_incomplete_reads:
+            return True
         elif isinstance(exception, requests.exceptions.HTTPError):
             status_code = exception.response.status_code
             ignored_codes = []