transmogrify.webcrawler 1.2.1

Crawling - html to import

transmogrify.webcrawler will crawl html to extract pages and files as a source for your transmogrifier pipeline. transmogrify.webcrawler.typerecognitor aids in setting ‘_type’ based on the crawled mimetype. transmogrify.webcrawler.cache helps speed up crawling and reduce memory usage by storing items locally.

These blueprints are designed to work with the funnelweb pipeline but can be used independently.

transmogrify.webcrawler

A source blueprint for crawling content from a site or local html files.

Webcrawler imports HTML either from a live website, for a folder on disk, or a folder on disk with html which used to come from a live website and may still have absolute links refering to that website.

To crawl a live website supply the crawler with a base http url to start crawling with. This url must be the url which all the other urls you want from the site start with.

For example

[crawler]
blueprint = transmogrify.webcrawler
url  = http://www.whitehouse.gov
max = 50

will restrict the crawler to the first 50 pages.

You can also crawl a local directory of html with relative links by just using a file: style url

[crawler]
blueprint = transmogrify.webcrawler
url = file:///mydirectory

or if the local directory contains html saved from a website and might have absolute urls in it the you can set this as the cache. The crawler will always look up the cache first

[crawler]
blueprint = transmogrify.webcrawler
url = http://therealsite.com --crawler:cache=mydirectory

The following will not crawl anything larget than 4Mb

[crawler]
blueprint = transmogrify.webcrawler
url  = http://www.whitehouse.gov
maxsize=400000

To skip crawling links by regular expression

[crawler]
blueprint = transmogrify.webcrawler
url=http://www.whitehouse.gov
ignore = \.mp3
                 \.mp4

If webcrawler is having trouble parsing the html of some pages you can preprocesses the html before it is parsed. e.g.

[crawler]
blueprint = transmogrify.webcrawler
patterns = (<script>)[^<]*(</script>)
subs = \1\2

If you’d like to skip processing links with certain mimetypes you can use the drop:condition. This TALES expression determines what will be processed further. see http://pypi.python.org/pypi/collective.transmogrifier/#condition-section

[drop]
blueprint = collective.transmogrifier.sections.condition
condition: python:item.get('_mimetype') not in ['application/x-javascript','text/css','text/plain','application/x-java-byte-code'] and item.get('_path','').split('.')[-1] not in ['class']

Options:

site_url:

• the top url to crawl

ignore:

• list of regex for urls to not crawl

cache:

• local directory to read crawled items from instead of accessing the site directly

patterns:

• Regular expressions to substitute before html is parsed. New line seperated

subs:

• Text to replace each item in patterns. Must be the same number of lines as patterns. Due to the way buildout handles empty lines, to replace a pattern with nothing (eg to remove the pattern), use <EMPTYSTRING> as a substitution.

maxsize:

• don’t crawl anything larger than this

max:

• Limit crawling to this number of pages

start-urls:

• a list of urls to initially crawl

ignore-robots:

• if set, will ignore the robots.txt directives and crawl everything

WebCrawler will emit items like

item = dict(_site_url = "Original site_url used",
           _path = "The url crawled without _site_url,
           _content = "The raw content returned by the url",
           _content_info = "Headers returned with content"
           _backlinks    = names,
           _sortorder    = "An integer representing the order the url was found within the page/site
            )

transmogrify.webcrawler.cache

A blueprint that saves crawled content into a directory structure

Options:

path-key:

Allows you to override the field path is stored in. Defaults to ‘_path’

output:

Directory to store cached content in

transmogrify.webcrawler.typerecognitor

A blueprint for assigning content type based on the mime-type as given by the webcrawler

Changelog