API for Spiders

If you want to you support a custom website, take a look at Supporting a new Website.

Spider class

A spider is a class in a module (Python file) in feeds.spiders that is a subclass of feeds.spiders.FeedsSpider, feeds.spiders.FeedsCrawlSpider or feeds.spiders.FeedsXMLFeedSpider.

  • FeedsXMLFeedSpider is used, if the spider is based on parsing an XML document as a basis. This is useful if the spider should start from an existing XML feed or a sitemap.

  • FeedsCrawlSpider is used, if the spider should crawl the site based on links that are found on the site. Patterns can be given to limit what links should be followed.

  • FeedsSpider is used in all other cases (this spider is usually used).

Class variables

  • name: The name of the spider (mandatory).

  • start_urls: A list of URLs to start (used if the start_requests(self) method is not overwritten).

  • feed_title: Title of the feed.

  • feed_subtitle: Subtitle of the feed.

  • feed_link

  • author_name: Author of the feed.

  • feed_icon: URL of a site favicon.

  • feed_logo: URL of a site logo.

Methods

  • start_requests(self): If the start request is more complicated than a simply GET to the URL(s) in the start_urls list, this method can be overwritten. It is expected to yield or return a scrapy.Request object. Please note that this method can only emit Request objects.

  • parse(self, response): After a URL from start_urls has been scraped, the parse() method is called and the response is given as an argument. It is also the default call back method for new scrapy.Request objects.

  • parse_node(self, response, node): A FeedsXMLFeedSpider calls parse_node() instead of parse() for every node in the XML document returned by the URL in start_urls.

FeedEntryItemLoader

A spider uses a FeedEntryItemLoader object to extract content from a response. The following fields are accepted and can be added to a item loader object:

  • link

  • title

  • author_name

  • author_email

  • content_html

  • updated

  • category

  • path

  • enclosure_iri

  • enclosure_type

A value can be added to an item loader with the add_value(), add_css() or add_xpath() methods like in the following example:

il = FeedEntryItemLoader(response=response)
il.add_value("link", response.url)
il.add_css("title", "h1::text")
il.add_css("author_name", "header .user-link__name::text")
il.add_css("content_html", ".interview-body")
il.add_css("updated", ".date::text")
return il.load_item()

Only the link field is required, all the other fields can be empty but usually it is adviced to add as many fields as possible (i.e. the original site provides).

If the updated field is not provided, the date and time during the extraction is used. If caching is enabled, the date and time when the item was first seen is cached and reused on following runs.

Input processing

Automatic rules are applied to fields depending on their type.

Default input rules

These rules are usually applied to every field.

  1. Empty strings and None are skipped.

  2. The content is stripped.

  3. The content is unescaped twice, i.e. &&xxx; is converted to its decoded (binary) equivalent.

title

  1. The default input rules apply.

  2. One title: “<title 1>”

  3. Two titles: “<title 1>: <title 2>”

  4. Three or more titles: “<title 1>: <title 2> - <title 3> - <title n>”

updated

  1. Empty strings and None are skipped.

  2. Unless the date is already a datetime object, it is parsed using dateutil.parser.parse() (with the year expected to be first, and the day not expected to be first). If dateutil can’t parse it because it’s a human readable string, dateparser is used. dayfirst (default False), yearfirst (default True) and ignoretz (default False) can be set in the FeedEntryItemLoader.

  3. If the datetime object is not already timezone aware, the timezone specified in the FeedEntryItemLoader is set.

  4. The first datetime object is used.

author_name

  1. The default input rules apply.

  2. Multiple author names are joined with “, “ (comma and space) as a separator.

path

  1. The default input rules apply.

  2. Multiple paths are joined with os.sep (e.g. /) as a separator.

content_html

  1. Empty strings and None are skipped.

  2. replace_regex in the FeedEntryItemLoader is a dict with pattern as a key and repl as a value. pattern and repl are used as parameters for re.sub(). pattern can be a string or a pattern object, repl a string or a function.

  3. convert_footnotes in the FeedEntryItemLoader is a list of CSS selectors which select footnotes or otherwise hidden text. Such elements are replaced with <small> elements and the text of the respective footnote in brackets.

  4. pullup_elems in the FeedEntryItemLoader is a dict with a CSS selector as a key and a distance as a value. A parent that is a given distance away from the selected element is replaced with the selected element. E.g. a distance of 1 means that the children replaces its parent.

  5. replace_elems in the FeedEntryItemLoader is a dict that contains a selector as a key and a string as a value. The selected element is replaced with the HTML fragment.

  6. remove_elems in the FeedEntryItemLoader is a list with CSS selectors of elements that should be removed.

  7. remove_elems_xpath in the FeedEntryItemLoader is a list with XPath queries of elements that should be removed.

  8. change_attribs in the FeedEntryItemLoader is a dict with a CSS selector as a key and a dict that describes how to change attribs as a value. The dict contains the old attrib name as a key and the new attrib name as a value. If the value is None, the attrib is removed.

  9. change_tags in the FeedEntryItemLoader is a dict with a CSS selector as a key and a new tag name as a value. The tag name of the selected element is changed to the new tag name.

  10. Attributes class, id and ones that start with data- are removed.

  11. Iframes are converted to a <div> that contains a link to the source of the iframe.

  12. Scripts, JavaScript, comments, styles and inline styles are removed.

  13. The HTML tree is flattened: Elements which do not have a text and are not supposed to be empty are removed. An element is replaced with is child if it has exactly one child and the child has the same tag.

  14. References in tags like <a> and <img> are made absolute.