crawler.link_extraction_regular_expression

Specifies the regular expression used to extract links from each document.

Key: crawler.link_extraction_regular_expression
Type: String
Can be set in: collection.cfg

Description

This option defines the regular expression that will be used to extract URLs from HTML links like the following:

<link rel="alternate"href="http://www.abc.net.au/mobile"/>
<a href="http://www.abc.net.au">ABC</a>
<img src="http://www.abc.net.au/logo.png"alt="ABC Logo"/>

Default Value

crawler.link_extraction_regular_expression=\s(href|src)(\s)*=(\s)*('|")?\s*(.*?)(>|\4|(\s\w+\=))>?([^<]+)?(</a)?

If no value is defined, then the above default is used.

Examples

crawler.link_extraction_group=5
crawler.link_extraction_regular_expression=\s(href|src)(\s)*=(\s)*(\'|\")?\\s*(.*?)(>|\"|\'|(\s\w+\=))

Extracted groups:

1. (href|src): handle link, a or img HTML tags.
2. (\s): optional spaces
3. (\s): optional spaces
4. (\'|\"):- quotes to begin the URL
5. (.*?): the URL (non-greedy pattern)
6. (>|\"|\'|(\s\w+\=)): end the URL

See Also

• Web collections
• crawler.link_extraction_group