A spider trap (or crawler trap) is a set of web pages that may intentionally or unintentionally be used to cause a web crawler or search bot to make an infinite number of requests or cause a poorly constructed crawler to crash. Web crawlers are also called web spiders, from which the name is derived. Spider traps may be created to "catch" spambots or other crawlers that waste a website's bandwidth. They may also be created unintentionally by calendars that use dynamic pages with links that continually point to the next day or year.
Common techniques used are:
- creation of indefinitely deep directory structures like http://foo.com/bar/foo/bar/foo/bar/foo/bar/.....
- dynamic pages like calendars that produce an infinite number of pages for a web crawler to follow.
- pages filled with a large number of characters, crashing the lexical analyzer parsing the page.
- pages with session-id's based on required cookies.
There is no algorithm to detect all spider traps. Some classes of traps can be detected automatically, but new, unrecognized traps arise quickly.
Read more about Spider Trap: Politeness, See Also
Famous quotes containing the words spider and/or trap:
“But chief to heedless flies the window proves
A constant death; where gloomily retired,
The villain spider lives, cunning and fierce,
Mixture abhorred! Amid a mangled heap
Of carcases in eager watch he sits,
O’erlooking all his waving snares around.”
—James Thomson (1700–1748)
“And boys, be in nothing so moderate as in love of man, a clever
servant, insufferable master.
There is the trap that catches noblest spirits, that
caught—they say—God, when he walked on earth.”
—Robinson Jeffers (1887–1962)